CH715440A2 - Illuminated display device. - Google Patents

Abstract

The present invention relates to a display device for a portable object comprising a dial (8) and at least one mobile needle (9), said at least one mobile needle (9) comprising a light source (1) or being coupled to a light source (1), the dial (8) comprising at least one secondary light waveguide (4), the light source (1) and the secondary waveguide (4) being arranged so that the source light (1) is coupled to the proximal end of the secondary waveguide (4) when the movable needle (9) passes through a predetermined sector of the dial (8), and the distal end of the secondary waveguide (4) being coupled to a display element (7) of the dial (8). The portable object is preferably a watch or an analog display measuring device.

Description

Field of the invention

The present invention relates to a light display device for a portable object. The present invention relates in particular to a luminous display device for a timepiece such as a wristwatch or a measurement device with analog display.

Technological background of the invention

The hands of a watch of course play a functional role, for example indicating the current time, but they also play a decorative role by contributing largely to the aesthetic aspect of the watch which they equip. For this purpose, the needles must meet strict criteria. A well-known technique in the watchmaking world to allow the needles to be visible in the dark is to coat the surface of the hands oriented towards the user with a layer of phosphorescent material. An example of such a material is a non-radioactive photoluminescent pigment sold by the Japanese company Nemoto & Co., Ltd. under the registered trademark Super-Luminova <®>. This pigment can also be used to coat the hour markers on the watch face. During the day, the layer of phosphorescent material absorbs light energy. This light energy is then restored at night by the layer of phosphorescent material in the form of light radiation. This technique of illuminating the hands of a watch is quite convenient in so far as the operation of the layer of phosphorescent material is completely passive and therefore does not require, for its operation, the actuation of any mechanical or electrical device, nor energy that would be supplied by the watch.

This technique of illuminating the hands of a watch, however, also has certain drawbacks, the foremost of which may be mentioned the fact that the layer of phosphorescent material needs to be previously illuminated by a light source before being able to emit of light energy. Likewise, the phenomenon of re-emission of light by phosphorescence effect is limited in time, so that as the phosphorescent layer releases the light energy which it has stored, its brightness decreases. The needles coated with a layer of phosphorescent material therefore do not have a constant appearance. Finally, the range of phosphorescent materials available on the market is limited, so that most of the watches in which such materials are used end up looking the same in the dark and even in broad daylight.

Document EP 2 950 167 proposes to illuminate the needles by means of a light source arranged close to the axis of the needle, the source being supplied with electricity via on the one hand a conductor linked to the axis, and secondly via a conductor in contact with the dial. The needle in this document includes a waveguide for diffusing light along the needle, allowing you to see its orientation. However, this document does not solve the problem of lighting the dial, and in particular the problem of lighting the indexes of the dial.

Summary of the invention

The present invention aims to remedy the aforementioned drawbacks as well as others by providing a display device for elements of a dial that can be illuminated at the request of the user, according to a large variety of colors and respecting the dimensional and aesthetic constraints to which the device is subjected.

To this end, the present invention relates to a display device for a portable object, the portable object comprising a dial and at least one movable needle rotating above the dial, said at least one movable needle comprising a light source or being coupled to a light source, the dial comprising at least one secondary light wave guide comprising a proximal end formed in a predetermined sector of the dial and a distal end defining a display area, the light source and the guide of secondary waves being arranged so that the light source is coupled to the proximal end of the secondary waveguide when the movable needle passes through a predetermined sector of the dial, and the distal end of the waveguide secondary being coupled to a display element of the dial provided in the display area.

Advantageously, said at least one movable needle comprises a primary light wave guide, a proximal end of the primary light wave guide being coupled to the light source, a distal end of the primary wave guide and a proximal end of the secondary waveguide being arranged so that the primary waveguide is coupled to the proximal end of the secondary waveguide when the movable needle passes through the predetermined sector of the dial.

Preferably, the light source is an annular zone fixed to the dial coupled to the proximal end of the primary waveguide.

According to an alternative of the invention, the light source is integrated into the movable needle.

According to another alternative, the needle is replaced by a movable disc comprising the primary light wave guide.

Advantageously, the movable needle comprises a transparent material in which is written said primary waveguide, said primary waveguide being curved so as to facilitate the extraction of light and the coupling with said guide secondary waves.

Preferably, the primary waveguide comprises a rectilinear portion connected at its two ends by two curved portions opening respectively opposite the light source and the proximal end of the secondary waveguide. In this case, the primary waveguide is preferably made in the thickness of the needle.

Preferably, the dial comprises at least one transparent layer in which is written said secondary waveguide, said secondary waveguide being curved so as to facilitate coupling with the light source and the display element .

Advantageously, the secondary waveguide comprises a rectilinear portion connected at its two ends by two curved portions opening respectively opposite the distal end of the primary waveguide and the display element. Preferably, the secondary waveguide is made in the thickness of the transparent layer of the dial.

Advantageously, the light source emits light at least at a wavelength less than 450 nm, the display element comprising fluorescent pigments emitting visible light when they are illuminated by said light source.

Microlenses preferably couple the light source to the secondary waveguide (s). In this case, the microlenses are advantageously arranged facing the distal end of the primary waveguide and the proximal end of the secondary waveguide.

Advantageously, the needle comprises an opaque decorative layer masking the primary waveguide or the light source.

Preferably, the dial comprises a plurality of secondary waveguides extending along radii angularly regularly distributed over 360 °.

Advantageously, the dial includes a first set of secondary waveguides, the distal end of each of which is associated with an index of minutes or five minutes or fifteen minutes of a revolution.

Preferably, the display device of the invention comprises a second needle movable in rotation above the dial, in that the dial comprises a second set of secondary waveguides, the second needle comprising a second light source or being coupled to a second light source, the second light source and the second set of secondary waveguides being arranged so that the second light source is coupled to the proximal end of a light guide secondary wave of the second set of secondary waveguides when the second movable needle passes through a second predetermined sector of the dial, and the distal end of the secondary waveguide of the second set of secondary waveguides being coupled to an element display area provided in the display area. In this case, the dial preferably comprises a second set of secondary waveguides, the distal end of each of which is associated with an index of hours of a revolution of hours.

Advantageously, the second needle comprises a primary light wave guide, a proximal end of the primary light wave guide being coupled to the second light source, a distal end of the primary wave guide and a proximal end of the guide of secondary waves being arranged so that the primary waveguide is coupled to the proximal end of a secondary waveguide of the second set of secondary waveguides when the second movable needle passes through the second predetermined sector of the dial.

Preferably the first and second light sources are combined.

Advantageously, the distal ends of the secondary waveguides of the first set of secondary waveguides and the distal ends of the secondary waveguides of the second set of secondary waveguides are each arranged along a circle of different diameter.

Another aspect of the invention relates to a watch, such as a wristwatch, comprising a display device according to the invention.

Preferably, the watch of the invention comprises two movable hands each comprising a primary waveguide the primary waveguide of one of the two needles being arranged so as to be successively coupled to elements of display designating the minute indexes of the watch, and the other hand being arranged so as to be successively coupled to display elements designating the hour indexes of the watch.

Brief description of the figures

Other features and advantages of the invention will emerge more clearly from the detailed description which follows of an embodiment of the invention, this example being given purely by way of non-limiting illustration in conjunction with the accompanying drawings. . <tb> Fig. 1 <SEP> is a view of an example of a wristwatch according to the invention. <tb> Fig. 2 <SEP> represents a sectional view of an example of a display device according to the invention illustrating its operating principle. <tb> Fig. 3 <SEP> represents a sectional view of another example of a display device according to the invention. <tb> Fig. 4 <SEP> represents a sectional view of another example of a display device according to the invention. <tb> Fig. 5 <SEP> represents a sectional view of an example of a display device comprising two needles. <tb> Fig. 6 <SEP> represents a schematic view of the general arrangement of the waveguides on a display device according to the invention.

Detailed description of an embodiment of the invention

The present invention proceeds from the general inventive idea which consists in illuminating a watch index or any type of display element 7 of a dial 8 by a light wave guide 4 integrated in the dial 8, the waveguide integrated 4 in the dial 8 being coupled to a waveguide 2 disposed in a needle 9 (or a movable disc) when this needle moves to a predetermined position. In this way, the display element 7 illuminated at a given time is determined by the position of the needle. Given the direction of light flow from the waveguide 2 of the needle 9 to the waveguide 4 of the dial 8, we will call in the rest of this description the waveguide 2 of the needle 9 the primary waveguide 2, and the waveguide 4 of the dial 8 the secondary waveguide 4.

The advantage of such an arrangement is to allow active display of the current hour or minute in a purely mechanical manner, without it being necessary to install as many light sources as there are indexes, and without addressing electronics making it possible to selectively illuminate the index corresponding to the current hour or minute.

According to a preferred embodiment of the invention, as shown in FIG. 2, the light source 1 supplying the primary waveguide 2 is fixed to the dial 8 in the immediate vicinity of the axis of the needle 9. The source can then advantageously be coupled to the primary waveguide 2 via a microlens 11 In this case, the source is preferably an LED of annular shape illuminating the base of the needle 9. According to a variant, the light source can be formed from an OLED source extending in a ring. Likewise, alternately to what is shown in FIG. 2, the microlens 11 could be integrated on the LED and have a curvature which corresponds to the digital opening of the primary waveguide 2. This variant advantageously makes it possible to couple more light in the primary waveguide 2. In such a way alternative, as shown in fig. 3, a light source 12 can be integrated into the needle 9. In this case, this light source 12 can for example be supplied by a system as described in document EP 2 950 167 and coupled to the primary waveguide 2 near the axis.

Finally, according to another alternative shown in FIG. 4, the light source can be placed directly under the needle 9, facing the coupling zone 6 of the secondary waveguide. However, such an arrangement can be made complicated by the fineness of the needles. However, in this case, the light source is directly coupled to the secondary waveguide 4, without the need for a primary waveguide.

In all cases, the light source 1, 12, 13 is preferably a high-efficiency source such as an LED or a low-power semiconductor laser.

Advantageously, the needle 9 comprises a layer of transparent material in which is written the primary waveguide 2. By "writing" a waveguide in a transparent material, we mean the production of a tubular volume forming a waveguide by a localized increase in the refractive index. Such writing can be obtained according to a known process such as the use of short pulse focused lasers (femto seconds). Such methods are for example described in documents WO 01/44 871 and WO 2014/170 872. The advantage of such a waveguide inscribed / written in a transparent material is on the one hand to avoid an assembly complex, and secondly to allow discrete integration.

The transparent material can also be covered with a layer of opaque material 10, which has the advantage of masking the light source 1, 12 and providing an aesthetic advantage.

According to a variant, the transparent material can be deposited on a conventional needle, for example in bronze brass, the waveguide then being written in the transparent material. By way of example, such a material can be a layer of diamond. This variant can of course also be implemented in conjunction with the dial which can be coated with a layer of transparent material and then written as mentioned above.

The secondary waveguide 4 is preferably integrated into a transparent layer in which said secondary waveguide 4 is inscribed. This inscription is particularly advantageous in the case of the dial 8. In fact, it will generally be necessary to register as many waveguides 4 as there are indexes, often twelve indexes 7 for displaying the hours and twelve indexes for the five-minute display, for a total of 24 separate waveguides. Writing with a laser beam allows such complexity with largely satisfactory precision.

Note that in the case of the dial and especially the fact that it is a larger element than a fine needle, the secondary guides 4 could alternatively be integrated into the thickness of the dial under forms plastic or transparent glass plates.

The coupling between the primary waveguide 2 and the secondary waveguide is preferably done via microlenses 5, 6 making it possible to reduce the loss of light in the coupling zone.

Preferably and so that there is permanently at least one illuminated display area for each needle 9 the coupling area 6 of the secondary waveguide 4 has a smaller area than the area projection of the incident light beam on the dial on the one hand and that the distance between two successive coupling zones 6 is less than the largest dimension of the incident beam on the dial.

The light from the secondary waveguide is preferably extracted by an area 7 having a frosted surface finish so as to diffuse the light in all directions.

Advantageously, the light injected into the primary waveguide 2 is UV or blue light having at least a wavelength less than 450 nm, preferably less than 380 nm, and the index zone 7 comprises fluorophores emitting in the visible spectrum when excited by blue or UV light. Such a combination makes it possible to reduce the stray light possibly perceived by the user and concentrates his attention on the illuminated index zone.

At least one secondary waveguide can advantageously be coupled to a detector coupled to a processor making it possible, for example, to precisely control the time displayed, and compare this data with a reference clock for possible automatic adjustment.

[0042] FIG. 5 shows a sectional view of a preferred example of a watch face according to a preferred example of the invention. This figure corresponds to the top view of FIG. 6.

We observe in FIG. 5 a hand 18 corresponding to the display of the hours whose light source 24 is coupled to one of the waveguides 22 illuminating the index via a microlens 24a, of the hours 20 when the hand passes opposite this one. Correspondingly, the light source 23 of the hand 17 corresponding to the minute display is coupled via a microlens 23a, to one of the waveguides 21 illuminating the index 19 of the minutes when the hand passes in sight. opposite this one.

Note that in the embodiment of FIG. 5 the input microlenses of the secondary waveguide have been omitted. Of course, according to a first variant, the input microlenses of the secondary waveguide can be added and, in a second variant, the microlenses 23a, 24a can also be omitted.

The proximal ends of the waveguides illuminating the hour markers are arranged on a first circumference 26, while the minute indices are arranged on a second circumference 25, so as to avoid interference between the two displays. It goes without saying that the fluorophores can also be of a different color for the hours and the minutes, or even between the minutes and the quarter hours, for example.

It goes without saying that the present invention is not limited to the embodiments which have just been described and that various modifications and simple variants can be envisaged by those skilled in the art without departing from the scope of the invention as defined by the appended claims. We can in particular provide that the display elements 7 have other shapes than those of pellets, for example segment shapes to form a number or a character and allow a digital display or any other figurative form. In the example described above, the waveguides are produced by a localized modification of the refractive index and invisible to the human eye, however we can also consider making these waveguides by generation of defect. inside to create a light diffusion path inside the material and thus creates visible waveguides for the human eye.

Legend of figures

[0047] <tb> 1 <SEP> Light source <tb> 2 <SEP> Primary waveguide <tb> 3 <SEP> Coupling area <tb> 4 <SEP> Secondary waveguide <tb> 5 <SEP> Primary waveguide output microlens <tb> 6 <SEP> Microlens of secondary waveguide input <tb> 7 <SEP> Display element <tb> 8 <SEP> Dial <tb> 9 <SEP> Movable needle <tb> 10 <SEP> Opaque layer <tb> 11 <SEP> Microlens of primary waveguide input <tb> 12 <SEP> Light source <tb> 13 <SEP> Light source <tb> 14 <SEP> Portable object <tb> 15 <SEP> Axis of the minute hand <tb> 16 <SEP> Axis of the hour hand <tb> 17 <SEP> Minute hand <tb> 18 <SEP> Hour hand <tb> 19 <SEP> Minute index <tb> 20 <SEP> Hour index <tb> 21 <SEP> Secondary minute waveguide <tb> 22 <SEP> Hourly secondary waveguide <tb> 23 <SEP> Light source minutes <tb> 23a <SEP> Primary waveguide output microlens <tb> 24 <SEP> Light source hours <tb> 24a <SEP> Primary waveguide output microlens <tb> 25 <SEP> Coupling circumference of the minutes <tb> 26 <SEP> Hour coupling circumference

Claims (24)

1. Display device for a portable object (14), the portable object (14) comprising a dial (8) and at least one needle (9, 17, 18) movable in rotation above the dial, said at at least one mobile needle (9, 17, 18) comprising a light source (12, 13) or being coupled to a light source (1, 12, 13, 23, 24), the dial comprising at least one light wave guide secondary (4, 21, 22) comprising a proximal end formed in a predetermined sector of the dial and a distal end defining a display area, the light source (1, 12, 13) and the secondary waveguide (4, 21, 22) being arranged so that the light source (1, 12, 13, 23, 24) is coupled to the proximal end of the secondary waveguide (4, 21, 22) when the movable needle (9) passes in the predetermined sector of the dial (8), and the distal end of the secondary waveguide (4, 21, 22) being coupled to an element of a display (7) of the dial (8) provided in the display area. 2. Display device according to claim 1, characterized in that said at least one movable needle (9, 17, 18) comprises a primary light wave guide (2), a proximal end of the primary light wave guide (2) being coupled to the light source (1, 12), a distal end of the primary waveguide (2) and a proximal end of the secondary waveguide (4, 21, 22) being arranged so that that the primary waveguide (2) is coupled to the proximal end of the secondary waveguide (4) when the movable needle (9, 17, 18) passes through the predetermined sector of the dial (8). 3. Display device according to claim 2, characterized in that the light source (1) is an annular zone fixed to the dial (8) coupled to the proximal end of the primary waveguide. 4. Display device according to claim 2, characterized in that the light source (12) is integrated into the movable needle (9, 17, 18). 5. Display device according to one of claims 2 to 4, characterized in that the movable needle (9, 17, 18) comprises a transparent material in which is written said primary waveguide (2), said primary waveguide (2) being curved so as to facilitate the extraction of light and the coupling with said secondary waveguide (4, 21, 22). 6. Display device according to claim 5, characterized in that the primary waveguide (2) comprises a rectilinear portion connected at its two ends by two curved portions opening respectively opposite the light source (12) and the proximal end of the secondary waveguide (4, 21, 22). 7. Display device according to claim 5 or 6 characterized in that the primary waveguide (2) is made in the thickness of the needle (9, 17, 18). 8. Display device according to one of the preceding claims, characterized in that the dial (8) comprises at least one transparent layer in which is written said secondary waveguide (4, 21, 22) said guide secondary waves (4, 21, 22) being curved so as to facilitate coupling with the light source (1, 12, 13, 23, 24) and the display element. 9. Display device according to claim 8, characterized in that the secondary waveguide (4, 21, 22) comprises a rectilinear portion connected at its two ends by two curved portions opening respectively opposite the distal end the primary waveguide and the display element. 10. Display device according to claim 8 or 9 characterized in that the secondary waveguide (4, 21, 22) is made in the thickness of the transparent layer of the dial. 11. Display device according to one of the preceding claims, characterized in that said light source (1, 12, 13, 23, 24) emits light at a wavelength less than 450 nm, the element d 'display (7) comprising fluorescent pigments emitting visible light when illuminated by said light source (1, 12, 13). 12. Display device according to one of the preceding claims, characterized in that it comprises microlenses (5, 6, 11) for coupling the light source (1, 12, 13) to the secondary waveguide (4 ). 13. Device according to claim 12 characterized in that the micro lenses (5, 6, 11) are arranged opposite the distal end of the primary waveguide and the proximal end of the secondary waveguide. 14. Display device according to one of the preceding claims, characterized in that the needle (9) comprises an opaque decorative layer (10) masking the primary waveguide (2) or the light source (12, 13 ). 15. Display device according to any one of the preceding claims, characterized in that the dial (8) comprises a plurality of secondary waveguides (21, 22) extending along radii angularly regularly distributed over 360 °. 16. Display device according to any one of the preceding claims, characterized in that the dial comprises a first set of secondary waveguides (21), the distal end of each of which is associated with a minute index (19) of an hour turn. 17. Display device according to claim 16 characterized in that it comprises a second needle movable in rotation above the dial, in that the dial comprises a second set of secondary waveguides, the second needle comprising a second light source or being coupled to a second light source, the second light source and the second set of secondary waveguides being arranged so that the second light source is coupled to the proximal end of a light guide secondary wave of the second set of secondary waveguides when the second movable needle passes through a second predetermined sector of the dial, and the distal end of the secondary waveguide of the second set of secondary waveguides being coupled to a display element of the dial provided in the display area. 18. Display device according to claim 17 characterized in that the distal end of each of the secondary waveguides of the second set of secondary waveguides is associated with an hour index of one hour turn . 19. Display device according to claim 17 or 18, characterized in that the second needle comprises a primary light wave guide, a proximal end of the primary light wave guide being coupled to the second light source, a distal end of the primary waveguide and a proximal end of the secondary waveguide being arranged so that the primary waveguide is coupled to the proximal end of a secondary waveguide of the second set of waveguides secondary waves when the second movable hand passes through the second predetermined sector of the dial. 20. Display device according to one of claims 17 to 19 characterized in that the first and second light sources are combined. 21. Display device according to claims 16 and 18 or 19 characterized in that the distal ends of the secondary waveguides of the first set of secondary waveguides and the distal ends of the secondary waveguides of the second set of secondary waveguides are each arranged along a circle of different diameter. 22. Display device according to any one of the preceding claims, characterized in that the movable needle or pins are replaced by a movable disc comprising said primary light wave guide 23. Watch comprising a display device according to any one of the preceding claims. 24. Watch according to claim 23, comprising two movable hands (9) each comprising a primary waveguide (2), the primary waveguide of one of the two needles being arranged so as to be successively coupled to display elements (7) designating the minute indexes, and the other hand being arranged so as to be successively coupled to display elements (7) designating the hour indexes.