Watch provided with a display lighting device
By employing electroluminescent units with transparent conductive areas and imperceptible gaps, the lighting device addresses high resistance and visibility issues, offering discreet and efficient lighting for analog watches.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- THE SWATCH GRP RES & DEVELONMENT LTD
- Filing Date
- 2024-12-20
- Publication Date
- 2026-06-24
Smart Images
Figure IMGAF001_ABST
Abstract
Description
Technical field of the invention
[0001] The present invention relates to the field of watches having an analog or digital display, generally at least of the current time, and a device for illuminating this display. More particularly, the invention relates to an active lighting device, that is to say, comprising at least one light source powered, in particular on command, by an electrical power source. Technological background
[0002] Several active lighting devices ('active' as opposed to passive lighting devices, including the arrangement of phosphorescent materials on the dial and / or hands) have already been proposed to allow reading of an analog display in a dark or black environment (i.e., a space not illuminated by an external light source).
[0003] In particular, document WO 02 / 23637 describes a watch with an analog display and a light-emitting diode (LED) mounted on the underside of the watch crystal, at its center. The LED is powered from the periphery of the crystal by two straight tracks made of a transparent conductive material, indium tin oxide (a mixture of indium oxide and tin oxide, also known as ITO). Such a lighting device has advantages, as the LED can be small, making its presence discreet, even almost imperceptible to the user, especially when aligned with the axis of a hand on the analog display. However, the lighting device described in the aforementioned document has two drawbacks.First, the distance between the periphery and the center of the glass is relatively long. This means the two straight conductive tracks are narrow and have significant resistance, limiting the current that can be supplied to the LED and therefore the amount of light it can emit for a given supply voltage. Second, although the ITO tracks are quite transparent, they remain visible even when the glass is slightly darkened. Under certain lighting conditions, a user can distinguish them, which is unsightly and might even suggest a manufacturing defect in the glass. Summary of the invention
[0004] The invention aims to solve the two prior art problems described above in the technological background.
[0005] To this end, the invention relates to a watch comprising a display, a glass arranged above the display and having a useful region, through which a user of the watch can see the display, and a lighting device comprising at least one electroluminescent unit arranged below the glass and above the display, this electroluminescent unit being formed of at least one light source, in particular of the LED or OLED type (acronym for 'Organic Light Emitting Diode').Said at least one electroluminescent unit is supplied with electricity, from peripheral contact areas located in axial superposition outside said useful region, via conductive areas, of transparent conductive material, which cover below at least the entire of said useful region of the glass except for a gap, in the case of a single electroluminescent unit having only two supply contacts, separating the two conductive areas, or gaps separating said conductive areas, in the case of an electroluminescent unit having at least three supply contacts or a plurality of electroluminescent units.Remarkably, each gap separates two adjacent conductive areas and has a width such that this gap is almost imperceptible or preferably imperceptible, in ordinary ambient light, to a watch user with normal vision, the width of said gap, or gaps respectively, being less than two hundred micrometers (200 µm).
[0006] In a preferred embodiment concerning the case of an electroluminescent unit having at least three supply contacts or a plurality of electroluminescent units, the individual conductive areas, which are each electrically connected to a single supply contact associated with a single light source, are configured so that each exhibits substantially the same electrical resistance between respective peripheral contact areas and respective supply contacts of the electroluminescent unit or plurality of electroluminescent units.
[0007] In a particular variant, a conductive area common to a plurality of said supply contacts is configured so as to exhibit a lower electrical resistance than said individual conductive areas. Brief description of the figures
[0008] The invention will be described in more detail below with reference to the accompanying drawings, given by way of non-limiting examples, in which: there Figure 1 is a schematic cross-section of a watch according to a first embodiment of the invention; the Figure 2 is a plan view of a first variant of the first embodiment, showing the part of the lighting device that is arranged under the watch glass; the Figure 3A is a plan view of a second variant of the first embodiment, showing the part of the lighting device that is arranged under the watch glass; the Figure 3B is a plan view of a third variant of the first embodiment, showing the part of the lighting device that is arranged under the watch glass; the Figure 4 is a schematic cross-section of a watch according to a second embodiment of the invention; the Figure 5is a plan view of a first variant of the second embodiment, showing the part of the lighting device that is arranged under the watch glass; and the Figure 6 is a plan view of a second variant of the second embodiment, showing the part of the lighting device that is arranged under the watch glass. Detailed description of the invention
[0009] With reference to Figures 1 to 3B We will describe below a first embodiment of a watch according to the invention.
[0010] In general, the watch 2 comprises a case 4, a movement 10, an analog display 12, a crystal 6 arranged above the analog display, and a lighting device. The lighting device includes at least one electroluminescent unit, of the LED or OLED type, which is arranged below the crystal and above the analog display. The crystal 6 has a viewing area 9, located superimposed within an upper opening 9a of the case 4, through which a wearer of the watch can view the analog display 12. In particular, the case 4 is formed by a case middle 4a, a bezel 4b, and a case back 4c. The analog display 12 includes a set of hands and a dial 11.
[0011] In a first variant represented at the Figure 2The light-emitting unit is an LED 14 arranged on a layer of structured conductive material 16, which is deposited on the lower surface 8 of the glass 6 and covers almost the entire usable area 9 of the glass within the watch case for a user. In the variant shown, the conductive layer 16 covers almost the entire lower surface 8 of the glass. The conductive layer 16 is structured to define conductive areas for powering the LED 14 or, in other variants described subsequently, the intended LEDs or OLEDs.More specifically, the LED 14 is supplied with electricity through two power contacts 24, which are arranged on the LED on the side of the conductive layer 16, from two peripheral contact areas 20a and 20b located axially superimposed outside said useful region 9, i.e., along the periphery 7 of this glass, via two conductive areas 22a and 22b, made of transparent conductive material, which cover at least the entire lower portion of the useful region 9 of the glass 6 except for a gap 26 separating the two conductive areas 22a and 22b. These two conductive areas (which can also be called 'electrodes') each extend over almost half of the useful region 9.
[0012] We now have access to very small light-emitting sources, mini-sources, which can be almost imperceptible or even imperceptible to the naked eye. These mini-light sources are extremely small (< 500 µm). Two main types are well known: LEDs and OLEDs, the latter being able to be very small and directly fabricated on a transparent substrate. Thus, the LED14 is generally smaller than one millimeter and advantageously smaller than 500 µm on each side so that the LED is barely visible to the human eye when switched off. In a particular variant, a mini-LED measuring 150 x 100 µm2 was selected, i.e., less than 200 µm on each side, which is almost imperceptible at approximately 30 cm to a user with normal vision.A mini LED with a size of approximately 100 x 100 µm² or smaller is preferred, as such a mini LED is imperceptible at about 30 cm to a watch wearer with normal vision—in other words, invisible to the naked eye. The mini LED can be blue, green, yellow, or red, but also white. To create a white LED, a phosphorescent material can be deposited on a blue LED to convert the blue light into yellow light. The mixture of the residual blue light from the LED with the yellow light generated by the phosphorescent material is perceived by the human eye as white light.
[0013] Advantageously, the transparent conductive pads 22a and 22b are structured by photolithography of a thin, transparent conductive layer 16 of a transparent conductive oxide, or by printing silver nanostructures. Known examples of transparent conductive oxides include indium tin oxide (ITO) and indium zinc oxide (IZO, from the acronym for 'Indium Zinc Oxide'). Other techniques for forming transparent conductive pads and other transparent conductive materials can be considered by those skilled in the art.
[0014] The electrical connection between the power contacts 24 of the LED 14 and the transparent conductive pads 22a and 22b can be achieved in various ways. For example, an isotropic or anisotropic conductive adhesive or a eutectic solder can be used. In the case of an isotropic conductive adhesive, particularly one based on silver particles, two very small, separate dots of adhesive each ensure the adhesion of the LED to the substrate and electrical conductivity between the contact surfaces / pads, referred to as the power contacts, of the LED and the transparent conductive pads 22a and 22b.In the case of an anisotropic conductive adhesive, particularly one based on gold microbeads, a single extended area of adhesive under the LED 14 ensures the adhesion of the LED to the substrate and electrical conductivity only along the axis orthogonal to the lower surface 8 of the glass 6 between the LED's power contacts 24 and the transparent conductive areas 22a, 22b. Note that in the figures, the power contacts 24 are drawn schematically as a continuous line, so that they are clearly visible and easily identifiable, whereas they are located under the LED substrate and are therefore hidden by this substrate in the bottom views of the various figures shown in plan view.
[0015] In the case of eutectic soldering, or low-melting-point alloy soldering, the LED's power contacts 24 are first coated with an alloy layer, such as Au / Sn, and the relevant areas of the conductive layer (substrate) are coated with a metallic layer, such as gold (Au). During the soldering process, the LED contacts are rubbed and heated against the substrate, causing the contact surface to melt. After cooling, the LED is firmly soldered to the substrate, forming a good contact with low electrical resistance. This process results in lower contact resistance and better adhesion compared to conductive adhesives, but requires more extensive preparation of both the LED contact surfaces and the substrate.
[0016] To the Figure 2The two peripheral contact areas 20a and 20b extend radially from the two conductive areas 22a and 22b. They are made of the same transparent conductive material as the conductive areas, by structuring the conductive layer 16, and they are also separated from each other by the gap 26. In fact, nothing distinguishes the two peripheral contact areas from the two conductive areas except that the peripheral contact areas are located, in axial superposition, outside the useful region 9 of the glass 6, outside the opening 9a in the plane of the glass, and run along the periphery 7 of the glass, so that the electrical connection 36 between the power supply circuit 34 and the peripheral contact areas 20a and 20b is not visible to a user of the watch 2.
[0017] It will be noted that, although the conductive areas in ITO or IZO are transparent, they exhibit a slight coloration and modify the reflection of light on the lower surface 8 of the glass 6, particularly in sapphire, relative to a portion of this lower surface that does not have such a conductive layer, so that the human eye can distinguish an area of the glass 6 having a portion of this conductive layer from a portion that does not. Furthermore, there is a slight difference in height at the edge of each conductive area, which creates fine lines visible to a watch wearer. According to the invention, generally, the gap 26 is provided with a width such that this gap is advantageously almost imperceptible, or preferably imperceptible, at approximately 30 cm, in typical ambient light, to a watch wearer with normal vision.One advantage of having larger contact areas is that it allows for a thinner conductive layer than in the case of conductive tracks, which are by definition narrow, while maintaining good electrical conductivity, even better than in such conductive tracks. A thinner conductive layer for the contact areas means better transparency and also less visibility of the edges of the conductive areas.
[0018] By 'gap', we mean a narrow space or gap between two material areas, separating them. To minimize the contrast between the conductive areas and the substrate, namely glass 6, the gap 26 (in other words, the space / gap) between the two conductive areas is preferably as thin as possible while still ensuring electrical insulation between them. For example, by structuring an ITO layer using photolithography, a very narrow gap, on the order of 10 µm, can be obtained between the two conductive areas.
[0019] In general, the gap width is less than two hundred micrometers (200 µm). In an advantageous variant, this width is less than one hundred micrometers (100 µm). In a preferred variant, this width is less than fifty micrometers (50 µm).
[0020] The transparent conductive areas 22a, 22b are connected to the electrical power supply circuit 34 by at least one connector. In the variant of the Figure 2 A cylindrical spring-loaded connector 36 is shown, which allows a single transparent conductive area to be connected to the power supply circuit. Thus, two connectors 36 are provided in the first variant, one for each of the two transparent conductive areas. In an alternative variant, the electrical connection is made by an anisotropic elastomer conductor (Zebra®) arranged in one of the two peripheral areas traversed by the gap 26. To ensure that the electrical connection means between the power supply circuit 34 and the peripheral contact areas 20a and 20b are not visible to a watch user, the connectors 36 are arranged behind a flange 38 defining the watch display area 2.
[0021] To Figures 3A and 3BA second and a third variant are shown. In these two variants, the light-emitting unit 14a consists of three LEDs arranged on a single support, each with a common anode or cathode and an individual cathode or anode, so that the light-emitting unit 14a has four power supply contacts 24. This light-emitting unit 14a is designed to provide white light by means of three LEDs (mini LEDs), producing red, green, and blue light respectively. In another variant, two LEDs are provided, one emitting blue light and the other yellow light. By independently powering the three LEDs, it is possible to adjust the color of the lighting as required to obtain a specific white light.
[0022] To the Figure 3AUnit 14a is powered from four peripheral contact areas 20c to 20f located at the edge of the crystal 6, via four conductive areas 22c to 22f made of transparent conductive material, covering the entire usable area 9 of the crystal within the watch, except for four gaps 26b to 26d that separate the conductive areas in pairs, i.e., each gap separating two adjacent conductive areas. Again, each gap has a width such that it is virtually imperceptible, and preferably imperceptible, at a distance of approximately 30 cm in typical ambient light for a wearer of the watch. The various advantageous width ranges given previously also apply to all other variants. In this second variant, each transparent conductive area extends approximately over a quarter of the lower surface of the glass, this variant being favorable when only one of the LEDs is activated at a given time.We therefore have four identical conductive areas 22c to 22f. The peripheral contact areas 20c to 20f, extending from the conductive areas, are distributed along the perimeter of the glass. This results in a certain drawback for the means of electrical connection to the power supply circuit, which must be located along the edge of the glass over an angular distance greater than 180°, and therefore for the electrical connection to the power supply circuit. In particular, four cylindrical spring-loaded connectors 36 can be provided, distributed along the edge of the glass or arranged in pairs on both sides of a gap, or two diametrically opposed anisotropic elastomer conductors can be used, each covering a gap, namely gaps 26a and 26c or gaps 26b and 26d.
[0023] The third variant, represented at the Figure 3BThis resolves the drawback of the second variant mentioned above. The peripheral contact areas 30a to 30d of the conductive areas 22g to 22j are arranged side by side in a single localized connection sector 29, which here extends over less than one-eighth of the circumference 7 of the glass, with the peripheral contact areas arranged in a line. In a general variant, the connection sector extends over less than one-eighth of the circumference 7. To achieve homogeneity of emitted light between the LEDs and maximum overall power, the structuring pattern of the conductive layer 16 is designed so that the individual electrodes / conductive areas, each electrically connected to a single power supply contact 24 specific to a single LED, each exhibit substantially the same electrical resistance between the power supply contacts and their respective peripheral contact areas. Figure 3BThe individual conductive areas are designated 22h to 22j. The common conductive area 22g, connected to a power supply contact 24 of the light-emitting unit 14a common to the three LEDs, is configured to exhibit lower electrical resistance than the individual conductive areas, each associated with a single LED. In the second variant, as shown in the Figure 3A , all the conductive areas are similar and have the same electrical resistance. It should be noted that in the second variant, it is also possible for the common conductive area to have a lower electrical resistance, for example by structuring the conductive layer 16 so that the common conductive area extends over a greater angular distance, in particular 150°, and the three individual conductive areas then extend over the same smaller angular distance, namely 70°.
[0024] The light source, although designed to emit light towards the dial, also emits some of it outwards, which can be unsightly and dazzle the watch wearer. This upward beam is generally more intense than the light reflected by the dial and impairs the display's readability. One solution is to add an opaque, and possibly reflective, shield between the outer surface of the glass and the light-emitting unit, specifically the LED.
[0025] To block the light emitted by the LED towards the user using a cover, several configurations are possible. Advantageously, the cover is made on the lower surface 8 of the glass, either directly on this lower surface or between the transparent conductive layer 16 and the LED. In the latter case, the cover must ensure both the desired optical opacity and the electrical conductivity to power the LED. Two possible embodiments are as follows: The cover is made from a structured black resin containing openings filled with a conductive material to establish electrical contact between the transparent electrodes and the power supply contacts of the light-emitting unit. The cover is made from an opaque, anisotropic, conductive adhesive used for fixing and electrically connecting the light-emitting unit; this adhesive may contain, for example, conductive metal beads embedded in a resin made optically opaque by the addition of non-conductive absorbent pigments.
[0026] A second embodiment will be described later with reference to Figures 4 to 6 Elements similar to the first embodiment and references already described will not be described again in detail here. Figures 5 And 6show respectively a plan view of a first variant and a second variant of a part of the lighting device, according to the second embodiment of the invention, which is arranged under the glass of the watch.
[0027] This second embodiment differs from the first embodiment primarily in two particular characteristics. First, several light-emitting units 14b, spaced apart, are arranged under the glass 6 in the useful region 9 defined by the opening 9a of the bezel 4b of the case 4. Second, the light-emitting units 14b are arranged on a transparent substrate 44, which is separate from the watch glass and bonded beneath it by a layer of transparent adhesive 50. Advantageously, OLED technology is used to fabricate the light-emitting units / light sources 14b, each of which has a micrometer-sized emitting surface, imperceptible to the naked eye at a distance of approximately 30 cm. Preferably, each OLED 14b has a planar surface area substantially equal to or less than 100 x 100 µm². The transparent substrate 44 can be made of glass, sapphire, PC, PMMA, or other transparent polymers.It should be noted that, in another variant, the light sources are placed under the transparent substrate 44, on the side of the analog display 12.
[0028] Unlike LEDs, which are generally fabricated in a preliminary step and then brought and fixed onto the glass 6 or onto the additional transparent substrate 44 (the envisaged variant), OLEDs are fabricated directly onto the lower surface 8 of the glass 6 (the envisaged variant) or onto the additional transparent substrate 44, which covers the entire useful region 9 of the glass, as shown in the Figure 4In the case of OLEDs, the light-emitting surfaces are obtained by structuring functional layers that define each OLED (anode, organic layers, cathode). In a first step, the transparent conductive areas 22g (common conductive area) and 22h to 22k (individual conductive areas) in the first variant, and respectively 22p (common conductive area) and 22n (individual conductive areas) in the second variant, are deposited on the transparent substrate 44. In a second step, the anodes of the OLEDs 14b are made on the respective contact areas of the individual conductive areas 22h to 22k. In a third step, the organic layers are deposited on the anodes, and in a fourth step, the cathodes are deposited on the organic layers, with a portion of each extending beyond the respective organic layers and covering a contact area of the common conductive area 22g.Finally, a protective layer, for example made of glass, covers the OLEDs in the conventional way.
[0029] According to the invention, as in the first embodiment, the electroluminescent units 14b are powered from peripheral contact areas 30a to 30e in the first variant, and 30a and 30n respectively in the second variant, via conductive areas 22g to 22k, and 22p and 22n respectively, which are made of transparent conductive material on the transparent substrate 44. The peripheral contact areas 30a to 30e, and 30a and 30n respectively, are arranged side by side, preferably in a line, within the same connection sector 29 located at the edge of the transparent substrate 44, outside the useful region of the glass 6 in axial projection, and situated within a restricted angular sector. The conductive areas cover at least the entire lower portion of the useful region 9 of the glass 6, with the exception of gaps 28 separating these conductive areas.Each gap separates two adjacent conductive areas and has a width such that this gap 28 is imperceptible, in ordinary ambient light, to a watch user observing the display. The advantageous range of values and the preferred range of values indicated previously for the gap widths also apply to the second embodiment.
[0030] Preferably, to achieve homogeneous light distribution between the light sources, namely the OLEDs 14b, and maximum overall light output, the transparent conductive areas within the conductive layer 16, which covers the transparent substrate 44, are structured to obtain low electrical resistances, which are substantially equal for the individual conductive areas, between the peripheral contact zones and the respective power supply contacts of the OLEDs 14b. This is made possible by the fact that the transparent conductive areas extend globally at least over the entire surface defined by the useful region 9 of the glass 6, with the exception of the gaps 28.Furthermore, as already mentioned, this advantageous feature makes the presence of the conductive electrodes extending opposite the lower surface 8 of the lens invisible, at least in axial projection within the useful region 9, since the gaps are very fine and almost imperceptible, preferably completely imperceptible to the naked eye. This makes the lighting device according to the invention very discreet. It should be noted that the term 'useful region of the lens' refers to a cylindrical space with an axial orientation and an outer perimeter defined by the opening 9a of the lens 4b in the box 4.
[0031] The common conductive area 22g, respectively 22p, connected to a plurality of respective power contacts of the OLEDs, is configured to exhibit less electrical resistance than the individual conductive areas 22h to 22k, respectively 22n between these power contacts and the peripheral contact area 30a, because this common conductive area carries a higher electrical current since it collects several electrical currents from the individual conductive areas.
[0032] The cathodes are preferably made of an opaque material that prevents the OLEDs from emitting axially through the glass 6. The cathodes are advantageously reflective. It is important that each cathode covers a very small area of the common conductive surface beyond the organic layers, so as not to be visible. To minimize the size of the cathodes, the contact areas of the common conductive surface 22g are located as close as possible to the light-emitting areas of the OLEDs, at the periphery of the light-generating organic layers. As in the first embodiment, it is possible to also provide an opaque and possibly reflective cover over each OLED; these covers are, for example, placed on the lower surface 8 of the glass, opposite the OLEDs.When assembling the glass 6 with the transparent substrate 44 using glue 50, care will be taken to align the quasi-point covers with the OLEDs, or alternatively with the LEDs in another embodiment using LEDs instead of OLEDs.
[0033] The electrical connection between the peripheral contact areas, aligned one after the other preferably along a straight line, and the electrical supply circuit 34 is made by a flexible printed circuit 48.
[0034] In the first variant ( Figure 5), the lighting device comprises four light sources 14b (light-emitting units, each consisting of a single OLED or LED) arranged at regular angular intervals, with two adjacent light sources having an angular distance of 90° between them. The common conductive area 22g occupies a central zone of the transparent substrate 44 and a bonding zone from this central zone to the peripheral contact zone 30a, while the individual conductive areas extend around the central zone. In the second variant ( Figure 6The lighting device comprises twelve light sources 14b, each light source being positioned above a different number indicating the hours one to twelve on the dial. The common conductive area 22p occupies a peripheral zone of the transparent substrate 44 and a substantially diametrical inner zone, while the individual conductive areas 22n fan out from the contact zones 30n. In this second variant, having a relatively large number of separate light sources 14b, the transparent substrate 44 includes an external projecting portion 45 on which the connection sector 29 is located.
[0035] The lighting device according to the invention can also be used as a 'frontlight' system in the case of a watch with a purely reflective digital display (also called an 'electronic display'), thus allowing the information to be read even in low light conditions. This type of digital / electronic display in a watch, particularly a very low-power LCD display, provides better contrast and readability during the day compared to a similar digital display equipped with a backlight system. In the latter case, the digital display must be transflective to allow backlight to reach the viewer, and therefore offers lower optical quality during the day.The present invention is particularly suitable for a digital display surmounted by a structure, in particular a decorative one, defining various display areas with a lighting device having several LEDs or OLEDs distributed in front of these display areas to illuminate these areas locally, simultaneously or selectively.
Claims
1. Watch (2, 42) comprising a display (12), a glass (6) arranged above the display and having a useful region (9), through which a user of the watch can see the display, and a lighting device comprising at least one electroluminescent unit (14, 14a, 14b) arranged below the glass and above the display, this electroluminescent unit being formed by at least one light source, in particular of the LED or OLED type; characterized in thatsaid at least one electroluminescent unit is supplied with electricity from peripheral contact areas (20a, 20b; 20c to 20f; 30a to 30d; 30a to 30e; 30a, 30n) located axially superimposed outside the useful region, via conductive areas (22a, 22b; 22c to 22f; 22g to 22j; 22g to 22k; 22p, 22n), made of transparent conductive material, which cover at least the entire lower portion of the useful region of the glass except for a gap (26) separating the two conductive areas (22a, 22b), in the case of a single electroluminescent unit (14) having only two power supply contacts, or gaps (26a to 26d; 28) separating said conductive areas, in the case of an electroluminescent unit (14a) having at least three power supply contacts or a plurality of electroluminescent units (14b); and in thateach gap (26; 26a to 26d; 28) separates two adjacent conductive areas and has a width that is less than or substantially equal to two hundred micrometers (200 µm).
2. Watch according to claim 1, characterized in that said width is less than one hundred micrometers (100 µm).
3. Watch according to claim 1, characterized in that said width is less than fifty micrometers (50 µm).
4. Watch according to any one of claims 1 to 3, characterized in that , in the said case of a single electroluminescent unit (14) having only two supply contacts, the two conductive areas (22a, 22b) each extend over almost half of the useful region (9) of the glass.
5. Watch according to any one of claims 1 to 3, characterized in that, in the case of an electroluminescent unit (14a) having at least three supply contacts or a plurality of electroluminescent units (14b), individual conductive areas (22d to 22f; 22h to 22j; 22h to 22k) among said conductive areas are configured so that each exhibits substantially the same electrical resistance between said respective peripheral contact areas (20d to 20f; 30b to 30d; 30b to 30e; 30n) and the respective supply contacts of the electroluminescent unit or plurality of electroluminescent units, the individual conductive areas being electrically connected each to a single supply contact associated with a single light source.
6. Watch according to claim 5, characterized in thata common conductive area (22c; 22g; 22p) is configured to exhibit less electrical resistance than said individual conductive areas, the common conductive area being connected to a plurality of said supply contacts and / or being associated with a plurality of light sources (14b) connected to the same supply contact.
7. Watch according to claim 5 or 6, characterized in that The peripheral contact areas are distributed along the perimeter of the lens.
8. Watch according to claim 5 or 6, characterized in that the peripheral contact areas are arranged in a single connection sector (29) which extends over less than a quarter of the perimeter (7), preferably over less than an eighth of the perimeter with the peripheral contact areas arranged in a line.
9. Watch according to any one of the preceding claims, characterized in thatsaid conductive areas are formed by a structured conductive layer (16) which is deposited on the lower surface (8) of the glass (6); and in that said at least one electroluminescent unit (14, 14a) is fixed to said conductive plates.
10. Watch according to any one of claims 1 to 8, characterized in that said conductive areas are formed by a structured conductive layer (16) which is deposited on the upper surface of a transparent substrate (44), said at least one electroluminescent unit (14b) being attached to said conductive areas; and in that the transparent substrate is glued against the lower surface (8) of the glass (6) and encloses said at least one electroluminescent unit.