CLOCK THAT INCLUDES A COVERING ELEMENT EQUIPPED WITH A PART MADE OF ZIRCONOXIDE

Description

Technical field of the invention

[0001] The present invention relates to a timepiece comprising at least one exterior element comprising at least one part made of a ceramic material. More specifically, the present invention relates to a timepiece presenting original plays of light, for a functional, aesthetic and / or recreational purpose. The present invention also relates to a use of such a timepiece to obtain original functional applications of illuminations on the timepiece. Technological background

[0002] Creating timepieces such as wristwatches with an improved aesthetic appearance is a constant concern for watch manufacturers, particularly those responsible for designing the various exterior elements. It would take too long to list here all the solutions that have been considered to give a timepiece the most neat and aesthetic appearance possible. As examples only, we can cite the guilloché technique for dials, the shape and / or color of the dial appliques or hands, or the addition of precious or semi-precious stones.

[0003] The present invention is part of the quest to offer customers watches whose appearance is at once aesthetic, surprising and functional.

[0004] In this context, it is known, for example from patent document WO 2010 / 146162 A1, to illuminate a timepiece of which at least one exterior element comprises a part made of an at least partially transparent or translucent material, in particular a ceramic material. The timepiece, typically a watch, comprises one or more light sources which make it possible to illuminate the ceramic material from the inside of the case, under the dial, by producing light which passes through the transparent or translucent part of this ceramic material. The ceramic part of the exterior element may be a part added to the latter. The lateral periphery of the caseband of the watch, areas around the winding crown and / or the push buttons, or even optical elements towards the bracelet strands may thus be illuminated.The dial can also be illuminated via selectively semi-transparent areas (appliques) provided on the latter.

[0005] However, a disadvantage of this type of timepiece is that it does not offer an optimal light transmission coefficient. In addition, when the ceramic material part of the exterior element is an added part, the assembly of such a part on the exterior element does not guarantee the watertightness and stability over time of the timepiece. Document EP3588203A1 shows a watch component, made of one or more materials, and whose heterogeneities in the material used make it possible to obtain opaque parts and transparent parts. Summary of the invention

[0006] The invention overcomes the drawbacks of the prior art by providing a timepiece that is waterproof and stable over time, and allows light to escape from inside a covering element of the piece with optimal light transmission, while presenting original plays of light, for functional, aesthetic and / or recreational purposes.

[0007] To this end, the present invention relates to a timepiece comprising, in addition to a crystal, the following exterior elements: a back, a middle, a dial, and two bracelet strands, at least one of these exterior elements comprising a body formed from at least a first part consisting of a first opaque material devoid of zirconia and at least a second part consisting of a second partially transparent or translucent material, said first material being integral with said second material and the timepiece further comprising at least one light source producing light which passes through said at least a second part consisting of a partially transparent or translucent ceramic material comprising zirconia.

[0008] The use of zirconia as a ceramic material that is at least partially transparent or translucent makes it possible to provide surprising illumination for the timepiece, giving it a precious and more or less diffuse, discreet, soft and pleasant appearance, these characteristics being able to be varied practically infinitely according to the desired aesthetic rendering, which increases the final aesthetic quality of the timepiece. In addition, zirconia stabilized in tetragonal phase by the addition of yttria (Y-TZP for "yttria-stabilized tetragonal zirconia polycrystals" in English) is the technical ceramic that offers both the best mechanical toughness and one of the best light transmission coefficients.Its use in a timepiece to allow light to escape from inside a casing element of the timepiece therefore makes it possible to give the latter very good light transmission, while allowing original plays of light, for functional, aesthetic and / or recreational purposes. The timepiece according to the invention may be, for example, an electronic, electromechanical and / or mechanical watch, and in particular a sports watch or a so-called "luxury" watch.

[0009] Furthermore, the extraction of light through the second zirconia part of the covering element does not require the assembly of different transparent components added to the covering element. Indeed, the second material being integral with the first material together forms the entire monobloc body of the covering element, which makes it possible to guarantee the sealing and stability over time of this covering element and therefore of the timepiece. Thanks to the invention there is therefore no need to provide specific light paths, machined in the part, and which would have to be sealed. It is therefore understood that in this configuration the covering element comprises a ceramic material such as zirconia. This covering element is preferably a monobloc part comprising the ceramic material of the zirconia type.

[0010] Preferably, the composition and thickness of the second zirconia part are chosen so that the average light transmission coefficient in the visible spectrum has a value of at least 30%, preferably 40% or more.

[0011] Particular forms of the timepiece are defined in dependent claims 2 to 23.

[0012] Preferably, the zirconia is white zirconia. More preferably, the zirconia is tetragonal zirconia. The zirconia is advantageously doped with alumina pigments, preferably doped with 5% by mass of alumina pigments. This allows the translucency level of the zirconia to be adjusted to different values ​​depending on the manufacturer's wishes.

[0013] According to a particular technical characteristic of the invention, said at least one light source comprises a light-emitting diode.

[0014] According to another particular technical characteristic of the invention, said at least one light source is an extended light source, configured to produce continuous or quasi-continuous lighting on the zirconia part of the cladding element.

[0015] According to a first embodiment of the invention, the light-emitting diode is an organic light-emitting diode evaporated or printed on the cladding element to be illuminated or on a substrate inserted in or under the cladding element to be illuminated, said organic light-emitting diode forming the extended light source. This makes it possible to give a predetermined shape to the extended light source, typically, without this being exhaustive or limiting, a shape of a number, letter, logo or even text.

[0016] According to a second embodiment of the invention, the extended light source comprises, in addition to the light-emitting diode, a light guide, said light guide being coupled to the light-emitting diode and being capable of diffusing the light injected by the light-emitting diode over its entire length. This makes it possible to obtain continuous illumination at the locations where desired on the cladding element, thus providing in particular original functional, aesthetic and / or playful applications limited to these locations.

[0017] Advantageously, the timepiece further comprises a shutter or an optical valve mounted on a moving part of the timepiece, the shutter or the optical valve being arranged opposite said at least one extended light source and being configured to have only one position at which the light emitted by the light source escapes from the inside of the timepiece to the outside of the latter. This thus gives the illusion of a luminous point which moves continuously on the exterior element, such an effect being able to advantageously be used in applications aiming for example to display a countdown or a luminous chronometer.

[0018] According to a particular technical characteristic of the invention, the second zirconia part of the cladding element to be illuminated comprises at least one inscription intended to be illuminated by the light coming from the light source.

[0019] Preferably, said at least one inscription is made in the second zirconia part via a method selected from the group consisting of: selective carburizing and / or nitriding of the zirconia surface; varying the thickness of the zirconia by mechanical or laser engraving; varying the density of the zirconia; opaque or semi-transparent printing on the zirconia surface; structured PVD physical vapor deposition on the zirconia surface or inside the zirconia part; and a combination of two or more of these methods.

[0020] Advantageously, when said at least one inscription is made in the zirconia part via selective carburizing and / or nitriding of the surface of the zirconia, the inscription forms an active conductive structure, of the electrical conduction track or antenna type. Such structures can be highlighted by illuminating the zirconia around these structures, but can also be advantageously used to bring the current necessary to the light source to produce the illumination.

[0021] Advantageously, said at least one inscription is configured to be invisible in natural light and only become visible when illuminated by light from the light source. The inscription may, for example, become visible by appearing in negative on the surface of the zirconia.

[0022] Advantageously, said at least one light source is mounted on a moving part of the timepiece, under the exterior element to be illuminated, for example mounted on a pseudo-hand configured to rotate around the axis of the hands. This makes it possible to obtain a dynamic and particularly aesthetic lighting rendering, in particular when the exterior element to be illuminated is the case or the bezel of the watch.

[0023] Another aspect of the invention relates to a use of a timepiece as described above, in which the timepiece comprises a plurality of light sources arranged in or under the exterior element comprising said at least one second part made of a second partially transparent or translucent material, and in that the switching on and off of the light sources are configured in such a way that the timepiece has, on the exterior element illuminated by the light sources, at least one visual indication of a function specific to the timepiece and / or relating to a measurement of an external parameter or a parameter concerning the user of the timepiece.

[0024] According to a particular technical characteristic of the invention, the switching on and off of the light sources are configured in such a way that the timepiece has, on the exterior element illuminated by the light sources, one or more visual indications relating to one or more of the following functionalities: indication of the hour, minutes and / or date; indication of a stopwatch or a countdown with illuminated zones of the exterior element which light up, respectively go out, as the time elapses; indication of a quantity measured by the timepiece by illumination modulated in color, rhythm, frequency and / or intensity on the exterior element, for example indication of a heart rate, a temperature, a running pace, a number of steps or a decibel level; indication of an alarm or a notification reception;indication of an active function for the timepiece; assistance in setting the timepiece.;

[0025] According to another particular technical characteristic of the invention, the switching on and / or off of the light sources is controlled simultaneously and / or in sequence. Brief description of the figures

[0026] The aims, advantages and characteristics of the timepiece according to the invention will appear better in the following description on the basis of at least one non-limiting embodiment illustrated by the drawings in which: there figure 1 is a sectional view of a watch case according to one embodiment of the invention, the watch case being equipped with a middle part comprising a zirconia part illuminated by a light source; the figure 2is a top view of a zirconia watch case along the inner side of which is fixed a diffusing optical fiber into which light is injected; the figure 3 is a top view of a wristwatch comprising a zirconia dial and / or bezel through which light passes; and the figure 4 is a top view of a wristwatch comprising two bracelet strands in which light diffuses by means of two zirconia parts arranged in the caseband. Detailed description of the invention

[0027] The present invention proceeds from the general inventive idea which consists of housing at least one light source in or under at least one exterior element of a timepiece. This exterior element comprises a body formed of at least a first part consisting of a first non-transparent or non-translucent or opaque or substantially opaque material, and at least a second part consisting of a second transparent or translucent or at least partially transparent or at least partially translucent material. In this body, the first material is integral with the second material. The second material consists essentially or exclusively or entirely of a ceramic material such as zirconia. In this configuration, the exterior element is preferably a single-piece part.It will be understood that the single-piece body of this covering element preferably consists solely of said at least one first part and said at least one second part. In addition, said at least one second part extends within the thickness of the body of the covering element defined between external and internal surfaces of this body. By thus extending within this thickness, this second part connects these external and internal surfaces together.

[0028] The first material is preferably present in the body of this cladding element in a greater proportion than the second material. In this context, this first material may also be called the main material and the second material, the secondary material. For example, the first material may constitute between 60 and 90% of the body of the cladding element, preferably 75%. It will be noted that the second material is visually identifiable in the cladding element because it corresponds to said at least one second transparent or translucent part or zone of the body of this cladding element.

[0029] In this context, it is understood that the total surface area occupied on the external or visible surface of the body of the cladding element by the second part(s) is less than the total surface area occupied on this same face by the first part(s).

[0030] However, in other alternatives, this first material may be in a lesser proportion than the second material in the body of this cladding element. For example, the first material may then constitute between 20 and 30% of the body of the cladding element, preferably 25%. It is understood that in this context the total surface area occupied on the visible face of the body of the cladding element by the first part(s) is less than the total surface area occupied on this same face by the second part(s).

[0031] The first material constituting the first part of the body of this cladding element is free of zirconia. The second material constituting the second part of the body of the cladding element which is transparent or translucent comprises the ceramic material comprising zirconia.

[0032] However, in an unclaimed alternative, the first material of the body of this cladding element may consist partly or entirely of non-transparent or non-translucent or opaque or substantially opaque zirconia. In this alternative, the second material then consists essentially or exclusively of transparent or translucent zirconia. In this configuration, the body of the cladding element is entirely made of zirconia.

[0033] It will be noted that the second part is the only portion of the body of the exterior element that is transparent or translucent. As already mentioned, the body of the exterior element comprises at least one second transparent or translucent part. This second part constitutes a portion of the exterior element through which the light produced by the light source can escape to the outside of the timepiece.

[0034] As we have seen, in the exterior element, the first material is integral with the second material. Such a configuration makes it possible to guarantee the waterproofness and stability over time of the exterior element and therefore of the timepiece. Moreover, thanks to the invention, there is no need to provide specific light paths, machined in the part, which would have to be waterproof. This provides a timepiece that is waterproof and stable over time, with original light effects providing surprising illumination for the timepiece, for functional, aesthetic and / or playful purposes. This makes it possible to give the timepiece a precious and more or less diffuse, discreet, soft and pleasant appearance, these characteristics being able to be varied practically infinitely according to the desired aesthetic rendering, and this without requiring the assembly of transparent components added to the exterior element.

[0035] In the following description, all parts of the timepiece which are well known to those skilled in the art will only be explained in a simplified manner.

[0036] There figure 1 is a sectional view of a case middle 1 delimiting with a bottom 2 and a dial 3 an interior volume 4 of a watch case 6. The watch case 6 is closed on top by a glass 34. For the purposes of the present description, it will be imagined that the watch is an electronic watch and that its movement M is arranged in the bottom of the watch case 6. In this way, it is possible to arrange above the movement M a support plate 8 of the printed circuit board or flexible PCB type on which are mounted a light source 10 for example of the light-emitting diode or LED type and its electronic control circuit 12. In the particular embodiment of the figure 1, the light source 10 is arranged in the caseband 1 to be illuminated. According to a variant not shown, the light source 10 is arranged under the exterior element to be illuminated. More precisely, the light source 10 is arranged directly under an internal surface of the body of the exterior element to be illuminated by being pressed against this internal surface. This light source can be pressed against a portion of the internal surface included in said at least one second part. It is also possible, according to a variant not shown, for the light source 10 to be mounted on a moving part of the timepiece, under the body of the exterior element to be illuminated. For example, when the exterior element to be illuminated is a bezel 26 mounted on the caseband 1, the light source 10 can be mounted on a pseudo-hand configured to rotate around the axis of the hands 29.

[0037] Any type of light source 10 can be used, whether point or extended. When the light source 10 is an extended light source, it produces continuous or quasi-continuous illumination on the second transparent or translucent zirconia part of the outer element in question through which the light will escape from the interior volume 4 of the watch case 6. In the particular embodiment illustrated in the figure 1 , a light-emitting diode is used for the light source 10. The light-emitting diode emits, for example, ultraviolet, violet, blue, white or infrared light in combination with a covering element loaded with fluorescent and / or phosphorescent particles. The covering element to be illuminated, in this case the middle part 1 made of zirconia in the particular embodiment of the figure 1, is loaded at the location or locations where light is desired to escape from inside the watch case 6. In this way, the fluorescent and / or phosphorescent particles absorb the radiation emitted by the diode and re-emit a homogeneous visible light. Depending on the type of particles chosen, fluorescent and / or phosphorescent, the luminous effect ceases immediately after the light source is switched off or, on the contrary, continues due to a remanence effect.

[0038] In the particular embodiment illustrated in the figure 2, the light source 10 is an extended light source which comprises a light-emitting diode 18 and a light guide 22. The light-emitting diode 18 is connected to an electronic control circuit 12. The light guide 22 is coupled to the light-emitting diode 18 and is fixed along the inner side of the zirconia caseband 1. The light guide 22 thus makes it possible to bring the light from the point where it is injected into the guide 22 to the level of the second part or parts made of transparent or translucent zirconia of the exterior element or elements in question through which the light will escape from the inner volume 4 of the watch case 6.According to a variant, the light guide 22 is an optical fiber which makes it possible to bypass any obstacles which may arise between the light-emitting diode 18 and the second transparent or translucent zirconia part of the covering element in question through which the light will escape from the interior volume 4 of the watch case 6. As illustrated in the . figure 2 , the optical fiber 22 may be an optical fiber that diffuses the injected light along its entire length. The fact that the optical fiber 22 is coupled to a single light-emitting diode 18 allows for savings in costs and energy used to achieve the illumination of the second zirconia part.

[0039] In another embodiment not shown in the figures, the light source 10 is an extended light source consisting of an organic light-emitting diode evaporated or printed on the cladding element to be illuminated or on a substrate inserted in or under the cladding element to be illuminated. For example, the organic light-emitting diode is evaporated or printed on the portion of the internal surface of the body of the cladding element which is included in the second part to be illuminated or on a substrate inserted in or directly under this portion.

[0040] In another embodiment not shown in the figures, the light source 10 is an extended light source having the shape of a number, letter, logo or text.

[0041] The light source 10 is powered for example by a rechargeable or interchangeable battery 14 and conventionally arranged under the watch movement M on the side of the back 2 of the watch case 6. It will be understood that the watch according to the invention can be electronic, electromechanical or even purely mechanical. In the latter case, it will be sufficient to provide a housing to receive a battery which will be intended to power only the light source 10 and its electronic control circuit 12. Thus, the present invention can be applied to any type of wristwatch, the only constraint to be respected being that there is no obstacle to the propagation of light between the light source and the exterior element through which said light must exit.

[0042] Until now, the present invention has been described in connection with the case middle 1 as the only exterior element made of the first material integral with the second material comprising zirconia which is at least partially transparent or translucent. The present invention is however applicable to any other exterior element of a timepiece whose body is made of the second material in zirconia which is at least partially transparent or translucent, such as for example the dial 3 (visible on the figure 3 ), the bottom 2, the bezel 26, a flange (not shown in the figures), or even strands 30 of the bracelet (visible on the figure 4). According to a particular embodiment, the second zirconia material constituting the second part(s) of this body of the covering element intended to be illuminated is included in an upper part of the caseband 1 or the bezel 26. According to another particular embodiment, the second zirconia material constituting this body of the covering element intended to be illuminated is a second part of a control member of the watch such as a push button 16, or a second part of a winding crown, possibly provided with a crown cap. In this case, the winding crown and / or the crown cap comprises at least a second part made of this second material which is at least partially transparent or translucent.

[0043] Another particular embodiment is illustrated in the figure 3, where the timepiece is a wristwatch. In this embodiment, it is possible, for example, to illuminate appliques 24 at the level of the bezel 26 and the dial 3. To this end, the bezel 26 and the dial 3 may each be provided with a first part that is completely opaque and only allow light to escape at the level of the appliques 24, the latter being the second parts of the body of this covering element made of the second material in transparent or translucent zirconia. In this configuration, the body of each of these covering elements is made proportionally of a greater quantity of first material than of second material. Conversely, the appliques 24 of the bezel 26 and / or the dial 3 may be made of the first opaque material and the rest of the body of each of these covering elements of the second material in transparent or translucent zirconia.In this configuration, the body of each of these cladding elements comprises proportionally more second material than first material. In this particular embodiment illustrated in the . figure 3 , the wristwatch may for example comprise several point light sources, more precisely as many point light sources as there are wall lights 24 (twelve in the illustrated example). Each point light source is then provided to directly or indirectly illuminate one of the wall lights 24. The wristwatch may alternatively comprise a single extended light source, typically an extended light source similar to that illustrated in the figure 2 , comprising a light-emitting diode and a light guide coupled to the diode. The light guide can then be provided to extend under the dial 3 to be illuminated, substantially opposite the periphery of the dial 3 and therefore the wall lights 24.

[0044] In another particular embodiment illustrated in the figure 4 , the light produced by the light source 10 is injected into the strands 30 of a transparent or translucent bracelet. For this purpose, a caseband 1 is provided which has two second parts made of a second material made of transparent or translucent zirconia 32a and 32b substantially at noon and at six o'clock, that is to say at the locations where the strands 30 of the bracelet are fixed to said caseband 1. On the inside of the watch case 6, two light sources 10 can be provided each facing one of the two second parts made of zirconia 32a, 32b of the caseband 1. The light produced by the two light sources 10 emerges from the watch case 6 through said two second parts made of second material 32a, 32b and is injected into the two transparent or translucent strands 30 of the bracelet in which it diffuses.

[0045] The watch's exterior element(s) that allow all or part of the light produced by the light source to pass through may be illuminated directly by this light source. These exterior elements may, however, also be illuminated indirectly by the light source.

[0046] Preferably, the second part of the cladding element to be illuminated is made of the second white zirconia material. Alternatively, the zirconia may be colored zirconia. Preferably, the zirconia is tetragonal zirconia. The zirconia is advantageously doped with alumina pigments, preferably doped with 5% by mass of alumina pigments.

[0047] Preferably, the composition and thickness of the second material of the second part extending into the body of the cladding element are chosen so that the average light transmission coefficient in the visible spectrum has a value of at least 30%, preferably 40% or more. It will be noted that when the first material of the first part consists partially or exclusively of non-transparent or non-translucent or opaque or substantially opaque zirconia, the composition and thickness of the body comprising this material are chosen so that the average light transmission coefficient in the visible spectrum is zero.

[0048] It is also possible to provide, when the first material is not integral with the second material, that this second material made of at least partially transparent or translucent zirconia constitutes an insert. The zirconia used in this insert is typically white zirconia. The insert is provided at the location or locations where it is desired that light escapes from the inside of the watch case 6. The remainder of the exterior element is then, for example, made of the first material.

[0049] According to an embodiment of the invention not shown in the figures, when the light source 10 is an extended light source, the timepiece further comprises a shutter or an optical valve mounted on a moving part of the timepiece. The moving part is for example a hand or a pseudo-hand of the timepiece. The shutter or the optical valve is arranged opposite the extended light source 10 and is configured to have only one position for which the light emitted by the light source 10 escapes from the inside of the timepiece to the outside of the latter.

[0050] According to another embodiment of the invention, not shown in the figures, the second part of the cladding element to be illuminated, made of the second zirconia material, comprises at least one inscription intended to be illuminated by the light coming from the light source 10. This inscription is for example produced in this second zirconia part: either by selective carburizing and / or nitriding of the zirconia surface, or by varying the thickness of the zirconia by mechanical or laser engraving (for example a shrinkage of a few 0.1 mm in the ceramic), or by varying the density of the zirconia, or by opaque or semi-transparent printing inside or on the surface of the zirconia cladding element, or by physical vapor deposition (PVD) or other, structured inside or on the surface of the zirconia part, or by a combination of these methods.

[0051] When the light emission from the light source 10 is switched on, the normally invisible inscription appears in negative on the surface of the second zirconia part.

[0052] Preferably, when the inscription is carried out in the second zirconia part by selective carburizing and / or nitriding of the surface of this second zirconia part, the inscription forms an active conductive structure, of the electrical conduction track or antenna type.

[0053] The timepiece according to the present invention can advantageously be used to provide various functional applications to a user of the timepiece. For this purpose, the timepiece comprises several light sources 10. Each light source 10 is arranged in or under the exterior element comprising the second zirconia part to be illuminated. In particular, each light source 10 can be arranged directly under the portion of the internal surface of the exterior element included in the second zirconia part to be illuminated. The light source is then positioned by plating, bonding or by any other type of means on this portion of the internal surface of this exterior element.The switching on and off of the light sources 10 are configured so that the timepiece has, on the exterior element illuminated by the light sources 10, at least one visual indication of a function specific to the timepiece and / or relating to a measurement of an external parameter or a parameter concerning the user of the timepiece. The switching on and / or off of the light sources 10 can be controlled by the electronic control circuit 12 simultaneously and / or in sequence. It will be noted that each light source 10 is switched on and off separately by this electronic control circuit 12.

[0054] Among the possible functional applications for the timepiece, we can for example cite: indication of a quantity measured by the timepiece by illumination modulated in color, rhythm, frequency, and / or intensity on the exterior element. For example: indication of the user's heart rate by illumination pulsed at the same frequency. The color of the illumination can also be varied according to the frequency, typically green for a low rhythm, then increasingly red as the heart rate rises; indication of the ambient temperature by illumination of the numbers or appliques 24 on the dial 3 in sequence (see figure 3), by adapting the color to the temperature (typically blue for low temperatures, and increasingly red for increasingly high temperatures); indication (absolute or relative) of the running pace for a sports watch; indication of the number of steps or any other measure of the user's sporting activity; indication of a decibel level (for example on a construction site, in a discotheque, etc.); indication of any type of alarm and use of different combinations of rhythms / intensities / colors for the different alarms. In this case, many elements of the timepiece's exterior can light up simultaneously or in sequence, including the bracelet.Examples of alarms: morning alarm; receipt of a message or an email (or acknowledgment of receipt of a message sent) or any other notification from any other application for a watch connected to a mobile device such as a mobile phone; acknowledgment of receipt for a payment for a watch with a contactless payment functionality; indication of the active function for a multitasking watch, in particular the “Time”, “Chrono”, “Baro” (for the barometer”), “Podo” (for the pedometer), etc. function: by illumination of a number or applies 24 on the dial 3 corresponding to the function (1 = Chrono, 2 = Barometer, etc.); by transmitting illumination of one or more inscriptions (for example small texts or logos) printed or engraved inside the watch (typically in the caseband 1 and / or the bezel 26), just below the surface, and which are invisible in the absence of illumination; assistance in setting the watch, in particular for touch watches whose setting is done without a button / crown, which can make the operations less intuitive: indication of the active setting level (or menu) when setting the watch by illumination of the numbers or appliques 24 on the dial 3 and / or small hidden texts and / or logos; illumination of the zirconia crown when it is pulled out to adjust the watch; light guide indicating which button(s) and / or part(s) of the watch the user can / must touch during the next setting step.The buttons themselves and / or an area around the buttons may be illuminated; light confirmation (e.g. via two or three pulses of light) to indicate to the user that their setting has been accepted by the watch.

[0055] Of course, the above list of functional applications made possible by the timepiece according to the invention is not exhaustive and those skilled in the art will be able to identify other functional applications.

Claims

1. A timepiece including, in addition to a crystal, the following external elements: a back (2), a middle part (1), a dial (3), and two bracelet strands (30), the at least one of these external elements comprising a body formed of at least one first portion made of a first opaque material zirconia-free and of at least one second portion made of a second partially transparent or translucent material, said first material being integral with said second material and the timepiece further including at least one light source (10) producing light which passes through said at least one second portion made of a partially transparent or translucent ceramic material comprising zirconia.

2. The timepiece according to claim 1, characterised in that said at least one light source (10) is arranged in or under the body of the external element.

3. The timepiece according to any one of the preceding claims, characterised in that the arrangement of said at least one light source (10) relative to said body of the external element is configured so that most or all of the light produced by said at least one light source passes through said at least one second portion of this body.

4. The timepiece according to any one of the preceding claims, characterised in that the zirconia is white zirconia.

5. The timepiece according to any one of the preceding claims, characterised in that the zirconia is tetragonal zirconia.

6. The timepiece according to any one of the preceding claims, characterised in that the zirconia is doped with alumina pigments, preferably doped with 5% by weight of alumina pigments.

7. The timepiece according to any one of the preceding claims, characterised in that said at least one light source (10) comprises a light-emitting diode (18).

8. The timepiece according to any one of the preceding claims, characterised in that said at least one light source (10) is an extended light source, configured to produce continuous or quasi-continuous illumination on said at least one second portion of the body of the external element.

9. The timepiece according to any one of claims 7 and 8, characterised in that the light-emitting diode is an organic light-emitting diode evaporated or printed on the body of the external element to be illuminated or on a substrate inserted in or under the external element to be illuminated, said organic light-emitting diode forming the extended light source.

10. The timepiece according to any one of claims 7 and 8, characterised in that the extended light source (10) includes, in addition to the light-emitting diode (18), a light guide (22), said light (22) being coupled to the light-emitting diode (18) and being capable of diffusing over its entire length the light injected by the light-emitting diode (18).

11. The timepiece according to any one of claims 8 to 10, characterised in that the timepiece further includes an optical shutter or valve mounted on a moving part of the timepiece, the optical shutter or valve being arranged facing said at least one extended light source (10) and being configured to have only one position at which the light emitted by the light source (10) escapes from the inside of the timepiece to the outside of the latter through said at least one second portion.

12. The timepiece according to any one of claims 8 to 11, characterised in that said at least one extended light source (10) has the shape of a number, letter, logo or text.

13. The timepiece according to any one of the preceding claims, characterised in that said at least one second portion of the body of the external element to be illuminated includes at least one inscription intended to be illuminated by the light coming from the light source (10).

14. The timepiece according to the preceding claim, characterised in that< / b> said at least one inscription is made in said at least one second zirconia portion via a method selected from the group consisting of: selective carburisation and / or nitriding of the surface of the zirconia; a variation in the thickness of the zirconia by mechanical or laser engraving; a variation in the density of the zirconia; an opaque or semi-transparent impression on the surface of the zirconia; a structured PVD physical vapour deposition on the surface of the zirconia or inside the zirconia portion; and a combination of two or more of these methods.

15. The timepiece according to the preceding claim, characterised in that said at least one inscription is made in said at least one second portion via selective carburisation and / or nitriding of the surface of this second portion, and in that said at least one inscription forms an active conductive structure, of the electrical conduction track or antenna type.

16. The timepiece according to any one of claims 11 to 12, and according claim 13, characterised in that said at least one inscription is configured to be invisible in natural light and only become visible once illuminated by the light from the light source (10).

17. The timepiece according to any one of the preceding claims, characterised in that said at least one light source (10) is mounted on a moving part of the timepiece, under the body of the external element to be illuminated, for example mounted on a pseudo-hand configured to rotate around the axis of the hands (29).

18. The timepiece according to any one of the preceding claims, further comprising a bezel (26) and / or a push-button (16) and / or a winding crown provided with a crown cap, characterised in that the bezel (26) and / or the winding crown and / or the crown cap and / or the push-button (16) is an external element comprising said at least one second portion.

19. The timepiece according to any one of the preceding claims, characterised in that said at least one light source (10) emits ultraviolet, violet, blue, white or infrared light and in that the external element to be illuminated is loaded with phosphorescent and / or fluorescent particles at the place(s) where it is desired that the light escapes from the inside of the timepiece.

20. The timepiece according to any one of the preceding claims, characterised in that the partially transparent or translucent ceramic material consists essentially or entirely of zirconia.

21. A use of a timepiece according to any one of the preceding claims, characterised in that the timepiece includes a plurality of light sources (10) disposed in or under the external element comprising said at least one second portion made of a second partially transparent or translucent material, and in that the switching on and off of the light sources (10) are configured in such a way that the timepiece has, on the external element illuminated by the light sources (10), at least one visual indication of a function specific to the timepiece and / or relating to a measurement of an external parameter or of a parameter relating to the user of the timepiece.

22. The use of a timepiece according to claim 21, characterised in that the switching on and off of the light sources (10) are configured in such a way that the timepiece has, on the external element illuminated by the light sources (10), one or more visual indications relating to one or more of the following functions: indication of the hour, minutes and / or date; indication of a timer or a countdown with luminous areas of the external element which light up, respectively go out, as the time elapses; indication of a magnitude measured by the timepiece by colour, rhythm, frequency and / or intensity-modulated illumination on the external element, for example indication of a heart rate, of a temperature, a running pace, a number of steps or else a decibel level; indication of an alarm or reception of notification; indication of an active function for the timepiece; assistance in adjusting the timepiece.

23. The use of a timepiece according to claim 21 or 22, characterised in that the switching on and / or the switching off of the light sources (10) is controlled simultaneously and / or sequentially.