Dial plate and watch

Abstract

To provide a dial capable of re-synchronizing the positions of an hour hand and a minute hand distorted by external disturbance.SOLUTION: One aspect of the invention relates to a dial 2a, 2b of a watch 1. The watch 1 includes a device for determining a position of at least one hand 24a, 24b of the watch 1. Such a dial 2a, 2b includes a visible face 20a and a hidden face, and the dial 2a, 2b is formed by a stack of thin layers of material extending between these two faces 20a. Each thin layer includes one or more of functional elements included in the determination device: at least one light-detecting element 23; at least a first light source 4a and at least a second light source 4b; a stand-alone power supply unit including a photovoltaic module; and a control unit for managing operation of each light source 4a, 4b and the at least one light-detecting element.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wristwatch including a dial, and more particularly to a wristwatch provided with a device for determining the position of at least one hand of the wristwatch on the dial, and such device is autonomous.

Background Art

[0002] Prior art documents describe electromechanical wristwatches with hands, where the hour and minute hands indicating the current time are driven by a gear train of the watch movement mechanism. In this context, the operation of the mechanism can be hindered by impacts on the wristwatch, the presence of electromagnetic fields or other disturbances. As a result, even if the internal clock of the wristwatch accurately indicates the current time, the hour and minute hands give a distorted display of this current time due to the disturbances applied to the wristwatch. Therefore, it may be necessary to resynchronize the positions of the hour and minute hands.

[0003] In this context, it is understood that there is a need to find a solution to overcome the drawbacks of the prior art.

Summary of the Invention

[0004] The object of the present invention is to overcome these drawbacks by proposing a wristwatch provided with a dial including a device for determining the position of at least one hand, said device being autonomous and its efficiency remaining constant over time.

[0005] One aspect of the present invention relates to a wristwatch dial including a device for determining the position of at least one hand of the wristwatch, said dial including a visible face and a hidden face, said dial being formed by a laminate of thin layers of material extending between these two faces, said layers each including functional elements comprised in said determining device, namely, · at least one light detection element, · at least a first light source and at least a second light source, · a stand-alone power supply unit including a photovoltaic module, · A control unit that manages the operations of each light source and the at least one light detection element includes one or more of the following.

[0006] In other embodiments, · The dial includes a through hole configured to receive a spindle that supports the at least one hand of the wristwatch, · The stack of thin layers of material consists of a first layer provided with the visible surface of the dial, and the first layer includes the at least one light detection element and the first and second light sources, · The stack of thin layers of material includes a second layer that includes a photovoltaic module, · The at least one first light source and the at least one light detection element are arranged such that a light beam emitted by the at least one first light source is reflected by the at least one hand toward the at least one light detection element, · The at least one first light source is configured to emit a light beam toward a reflection area of the at least one hand, and the reflection area is configured to reflect this light beam toward the at least one light detection element, · The reflection area includes an inclined reflection surface formed on the lower surface of the at least one hand, · The reflection area includes a diffraction grating formed on the lower surface of the at least one hand, and the diffraction grating is configured to reflect a light beam toward the at least one light detection element, · The at least one first light source is a vertical cavity surface emitting laser light source, · The at least one second light source is capable of generating a visual message according to a determined position of the at least one hand, · The first layer is configured such that light radiation, particularly sunlight radiation and light radiation emitted by the first and second light sources, can pass through it completely or partially, · The second layer includes a substrate on which a photovoltaic module is printed, · The photovoltaic module is arranged in the effective area of the second layer, and the area is arranged to receive light rays emitted from the first layer of the stack of thin layers. · The stack of thin layers includes a third layer comprising an electrical energy accumulator that constitutes a stand-alone power unit. · The third layer includes a substrate on which the electrical energy accumulator is printed. · The stack of thin layers includes a fourth layer that forms the hidden side of the dial including a control unit. · The stack of thin layers includes a third layer including the hidden side of the dial including a control unit and an electrical energy accumulator that constitutes a stand-alone power unit. · The first layer is rigid compared to the other flexible layers in the stack.

[0007] Another aspect of the present invention relates to a wristwatch including such a dial.

[0008] Advantageously, the wristwatch includes a mechanical or electromechanical movement.

Brief Description of the Drawings

[0009] The objects, advantages, and features of the wristwatch according to the present invention will become clear in the following description given based on at least one non-limiting embodiment shown in the drawings.

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0011] Figure 1 schematically shows a wristwatch 1 including a case 19 having an intermediate part to which a back cover and a crystal 22 are attached, a set of components forming a timepiece movement, and dials 2a, 2b disposed between the timepiece movement and the crystal 22.

[0012] In a manner well known to those skilled in the art, the timepiece movement drives a set of hands including an hour hand 24a, a minute hand 24b, and optionally a second hand. For this purpose, the dials 2a, 2b include through-holes for receiving the arbors 25 of these hands. Each of these hands 24a, 24b has a reflective lower surface disposed facing the dials 2a, 2b. This lower surface is wholly or partially reflective. Specifically, referring to FIGS. 6 and 7, this lower surface includes a reflective area 26 including an inclined surface 27 or a diffraction grating 28.

[0013] Such dials 2a, 2b further include two surfaces 20a, 20b, namely, · a so-called visible surface 20a, referred to as the "visible part" or "visible upper part" of these dials 2a, 2b, which is visible from the outside of the wristwatch 1, and · A so-called hidden surface 20b, which is referred to as the "hidden part" or "hidden lower part" of these dials 2a, 2b and is arranged opposite the timepiece movement in the enclosure of the case 19 of the wristwatch 1 is included.

[0014] Such a visible surface 20a may, in a non-limiting and non-exhaustive manner, · Contribute to the display of horological information / horological measurements, or physical information / physical measurements obtained by sensors included in the movement, regardless of the presence or absence of hands, for example, reference (or display) elements such as numbers, indices, lines or points, · Include at least one graphic representation such as an inscription, pattern, text, logo, etc. may be included.

[0015] This visible surface 20a and this hidden surface 20b are substantially flat and / or parallel and / or on opposite sides of each other. They are also connected to each other by the peripheral walls of these dials 2a, 2b.

[0016] Also, it should be noted that in the embodiments shown in FIGS. 1 to 7, the dials 2a, 2b preferably have a circular shape. It is understood that the present invention can also be implemented for dials 2a, 2b having other shapes, such as a triangular shape or a shape similar to a quadrilateral shape.

[0017] In an embodiment of the present invention, the timepiece movement is a mechanical movement. Alternatively, this movement may be an electromechanical movement. In the following description, a mechanical wristwatch is referred to when the movement is mechanical, and an electromechanical wristwatch is referred to when the movement is electromechanical.

[0018] Referring to FIGS. 2 and 4, such dials 2a, 2b include an autonomous device 3 that determines the position of at least one hand 24a, 24b of the watch 1. This determining device 3 includes its own power supply means, as will be described later. Such a determining device 3 is said to be autonomous, particularly with respect to the movement of the watch 1 and particularly with respect to the power source of this movement, for example when this power source is an electrical power source such as an electromechanical movement. In these situations, it is understood that the power used by this determining device 3 does not impair the autonomy of the movement.

[0019] In this context, the dials 2a, 2b can be removably mounted on the watch 1 regardless of the type of the watch 1. The only condition to be met is that the dials 2a, 2b include this determining device 3 that is autonomous with respect to the movement of the watch 1. Since these dials 2a, 2b are not electrically connected to the movement of the watch 1, they are also referred to as "autonomous dials". These dials 2a, 2b can be regarded as separate parts attached to the watch 1.

[0020] This determining device 3 included in these dials 2a, 2b includes light sources 4a, 4b, a stand-alone power supply unit 21, at least one light detection element 23, and a control unit 7.

[0021] These light sources 4a, 4b include at least a first light source 4a that is used to evaluate the position of at least one hand 24a, 24b of the wristwatch 1 by cooperating with the at least one detection element 23. As will be seen below, this first light source 4a and the detection element 23 are arranged under or in contact with the visible surface 20a of the dial 2a, 2b. In this configuration, this first light source 4a can then emit a light beam 29a towards the hands 24a, 24b that move above the visible surface 20a, and the hands 24a, 24b can reflect this light beam 29a into a light beam 29b towards the detection element 23. Such a first light source 4a is preferably a Vertical-Cavity Surface-Emission Laser (VCSEL).

[0022] These light sources 4a, 4b also include at least one second light source 4b that is used in particular to display visual messages related to the determination of the position of the hands 24a, 24b. This second light source 4b is preferably · an electroluminescent capacitor or LEC, · a light-emitting diode of the LED (light-emitting diode) type, OLED (organic light-emitting diode) type, AMOLED (active matrix organic light-emitting diode) type, or QLED (quantum light-emitting diode) type, · any light-emitting material activated by a local electric field, · any light-emitting material activated by an electric current, · any combination of these light-emitting elements and includes any light-emitting element selected from the non-exhaustive and non-limiting list comprising.

[0023] It should be noted that this second light source 4b may be a light source 4b capable of forming an area light source in a predetermined embodiment of the present invention. Thereby, a predetermined shape can be given to the area light source. Typically, but not exhaustively or restrictively, a shape related to a graphic representation of numbers, letters, logos or text can be given. Also, it should be noted that this second light source 4b can generate light of any color and / or in any direction.

[0024] In this determination device 3, the stand-alone power supply unit 21 includes an electrical energy accumulator 6 and a photovoltaic module 5 including at least one photovoltaic cell also referred to as a solar cell. This photovoltaic power generation module 5 is connected to the electrical energy accumulator 6 via connection elements indicated by reference numerals 17b and 18 in FIGS. 3 and 5. This photovoltaic module 5 may include one or more basic cells of a heterojunction type or a multi-junction type connected in parallel or in series. Each photovoltaic cell of this module 5 may be made of copper-based, indium-based, gallium-based and selenium-based semiconductor materials, cadmium telluride-based semiconductor materials, single-crystal gallium arsenide-based semiconductor materials, single-crystal or polycrystalline silicon-based semiconductor materials, or perovskite-based semiconductor materials in a manner well known to those skilled in the art. It should be noted that these examples are not limiting, and those skilled in the art can find a type of photovoltaic cell suitable for the present invention.

[0025] In this decision device 3, a control unit 7, also referred to as a microcontroller, includes an electronic circuit 8. The electronic circuit 8 includes hardware resources, in particular, memory elements, and at least one processor cooperating with an address bus, a data bus, and a control bus. This control unit 7 is connected to the first and second light sources 4a, 4b, the at least one light detection element 23, and a stand-alone power supply unit 21. The memory elements of this control unit 7 include an algorithm for managing the positions of at least one hand 24a, 24b of the wristwatch. Such an algorithm is executed by the processor of this control unit 7, particularly taking into account the light intensity measurement data from the at least one light detection element 23 included in the decision device 3. Such an algorithm · serves to determine this position, · generate a visual message according to the determined positions of the hands 24a, 24b, · control the second light source 4b, · implement at least one function of the wristwatch that requires the determined position of the hand and is useful for.

[0026] It should be noted that the decision device 3 may include at least one event sensor that allows for refining the determination of the position of the hands 24a, 24b and also contributes to displaying the visual message. That is, this sensor can generate data that is subsequently used by this algorithm. Such data may include information about the event detected by this sensor, and the event is likely to contribute to the operation of the first and second light sources 4a, 4b. These events include, in a non-limiting and non-exhaustive manner, detection of a specific luminance level in the environment of the wristwatch 1, detection of a specific audio element or a specific audio level, detection of a specific visual object, or detection of movement by a part of the body of the user in which this wristwatch 1 is included.

[0027] In this context, the event sensor of this autonomous decision device 3 includes, in particular, in a non-limiting and non-exhaustive manner, · A luminance sensor that detects the ambient luminance level, · A motion sensor that senses movement by a part of the user's body including the wristwatch 1, such as a gyro sensor and / or an inertial sensor in the form of an electronic component of a gyro and / or inertial electromechanical microsystem circuit type, · A microphone-type voice sensor, and / or · A photographic-type optical sensor may be included.

[0028] Furthermore, when the decision device 3 includes a plurality of second light sources 4b, its operation may be managed / controlled simultaneously and / or sequentially by the control unit 7. Further, each of the second light sources 4b is individually managed / controlled by this control unit 7. In this context, the management of the operation of each of the second light sources 4b may be constituted by performing the following operations in a non-limiting and non-exhaustive manner, namely, sequential switching on or off, simultaneous switching on or off of two or more second light sources 4b, flashing of one or more second light sources 4b, definition of the flashing frequency of each of the second light sources 4b, the flashing time of each of the second light sources 4b, or the switching on or off time of each of the second light sources 4b, etc.

[0029] The memory element of such a control unit 7 may further include an algorithm for managing the electrical energy accumulator 6, particularly an algorithm for managing the charging by the photovoltaic module 5, and an algorithm for managing the electrical consumption of the light sources 4a, 4b and the at least one light detection element 23.

[0030] As described above, the autonomous decision device 3 is therefore included in the dials 2a, 2b. In this configuration, the components of this decision device 3, namely, the first and second light sources 4a, 4b, the electrical energy accumulator 6, the photovoltaic module 5, the at least one light detection element 23 and the control unit 7 are included in one or more layers 10, 11, 12, 13, 14 forming this dial 2a, 2b.

[0031] Referring to FIGS. 2 to 5, these dials 2a, 2b are constituted or formed by laminates 9a, 9b of thin layers 10, 11, 12, 13 of material. These layers 10, 11, 12, 13, 14 are joined and integrated together by a joining element such as an adhesive material in order to obtain a laminate 9a, 9b of monolithic layers, and thus to form an integral dial 2a, 2b. This joining element may be a clip or a screw. Such layers 10, 11, 12, 13, 14 are stacked on top of each other within the laminate 9a, 9b. That is, within these dials 2a, 2b, one is arranged on top of the other in a defined order. It should be noted that such a laminate 9a, 9b of layers may also be referred to as an assembly of layers. In this laminate 9a, 9b, the plurality of layers are substantially similar, have upper and lower surfaces of substantially the same area / surface, and thus contribute to the formation of the peripheral wall of the dial 2a, 2b without relief.

[0032] It should be noted that these thin layers are each layers having a micrometer thickness. Specifically, each layer may have a thickness of 1 to 100 μm, preferably 2 μm, more preferably 3 μm. With respect to the thickness of the dials 2a, 2b, this thickness may be 8 to 400 μm, preferably 6 μm, more preferably 12 μm, still more preferably 100 μm, still more preferably 200 μm, or still more preferably 300 μm.

[0033] In addition to facilitating its integration in the case 19 of the wristwatch 1, such an integral dial 2a, 2b also has the additional advantage that it can be removably mounted on this case 19.

[0034] In a first alternative embodiment of this laminate 9a shown in FIG. 3, this laminate 9a is constituted or formed by the following four consecutive thin layers 10, 11, 12, 13. That is, · A first layer 10 forming / composing the visible surface 20a of the dial 2a, which includes the at least one first light source 4a, the at least one second light source 4b, and the at least one light detection element 23 of the determination device 3. · A second layer 11 including a photovoltaic module 5, · A third layer 12 including an electrical energy accumulator 6, also referred to as a rechargeable battery, and · A fourth layer 13 forming a hidden surface 20b of the dial 2a including a control unit 7 are provided.

[0035] The first layer 10 of this laminate 9a is preferably rigid or semi - rigid compared to the second, third, and fourth layers 11, 12, 13 which are preferably soft or flexible. It is understood that such a first layer 10 contributes to the structural rigidity of the laminate 9a and thus the dial 2a.

[0036] In this laminate 9a, each of the first, second, third, and fourth layers 10, 11, 12, and 13 includes an upper surface and a lower surface.

[0037] The first layer 10 is formed of a transparent, translucent, at least partially transparent, or at least partially translucent rigid or semi - rigid substrate. Such a substrate is made of a material having a transmittance (also known as UVT, "ultraviolet transmittance") to sunlight, particularly ultraviolet rays, between 65 and 95%. This transmittance is preferably 85 percent. Such a material may be transparent or translucent. This material may be a polymer, glass, or ceramic in a non - limiting and non - exhaustive manner.

[0038] As understood in this context, this substrate is · configured such that the light generated by the first and second light sources 4a, 4b can escape outside the dials 2a, 2b and thus outside the watch 1, and · configured such that the light emitted from the environment of the wristwatch 1 (which includes solar radiation if it is of natural origin) can pass through the dials 2a, 2b in the direction of the photovoltaic module 5 of the communication device 3.

[0039] In other words, this transparent or translucent substrate is configured such that the light that can be supplied to the photovoltaic module 5 passes therethrough, and the photovoltaic module 5 can convert solar energy from this radiation into electrical energy.

[0040] This first layer 10 further includes first and second light sources 4a, 4b arranged in the body of the substrate.

[0041] Such an arrangement of said at least one first light source 4a within / on the substrate is configured such that a light beam 29a is radiated upwardly towards said at least one needle 24a, 24b. This first light source 4a may be arranged on or under the upper surface of this substrate forming the first layer 10. When arranged within the substrate, this first light source 4a is positioned in a blind cavity formed in this upper surface. In an alternative embodiment, this may be arranged in a blind cavity made in the lower surface of this substrate having this upper surface as its bottom. In this configuration, the light beam 29a that can be emitted from this first light source 4a then passes through this bottom before reaching the needles 24a, 24b.

[0042] Such an arrangement of said at least one second light source 4b in this substrate is configured to ensure illumination of all or part of the visible surface 20a of the dial 2a, and in particular, a visual message (e.g., a graphic representation related to this position such as a pattern, number or letter, and / or a reference element (or display) such as a number, index, line, point, etc., or illumination of one or more needles, and further illumination of all or part of the visible surface of the dial 2a) that is a function of the determined position of the needles 24a, 24b. In an alternative embodiment, this second light source 4b may have a predetermined shape such as the shape of a number, letter, index, line, point, logo, or text.

[0043] This lighting can be backlight illumination or semi - direct illumination when the second light source 4b is arranged in a cavity defined in the substrate. Specifically, this cavity may be a blind opening made on the lower surface of this substrate. In this configuration, if the bottom of this cavity contains a graphic representation, the light emission or light generated by this second light source 4 can escape outside the dial 2a through the visible surface 20a of this dial 2a, and thus, at least one graphic representation can be seen in the dark. Specifically, the light emission escaping from the visible surface 20a outlines the contour of this graphic representation. In this context, this graphic representation included on the upper or lower surface of the substrate forming the first layer 10 is preferably opaque, non - transparent or non - transmissive.

[0044] This lighting can be direct illumination when the second light source 4b is arranged in a cavity defined in the substrate. This cavity may be a blind opening made on the lower surface of this substrate and there is no graphic representation at its bottom. In this configuration, the light emission or light generated by this second light source 4b can escape through the bottom of this cavity towards the outside of the dial 2a, and thus can escape through the visible surface 20a of this dial 2a.

[0045] This lighting may also be direct illumination when the second light source 4b is arranged in a through - opening extending through the thickness of the substrate of the first layer 10 and each of its two ends opens to the upper and lower surfaces of this substrate respectively. In this configuration, all or part of the second light source 4 may protrude from the upper surface of this substrate, and thus from the first layer 10, or from the visible surface 20a of the dial 2a, so as to form a graphic representation such as an index, a number, a dot, or a line.

[0046] Such illumination may also be remote illumination when the at least second light source 4b is coupled to at least one waveguide. This waveguide, also referred to as an optical guide, is used to carry light from the point where the light is incident on the guide to the substrate or to an area of the substrate close to the upper surface of the substrate (e.g., a cavity or a through-opening). Such an optical guide may be an optical fiber on the substrate that can bypass obstacles that may occur, for example, between an electroluminescent element and an area on the substrate close to the upper surface of the substrate, and light escapes through this optical fiber. In this alternative embodiment, light is thus brought from the electroluminescent element via the waveguide to this area of the substrate to be irradiated.

[0047] In such a configuration, the first end of the waveguide is coupled to the second light source 4b, and the second end of this waveguide is · It may be arranged in a cavity that can be a blind opening made on the lower surface of the substrate of this first layer 10, or · It may be arranged in a through-opening extending through the thickness of the substrate of the first layer 10, with both ends of which opening to the upper and lower surfaces of this substrate and thus of the first layer 10. That is, this second end may protrude from the upper surface of the substrate or of this first layer 10, or from the visible surface 20a of the dial 2a, to form a graphic representation of a reference element such as an index, a number, a dot or a line, etc.

[0048] In this context, indirect illumination is achieved by a single second light source 4b included on the lower surface of the substrate of this first layer 10 by being coupled to a plurality of waveguides, and these second ends are · Each arranged in a cavity that emits light radiation from this second light source 4b (since this radiation escapes outside the dial 2a through the visible surface 20a, at least one graphic representation can be viewed in the dark. In this context, this graphic representation included on the visible surface 20a of the dial 2a or on the upper surface of the substrate is preferably opaque), and / or · They are arranged in through-holes, which may or may not protrude from the upper surface of the substrate, forming reference elements such as indices, lines, or points that each emit light radiation from the second light source 4b.

[0049] In this first layer 10, the second light source 4b is applied / fastened by printing or vapor deposition on the lower surface of the substrate of this first layer 10 that is in the cavity or on the inner wall of the aforementioned through-hole.

[0050] In this first layer 10, the light detection element 23 is arranged within / on the substrate with respect to the first light source 4a so as to be able to receive the light beam 29b reflected by the needles 24a, 24b emitted by this light source 4a. This detection element 23 may be arranged on or under the upper surface of the substrate forming the first layer 10. When this detection element 23 is arranged within the substrate, it is positioned in a blind cavity formed in this upper surface. In an alternative embodiment, it may be arranged in a blind cavity made in the lower surface of this substrate having this upper surface as its bottom. In this configuration, the light beam 29b reflected by the needles then passes through this bottom before reaching the aforementioned detection element 23.

[0051] It should also be noted that the lower surface of this first layer 10 may be self-adhesive so as to be assemblable with the second layer 11.

[0052] In this laminate 9a, the second layer 11 includes a substrate containing the photovoltaic module 5. Such a substrate is preferably flexible or soft. The substrate of the second layer 11 may be a film on which the photovoltaic module 5 is arranged, or may be made of a material belonging to the polymer system.

[0053] In this second layer 11, the photovoltaic module 5 preferentially spreads over the entire so-called active area on the upper surface of this substrate. This active area is a part of the upper surface of the substrate that can receive light from the lower surface of the first layer 10 of the dial 2a. This light that has passed through all or part of the first layer 10 comes from the external environment of the dial 2a and thus the wristwatch 1, and in this case mainly from sunlight in the case of natural origin.

[0054] It should be noted that the photovoltaic module 5 is applied to the upper surface of this substrate using an inkjet printing or screen printing process, or using a thermal evaporation printing process. Here, mention is also made of the second layer 11 including the printed photovoltaic module 5, in particular the photovoltaic module 5 printed on the substrate of the second layer 11.

[0055] It should be noted that when the photovoltaic module 5 is applied to the substrate, a layer of self - adhesive material may be deposited on all or part of the upper and / or lower surfaces of the substrate. In these situations, the second layer 11 can be a self - adhesive layer that helps facilitate the assembly with other layers, in particular the first layer 10 and / or the third layer 12 of this laminate 9a.

[0056] In the laminate 9a, this third layer 12 also preferably includes a flexible or soft substrate. That substrate includes the electrical energy accumulator 6 of the autonomous decision - making device 3. This substrate of the third layer 12 can be a film on which the accumulator 6 is arranged. Such a substrate can be made of materials belonging to the polymer family.

[0057] This accumulator 6 can be a lithium battery or a semiconductor battery. Such a battery 6 is applied to the upper surface of this substrate using processes known in the prior art as follows. · A printing process on a flexible polymer substrate (this is involved, for example, in lithium - ion batteries), or · A three - dimensional printing process (this is involved in semiconductor batteries such as lithium - metal semiconductor batteries).

[0058] Reference is also made here to a third layer 12 including a printed electrical energy accumulator 6, in particular an electrical energy accumulator 6 printed on a substrate of the third layer 12.

[0059] Such a process enables a flexible and extremely thin third layer 12 including this accumulator 6 to be obtained.

[0060] Furthermore, it should be noted that once the accumulator 6 is applied to the substrate, a layer of self - adhesive substance can be deposited on all or part of the upper and / or lower surfaces of this substrate. In these situations, the third layer 12 can be a self - adhesive layer that helps facilitate the assembly with other layers, in particular the second layer 11 and / or the fourth layer 13 of this laminate 9a.

[0061] It should be noted that this accumulator 6 is used to store the electrical energy generated by the photovoltaic module 5 and to release power as required to supply power to the decision device 3, in particular to the first and second light sources 4a, 4b and said at least one detection element 23.

[0062] In this laminate 9a, this fourth and last layer 13 forms the hidden face of the dial 2a. Such a fourth layer 13 is formed by a substrate, preferably flexible or soft, including a control unit 7. Such a substrate for the fourth layer 13 can be, for example, a flexible PCB (printed circuit board) on which this control unit 7 is arranged, and this control unit 7 is arranged on the upper surface of this PCB and thus of the substrate. In this context, the control unit 7 can be constructed on this upper surface of the substrate using a three - dimensional printing process or a polymer printing process.

[0063] In a second alternative embodiment, the laminate 9b forming the dial 2b includes three thin layers 10, 11, 14 joined together. It should be noted that this second alternative embodiment differs from the first alternative embodiment in that it includes three layers 10, 11, 14 instead of four layers 10, 11, 12, 13 as in the first alternative embodiment. In this second alternative embodiment, the electrical energy accumulator 6 of the self-determination device 3 is here included, together with the control unit 7, in the third and final layer 14 of this laminate 9b.

[0064] This third and final layer 14 of this laminate 9b forms the hidden face of the dial 2b and preferably consists of a flexible or soft substrate. On this substrate, preferably on the upper surface of this substrate, the battery 6 and the electronic circuit 8 constituting the control unit 7 are constructed. The accumulator 6 and the control unit 7 may be constructed on this upper surface of the substrate using a three-dimensional printing process or a polymer printing process. It should be noted that such a substrate may be, for example, a flexible PCB.

[0065] In summary, in this second alternative embodiment, the laminate 9b · a first layer 10 forming the visible face 20a of the dial 2b including the first and second light sources 4a, 4b and the detection element 23, · a second layer 11 including the photovoltaic module 5, · a third layer 14 forming the hidden face 20b of the dial 2b including the accumulator 6 and the control unit 7 is included.

[0066] It should be noted that in this second alternative embodiment, the first and second layers 10, 11 are the same as those of the first alternative embodiment of the laminate 9a.

[0067] Furthermore, referring to FIGS. 3 and 5, the electronic circuit 8 of the control unit 7 includes a connection element 16 to the first and second light sources 4a, 4b and a first connection element 15a connected to the at least one detection element 23 to determine the position of the needle and display a visual message according to this position. This electronic circuit 8 further includes a second connection element 15b connected to the first connection element 17a of the accumulator 6.

[0068] In a third alternative embodiment (not shown), the laminate forming the dial includes two interconnected layers. It should be noted that this third alternative embodiment differs from the second alternative embodiment in that it includes two layers instead of the three layers 10, 11, 14 as in the second alternative embodiment. In this third alternative embodiment, the photovoltaic module 5 of the self-determination device 3 is here included in the first layer, particularly on the lower surface of the substrate forming this first layer. This photovoltaic module 5 can be applied to this lower surface of the substrate of this first layer using an inkjet printing process or a screen printing process, or using a thermal evaporation printing process. Therefore, this first layer is similar to the first layer 11 of the first and second alternative embodiments, but it should be noted that in this third alternative embodiment, the first layer additionally includes a photovoltaic module.

[0069] In the third alternative embodiment, similar to the second alternative embodiment, the electrical energy accumulator 6 of the self-determination device 3 is included in the second and final layer of this assembly, together with the control unit 7. Such a second layer forming the hidden surface of the dial preferably consists of a flexible or soft substrate. On the upper surface of this substrate, preferably, the battery 6 and the electronic circuit 8 constituting the control unit 7 are constructed. This accumulator 6 and control unit 7 may be constructed on this upper surface of the substrate using a three-dimensional printing process or a polymer printing process. It should be noted that such a substrate may be, for example, a flexible PCB.

[0070] In summary, in this third alternative embodiment, the laminate ·A first layer forming a visible surface 20a of the dial plate, including the first and second light sources 4a, 4b, the at least one detection element 23, and the photovoltaic module 5 of the determination device 3; ·A second layer forming a hidden surface 20b of the dial plate, including the accumulator 6 and the control unit 7; and it includes them.

[0071] Furthermore, it should be noted that the event sensor of the determination device 3 described above is preferably arranged in the first layer 10 and / or the last layers 13, 14 of the multi-layer stack 9a, 9b and is connected to the control unit 7 of this device 3.

[0072] Therefore, in this dial plate 2a, 2b, the determination device 3 preferably includes a detection element 23 for measuring the light intensity, dedicated to each hand. At the determined positions of the hands 24a, 24b, the light beam 29a emitted by the first light source 4a is reflected by these hands 24a, 24b to become a light beam 29b and heads towards this light detection element 23. Specifically, this emitted light beam 29a is reflected by a reflection area 26 defined on the lower surface of the hand. This area 26 includes an inclined reflection surface 27 or a diffraction grating 28 formed on this lower surface. The inclined reflection surface 27 and the diffraction grating 28 are configured to reflect such a light beam 29a towards the detection element 23. In this configuration, the light intensity is measured by this element 23 and transmitted to the control unit, which processes and archives it. As soon as the measured value of this intensity suddenly increases as a result of the hand passing above the detection element 23, the control unit determines the position of this hand. During this passage, the detection element measures the light intensity obtained from the reception of the light beam 29b reflected by the reflection area of the hand by this element 23. Usually, since the minute hand is positioned above the hour hand, due to this difference in height, a difference occurs in the light intensity sensed by the detection element 23. Advantageously, it is possible to identify each hand with a single first light source 4a and a single light detection element 23.

[0073] By determining the position of this hand, the dials 2a, 2b can be allowed to implement various functions of this wristwatch. For example, one function of this wristwatch can be to cope with a decrease in timing accuracy. This is because, in the case of an electromechanical movement, due to an impact on the wristwatch, the presence of an electromagnetic field, or other disturbances, drive steps are lost. As a result, even if the internal clock of the wristwatch displays the current time accurately, the hour hand and the minute hand give a distorted display of this current time because the gears have skipped several steps due to the influence of the disturbance applied to the wristwatch. Therefore, it is necessary to resynchronize the positions of the hour hand and the minute hand. Therefore, as part of this function, the control unit 7 controls / drives one or more second light sources 4b by generating a visual message according to this position, thereby notifying of this decrease in accuracy.

[0074] Another function of the wristwatch that uses the determination of the position of at least one of its hands can be to provide detection of the number of passes of the hands 24a, 24b above the detection element 23. For example, each pass of the minute hand 24b lights up a second light source 4b, for example a light source facing an index, for the purpose of measuring the basic timing of the elapse of a predetermined time. Start / stop / reset can be achieved by covering the crystal. This change in brightness is interpreted as a start / stop / reset signal by the control unit 7 (either via the light detection element 23 or due to the sudden absence of energy production in the photovoltaic module 5). In this example, the number of passes of the hour hand 24a can be counted. After a given number of passes, the second light source 4b is switched on to indicate that the wristwatch needs repair. After further passes, a second color, or blinking, may indicate that repair is needed.

[0075] Another function related to this determination of the position of at least one of the hands of the wristwatch can be to participate in the display of the time system by displaying "AM" and "PM". For example, each time the hour hand 24b passes over the detection element 23, the second light source 4b is switched on and off to indicate the period of the day (AM or PM).

[0076] Other functions related to this determination of the position of at least one hand of this wristwatch can illuminate the positions of the hands 24a, 24b or backlight the hands 24a, 24b (instead of using a luminescent material). In the event that low light intensity is detected by the control unit 7 (either via the light detection element 23 or by the absence of energy production in the photovoltaic module 5), various second light sources 4b are switched on to indicate the position of the hands. For example, 12 detection elements, each arranged on the opposite side of the index, can detect the positions of the two hands with an accuracy of 5 minutes in this configuration. The absence of detection of the minute hand indicates that the two hands are overlapping.

[0077] Other functions related to this determination of the position of at least one hand of the wristwatch can count the number of passes of at least one of the hands 24a, 24b. For example, it becomes possible to determine the actual operating time of this wristwatch 1, for example, the time between two repair or maintenance operations of this wristwatch.

[0078] Needless to say, the present invention is not limited to the above-described embodiments, and various simple alternatives and modifications can be conceived by those skilled in the art without departing from the scope of the present invention defined by the appended claims.

Claims

**Claim 1** A dial (2a, 2b) of a wristwatch (1), comprising a device (3) for determining the position of at least one hand (24a, 24b) of this wristwatch (1), said dial (2a, 2b) comprising a visible face (20a) and a hidden face (20b), said dial (2a, 2b) being formed by a laminate (9a, 9b) of thin layers (10, 11, 12, 13, 14) of material extending between these two faces (20a, 20b), said layers (10, 11, 12, 13, 14) each containing - at least one light detection element (23), - at least a first light source (4a) and at least a second light source (4b), - a stand-alone power supply unit (21) comprising a photovoltaic module (5), - a dial (2a, 2b) comprising one or more of the functional elements of a control unit (7) for managing the operation of each light source (4a, 4b) and said at least one light detection element (23). **Claim 2** The dial (2a, 2b) according to claim 1, comprising a through hole configured to receive a mandrel (25) intended to carry said at least one hand (24a, 24b) of said wristwatch (1). **Claim 3** The dial (2a, 2b) according to claim 1, wherein the laminate (9a, 9b) of said thin layers (10, 11, 12, 13, 14) consists of a first layer (10) on which the visible face (20a) of said dial (2a, 2b) is provided, said first layer (10) containing said at least one light detection element (23) and said first and second light sources (4a, 4b). **Claim 4** The dial (2a, 2b) according to claim 1, wherein the laminate (9a, 9b) of said thin layers (10, 11, 12, 13, 14) contains a second layer (11) provided with said photovoltaic module (5). **Claim 5** The dial (2a, 2b) according to claim 1, wherein said at least one first light source (4a) and said at least one light detection element (23) are arranged such that a light beam (29a) emitted by said at least one first light source (4a) is reflected by said at least one hand (24a, 24b) towards said at least one light detection element (23). **Claim 6** The at least one first light source (4a) is configured to emit a light beam (29a) toward a reflection area (26) of the at least one needle (24a, 24b), and the reflection area (26) is configured to reflect this light beam (29a) toward the at least one light detection element (23), the dial (2a, 2b) according to claim 1.

7. The at least one first light source (4a) is configured to emit a light beam (29a) toward a reflection area (26) of the at least one needle (24a, 24b), and the reflection area (26) is configured to reflect this light beam (29a) toward the at least one light detection element (23), and the reflection area (26) includes an inclined reflection surface (27) formed on a lower surface of the at least one needle (24a, 24b), the dial (2a, 2b) according to claim 1.

8. The at least one first light source (4a) is configured to emit a light beam (29a) toward a reflection area (26) of the at least one needle (24a, 24b), and the reflection area (26) is configured to reflect this light beam (29a) toward the at least one light detection element (23), and the reflection area (26) includes a diffraction grating (28) formed on a lower surface of the at least one needle (24a, 24b), and the grating (28) is configured to reflect the light beam (29a) toward the at least one light detection element (23), the dial (2a, 2b) according to claim 1.

9. The at least one first light source (4a) is a vertical cavity surface emitting laser light source, the dial (2a, 2b) according to claim 1.

10. The at least one second light source (4b) is capable of generating a visual message according to the determined position of the at least one needle, the dial (2a, 2b) according to claim 1.

11. The first layer (10) is configured such that light radiation, particularly sunlight radiation and light radiation emitted by the first and second light sources (4a, 4b), can pass through completely or partially, the dial (2a, 2b) according to claim 1.

12. The second layer (11) includes a substrate on which the photovoltaic module (5) is printed, the dial (2a, 2b) according to claim 1.

13. The photovoltaic module (5) is arranged in the active area of the second layer (11), and the area is arranged to receive light rays emitted from the first layer (10) of the laminate (9a, 9b) of the thin layers (10, 11, 12, 13, 14), the dial (2a, 2b) according to claim 1.

14. The laminate (9a) of the thin layers (10, 11, 12, 13) includes a third layer (12) having an electrical energy accumulator (6) constituting the stand-alone power supply unit (21), the dial (2a) according to claim 1.

15. The laminate (9a) of the thin layers (10, 11, 12, 13) includes a third layer (12) having an electrical energy accumulator (6) constituting the stand-alone power supply unit (21), and the third layer (12) includes a substrate on which the electrical energy accumulator (6) is printed, the dial (2a) according to claim 1.

16. The laminate (9a) of the thin layers (10, 11, 12, 13) includes a fourth layer (13) forming the hidden surface (20b) of the dial (2a) including the control unit (7), the dial (2a) according to claim 1.

17. The laminate (9b) of the thin layers (10, 11, 14) includes a third layer (14) including the hidden surface (20b) of the dial (2b) constituting the control unit (7) and an electrical energy accumulator (6) constituting the stand-alone power supply unit (21), the dial (2b) according to claim 1.

18. The first layer (10) is rigid compared to the other layers (11, 12, 13, 14) that are flexible in the laminate (9a, 9b), the dial (2a, 2b) according to claim 1.

19. A wristwatch (1) including the dial (2a, 2b) according to claim 1.

20. The wristwatch (1) according to claim 19, including a mechanical or electromechanical timekeeping movement.

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