CH707949B1 - Timepiece including a digital information display device. - Google Patents

Abstract

Timepiece comprising a dial (2) under which is disposed a digital information display device, a window (10) formed in the dial (2) of the watch allowing a user to read the information displayed by the digital information display device, the dial (2) having an upper face (4) and a lower face (6) and the digital information display device having an upper information display surface, the part watchmaking being characterized in that the digital information display device is fixed directly by its upper information display surface on the underside (6) of the dial (2).

Description

The present invention relates to a timepiece and its manufacturing method, as well as a display module comprising a digital information display device. More specifically, the invention relates to such a timepiece in which the digital display of information is more aesthetic and more easily readable.

Wrist watches with a digital information display device such as a liquid crystal cell have been known for a long time. Such wristwatches typically include a dial beneath and at a distance from which is arranged for example a liquid crystal cell. A window in the watch face allows the user to read the hourly or other information displayed by the liquid crystal cell. The liquid crystal cell is fixed on a plate housed in the watch case at a distance from the dial. There is therefore an unsightly space between the surface of the dial and the display surface of the liquid crystal cell. In addition, depending on the angle from which the user looks at his watch, his vision may be hampered by the shadow cast by the edges of the window on the display surface of the liquid crystal cell.

[0003] Furthermore, the liquid crystal cells which equip wristwatches of the type described above most often comprise glass substrates joined together by means of a sealing frame. These glass substrates are usually square or rectangular because, even if it is technically possible to give such glass substrates shapes which deviate from the square or rectangular shape, this is hardly possible from a point of view. economic view.

The present invention aims to overcome the problems mentioned above as well as others by providing a timepiece provided with a digital information display device in which the information display is more aesthetic and more readable.

To this end, the present invention relates to a timepiece comprising a dial under which is disposed a digital information display device, a window in the watch dial allowing a user to read the information displayed by the digital information display device, the dial having an upper face and a lower face and the digital information display device having an upper information display surface, the timepiece being characterized in that that the digital information display device is fixed directly by its upper information display surface on the underside of the dial.

Thanks to these characteristics, the present invention provides a timepiece in which the digital information display device is fixed directly by its upper surface for displaying information against the underside of the dial. Consequently, the difference separating the upper face of the dial from the upper surface of the digital information display device is at most equal to the thickness of the dial. As a watch face has a very small thickness, the gap between the dial and the digital information display device is reduced to a minimum, so that the information display is more aesthetic and easier to read. In particular, even when the wearer of the watch looks at the digital information display device at an angle, he is not bothered by the shadow cast by the edges of the dial. It will be noted that, within the meaning of the invention, the term "fixing" means any technique allowing two parts to be mechanically linked together.

According to a complementary feature of the invention, the digital information display device is secured to the underside of the dial. For the purposes of the present invention, the term "joining" means any technique consisting of gluing two pieces to one another. Preferably, the digital information display device according to the invention is secured to the underside of the dial by means of a layer of optically transparent adhesive.

According to yet another characteristic of the invention, the digital information display device comprises two flexible front and rear substrates. Preferably, the digital information display device is a flexible liquid crystal display cell comprising two front and rear substrates made of a plastic material and joined together by a sealing frame.

In a preferred embodiment of the invention, the timepiece comprises a solar cell arranged under and at a short distance from the dial, the solar cell comprising an opening in which is housed the digital display device of the information when the solar cell is mounted under the dial.

If there is a solar cell of the same dimensions as the dial under the dial, part of the surface of the solar cell will be masked by the digital information display device. However, we realized that the photovoltaic conversion efficiency of the solar cell was more degraded by the partial darkening due to the presence of the digital information display device than by a reduction of its active surface in the case where the shaped opening is provided in which the digital information display device is housed.

The invention also relates to a display module for a timepiece, this display module comprising a display device formed by a dial on a lower face of which is fixed a digital display device d information, a solar cell and a plate, the display device and the solar cell, arranged on an upper side of the plate, being detachably fixed on the latter, the solar cell being placed under and at a distance from the dial. Advantageously, the display module is supplemented by a backlighting device arranged on a lower side of the plate and removably fixed thereon.

A complete display module is thus obtained which can be exchanged part by part in the event of a malfunction. In the event of a problem, it is even possible to remove the display module and replace only the defective component (s), which is very advantageous from an economic point of view.

The present invention also relates to a method of manufacturing a timepiece comprising a dial under which is disposed a digital information display device, a window in the watch face allowing a user to reading the information displayed by the digital information display device, the dial having an upper face and a lower face and the digital information display device having an upper information display surface, the method being characterized in that we provide the upper information display surface with an adhesive layer and that we laminate the digital information display device on the underside of the dial through the adhesive layer .

According to an additional characteristic of the invention, after fixing the digital device for displaying information on the dial, the assembly is passed through an autoclave in order to expel any air trapped between the adhesive layer and the dial. . Preferably, the pressure in the autoclave is 6 bars, the treatment temperature is of the order of 50 ° C. and the treatment time is approximately 30 min.

Other features and advantages of the present invention will become more apparent from the detailed description which follows of an embodiment of the timepiece according to the invention, this example being given purely by way of illustration and not limitation only in conjunction with the attached drawing in which: <tb> - <SEP> Figure 1 is a perspective and exploded view of a first embodiment of the timepiece according to the invention; <tb> - <SEP> FIG. 2 is a perspective and exploded view of a second embodiment of the timepiece according to the invention, and <tb> - <SEP> FIGS. 3A and 3B are respectively overall views and details on a larger scale of a plastic dial which is imparted an appearance of composite material of the carbon fiber type.

The present invention proceeds from the general inventive idea which consists in fixing a digital information display device on the underside of a dial. Thanks to this feature, the distance between the upper face of the dial and the surface of the digital information display device is reduced to a minimum, so that the aesthetic appearance of the watch and the readability of the information displayed are improved. Furthermore, in the case where the timepiece is a wristwatch of the solar type in which the solar cell is arranged under and at a short distance from the dial, it is taught to provide in the solar cell an opening whose shape and dimensions are adapted to those of the digital information display device. Consequently, when the solar cell is placed under the dial, the digital information display device is housed in the opening, so that the solar cell can be mounted a short distance from the dial. Furthermore, from the point of view of the efficiency of the photoelectric conversion phenomenon, it has been observed that it was preferable to provide an opening in the solar cell and therefore to reduce the active surface of the latter, rather than using a solar cell. of a size similar to that of the dial and which would therefore be partially masked by the digital information display device.

Figure 1 is a perspective and exploded view of a first embodiment of a display module for a timepiece according to the invention. Designated as a whole by the general reference numeral 1, this display module includes a dial 2 which, in the example illustrated, is of generally circular shape. It will however be understood that the shape of the dial can deviate from a circular profile and can for example be square or else rectangular. The dial 2 has an upper face 4 and a lower face 6 and is pierced with a hole 8 in its center for the passage of a set of axes of the minute and second hands (not shown in the drawing). A window 10 is provided in the dial 2. In the case where the dial 2 is made of a transparent material, the decorative layer with which the dial 2 is coated is omitted at the place corresponding to the window 10. Another solution for forming the window 10 consists of drilling the dial 2 at the desired location.

The display module 1 also includes a digital information display device. In the example shown in the drawing, this digital information display device consists of a flexible liquid crystal display cell 12 which has a substantially semi-circular shape. This liquid crystal display cell 12 comprises a front substrate 14 which defines an upper display surface and a rear substrate 16. The front substrates 14 and rear 16 are produced by means of a flexible plastic material and are conventionally connected between them by a sealing frame (not visible in the drawing) which delimits a closed volume for the confinement of the liquid crystal. It goes without saying that this example is given purely by way of illustration and that the digital information display device can be of the electrophoretic type or else use an electronic ink. A flexible electrical connector 18 makes it possible to connect the electrodes of the liquid crystal display cell 12 to an electronic control circuit (not shown).

According to the invention, the front substrate 14 of the liquid crystal display cell 12 is coated with an adhesive layer 20 formed of an optically transparent glue and through which the display cell liquid crystal 12 is applied against the underside 6 of the dial 2. Preferably but not limited to, the liquid crystal display cell 12 is mechanically laminated against the underside 6 of the dial 2, then the assembly formed by the dial 2 and the liquid crystal display cell 12 is passed through an autoclave in order to expel the air possibly trapped between the adhesive layer 20 and the dial 2. For example, the pressure in the autoclave is 6 bars, the treatment temperature is around 50 ° C and the treatment time is around 30 min.

The assembly is completed by a first solar cell 22. It will be understood that the use of this solar cell 22 corresponds to the preferred embodiment of the invention but that, in the basic variant of the invention, the module display 1 includes only the dial 2 and the liquid crystal display cell 12. In the example illustrated in FIG. 1, the solar cell 22 has a shape substantially in a semicircle complementary to the shape of the cell liquid crystal display panel 12. The sum of the surface area of the liquid crystal display cell 12 and the solar cell 22 corresponds substantially to that of the dial 2.

The solar cell 22 is arranged under and at a short distance from the dial 2. For this purpose, it is received in a plate 24 which is adapted in shape and dimensions to those of the dial 2. For the axial maintenance of the cell solar 22, the plate 24 comprises a bearing surface 26 whose area is substantially equal to that of the solar cell 22. For its radial maintenance, the solar cell 22 is provided along its outer perimeter with at least one and, preferably, two lugs 28 which are engaged in two corresponding housings 30 provided on the periphery of the plate 24. As can be seen in the drawing, the bearing surface 26 is pierced with two diametrically opposite through holes 32 in which springs 34 are engaged which make it possible to ensure electrical contact between the two terminals of the solar cell 22 and the electrical power supply circuit of the watch (not shown).

The assembly formed by the dial 2 and the liquid crystal display cell 12 is disposed over the solar cell 22 and bears on a peripheral flange 36 of the plate 24. It can be seen that the cell d liquid crystal display 12 is located directly above an opening 38 formed in the plate 24 and the extent of which corresponds substantially to the surface of the liquid crystal display cell 12. This opening 38 allows a device backlight 40 mounted from below the plate 24 to illuminate the liquid crystal display cell 12 from the rear.

Finally, the assembly formed by the dial 2, the liquid crystal display cell 12 and the solar cell 22 is detachably immobilized on the plate 24 by means of flexible locking hooks 42. This gives a display module 1 complete which can be replaced part by part in the event of a malfunction. In the event of a problem, it is even possible to remove the display module 1 and to replace only the defective component (s), which is very advantageous from an economic point of view.

Figure 2 is a perspective and exploded view of a second embodiment of a display module for a timepiece according to the invention. In all that follows, elements identical or analogous to those already described in connection with FIG. 1 will be designated by the same reference numerals.

It can be seen in FIG. 2 that the dial 2 comprises a window 10 adapted in shape and dimensions to the shape and dimensions of the front substrate 14 which defines the upper display surface of the liquid crystal display cell 12. We also see that a second solar cell 220 has substantially the same dimensions as the dial 2 and is provided with an opening 221 in which is housed the liquid crystal display cell 12 when the solar cell 220 is placed under the dial 2. It is understood that, when a solar cell of the same dimensions as the dial 2 is placed under the dial 2, part of the surface of the solar cell will be masked by the liquid crystal display cell 12. However, we have realized that the photovoltaic conversion efficiency of a solar cell with a given active surface is less good when the solar cell is partially obscured than when the active surface of the solar cell is reduced. due to the presence of a shaped opening in which the digital information display device is housed.

For the rest, the display module illustrated in Figure 2 is identical to that described above in conjunction with Figure 1. The liquid crystal display cell 12 is fixed on the underside 6 of the dial 2 preferably by lamination and the solar cell 220 is received in the plate 24. Subsequently, the assembly formed by the dial 2 and the liquid crystal display cell 12 is disposed above the solar cell 220, so that the solar cell 220 is located under and at a short distance from the dial 2 and the liquid crystal display cell 12 is housed in the opening 221. A backlight device 40 mounted from below the plate 24 allows '' illuminate the liquid crystal display cell 12 from the rear through the opening 38 formed in the plate 24. The assembly formed by the dial 2, the liquid crystal display cell 12 and the solar cell 220 is detachably attached to the plate 24 by means of a plurality flexible locking hooks 42.

As can be seen in the drawing, the bearing surface 26 is pierced with two through holes 32 arranged close to each other on a diameter portion of the bearing surface 26 in which are engaged springs 34 which make it possible to ensure electrical contact between the two terminals of the solar cell 220 and the electrical supply circuit of the watch (not shown). It can also be seen that, for its radial retention, the solar cell 220 is provided on its peripheral with at least one and, preferably, three notches 44 which cooperate with three corresponding pins 46 of the plate 24.

In the case where the timepiece is of the solar watch type, the dial 2 must be at least partially transparent in order to allow a sufficient amount of light to pass through to allow the solar cell 22, 220 to effectively recharge the watch accumulator while masking the solar cell 22, 220 from the wearer's gaze.

For example, the dial 2 can be made of a transparent plastic material and be covered with a layer of paint, the opacity of which is adjusted according to the thickness of the layer of paint and / or the concentration of pigments in the paint. The transmittance of a dial 2 made of transparent plastic covered with paint is around 45%. In other words, 45% of the incident light is transmitted to the solar cell 22, 220 and the rest of the light is absorbed by the dial 2, which is enough to hide the solar cell 22, 220 from the view of the user. According to another example, the dial 2 made of plastic can be covered with a layer of mother-of-pearl whose thickness is typically 150 μm ± 20 μm and whose transmittance is adjusted to 35%. The mother-of-pearl layer is fixed to the upper face 4 of the dial 2 by means of a layer of optically transparent glue.

According to yet another aspect of the invention, it is sought to give the plastic dial 2 an appearance of composite material of the carbon fiber type. It is known that such a composite material is obtained by means of intertwined carbon fibers which are impregnated with resin, the surface condition of the resulting material having areas in slightly relief which are repeated periodically.

To imitate such a texture, two solutions are envisaged. The first solution consists in machining in the interior wall of the mold into which the plastic is injected, the structures which will form as many raised zones on the upper face of the dial 2. The second solution uses the principle of a conventional pad printing ( decal with cliché) or an electronic print which is also possible from a technical point of view but whose rendering for the eye is however a little worse. As illustrated in FIGS. 3A and 3B annexed to the present patent application, the carbon effect is obtained by the alternating and periodic repetition of horizontal lines 48 and vertical lines 50. Even if the horizontal lines 48 seem lighter, this is only due to the angle of incidence of the light. This effect makes the dial “alive” according to the light and it is exactly the same with real carbon. The lines are black (horizontal lines and vertical lines). We could also have used a mixture of black (vertical lines) and gray (horizontal lines) to obtain the carbon effect, but in this case it would be independent of light and fairly static.

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. It will be noted in particular that in the embodiment illustrated in FIG. 1, the liquid crystal display cell 12 and the first solar cell 22 each have a clearance, respectively 52 and 54, for the passage of the pins axes of the hours and minutes. Similarly, a through hole 56 is formed on the edge of the bearing surface 26 of the plate 24 and the backlight device 40 is pierced with a hole 58. Similarly, the second solar cell 220 is pierced with a hole 60 in its center and the plate 24 is provided with a hole 62 delimited by a guide flange 64.

Claims (23)

1. Timepiece comprising a dial (2) under which is disposed a digital information display device, a window (10) formed in the dial (2) of the timepiece allowing a user to read the information displayed by the digital information display device, the dial (2) having an upper face (4) and a lower face (6) and the digital information display device having an upper display surface information, the timepiece being characterized in that the digital information display device is fixed directly by its upper surface for displaying information on the lower face (6) of the dial (2). 2. Timepiece according to claim 1, characterized in that the digital information display device is secured by bonding to the underside (6) of the dial (2). 3. Timepiece according to claim 2, characterized in that the digital information display device is secured to the underside (6) of the dial (2) by means of an adhesive layer (20). 4. Timepiece according to one of claims 1 to 3, characterized in that the digital information display device is flexible. 5. Timepiece according to claim 4, characterized in that the digital information display device is a liquid crystal display cell (12). 6. Timepiece according to claim 5, characterized in that a solar cell (22, 220) is arranged under and at a short distance from the dial (2), this solar cell (22, 220) having a shape complementary to the shape of the liquid crystal display cell (12), the sum of the surface of the liquid crystal display cell (12) and the solar cell (22, 220) substantially that of the dial (2) . 7. Timepiece according to claim 6, characterized in that the solar cell (22, 220) comprises an opening (221) in which is housed the digital information display device when the solar cell (22, 220 ) is mounted under the dial (2). 8. Timepiece according to one of claims 6 and 7, characterized in that the dial (2) is made of a transparent plastic material and is covered with a decorative layer whose opacity is adjusted according to the transmittance sought. 9. Timepiece according to claim 8, characterized in that the upper face (4) of the dial (2) is covered with a pattern consisting of an alternating and periodic repetition of horizontal lines (48) and vertical lines ( 50) to imitate a carbon texture, these horizontal lines (48) and these vertical lines (50) being obtained either by injection of a plastic material in a mold in an interior wall of which are machined structures to form as many areas in relief on the upper face (4) of the dial (2), either by pad printing or by electronic printing. 10. Timepiece according to one of claims 8 and 9, characterized in that the dial (2) is covered with a layer of paint, the opacity of which is adjusted as a function of the thickness of the layer of paint. and / or the concentration of pigments in the paint. 11. Timepiece according to claim 10, characterized in that the transmittance of the dial (2) of transparent plastic coated with paint is of the order of 45%. 12. Timepiece according to claim 6, characterized in that the dial (2) is covered with a layer of mother-of-pearl whose thickness is 150 µm) ± 20 µm and whose transmittance is adjusted to 35%. 13. Timepiece according to claim 12, characterized in that the mother-of-pearl layer is fixed on the upper face (4) of the dial (2) by means of a layer of optically transparent glue. 14. Display module for a timepiece, this display module (1) comprising a dial (2) under which is disposed a digital information display device, a window (10) formed in the dial (2) allowing a user to read the information displayed by the digital information display device, the dial (2) having an upper face (4) and a lower face (6) and the digital display device d information having an upper surface for displaying information, the digital information display device being fixed directly by its upper surface for displaying information on the lower face (6) of the dial (2). 15. Display module according to claim 14, characterized in that it further comprises a solar cell (22; 220) and a plate (24), the solar cell (22; 220) being received in the plate (24 ) so that the solar cell (22; 220) is located under and at a short distance from the dial (2), the assembly formed by the dial (2) and the digital information display device being disposed above the solar cell (22; 220). 16. Display module according to claim 15, characterized in that the assembly formed by the dial (2) and the digital information display device on the one hand, and the solar cell (22; 220) d 'on the other hand, are removably attached to an upper side of the plate (24). 17. Display module according to claim 16, characterized in that the assembly formed by the dial (2) and the digital information display device on the one hand, and the solar cell (22) on the other part are detachably immobilized on the plate (24) by means of flexible locking hooks (42). 18. Display module according to one of claims 15 to 17, characterized in that a backlighting device (40) is arranged on a lower side of the plate (24) and is detachably fixed thereon. this. 19. Display module according to claim 18, characterized in that, for the axial maintenance of the solar cell (22; 220), the plate (24) comprises a bearing surface (26) whose area is substantially equal to that of the solar cell (22; 220) and in that, for its radial retention, the solar cell (22; 220), is provided along its outer perimeter with at least one lug (28) or a notch (44) which cooperates with a housing (30), respectively with a corresponding stud (46) provided on the periphery of the plate (24). 20. Display module according to claim 19, characterized in that the assembly formed by the dial (2) and the digital information display device is disposed over the solar cell (22) and comes to bear on a peripheral edge (36) of the plate (24), the digital information display device located directly above an opening (38) formed in the plate (24) and the extent of which corresponds substantially on the surface of the digital information display device, this opening (38) allowing the backlight device (40) mounted on the underside of the plate (24) to illuminate the digital information display device by the 'back. 21. A method of manufacturing a timepiece comprising a dial (2) under which is disposed a digital information display device, a window (10) formed in the dial (2) of the timepiece allowing a user to read the information displayed by the digital information display device, the dial (2) having an upper face (4) and a lower face (6) and the digital information display device having an upper information display surface, the method being characterized in that the upper information display surface is provided with an adhesive layer (20) and in that the digital display device is laminated information in order to be able to fix it directly by its upper surface for displaying information on the lower face (6) of the dial (10) by means of the adhesive layer (20). 22. Method according to claim 21, characterized in that, after fixing the digital information display device on the dial (10), the assembly is passed through an autoclave in order to expel any air trapped between the layer adhesive (20) and the dial (10). 23. Method according to claim 22, characterized in that the pressure in the autoclave is 6 bars, the treatment temperature is of the order of 50 ° C and the treatment time is approximately 30 min.