Needle solar for portable object such as a timepiece or a measuring instrument.

[0001] l'invention relates to a needle solar display for a portable object. The present invention relates in particular to a needle set display solar for a timepiece such as a wristwatch or a measuring apparatus with analog display.

[0002] in a known manner, to timepieces are equipped with a dial formed of a solar cell comprising a substrate, at least a plurality of superimposed layers defining at least one element n-aldehydes or P-n junction and a conductive layer forming a first electrode arranged to be exposed to light to be able to supply a clockwork or an electrical circuit of a timepiece such as a watch.

[0003] the document EP is 0,872 783 describes a dial formed of a solar cell for a timepiece. Such a dial is an aesthetically objectionable and average electrical performance. Indeed, a dial formed of a solar cell is to be translucent so that it less visible and cannot receive any kind of finishes or specific color.

[0004] l ' present invention has amongst its aims to overcome the various disadvantages of these known techniques.

[0005] more specifically, an object of the invention is to provide a needle display formed of a solar cell to be able to circumvent sundials.

[0006] these objectives, as well as others which will appear more clearly later, are achieved according to the invention using a needle display for a portable apparatus providing an indication through the needle display, wherein is housed a power source into electrical energy.

[0007] according to the invention, the needle display is formed of at least one solar cell, the electrical energy power source being connected to the at least one needle display to be recharged.

[0008] thus, the object of the present invention, structural and functional aspects different parses described above, provides a control member relatively compact while having a long stroke.

[0009] in accordance with a preferred embodiment of the invention, the solar cell is a heterojunction. l'invention also relates to a portable apparatus comprising at least a first needle and a second needle display display each being formed of at least one solar cell.

[0011] according to an advantageous feature of the invention, the first and second needle display are superimposed and each provided with a hole for the passage of a drive axis, the drive axis of the second needle display being arranged concentrically within the drive axis of the first needle display with interposition of an insulating layer between the two drive shafts, each of the first and second needles display comprising a first and a second pole, the first pole of the first needle display being electrically connected to a first terminal of the power source through the drive axis of the first needle display, the second pin of the first needle display being connected to the first pole of the second needle display via a contact piece which provides electrical continuity between the first and second needle display, and the second pin of the second needle display being connected to the second terminal of the power source through the drive axis of the second needle display.

[0012] according to a further preferred feature, the contact part is centered on the drive axis.

[0013] advantageously, each of the first and second needles display comprises a first, a second ring member respectively at the center a hole for passage of the drive axis of the first, respectively the second needle display, the first and second ring members each having a top surface portion facing towards the side of an observer, and a portion of lower surface opposite the upper surface portion, the first and second ring members being formed of an electrically conductive material, the first and second annular members each supporting the first and second needle display.

[0014] l'invention also relates to a timepiece comprising at least one needle according to the invention.

[0015] d'other features and advantages of the invention will appear more clearly upon reading of the following description of a particular embodiment of the invention, given as a single illustrative example and not limiting, and figures included, among which:

the Figures 1 and 2

figures 3 and 4 the

Figure 5

are views of top and bottom by a needle set includes a solar cell according to the invention;

are exploded views of a needle set comprising a solar cell according to the invention, is a sectional view of a needle set comprising a solar cell according to the invention.

[0016] a control member according to a particular embodiment will now be described in the following with reference to Figures 1 and 2 together.

[0017] l'a needle display 1 for a portable apparatus providing an indication through the needle display 1, and in which is housed a power source 36 into electrical energy.

[0018] according to the invention, the needle display 1 is formed of at least one solar cell, the power source 36 into electrical energy being connected to the needle display 1 to be recharged.

[0019] although the skilled person may think that a needle set 1.2 solar cannot suffice as a source of energy compared to a dial, the inventor has demonstrated that a set of paints and the like solar could provide a source of energy that is comparable.

[0020] assuming that at the surface of the watch has been a luminance-L, the power produced by the watch sundial is given by the following equation:

The PC=LxR e_C. X-T-_C. X-TH_C. (1) x tan

[0021] where SC is the surface of the dial, the T_C. the transmission, I_C. the efficiency of the solar cell and T_G transmitting the ice.

[0022] typically, observed the following values for the equation (1):

- E_C. X preferably Lo W-=8; T-_C. =0.35; I_C. =0.04

[0023] by integrating these values in the equation (1), there is obtained:

The PC=X-LxTq 1.12 x 10"⁵ (2) W IS

[0024] for a portable apparatus, such as a watch, with needles solar, the power produced is given by the following equation:

P_A =LXR E_A X-TH_A X-T-_G (3)

[0025] where s_A is the surface of two hands, and e_A the efficiency of the solar cell of the needles.

[0026] for a needle set hour minute the surface S._A =4.4 x 10^-5 the m² .

[0027] according to a preferred embodiment of the invention, the solar cell forming the needle display 1 is a heterojunction.

[0028] the heterojunction solar cells are obtained by contacting materials different energy gap. For example, the heterojunction silicon comprises contacting the hydrogenated amorphous silicon (-Si: hr) with the crystalline silicon (c-Si), the energy gap doped a-Si: H being higher than that of the c-if. The conductivity doped a-Si: H being very much less than that of the c-if, to add a conductive layer over its entire surface in order to collect current. On the illuminated face of the cell, this conductive layer is typically formed of a transparent conductive oxide (CTO) which collects the current. The CVB also ensures good contact with the metal electrodes, while acting as an anti-reflection coating.

[0029] heterojunction cells currently available efficacy with th_A =0.22. The thickness of such a cell is 150 MW, which is comparable to the thickness of the needles traditionally used in the portable objects such as watches.

[0030] by integrating the previous values in the equation (3), obtained:

P_A =T-LxR_G the X 0.97 x 10^-5 (4) W.

[0031] the luminance and transmitting the ice being the same for both cases, the power obtained in the equations (2) and (4) is to the conditions in both cases.

[0032] thus, the solution of the needles solar present to appreciate that circumvent restrictions on the decorations of the dial for a watch for example, the dial can be realized in the material, the color and the desired finish.

[0033] the needles solar can be realized by using a known method and described in EP 0,948 060 on behalf of Asulab its. Patent describes the manufacture of a photovoltaic cell forming a circular dial for a timepiece such as a watch. However, in this Patent the invention is not limited to the dials, and can be used in the manufacture of photovoltaic cells of any other shape, especially the manufacture of solar needles.

[0034] to convey the solar energy collected by the needles, a particular structure is to be provided by that one of the poles of one of the hands solar is connected to one of the poles of the other hand solar by electrical contact between the two needles, thereby enabling the use of the drive shafts of the two needles for electrical connection of solar needles across the power source. Such a structure is described by the applicant in the specification of European Patent Number 14,170 094, 8. In the description that follows, the structure of this application has been tailored to solar using needles.

[0035] in the example illustrated in fig. 1 and 2 to, the needle set according to the invention comprises a first and a second needle display, respectively 1 and 2. the first needle display 1 is formed of a first annular member 4 extended by a portion 6 can be formed by at least one solar cell and extending substantially plane. The first annular member 4 has in its center a hole 8 for the passage of a drive shaft 10 of the first needle display 1. the first annular member 4 is provided with an upper surface portion 12 facing towards the side of an observer, and a lower surface portion 14 opposite the upper surface portion 12. the portions of top surface 12 and bottom 14 of the first annular member 4 are connected to each other all along their perimeter by a side surface 16. According to a feature of the invention that will be described in more detail below, the first annular member 4 is coated with a layer of electrically conductive material on its upper surface portions 12 and 14 as well as in the lower hole 8 into which engages a drive shaft 10.

[0036] similarly to the first needle 1 display, the second display hand 2 is formed of a second annular member 18 extended by a portion 20 can be formed by at least one solar cell and extending substantially plane. The second ring member 18 of the second needle display 2 has in its center a hole 22 for the passage of a drive shaft 24 disposed concentrically within the drive shaft 10 of the first needle display 1. the second ring member 18 is provided with an upper surface portion 26 directed at the side of an observer, and a lower surface portion 28 opposite the upper surface portion 26. The portions of upper surface 26 and bottom 28 of the second annular member 18 are connected to each other all along their perimeter by a side surface 30. According to a feature of the invention that will be described in more detail hereinafter, the second ring member 18 is also coated with a layer of electrically conductive material on its upper surface portions 26 and 28 as well as in the lower hole 22 into which engages a drive shaft 24.

[0037] the first and second needles 1 and 2 comprise first and second poles, respectively 32a, 32b and 34a, 34b, for their electrical connection to a power source 36 into electrical energy housed within a frame for example a wristwatch fitted with the needle set display 1.2. The power source 36 into electrical energy is for example a rechargeable battery.

[0038] the first pole 32a of the first light source 32 is connected to the power source 36 via the drive shaft 10 of the first needle 1, and the second pole 32b of the first light source 32 is connected to the first pole 34a of the second light source 34 in a manner which will be described in detail below. As to the second pole of the second source 34b light 34, it is connected to the power source 36 via the drive shaft 24 of the second needle display 2. to this end, the drive shafts 10 and 24 first and second needles display 1 and 2 must be electrically conductive and must be electrically insulated with respect to each other by interposing an insulating layer 38.

[0039] as mentioned above, the first and second ring members 4 and 18 are coated on their upper and lower surface portions of a layer of an electrically conductive material. More specifically, the drive shaft 24 is displaced into a hole 22 formed in the metalized second annular member 18. consequently, the upper surface portion 26 of the second annular member 18 is increased to the same electrical potential as the drive shaft 24. In contrast (see fig. 4), a continuous trench 40 formed in the lower surface portion 28 of the second annular member 18 and rendered electrically insulating by local ablation of the electrically conductive material surrounds the drive shaft 24, so that said lower surface portion 28 is electrically isolated from the drive axis 24. Similarly, a continuous trench 42 which closes on itself and which is rendered insulative in the same way as the continuous trench 40 is formed in the upper surface portion 26 of the second annular member 18, so as to create an island 44 electrically isolated from the remainder of the upper surface portion 26. A through hole 46 bored in the thickness of the metalized second ring member 18 in order to electrically connect together the island 44 formed in the upper surface portion 26 and lower surface portion 28.

[0040] similarly, the drive shaft 10 is displaced into a hole 8 formed in the metalized first annular member 4. consequently, the lower surface portion 14 of the first annular member 4 is supported at the same electric potential as the drive shaft 10. In contrast, a continuous trench 48 formed in the upper surface portion 12 of the first annular member 4 and rendered electrically insulating by local ablation of the electrically conductive material surrounds the drive shaft 10, so that the upper surface portion 12 is electrically isolated from the drive shaft 10. Similarly, a continuous trench 50 which closes on itself and which is rendered insulative in the same way as the continuous trench 48 is provided in the portion of lower surface 14 of the first annular member 4, so as to create an island 52 electrically isolated from the remainder of said lower surface portion 14. A through hole 54 drilled in the thickness of the metalized first annular member 4 in order to electrically connect each other pile 52 formed in the lower surface portion 14 and the upper surface portion 12.

[0041] finally, lower surface portion 28 of the second annular member 18 is brought into contact with the upper surface portion 12 of the first annular member 4 via a contact piece 56 mechanically resilient electrically conductive and disposed between the first and second needles display 1 and 2 and centered on the drive shaft 10. The island 44 formed in the upper surface portion 26 is thus electrically connected to the upper surface portion 12 of the first annular member 4, the upper surface portion 12 itself being electrically connected to the island 52 formed in the lower surface portion of the first annular member 14 4.

[0042] according to the invention, the first pole 32a is electrically connected to a first terminal of the power source 36 via the drive shaft 10 of the first needle display 1. To this end, the first pole 32a is connected, for example by wiring by wire known widely as its terminology transceivers "Bonding", to the lower surface portion of the first annular member 14 as to the second pole 4 . 32b, it is connected to the first pole 34a via the contact piece 56 which provides electrical continuity between the first and second needle display 1, for this 2 ., the second pole 32b is connected to the island 52 formed in the lower surface portion of the first annular member 14 4. via the plated-through hole 54 drilled in the thickness of the first annular member 4, the island 52 is electrically connected to the upper surface portion 12 of the first annular member 4, this upper surface portion 12 itself being connected by the contact piece 56 to lower surface portion 28 of the second annular member 18. lower surface portion 28 of the second annular member 18 is in turn connected to the island 44 formed in the upper surface portion 26 of the second annular member 18 via the metalized through 46. Finally, the first pole 34a is electrically connected to the island 44 formed in the upper surface portion of the second annular member 18 . 26 as to the second pole 34b, it is connected to the second terminal of the power source 36 via the drive shaft 24. For this, the second pole 34b is electrically connected to the upper surface portion 26 of the second annular member 18.

[0043] of course, the present invention is not limited to the illustrated example and is suitable for various variations and modifications apparent to those skilled in the relevant arts.

[0044]

1. first needle display,

2. second needle display,

4. ring element,

6. portion extending substantially plane,

8. hole,

10. Drive axis,

12. upper surface portion,

14. Lower surface portion,

16. Side surface,

18. ring element,

20. Portion extending substantially plane,

22. hole,

24. Drive axis,

26. Upper surface portion,

28. Lower surface portion,

30. Side surface,

32A, 32B. First and second poles,

24A, 34B. First and second poles,

36. Power source into electrical energy,

38. Insulating layer,

56. Contact piece.