Luminous display device for a timepiece, in particular a watch comprising means for improving the appearance of the timepiece

Abstract

To provide a light-emitting display device that avoids both a hot spot and direct view of a light source while enabling optimal dimensions and arrangement of components of the display device.SOLUTION: A display device (1) is provided with a dial (2) provided with a dial body (20) having a center hole and an upper surface (21), and needles (3, 4, 5) arranged above the dial and attached to a rotary arbor passing through the center hole of the dial body, wherein the needles are provided with layers (31, 41) forming a light guide body arranged to diffuse a light beam emitted by an illumination module (70) provided with an open partitioned space (10) bounded by a back surface (26) formed by a dial receiving base (7) and a peripheral wall (22) forming a shield formed integrally with the dial, the wall is positioned around the rotary arbor of the needle and extends above the dial body over a defined height, and the illumination module is provided with a light source (6) positioned on the back surface of the space and arranged to emit a light beam toward the needle in order to illuminate the needle from below.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the field of displays for timepieces, in particular wristwatches, and in particular to luminous displays for such timepieces.

[0002] The invention more particularly relates to a luminous display device for a timepiece, said device comprising a dial comprising a dial body provided with a central hole and having an upper surface, and at least one hand mounted on a rotating arbor arranged above the dial and passing through the central hole of the dial body, the hand comprising a layer forming a light guide arranged to transmit all or part of the light beam emitted by the light source, and at least one light source arranged to emit a light beam towards the hand to illuminate it from below, said light source being located below the upper surface of the dial. [Background technology]

[0003] Patent document 1 describes a luminous display device for a timepiece, which includes a luminous indicator hand that can rotate about a rotation axis and has a transparent light-guiding layer arranged to receive and transmit the light beam from a light source, a dial arranged below the indicator hand, and at least one fixed light source arranged to illuminate the hand from below. The fixed light source advantageously includes a plurality of LEDs arranged around the axis of the indicator hand.

[0004] The LEDs are positioned below the top surface of the dial to avoid or at least limit undesirable very strong luminous points (hot spots) when viewed directly. Placing the LEDs far away from the indicator hands has the disadvantage of affecting optical performance. Furthermore, in simple designs, i.e., where the display device has no additional optical elements between the LEDs and the indicator hands, and where the distance and dimensions are optimized to improve optical performance, the LEDs are visible to the user when the display device is viewed at an observation angle greater than approximately 30 degrees relative to the axis of rotation of the hands. Figure 1 shows a depiction of the minimum angle at which the LEDs are visible. In this figure, the symbols C, L, and A denote the dial, LED, and indicator hand, respectively, and the symbol α denotes the observation angle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent Application Publication No. 3845974 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to solve these problems by providing a light-emitting display device for a timepiece, in particular a watch, especially a wristwatch, which avoids both hot spots and direct viewing of the light source while allowing optimal sizing and placement of the display components.

[0007] Another object of the light emitting display device according to the present invention is to reduce light leakage.

[0008] Another object of the light emitting display device according to the present invention is to improve optical performance.

[0009] The luminescent display device according to the invention also aims to provide an improved visual appearance, both in terms of the optical and aesthetic appearance of a watch equipped with such a display device. [Means for solving the problem]

[0010] To this end, the invention provides a luminous display device adapted to be mounted on a watch case, the display comprising a dial comprising a dial body provided with a central hole and having an upper surface, and at least one hand attached to a rotating arbor arranged above the dial and passing through the central hole in the dial body, the hand comprising a layer forming a light guide arranged to diffuse all or part of the light beam emitted by an illumination module comprising an open partitioned space bounded by a back surface formed by a dial base and by a peripheral wall forming a shield formed integrally with the dial, the wall being arranged around the rotating arbor of the hands and extending above the dial body over a defined height, the illumination module comprising a light source located at the back surface of this space and arranged to emit a light beam towards the hands to illuminate them from below.

[0011] By "defined height" is meant a height sufficient to conceal the light source when the watch is viewed by a user from all viewing angles. The height is therefore determined according to the dimensions of the particular components of the watch (dial, hands, light source) and their relative positions. This height is also determined to provide sufficient clearance for air to circulate within the partitioned space to regulate the temperature within this space, which may vary due to the influence of heat generated by the light source. This height defines a gap known as the ventilation gap between the top 24 of wall 22 and the inner surface 25 of lower hand 4.

[0012] Thus, due to the presence of the peripheral wall defined above, the light source is hidden from view regardless of the viewing angle from which the watch is viewed, avoiding directly visible hot spots, thereby making it possible to provide a light-emitting display device with optimal dimensions and placement, without the drawbacks of prior art displays (hot spots, light leakage) and with optimal optical performance.

[0013] Advantageously, the rear surface of the partitioned space comprises a printed circuit board comprising the light source.

[0014] Advantageously, the light source comprises at least one electroluminescent diode and / or a compact laser light source, for example of the VCSEL type.

[0015] Advantageously, the light source comprises a plurality of electroluminescent diodes and / or miniature laser light sources mounted on a printed circuit board and arranged so as to be distributed around the periphery of the rotating arbor.

[0016] Advantageously, the peripheral wall is formed integrally with the dial body, in other words the peripheral wall and the dial form a single part.

[0017] Advantageously, the peripheral wall comprises an apex dimensioned to abut the lower needle.

[0018] Advantageously, the peripheral wall has an inner surface capable of reflecting the light beam emitted by the light source.

[0019] Advantageously, the peripheral wall is made of metal, polymer or ceramic.

[0020] Advantageously, the needle has a needle body comprising at least two layers, one of the layers being opaque and the other being a transparent layer forming a light guiding layer.

[0021] Advantageously, the light source comprises miniature laser light sources, for example of the VCSEL type and / or electroluminescent diodes, distributed around the periphery of the rotating arbor of the needle.

[0022] Advantageously, the light source is vertically aligned with the transparent lower layer forming the light guiding layer.

[0023] Advantageously, the partitioned space opens onto a flat or substantially flat portion of the lower needle.

[0024] Advantageously, the lower needle comprises a flat or substantially flat portion of its inner surface which completely conceals / covers the opening of the partitioned space.

[0025] Advantageously, the display device comprises a plurality of hands each mounted on a respective rotating arbor that is coaxially mounted to one another so as to rotate about a common axis of rotation, and at least the lower hand closest to the dial has at least one orifice (hole) arranged in close proximity to the rotating arbor to allow the light beam to pass through the lower hand so that at least a portion of the light beam is absorbed by the light-guiding layer of the hand located directly above the lower hand.

[0026] The present invention also relates to a portable timepiece such as a wristwatch having a case with the above-mentioned display device. [Brief explanation of the drawings]

[0027] Other features and advantages of the present invention will become apparent from the following detailed description of the invention, given by way of example and made with reference to the accompanying drawings. [Figure 1] 1 shows a partial schematic diagram of a prior art light-emitting display device showing a depiction of the minimum angle at which an LED is visible; [Figure 2] 1 shows a partial cross-sectional view of a luminous display device for a watch according to an exemplary embodiment of the present invention. [Figure 3] 3 shows a diagram of a dial attached to the light-emitting display device of FIG. 2; DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 2 shows a partial cross-sectional view of a light emitting display device 1 designed to be mounted in a watch case, such as a watch case.

[0029] In this context, the watch case therefore comprises this display device 1, in particular comprising a dial 2, hands 3, 4, 5 arranged above the dial 2, and a light source 6 arranged to emit a light beam towards the hands 3, 4, 5 in order to illuminate them from below. As shown, the light source 6 is located below the upper surface of the dial 2.

[0030] More specifically and conventionally, the dial 2 comprises a frame body 20 having an upper surface 21 provided with indications for the hours and optionally minutes and / or seconds, for example in the form of numbers or any other predetermined symbols such as dots.

[0031] In the illustrated example, there are three hands 3, 4, 5, including an hour hand 3, a minute hand 4, and a second hand 5. The lower hand closest to the dial 2 is the minute hand 4, the upper hand directly above the lower hand is the hour hand 3, and the upper hand furthest from the dial 2 is the second hand 5. Of course, this is an exemplary embodiment, and it is clear that a different number of hands and different relative positions of the hands can be envisaged depending on the desired functionality of the watch.

[0032] The hands 3, 4, 5 are securely mounted on respective coaxial arbors 30, 40, 50. The arbors 30, 40, 50 are rotated about a common axis of rotation by a watch movement (not shown). The hands 3, 4, 5, which are positioned above the dial 2, together with the indications on the upper surface 21 of the dial body 20, form the time display means.

[0033] The hour hand 3 and the minute hand 4 each have a hand body comprising at least two superimposed layers 31, 32, 41, 42, the lower layers 31, 41 being transparent layers forming a light guiding layer arranged to transmit all or part of the light flux emitted by the light source 6, and the upper layers 32, 42 being opaque layers, advantageously metal layers. According to a particular configuration, an optically insulating layer can be provided between the light guiding layer and the opaque layer (not shown).

[0034] The lower hand (in this example, minute hand 4) advantageously has at least one orifice 43 located close to the rotating arbor 40 on which the lower hand is mounted, in order to enable the light beam emitted by the light source 6 to pass through the orifice 40 and to be at least partially absorbed by the light guiding layer 31 of the hand located directly above the lower hand. Of course, this is an exemplary embodiment, and it is clear that it can be envisaged that the hand located directly above the lower hand and optionally the upper hand, i.e. the hand furthest from the dial, are provided with orifices located close to the rotating arbor, so that the lower hand, the hand directly above the lower hand and optionally the upper hand are illuminated. In this case, these hands advantageously comprise a layer forming a light guide.

[0035] The dial 2, located below the hands 3, 4, 5, has a substantially flat dial body 20, which is provided with a central hole for the passage of the rotating arbors 30, 40, 50 on which the corresponding hands 3, 4, 5 are respectively mounted. The dial body has a peripheral wall 22 formed by the neck of the dial extending towards the hands, said peripheral wall 22 delimiting the central hole. Figure 3 shows a view of the dial 2.

[0036] The dial 2 rests on an annular mount 7, which in the illustrated example has a central hole through which the coaxial arbors 30, 40, and 50 pass. The central hole of the mount has a smaller diameter than the central hole of the dial 2, so that a circular peripheral countersink 8 is provided on the inside of the mount 7. The "inside of the mount" refers to the side closest to the central hole of the mount 7. In a watch case, the mount 7 separates the dial 2 from the movement; in other words, the movement is located between the mount and the case back.

[0037] In this configuration, the dial body 20 is preferably made from metal using a manufacturing method that includes a stamping and / or machining operation. Alternatively, the dial body 20 can be made from a polymer using a manufacturing method that includes an injection operation. As another alternative, the dial body 20 can be made from ceramic using a manufacturing method that includes a stamping or sintering operation.

[0038] The light source 6 is located below the upper surface 21 of the dial 2. In the example shown, the light source 6 is located near the bottom of the dial 2, at the level of a circular countersunk hole 8 formed between the coaxial arbor and the dial 2.

[0039] The light sources 6 advantageously comprise electroluminescent diodes 60 mounted on a printed circuit board and arranged so as to be distributed around the periphery of the rotary arbor. Advantageously, the printed circuit board is supported by or integrated into the dial holder 7.

[0040] According to the invention, the display device 1 comprises at least one element forming a shield arranged around the coaxial arbors 30, 40, 50, which element extends above the dial body 20 over a defined height to delimit a partitioned space in which the light source 6 is embedded. The light source 6 is thus hidden regardless of the observation angle from which the watch is viewed.

[0041] This partitioned space 10 is an open cavity or blind hole. Thus, the partitioned space 10 has an opening arranged facing the inner surface of the lower needle 4. In this configuration, the partitioned space 10 opens onto a flat or substantially flat portion of the lower needle 4. In other words, the lower needle 4 has a flat or substantially flat portion on its inner surface that completely covers this opening of the partitioned space 10.

[0042] In the illustrated example, the shielding element is formed by a peripheral wall 22, also called the dial neck, which is preferably made / formed when the dial body is manufactured. If the dial body is made of metal, this shielding element is manufactured / formed by pressing and / or machining operations in the area of ​​the dial body 20 around the edge of the central hole. These operations are performed to create a raised layer of material sufficient to form the peripheral wall 22 over a height such that, when the dial 2 is mounted on the display device 1, the raised layer extending toward the hands 3, 4, and 5 conceals the light source 6 while ensuring a sufficient gap E for air to pass through the enclosed space 10. Preferably, the shielding peripheral wall 22 extends close to the lower hand. Advantageously, the height of the portion of the peripheral wall included between the visible surface of the dial 2 and the inner surface of the lower hand 4 is between 0.32 and 0.38 mm, preferably about 0.35 mm.

[0043] Thus, in addition to its function of hiding the light source 6, the peripheral wall 22 of the dial 2 also functions as a reflector, so that part of the light beam from the light source 6 can be reflected by the inner surface 23 of this peripheral wall 22 and returned to the hands 3, 4, 5. This has the advantage of improving the optical performance. Furthermore, the optical performance is further improved by the fact that part of the light beam reflected by the hands can be reflected by the inner surface of the peripheral wall 22 and returned to the hands. According to an alternative embodiment in which the dial 2 is made of a material other than metal, it is envisaged that the inner surface 23 of the peripheral wall 22 can be plated with a reflective layer.

[0044] Note that the light source is vertically aligned with the transparent lower layer 31 of the lower needle 4, forming a light guiding layer.

[0045] Advantageously, the peripheral wall 22 is in the shape of a truncated cone and widens towards the needles 3, 4 and 5. This has the advantage that the light rays reflected from the inner surface 23 of this peripheral wall 22 are directed towards the needles 3, 4, 5.

[0046] In the example just described, the peripheral wall 22 is made integral with the dial body 20. In other words, this peripheral wall 22 is made of the same material as the dial 2. More specifically, the peripheral wall 22 forms an integral part of the dial 2. The advantage of making the shielding element by deforming the dial is that it limits the risk of parts separating in the event of an impact. Also, the resulting assembly (dial and shielding element) is more robust and does not require assembly, making it easier to install the parts.

[0047] It should be noted that in an alternative embodiment, this peripheral wall 22 can be an accessory or additional part, for example tubular in shape, separated from the dial 2 and thus from the dial body. In such a configuration, this part is inserted between the dial 2 or dial body and the light source 6. In such a situation, the material from which this insert is made is therefore compatible with all materials, including mother-of-pearl, aventurine, glass, etc.

[0048] While specific embodiments have been described in detail, those skilled in the art will recognize that numerous modifications and alternatives may be developed in light of the overall teachings provided by this disclosure. Accordingly, any specific configurations and / or methods described herein are intended to be illustrative only and are not intended to limit the scope of the invention. [Explanation of symbols]

[0049] 1 Display device 2 dial 3, 4, 5: hour hand, minute hand, second hand 6 light source 7 Dial holder 8 circular countersinks 10 Partitioned Space 20 Dial body 21 Top of the dial 22 Perimeter wall of a partitioned space 30, 40, 50 Rotating Arbor 31, 41 Light guide layer 32, 42 Opaque layer 60 Electroluminescent Diode 70 Lighting Module

Claims

1. A light-emitting display device (1) configured to be mounted on a watch case, the display device (1) comprising a dial (2) having a dial body (20) with a central hole and an upper surface (21), and at least one hand (3, 4, 5) mounted on a rotary arbor disposed above the dial (2) and passing through the central hole of the dial body (20), the hand (3, 4) having an open finish bounded by a back surface (26) formed by a dial base (7) and a peripheral wall (22) forming a shield integrally formed with the dial.

1. A light-emitting display device (1), comprising: a layer (31, 41) forming a light guide arranged to diffuse all or part of a light beam emitted by an illumination module (70) having a cut space (10), the wall (22) being arranged around a rotating arbor of the hands (3, 4, 5) and extending above the dial body (20) over a defined height; the illumination module (70) comprising a light source (6) located on a back surface (26) of the space (10) and arranged to emit a light beam towards the hands (3, 4, 5) to illuminate them from below.

2. 2. The light-emitting display device (1) according to claim 1, wherein the rear surface (26) of the partitioned space (10) comprises a printed circuit board comprising the light source.

3. 2. A luminescent display device (1) according to claim 1, wherein the light source (6) comprises at least one electroluminescent diode and / or a miniature laser light source.

4. 2. A light-emitting display device (1) according to claim 1, wherein the light source (6) comprises a plurality of electroluminescent diodes (60) and / or miniature laser light sources mounted on a printed circuit board and arranged in a distributed manner around the periphery of the rotating arbor.

5. 2. A light-emitting display device (1) according to claim 1, wherein the peripheral wall (22) has an inner surface (23) capable of reflecting the light beam emitted by the light source (6).

6. 2. A light-emitting display device (1) according to claim 1, wherein the peripheral wall is made of metal, polymer or ceramic.

7. 2. The light-emitting display device (1) of claim 1, wherein the height defines a gap called a space ventilation gap (10) between the top (24) of the wall (22) and the inner surface of the lower needle (4).

8. 2. The light-emitting display device (1) of claim 1, wherein the needles (3, 4, 5) have a needle body comprising at least two layers, one of which is an opaque layer (32, 42) and the other of which is a transparent layer forming a light-guiding layer (31, 41).

9. 2. A light-emitting display device (1) according to claim 1, wherein the light source is vertically aligned with a lower transparent layer (31) forming a light-guiding layer.

10. 2. A light-emitting display device (1) according to claim 1, wherein the partitioned space (10) opens onto a flat or substantially flat part of the lower needle (4).

11. 2. A light-emitting display device (1) according to claim 1, wherein the lower needle (4) comprises a flat or substantially flat portion of its inner surface which completely conceals / covers the opening of the partitioned space (10).

12. 2. The light-emitting display device (1) of claim 1, comprising a plurality of hands (3, 4, 5) each attached to a respective rotary arbor (30, 40, 50) coaxially mounted to one another so as to rotate about a common rotation axis, wherein at least the lower hand (4) closest to the dial (2) has at least one orifice arranged in close proximity to the rotary arbor (40) to allow the light beam to pass through the lower hand (4) so ​​that at least a portion of the light beam is absorbed by a light-guiding layer (31) of the hand (3) located directly above the lower hand (4).

13. A portable watch having a case equipped with the light-emitting display device (1) according to claim 1.

14. 14. The watch of claim 13, which is a wristwatch.

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