CH718714A2 - Timepiece comprising a covering element provided with a zirconia part. - Google Patents

Abstract

The invention relates to a timepiece comprising, in addition to a crystal, the following trim elements: a back (2), a middle part (1), a dial (3) and two bracelet strands, the at least one of these casing elements comprising at least one part consisting of an at least partially transparent or translucent ceramic material, the timepiece further comprising at least one light source (10) arranged in or under the casing element comprising ceramic material, said at least one light source (10) producing light which passes through the ceramic material of said casing element, the timepiece being characterized in that the ceramic material at least partially transparent or translucent is zirconia. The invention also relates to the use of such a timepiece for the visual indication of at least one function specific to the timepiece and/or relating to the measurement of an external parameter.

Description

Technical field of the invention

The present invention relates to a timepiece comprising at least one covering element comprising at least one part made of a ceramic material. More specifically, the present invention relates to a timepiece exhibiting original play of light, for a functional, aesthetic and/or playful purpose. The present invention also relates to a use of such a timepiece to obtain original functional applications of illuminations on the timepiece.

Technology background

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

The present invention is part of the quest to provide customers with watches whose appearance is both 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 trim element comprises a part made of a material that is at least partially transparent or translucent. , 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 inside the case, under the dial, by producing light which passes through the transparent or translucent part of this ceramic material. The ceramic material part of the covering element can be a piece attached to the latter. The lateral periphery of the middle part of the watch, the zones around the winding crown and/or the push-buttons, or even the optical elements towards the bracelet strands can thus be illuminated. The dial can also be illuminated via selectively semi-transparent zones (appliques) provided on the latter.

[0005] However, a drawback of this type of timepiece is that it does not offer an optimum light transmission coefficient. In addition, when the ceramic material part of the trim element is an added part, the assembly of such a part on the trim element does not make it possible to guarantee sealing and stability over time. of the timepiece.

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 part. with optimal light transmission, while presenting original plays of light, for a functional, aesthetic and/or playful purpose.

[0007] To this end, the present invention relates to a timepiece comprising, in addition to a crystal, the following covering elements: a bottom, a middle part, a dial and two bracelet strands, one at the least of these casing elements comprising at least one part made of an at least partially transparent or translucent ceramic material, the timepiece further comprising at least one light source arranged in or under the casing element comprising the ceramic material, said at least one light source producing light which passes through the ceramic material of said trim element. According to the invention, the at least partially transparent or translucent ceramic material is zirconia.

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

[0009] In addition, the extraction of light through the zirconia part of the trim element does not require the assembly of various transparent components attached to the trim element. Indeed, the zirconia part can be provided to constitute the entirety of the covering element, which makes it possible to guarantee the tightness and the stability over time of this covering element and therefore of the part of watchmaking. 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.

[0010] Preferably, the composition and the thickness of the 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 shapes of the timepiece are defined in dependent claims 2 to 17.

[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 weight of alumina pigments. This allows the level of translucency of the zirconia to be adjusted to different values depending on the wishes of the manufacturer.

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 covering element. .

According to a first embodiment of the invention, the light-emitting diode is an organic light-emitting diode evaporated or printed on the trim element to be illuminated or on a substrate inserted in or under the trim 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, the shape of a number, letter, logo or even text.

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 over its entire length. the light injected by the light-emitting diode. This makes it possible to obtain continuous illumination at the places where it is desired on the covering element, thus providing in particular functional, aesthetic and/or playful applications which are original and circumscribed at these places.

[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 facing said at least one extended light source and being configured to have only one position at which light emitted by the light source escapes from the inside of the timepiece to the outside of this last. This thus gives the illusion of a point of light which moves continuously on the covering element, such an effect being advantageously able to be used in applications aimed for example at displaying a countdown or a luminous chronometer.

[0018] According to a particular technical characteristic of the invention, the zirconia part of the covering 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 zirconia part via a method chosen from the group consisting of: selective carburization 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 vapor deposition on the surface of the zirconia 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 carburization 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 illumination of the zirconia around these structures, but 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 to natural light and only become visible once illuminated by the light from the light source. The inscription can 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 casing element to be illuminated, for example mounted on a pseudo-needle configured to rotate around the needle axis. This makes it possible to obtain a dynamic and particularly aesthetic rendering of lighting, in particular when the trim element to be illuminated is the middle part or the bezel of the watch.

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 element of casing comprising the zirconia part, and in which the switching on and off of the light sources are configured in such a way that the timepiece has, on the casing element illuminated by the light sources, at least a 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.

[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 covering element illuminated by the light sources , 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 stopwatch or a countdown with luminous areas of the trim element which light up, respectively go out, as the time elapses; indication of a magnitude measured by the timepiece by illumination modulated in color, rhythm, frequency and/or intensity on the covering element, for example indication of a heart rate, of a temperature, a running pace, a number of steps or even a decibel level; indication of alarm or notification receipt; indication of an active function for the timepiece; assistance in setting the timepiece.

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

Brief description of figures

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: FIG. 1 is a cross-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; FIG. 2 is a top view of a watch middle part made of zirconia along the inner side of which is fixed a diffusing optical fiber into which light is injected; FIG. 3 is a top view of a wristwatch comprising a dial and/or a zirconia bezel through which light passes; and FIG. 4 is a top view of a wristwatch comprising two bracelet strands in which the light diffuses by means of two zirconia parts formed in the middle part.

Detailed description of the invention

The present invention proceeds from the general inventive idea which consists in housing at least one light source in or under at least one covering element of a timepiece comprising a transparent or translucent zirconia part, the light produced by the light source being able to escape towards the outside of the timepiece by passing through the zirconia part. This provides a timepiece that is watertight 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 aspect, these characteristics being able to be varied practically infinitely according to the desired aesthetic rendering, and this without requiring the assembly of components. transparencies attached to the trim element.

[0028] In the following description, all the parts of the timepiece which are well known to those skilled in the art will only be explained in a simplified manner.

[0029] Figure 1 is a sectional view of a middle part 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 the 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 placed in the bottom of the watch case 6. In this way, one can place 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 FIG. 1, the light source 10 is placed in the caseband 1 to be illuminated. According to a variant not shown, the light source 10 is arranged under the trim element to be illuminated, preferably flat against an internal surface of the trim element to be illuminated. Provision can also be made, according to a variant not shown, for the light source 10 to be mounted on a moving part of the timepiece, under the casing element to be illuminated. For example, when the covering 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.

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 transparent or translucent zirconia part of the trim element considered through which the light will escape from the interior volume 4 of the watchcase 6. In the particular embodiment illustrated in FIG. 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 charged with fluorescent and/or phosphorescent particles. The trim element to be illuminated, in this case the middle part 1 in zirconia in the particular embodiment of FIG. 1, is loaded at the place or places where it is desired that the light escapes 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 has been switched off or, on the contrary, continues through the afterglow effect.

In the particular embodiment illustrated in Figure 2, the light source 10 is an extended light source which includes a light emitting diode 18 and a light guide 22. The light emitting diode 18 is connected to an electronic circuit of control 12. The light guide 22 is coupled to the light-emitting diode 18 and is fixed along the inner side of the middle part 1 made of zirconia. The light guide 22 thus makes it possible to bring the light from the point where it is injected into the guide 22 up to the level of the transparent or translucent zirconia zone(s) of the trim element(s) considered through which the light goes. escape from the interior volume 4 of the watch case 6. According to a variant, the light guide 22 is an optical fiber which makes it possible to circumvent any obstacles which may arise between the light-emitting diode 18 and the transparent or translucent zone in zirconia of the covering element considered through which the light will escape from the interior volume 4 of the watch case 6. As illustrated in FIG. 2, the optical fiber 22 can be an optical fiber which diffuses the light injected onto its entire length. The fact that the optical fiber 22 is coupled to a single light-emitting diode 18 saves costs and energy used to achieve the illumination of the zirconia part.

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 trim element to be illuminated or on an inserted substrate in or under the trim element to be illuminated.

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.

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 bottom 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 suffice 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 observed being that there is no obstacle to the propagation of light between the light source and the covering element through which said light must exit.

[0035] So far, the present invention has been described in connection with the caseband 1 as the only trim element consisting of at least partially transparent or translucent zirconia. The present invention is however applicable to any other covering element of a timepiece comprising a part made of at least partially transparent or translucent zirconia, such as for example the dial 3 (visible in FIG. 3), the bottom 2, the bezel 26, a flange (not shown in the figures), or bracelet strands 30 (visible in Figure 4). According to a particular example of embodiment, the part of the zirconia covering element intended to be illuminated is an upper part of the middle part 1 or of the bezel 26. According to another particular example of embodiment, the part of the zirconia casing intended to be illuminated is part of a control member of the watch such as a push-button 16, or part of a winding crown, optionally provided with a crown cap. In this case, the winding crown and/or the crown cap comprises at least one part made of at least partially transparent or translucent zirconia.

Another particular embodiment is illustrated in Figure 3, where the timepiece is a wristwatch. In this embodiment, it is possible, for example, to illuminate the appliques 24 at the level of the bezel 26 and of the dial 3. To this end, the bezel 26 and the dial 3 can be provided completely opaque and only allow light to escape at the level of the appliques 24, the latter being made of transparent or translucent zirconia. Conversely, the bezel 26 and/or the dial 3 can be made of transparent or translucent zirconia and the appliques 24 can be opaque. It is also possible to envisage that the bottom 2, the middle part 1 and the dial 3 are opaque and that only a flange arranged between the bezel 26 and the dial 3 is made of transparent or translucent zirconia, thus creating a luminous ring all around the crystal. 34. According to this particular embodiment illustrated in FIG. 3, the wristwatch can for example comprise several point light sources, more precisely as many point light sources as there are appliques 24 (twelve in the example shown). Each point light source is then provided to directly or indirectly illuminate one of the appliques 24. The wristwatch may alternatively comprise a single extended light source, typically an extended light source similar to that illustrated in FIG. 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 of the appliques 24.

In another particular embodiment illustrated in Figure 4, the light produced by the light source 10 is injected into the strands 30 of a transparent or translucent bracelet. To this end, provision is made for a middle part 1 which has two zones of transparent or translucent zirconia 32a and 32b substantially at noon and six o'clock, that is to say at the places where the strands 30 of the bracelet are fixed to said middle part 1 On the inside of the watch case 6, two light sources 10 can each be provided opposite one of the two zirconia zones 32a, 32b of the caseband 1. The light produced by the two light sources 10 emerges of the watch case 6 by said two zirconia zones 32a, 32b and is injected into the two transparent or translucent strands 30 of the bracelet in which it diffuses.

[0038] The trim element(s) of the watch which allow all or part of the light produced by the light source to pass can be illuminated directly by this light source. These trim elements can nevertheless also be illuminated indirectly by the light source.

[0039] Preferably, the zirconia of the covering element to be illuminated is white zirconia. 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 weight of alumina pigments.

[0040] Preferably, the composition and the thickness of the 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.

It is also possible, in a variant not shown, for the covering element to be illuminated to comprise an at least partially transparent or translucent zirconia insert. The zirconia used for the insert is typically white zirconia. The insert is provided at the place or places where it is desired that the light escapes from the inside of the watchcase 6. The rest of the covering element is then for example made up of a material distinct from zirconia, typically an opaque material.

[0042] 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 facing 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 towards the outside of the latter.

According to another embodiment of the invention, not shown in the figures, the zirconia part of the covering element to be illuminated comprises at least one inscription intended to be illuminated by the light coming from the source of light 10. This inscription is for example made in the zirconia part: either by selective carburization and/or nitriding of the surface of the zirconia, either by varying the thickness of the zirconia by mechanical or laser engraving (for example a shrinkage of some 0.1 mm in the ceramic), either by variation in the density of the zirconia, either by an opaque or semi-transparent print inside or on the surface of the zirconia trim element, or by physical vapor deposition PVD (Physical Vapor Deposition) or other, structured inside or on the surface of the zirconia part, or by a combination of these methods.

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

Preferably, when the inscription is made in the zirconia part by carburizing and/or selective nitriding of the surface of the zirconia, the inscription forms an active conductive structure, of the electrical conduction track or antenna type.

The timepiece according to the present invention can advantageously be used to provide various functional applications to a user of the timepiece. To this end, the timepiece comprises several light sources 10. Each light source 10 is arranged in or under the covering element comprising the zirconia part to be illuminated. The switching on and off of the light sources 10 are configured so that the timepiece has, on the covering 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. The switching on and/or the switching off of the light sources 10 can be controlled by the electronic control circuit 12 simultaneously and/or in sequence.

Among the possible functional applications for the timepiece, mention may be made, for example: - indication of a quantity measured by the timepiece by modulated illumination in color, in rhythm, in frequency, and/or in intensity on the trim element. For example: • indication of the user's heart rate by pulsed illumination at the same frequency. You can also vary the color of the illumination depending on the frequency, typically green for a low rhythm, then increasingly red the higher the heart rate; • indication of the ambient temperature by illumination of the numbers or appliques 24 on the dial 3 in sequences (see FIG. 3), by adapting the color to the temperature (typically blue for low temperatures, and increasingly red for temperatures of higher and higher); • indication (absolute or relative) of running pace for a sports watch; • indication of the number of steps or any other measurement of the sporting activity of the user; • indication of a decibel level (for example on a building 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 exterior elements of the timepiece can light up simultaneously or in sequence, including the bracelet. Examples of alarms: • morning alarm clock; • receipt of a message or an electronic mail (or acknowledgment of receipt of a message sent) or any other notification from any other application for a watch connected to a mobile device of the mobile telephone type; • acknowledgment of receipt for payment for a watch with 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) function, etc.: • by illumination of a figure or applique 24 on dial 3 corresponding to the function (1 = Chrono, 2 = Barometer, etc.); • by transmission illumination of one or more inscription(s) (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-sensitive watches whose setting is done without a button/crown, which can make operations less intuitive: • indication of the setting level (or menu) active when setting the watch by illumination of the numerals or appliques 24 on the dial 3 and/or small texts and/or hidden 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 can be illuminated; • luminous confirmation (for example via two or three pulses of light) to indicate to the user that his setting has indeed been accepted by the watch.

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 (20)

1. Timepiece comprising, in addition to a crystal, the following covering elements: a bottom (2), a middle part (1), a dial (3), and two bracelet strands (30), the at least one of these casing elements comprising at least one part made of an at least partially transparent or translucent ceramic material, the timepiece further comprising at least one light source (10) arranged in or under the casing element comprising ceramic material, said at least one light source (10) producing light which passes through the ceramic material of said casing element, the timepiece being characterized in that the ceramic material at the least partially transparent or translucent is zirconia. 2. Timepiece according to claim 1, characterized in that the zirconia is white zirconia. 3. Timepiece according to claim 1 or 2, characterized in that the zirconia is tetragonal zirconia. 4. Timepiece according to any one of the preceding claims, characterized in that the zirconia is doped with alumina pigments, preferably doped with 5% by weight of alumina pigments. 5. Timepiece according to any one of the preceding claims, characterized in that said at least one light source (10) comprises a light-emitting diode (18). 6. Timepiece according to any one of the preceding claims, characterized in that the said at least one light source (10) is an extended light source, configured to produce continuous or quasi-continuous illumination on the part in zirconia of the trim element. 7. Timepiece according to claims 5 and 6 taken together, characterized in that the light-emitting diode is an organic light-emitting diode evaporated or printed on the trim element to be illuminated or on a substrate inserted in or under the element covering to be illuminated, said organic light-emitting diode forming the extended light source. 8. Timepiece according to claims 5 and 6 taken together, characterized in that the extended light source (10) comprises, in addition to the light-emitting diode (18), a light guide (22), said light guide ( 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). 9. Timepiece according to any one of claims 6 to 8, characterized in that 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 (10) and being configured to present only a single position at which the light emitted by the light source (10) escapes from the inside the timepiece towards the outside of the latter. 10. Timepiece according to any one of claims 6 to 9, characterized in that said at least one extended light source (10) has the form of a number, letter, logo or text. 11. Timepiece according to any one of the preceding claims, characterized in that the zirconia part of the covering element to be illuminated comprises at least one inscription intended to be illuminated by the light coming from the light source (10). 12. Timepiece according to the preceding claim, characterized in that said at least one inscription is made in the zirconia part via a method chosen from the group consisting of: selective carburization 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 vapor deposition on the surface of the zirconia or inside the zirconia part; and a combination of two or more of these methods. 13. Timepiece according to the preceding claim, characterized in that said at least one inscription is made in the zirconia part via selective carburization and/or nitriding of the surface of the zirconia, and in that said at least one inscription forms an active conductive structure, of the electrical conduction track or antenna type. 14. Timepiece according to any one of claims 11 to 13, characterized in that said at least one inscription is configured to be invisible to natural light and only become visible once illuminated by the light from the light source (10). 15. Timepiece according to any one of the preceding claims, characterized in that said at least one light source (10) is mounted on a moving part of the timepiece, under the covering element to illuminate, for example mounted on a pseudo-needle configured to rotate around the axis of the needles (29). 16. 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, characterized in that the bezel (26) and/or the winding crown and/or the crown cap and/or the push-button (16) is a covering element comprising at least one part made of zirconia. 17. Timepiece according to any one of the preceding claims, characterized in that the said at least one light source (10) emits ultraviolet, violet, blue, white or infrared light and in that the element of the casing to be illuminated is loaded with phosphorescent and/or fluorescent particles at the place or places where it is desired that the light escapes from the inside of the timepiece. 18. Use of a timepiece according to any one of the preceding claims, characterized in that the timepiece comprises a plurality of light sources (10) arranged in or under the covering element comprising the zirconia part, 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 trim 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. 19. Use of a timepiece according to claim 18, characterized in that the switching on and off of the light sources (10) are configured in such a way that the timepiece present, on the element covering 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 stopwatch or a countdown with luminous areas of the trim element which light up, respectively go out, as the time elapses; indication of a magnitude measured by the timepiece by illumination modulated in color, rhythm, frequency and/or intensity on the covering element, for example indication of a heart rate, of a temperature, a running pace, a number of steps or even a decibel level; indication of alarm or notification receipt; indication of an active function for the timepiece; assistance in setting the timepiece. 20. Use of a timepiece according to claim 18 or 19, characterized in that the switching on and/or the switching off of the light sources (10) is controlled simultaneously and/or in sequence.