Method for manufacturing a luminous needle

Abstract

The present invention relates to a method (500) for manufacturing at least one luminous hand (100) for a timepiece movement, preferably for a wristwatch. The manufacturing method (500) comprises at least the steps (510) of providing at least one support (110) with at least one light guide (150) and structuring (560) at least one exit surface (190) of the at least one light guide (150) to extract a maximum amount of light (910) from the at least one luminous hand (100). The at least one luminous hand (100) comprises at least one luminous material layer (130) on its underside, which comprises one or more phosphor layers opposite a light source (900). The light source (900) is mounted, for example, close to the axis of rotation or further away from the axis of rotation, but at a distance from the at least one luminous material layer (130). Therefore, unlike the prior art, the light source (900) is not located on the at least one light-emitting needle (100).

Description

[Technical field]

[0001] The present invention relates to the field of luminous needles, and more particularly to the manufacture of luminous needles. [Background technology]

[0002] There are several methods for making hands for a clock movement.

[0003] Nevertheless, these methods are not suitable for producing luminous needles, since they too often return only a small amount of light or concentrate most of the light at a single point, which is not necessarily the effect desired by the applicant.

[0004] In fact, some manufacturing methods result in low brightness of the needle because the light is only extracted from one side of the needle or is reflected internally. Summary of the Invention

[0005] The present invention aims to overcome all or part of the aforementioned drawbacks by virtue of a method for manufacturing at least one luminous hand for a timepiece movement, preferably for a wristwatch, said manufacturing method comprising at least one: providing at least one support, the at least one support comprising at least one light guide, the at least one light guide comprising at least one exit surface and configured to guide light; and structuring the at least one exit surface.

[0006] Thanks to this configuration it is possible to produce luminous hands for clock movements with light distribution.

[0007] According to one embodiment, the at least one structuring is performed by grinding, by ablation, by sandblasting, by stamping and / or Building with Light It is performed by.

[0008] Thanks to this configuration it is possible to distribute the light by multiplying said at least one exit surface.

[0009] According to one embodiment, the at least one preparation of the at least one support comprises deposition of at least one first optical material layer, the at least one first optical material layer having a first refractive index.

[0010] According to one embodiment, the deposition of the at least one first optical material layer includes a heat treatment step.

[0011] Thanks to any of these aforementioned configurations it is possible to manufacture luminous needles with a reflective layer.

[0012] According to one embodiment, said at least one preparation of at least one support comprises at least one deposition of at least one luminescent material layer.

[0013] Thanks to this configuration it is possible to produce a luminous needle.

[0014] According to one embodiment, the at least one preparation of the at least one support comprises deposition of at least one layer of a second optical material, the at least one layer of the second optical material having a second refractive index.

[0015] According to one embodiment, the first refractive index is lower than the second refractive index.

[0016] Thanks to this configuration it is possible to refract light towards said at least one exit surface.

[0017] The present invention comprises at least one a support, the at least one support being configured to form a needle; It is an object of the present invention to solve all or part of the aforementioned drawbacks by at least one light emitting needle comprising a light guide, the at least one light guide having at least one exit surface that is roughly configured for extracting light from the at least one light guide.

[0018] Thanks to this configuration it is possible to have at least one light emitting needle capable of extracting maximum light from said at least one exit surface.

[0019] According to one embodiment, the at least one light guide comprises at least one first layer of optical material having a first refractive index and at least one second layer of optical material having a second refractive index, the first refractive index being lower than the second refractive index.

[0020] Thanks to this configuration it is possible to direct light towards said at least one exit surface.

[0021] The invention is explained in more detail below using the accompanying drawings, given as a in no way limiting example, in which: [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 illustrates the deposition 520 of at least one layer of a first optical material 120 after the provision 510 of at least one support 110, according to one embodiment. [Diagram 2] FIG. 2 illustrates the heat treatment step 525 according to one embodiment. [Diagram 3] FIG. 3 illustrates the deposition 530 of at least one luminescent material layer 130 according to one embodiment. [Figure 4] FIG. 4 illustrates the deposition 540 of at least one layer of second optical material 140 according to one embodiment. [Diagram 5] FIG. 5 illustrates the formation 550 of at least one layer of second optical material 140 according to one embodiment. [Figure 6] FIG. 6 is a diagram illustrating step 560 of constructing the at least one exit face 190 according to one embodiment. [Figure 7] FIG. 7 is a diagram illustrating the notch 570 of at least one light emitting needle 100. [Figure 8] FIG. 8 illustrates the at least one light emitting needle 100 in operation according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] There are several types of luminous needles on the market. Nevertheless, the applicant proposes a new generation of luminous needles.

[0024] Indeed, the applicant proposes at least one luminous needle 100, as seen in FIG. 8, comprising at least one support 110 configured to form a needle and at least one light guide 150 having at least one exit surface 190 roughly configured to extract light 910 from the at least one light guide 150.

[0025] Said at least one luminous hand 100, intended to be used in a timepiece movement, preferably for a wristwatch, can be obtained thanks to the Applicant's manufacturing method 500. To this end, said manufacturing method comprises at least one preparation 510 of at least one support 110, preferably a metal plate 110, as shown in FIG.

[0026] The at least one support 110 receives during deposition 520 at least one first optical material layer 120, preferably at least one optical insulating layer having a first refractive index, and then undergoes a heat treatment 525 at a determined temperature 521, making it possible to prevent light from being absorbed by the metal plate 110. Before the deposition 520 of the at least one first optical material layer 120, the metal plate 110 or the at least one support 110 can be cleaned or, after cleaning, a plasma treatment can be applied to promote adhesion of the at least one first optical material layer 120. In this case, the at least one first optical material layer 120 can be, for example, a POLYRISE TM The first refractive index may be a resin commercialized by the company Sigma, the purpose of which is to optically isolate the surface of the at least one support 110 and thus to absorb as little light as possible, said optical isolation being possible thanks to said first refractive index not exceeding 1.60, in particular 1.45, preferably 1.35.

[0027] The at least one first optical material layer 120 can be deposited, for example, by printing or spraying, since spraying allows the at least one first optical material layer 120 to be selectively deposited on useful parts, avoiding waste.

[0028] As previously mentioned, the at least one first optical material layer 120 is subjected to the heat treatment 525, for example at 300° C. for 1 hour under nitrogen, to allow the solvent in the at least one first optical material layer 120 to evaporate, which can be seen in FIG. 2.

[0029] As shown in Fig. 3, at least one deposition 530 of at least one luminescent material layer 130 can be carried out on said at least one support 110, preferably on said at least one first optical material layer 120. said at least one luminescent material layer 130 preferably comprises a fluorescent pigment and an adhesive allowing attachment by polymerization and is intended to illuminate said at least one luminescent needle 100 when said at least one luminescent material layer 130 is illuminated by a light source having, for example, a wavelength range below 530 nm.

[0030] Indeed, fluorescent pigments may be the source of secondary fluorescence. In a watch, the fluorescent pigments may be excited remotely, for example by a source of blue or ultraviolet light. It is noted that other techniques, such as screen printing or digital printing, may be used for the at least one deposition 530 of the at least one luminescent material layer 130.

[0031] Then, for example, MICRORESIST TECHNOLOGY TM A UV plasma treatment for several minutes is performed to promote adhesion of at least one layer of second optical material 140 of ORMOCLEAR® 10 resin type from Ormoclear, Inc., which is performed by rod coating or, for example, by doctor blade type deposition 540, which can also be referred to as spread coating, as shown in FIG. 4.

[0032] As further shown with reference to FIG. 4, it can be observed that the at least one layer of second optical material 140 can be pushed by the blade to fill any various cavities that may be present.

[0033] It should be noted that the at least one second optical material layer 140 has a second refractive index greater than the first refractive index to guide the fluorescent light emitted by the at least one luminescent material layer 130.

[0034] 5, the at least one second optical material layer 140 may be fixed by irradiation with ultraviolet light 552 under vacuum 551. Alternatively, it may be possible to laminate a plastic film to expel air prior to irradiation under ultraviolet light.

[0035] Indeed, the underside of the at least one second optical material layer 140 comprises one or more deposits of phosphor material opposite the light source 900 in order to establish optical contact with the at least one luminescent material layer 130, which, as mentioned above, can be formed of a fluorescent pigment contained in an adhesive, or the phosphor material can be embedded in a light guiding layer.

[0036] In operation, the light source 900 illuminates the at least one luminescent material layer 130 with light having a shorter wavelength than that re-emitted by the at least one luminescent material layer 130. The at least one luminescent material layer 130 absorbs and re-emits 910 this incident light, particularly in the at least one second optical material layer 140. The presence of the at least one first optical material layer 120 allows total internal reflection of the fluorescent light propagating in the at least one second optical material layer 140, thus avoiding gradual absorption in the at least one support 110.

[0037] The difference in refractive index between the at least one support 110 and the at least one second optical material layer 140 is comprised within the range of 0.5 to 0.9, preferably 0.55 to 0.8, more preferably 0.6 to 0.75, making it possible to increase the value of the critical angle and therefore the numerical aperture of the at least one second optical material layer 140 in order to maximize the coupling of the fluorescent light. It should be noted that the presence of the at least one first optical material layer 120 allows a lossless transmission in the at least one second optical material layer 140 once the light has been coupled in, and that the refractive index of the at least one first optical material layer 120 influences the amount of light that is coupled in. The at least one first optical material layer 120 can have a thickness within the range of 2 μm to 15 μm, preferably 3 μm to 12 μm, even more preferably 5 μm to 10 μm. Multiple total internal reflections in the at least one second optical material layer 140 continue until the light beam reaches one end of the at least one light emitting needle 100, where it is transmitted outward.

[0038] Finally, a step 560 of structuring said at least one exit surface 190, as shown diagrammatically in FIG. 6, may be carried out by polishing 565, by ablation 565, by sandblasting 565, by stamping 565 and / or by structuring said at least one exit surface 190 in order to increase, for example, the total or partial escaping light 910, which is re-refracted so that a large proportion of the light is concentrated at one point. Building with Light 565. Indeed, a surface structure may be provided for the material of the at least one second optical material layer 140, i.e. on the at least one exit surface 190 of the at least one second optical material layer 140, which may be locally peeled off to induce roughness, thereby facilitating the extraction of light 910 from second optical material layer 140.

[0039] In addition, a light diffusing area, which can be made by deposition of resin, is added to the at least one luminous needle 100, which extends beyond the at least one support 110, i.e. protrudes from the at least one support 110, in order to facilitate leakage of the light flux and to obtain a decorative pattern at the tip. According to an embodiment not shown, not only the tip of the at least one luminous needle 100 but also the edge and possibly also the head of the at least one luminous needle 100 constitute the at least one exit surface 190.

[0040] The step 570 of cutting the at least one light emitting needle 100 is preferably performed, for example, by a laser 571, because the laser 571 can melt the at least one light guide 150, which is composed of the at least one first optical material layer 120 and the at least one second optical material layer 140, and generate the polished surface state of FIG.

[0041] In the example of Fig. 8, the at least one exit surface 190 corresponds to the circumferential surface of the at least one light-emitting needle 100 in order to illuminate the contour of the at least one light-emitting needle 100. Indeed, when the at least one light-emitting material layer 130 is exposed to the light source 900 having a wavelength comprised between 330 nm and 560 nm, the at least one light-emitting material layer 130 generates the light 910 that is extracted through the at least one exit surface 190 of the at least one light guide 150. Of course, it is also possible to place the light source LED in a location suitable for the product under consideration, for example near or away from the axis of rotation, and to add an optical coupler that allows the light flux of the light source 900 to be moved to a suitable location to excite the fluorescent material of the at least one light-emitting needle 100. Thus, unlike the prior art, the light source 900 is not placed on the at least one light-emitting needle 100.

Claims

1. A method (500) for manufacturing at least one luminous hand (100) for a timepiece movement, said method (500) comprising: Providing (510) at least one support (110) for supporting said light emitting needle (100); forming, on the at least one support (110), a light guide (150) having at least one exit surface (190) and configured to guide light (910), the forming step comprising the following sub-steps: Deposition (520) of at least one first optical material layer (120) on the support (110), the first optical material layer (120) having a first refractive index and capable of preventing the light from being absorbed by the support (110); depositing (530) at least one layer of luminescent material (130) on the at least one layer of first optical material (120); depositing (540) at least one layer of a second optical material (140), the at least one layer of the second optical material (140) having a second refractive index; and structuring (560) at least one exit surface (190) such that the exit surface (190) is roughened to extract the light (910) from the at least one light guide (150).

2. 2. The manufacturing method (500) of claim 1, wherein at least one of said structuring (560) is performed by polishing (565), by ablation (565), by sandblasting (565), by stamping (565) and / or by photostructuring (565).

3. 10. The method (500) of claim 1, wherein the depositing (520) of at least one of the first optical material layers (120) includes a heat treatment step (525).

4. The method (500) of any one of claims 1 to 3, wherein at least one of the deposits (530) of at least one of the luminescent material layers (130) comprises a luminescent pigment (130).

5. The method of claim 1 , wherein the first refractive index is lower than the second refractive index.

6. A luminous hand (100) for a clock movement, comprising: A support (110) for supporting the luminous needle; A light guide (150), wherein at least one of the light guides (150) comprises at least a first optical material layer (120) having a first refractive index and capable of preventing light from being absorbed by the support (110); a layer of luminescent material (130) on at least one of the first optical material layers (120); and a second optical material layer (140) having a second refractive index and having an exit surface (190) that is configured to be rough for extracting the light (910) from at least one of the light guides (150).

7. The luminous needle (100) of claim 6, wherein the first refractive index is lower than the second refractive index.

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