CH716226B1 - WATCHMAKING PART EQUIPPED WITH A LIGHTING DEVICE INCLUDING AN ULTRAVIOLET LIGHT-LUMINESCENT DIODE. - Google Patents

Abstract

The invention relates to a timepiece provided with a crystal (3) having an inner face and an outer face to the timepiece and a lighting device (4) comprising at least one ultraviolet light-emitting diode for illuminate at least one area (9) incorporating fluorescent and / or phosphorescent pigments of an indicator element (7) visible through the lens, characterized in that said light-emitting diode is arranged on the periphery of the lens forming a guide d wave capable of diffusing ultraviolet light and in that means (12; 13; 15) for diffusing the ultraviolet light from the glass towards the interior of the timepiece are arranged on the path of the ultraviolet light.

Description

TECHNICAL AREA

[0001] The present invention relates, in general, to a timepiece such as a wristwatch provided with a lighting device for illuminating an indicator element such as hands and / or indices. The invention relates more particularly to a lighting device comprising at least one ultraviolet or blue light-emitting diode for illuminating at least one area incorporating fluorescent and / or phosphorescent pigments of the indicator element to enhance the visibility of the latter in a dark environment. The term “ultraviolet or blue light-emitting diode” is understood to mean a diode whose light emission spectrum covers in particular the wavelengths of ultraviolet or blue light, such a diode also being able to emit in the visible range.

TECHNOLOGICAL BACKGROUND

It is already known in the prior art, watches whose dial and hands are illuminated by means of an ultraviolet light source. Various areas of the dial and of the hands are formed or covered by a substance reacting to ultraviolet light and reflecting the latter in visible light through the glass, thus making it possible to visualize said areas in a dark environment.

[0003] For example, document WO 2004/034153 describes a watch comprising a light emitting diode or LED (in English: light emitting diode) emitting light in the ultraviolet (UV) spectrum and arranged on the inner periphery of the box. watch, between the dial and the watch crystal. This LED is fixed in a groove by a transparent resin which allows ultraviolet rays to pass. By reacting with ultraviolet rays, a so-called “luminous” material mixed with the transparent resin emits visible light. The dial and hands, also provided with this “luminous” material, are illuminated by the LED with both UV and visible light, thus making it easier to read the time in a dark environment.

[0004] This type of watch which combines an ultraviolet light source with a luminous material requires an input of energy, for example in the form of electrical energy with a battery. The energy transformed by the LED into ultraviolet light will be largely dispersed, with part of the ultraviolet rays escaping through the watch crystal in the direction of the user's eyes, which presents a risk for the latter. In addition, the respective surface of the hands and the indices of the dial being relatively small, only a limited amount of ultraviolet light will be transformed into visible light by the “luminous” material, which in terms of efficiency and illumination is not satisfactory.

[0005] Document JP 2003-248445 describes a watch provided with an ultraviolet light source associated with a waveguide present under the dial of the watch. The latter is pierced with holes filled or not with a luminescent material which reacts to ultraviolet rays so as to emit visible light, but which can also allow ultraviolet light to pass through the dial. Such a solution requires the use of a particular dial specifically dedicated to this application, superimposed on the waveguide, which presents a drawback both in terms of the mounting method, which must be adapted, and in terms of the resulting thickness. of the timepiece which is then significantly larger.

[0006] Moreover, although in this type of watch, the use of a waveguide makes it possible to reduce the losses somewhat by concentrating the ultraviolet light on the luminescent materials, the losses caused however remain significant, the ultraviolet light which has not been transformed into visible light also partly escaping through the glass of the watch towards the eyes of the user.

[0007] In all the cases mentioned above, the lighting devices include an LED which does not allow optimized time reading in a dark environment.

SUMMARY OF THE INVENTION

The main aim of the present invention is to overcome the aforementioned drawbacks by optimizing the visibility of the indicator elements in a dark environment while ensuring the simplicity, in terms of the dial, and the compactness, in terms of thickness, of the part. clockwork. For this purpose, provision is made to produce a timepiece according to independent claim 1, namely a timepiece such as a wristwatch using ice as a waveguide associated with means making it possible to optimize the diffusion of the ultraviolet light towards the interior of the timepiece while not requiring the use of a particular dial or additional waveguide.

[0009] Advantageous embodiments of the timepiece according to the invention are described in the context of the dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

[0010] Other characteristics and advantages of the present invention will emerge more clearly on reading the following detailed description of embodiments of the invention given solely by way of non-limiting example and illustrated by the appended drawings where: FIG. 1 represents the timepiece seen from above in an embodiment according to the present invention; FIG. 2 schematically represents the timepiece according to section A-B in several embodiments according to the present invention; FIG. 3 schematically represents the timepiece according to section A-B in other embodiments according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided only by way of example and refers to Figures 1 to 3, in particular Figures 2 and 3, in which are shown the main elements of the timepiece necessary for understanding of the realization of the latter according to the invention.

The timepiece 1 described here is a wristwatch comprising a watch case 2, a crystal 3 closing the latter and a lighting device 4a, 4b and 4c intended to illuminate the display means. The wristwatch 1 also includes other elements (not shown) necessary for its operation which we will not describe here, but which are well known to those skilled in the art. The display means generally comprise a dial 5 and indicator elements 6 arranged opposite or on the latter, such as hands 7 and indices 8. In the example shown, three hands 7 are present to respectively indicate the hours. , minutes and seconds, but it is of course possible to provide any predetermined number of hands 7 to cover the indicator functions of the wristwatch 1. These hands 7, visible through the crystal 3 of the wristwatch 1, comprise at least one zone 9 integrating fluorescent and / or phosphorescent pigments. Dial 5 is provided with indices 8 indicating the hours, minutes and seconds, for example in the form of numbers, letters or any other predetermined sign; a predetermined number of indices 8 possibly also comprising a zone 9 integrating fluorescent and / or phosphorescent pigments. In order to be able to read the time in a dark environment, the wristwatch 1 comprises at least one ultraviolet light-emitting diode 4a, or ultraviolet LED, preferably placed on the edge of the glass 3 then serving as a waveguide, as will be detailed in detail. further in conjunction with Figures 2 and 3. Alternatively according to another variant embodiment not shown, the ultraviolet LED could be placed on a printed circuit under the dial, the light then being conducted by means of an additional waveguide right down to the edge of the ice serving as a waveguide. According to another variant also not shown, the ultraviolet LED could be arranged at the periphery under the edge of the glass, the latter then being hemispherical, or at least having a very convex curvature.

The light-emitting diode makes it possible to illuminate with ultraviolet light, or UV light, the zones 9 integrating the fluorescent and / or phosphorescent pigments of the needles 7 and of the indices 8. In general, a manual or automatic control member 10 is intended to activate the ultraviolet LED 4a. The fluorescent and / or phosphorescent zones 9 of the needles 7 and of the indices 8 are preferably formed by a translucent resin mixed with fluorescent and / or phosphorescent pigments which react with UV light so as to emit visible light. The needles 7 and the indicia 8 can for example be covered with this fluorescent and / or phosphorescent resin, have hollowed-out regions filled with the latter or be made partially of it, in cooperation with a metallic or synthetic support material, or else also be made entirely of resin. This lighting device has the advantage of using a source of ultraviolet light, that is to say in the invisible domain, which gives a certain aesthetic effect, when the needles or other indicator elements.

Still with the aim of obtaining an aesthetic effect, provision may be made to partially cover the glass, preferably on its underside, with a 16 nanometric layer of fluorescent and / or phosphorescent pigments making it possible to remain invisible to light. of the day, due to its very low thickness, and to appear in the form for example of a logo or a hidden image or even hour indices when illuminated with ultraviolet light.

Consider now Figure 2, which is a view along section A-B of Figure 1, showing various embodiments of the present invention. The crystal 3 of the wristwatch 1 forms a waveguide which is able to diffuse the UV light downwards in a relatively homogeneous and uniform manner. The ultraviolet LED 4 is placed in a housing 11 provided in the watch case 2 opposite the edge of the glass 3 to emit the UV light essentially in the plane of the waveguide. Advantageously, there is provided, as shown in FIG. 1, three ultraviolet LEDs 4a, 4b, 4c arranged regularly on the periphery of the mirror, ie spaced at a substantially equal angle of 120 ° C, making it possible to obtain a even more homogeneous and uniform lighting.

In order to optimize the diffusion of the ultraviolet light from the glass 3 towards the inside of the watch, means for diffusing this ultraviolet light are provided. These diffusion means make it possible on the one hand to limit the emission of ultraviolet light towards the outside of the watch and consequently towards the eyes of the user and, on the other hand, to increase the desired luminous effect on the watch. the fluorescent and / or phosphorescent zones 9 arranged on the indicator elements 6, 7.

According to a first variant, it is planned to deposit a diffusing layer 12 on the inner surface of the ice 3, which has the advantage of being able to use a conventional glass while optimizing the diffusion of UV light from the ice. towards the inside of the watch. Examples of materials which can be used for such a diffusing layer are metal oxides, such as, for example, zinc oxide or titanium dioxide. This diffusing layer 12 is made invisible due to its submicron thickness, for example nanometric. The diffusion property is obtained either by controlling the density of this layer or by producing a semi-reflective screen consisting in producing a submicron gradient of dots with a variable density. The fluorescent and / or phosphorescent partial layer 16 mentioned in the context of FIG. 1, is preferably deposited between the inner face of the lens and the diffusing layer 12.

Still with the objective of diffusing the ultraviolet light from the crystal towards the inside of the watch, a second variant of the diffusion means consists in providing a reflective or diffusing / reflecting layer 13 deposited on the upper face of the crystal. Such a reflective layer is obtained by depositing a continuous and uniform layer, it is made invisible by its submicron thickness, for example nanometric. Alternatively, such a diffusing / reflecting layer is obtained by depositing a discontinuous layer, for example in the form of a frame. In this variant providing for a layer 13 deposited on the outer face of the lens, it is advantageously provided to deposit an additional protective layer 14 over this reflecting layer. This protective layer 14 is preferably made of a material of the sol-gel type providing on the one hand the necessary transparent effect and on the other hand the protective effect due to its hardness. This second variant has the advantage of having to apply additional layers only to the outside of the lens, therefore making it possible to obtain the desired effect without making the method of mounting the lens more complicated.

[0019] According to a third variant, the diffusion means provided consist in using a crystal 3 of convex shape optimized to direct the ultraviolet rays circulating through towards the inside of the watch and more particularly on the fluorescent and / or phosphorescent zones.

[0020] According to a fourth variant, the diffusion means provided consist in providing reflective zones 15 arranged on the edge of the glass 3 so as to keep all the ultraviolet light circulating in the glass forming a waveguide, thus avoiding any absorption on the edges of the ice. It is understood that these reflecting zones do not cover the edge of the ice at the level of the light-emitting diodes 4a, 4b, 4c arranged at its periphery. This fourth variant also has the advantage of simplicity in terms of the method of mounting the internal components of the watch.

Note that to optimize the lighting in dark environment as well as to prevent the emission of ultraviolet rays to the outside of the watch, on the one hand, while benefiting from the various advantages mentioned in connection with each of the four variants described above, on the other hand, all the combinations of diffusion means corresponding to the four variants are possible and even advantageously are all implemented in order to combine the effects thereof.

Still with the objective of strengthening the lighting of the fluorescent and / or phosphorescent areas 9 it can be provided to provide inside the wristwatch other of its constituents with layers or reflectors reflecting UV light. such as for example a flange 17 or a layer 18 reflecting UV light at least partially covering the upper face of the dial 5.

Consider now Figure 3, which is also a view in section AB of Figure 1. Figure 3 shows two other embodiments according to the present invention of means for diffusing ultraviolet light from the glass to the inside the watch. These variants, although presented for reasons of clarity separately from the first four variants presented in connection with FIG. 2, can quite well be combined together.

[0024] Thus, according to a fifth variant embodiment, the diffusion means consist in injecting a nano-powder 19 into the ice forming a waveguide. This nano-powder consists of submicron grains, for example nanometric grains, of metal oxide allowing the diffusion of ultraviolet light. To obtain a homogeneous diffusion, a higher grain density is provided in the areas far from the light-emitting diodes and less in the areas close to the diodes. This fifth variant has the advantage of requiring only a different step during the manufacture of the crystal itself, the watch assembly method remaining traditional.

[0025] According to a sixth variant embodiment, the diffusion means consist of microstructures and / or nanostructures 20 formed in the ice, preferably on the underside of the latter. These microstructures 20 are able to conduct UV rays downward from the crystal to the inside of the watch. These microstructures 20 can, depending on their geometric arrangement and their shape, direct the UV rays in the direction of the fluorescent and / or phosphorescent zones 9 concerned. Advantageously, these microstructures and / or nanostructures are arranged in annular form so as not to hinder the visibility of the indicator elements of the watch. It will be noted that their positioning on the underside of the crystal makes it possible to avoid their clogging, which would adversely affect the optical efficiency of the crystal and the aesthetic appearance of the watch.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the timepiece according to the invention described above without departing from the scope of the invention defined by the appended claims. It is also possible to provide for example a combination of certain characteristics of the different embodiments described above.

One can also provide a brightness detector associated with the control member of the ultraviolet LED, to engage the latter in a predetermined condition or to adjust the light intensity by modulating the intensity of the electric current.

In addition, it is also possible to consider the use of a light emitting diode emitting blue light, or blue LED, which allows by fluorescence and / or phosphorescence to emit green light, yellow, orange or red. In this embodiment, it is possible to at least partially cover the upper face of the glass of the timepiece with a layer reflecting blue light, which generally gives the crystal a smoky appearance in daylight. .

Claims (17)

1. Timepiece (1) provided with a crystal (3) having an inner face and an outer face to the timepiece and a lighting device (4) comprising at least one ultraviolet light-emitting diode or blue (4a, 4b, 4c) to illuminate at least one zone (9) incorporating fluorescent and / or phosphorescent pigments of an indicator element (6, 7) visible through the glass, characterized in that the ultraviolet light or blue emitted is directed on the periphery of the ice forming a waveguide capable of diffusing the ultraviolet light and in that means for diffusing the ultraviolet or blue light (12, 13, 15, 19, 20) from the glass towards the interior of the timepiece are arranged on the path of the ultraviolet or blue light. 2. Timepiece according to claim 1, characterized in that the means for diffusing ultraviolet or blue light comprise an invisible diffusing layer (12) deposited on the inner face of the crystal. 3. Timepiece according to claim 2, characterized in that said diffusing layer is composed of a nanometric coating of metal oxide of controlled density. 4. Timepiece according to claim 2, characterized in that said diffusing layer is composed of a nanometric coating of metallic oxide structured in a semi-reflecting frame. 5. Timepiece according to one of claims 2 to 4, characterized in that a submicron layer, for example nanometric, fluorescent and / or phosphorescent (16) is deposited between the inner face of the crystal and the diffusing layer ( 13) allowing a pattern to appear during lighting by the diode. 6. Timepiece according to one of claims 1 to 5, characterized in that the means for diffusing the ultraviolet or blue light comprise a nano-powder (19) incorporated in the crystal. 7. Timepiece according to one of claims 1 to 6, characterized in that the crystal diffuses the ultraviolet or blue light in a homogeneous and uniform manner towards the interior of the timepiece by means of microstructures (20) and / or nanostructures arranged on its inner face. 8. Timepiece according to claim 7, characterized in that said microstructures and / or nanostructures are arranged in the form of at least one ring so as not to hinder the visibility of the fluorescent and / or phosphorescent zones arranged at the inside the watch. 9. Timepiece according to one of claims 1 to 8, characterized in that the means for diffusing ultraviolet or blue light comprise a diffusing reflective coating disposed on the outer face of the crystal. 10. Timepiece according to claim 9, characterized in that the means for diffusing ultraviolet or blue light further comprise an invisible diffusing layer deposited between the outer face of the crystal and the diffusing reflective coating. 11. Timepiece according to claim 9 or 10, characterized in that a layer of sol-gel material (14) is deposited on the diffusing reflective coating to protect the latter. 12. Timepiece according to one of claims 6 to 11, characterized in that a submicron layer, for example nanometric, fluorescent and / or phosphorescent is deposited under the inner face of the crystal allowing a pattern to appear during lighting by the diode. 13. Timepiece according to one of claims 1 to 12, characterized in that the means for diffusing the ultraviolet or blue light comprise a reflective coating diffusing the ultraviolet or blue light on the edge of the crystal except of the zone where said at least one ultraviolet or blue light-emitting diode is arranged. 14. Timepiece according to one of the preceding claims, characterized in that it comprises a dial (5) whose upper face, facing the inner face of the crystal, is covered at least partially with a layer. reflecting ultraviolet or blue light (18). 15. Timepiece according to one of the preceding claims, characterized in that inside the timepiece a predetermined number of its constituents are provided with layers and / or reflectors reflecting ultraviolet or blue light. on indicator elements (6), one of said components advantageously being a flange (17). 16. Timepiece according to one of the preceding claims, characterized in that the crystal has a predetermined convex curvature so as to redirect the ultraviolet or blue light more particularly onto the indicator elements. 17. Timepiece according to one of the preceding claims, characterized in that said at least one light-emitting diode is directly arranged on the periphery of the crystal forming the waveguide.