COVER COMPONENT OF A CLOCK WITH A PHOTOVOLTAIC CELL AND CLOCK WITH THIS COVER COMPONENT

Description

Technical field of the invention

[0001] The invention falls within the field of watch case components.

[0002] More specifically, the invention relates to a watch case component comprising a photovoltaic cell and a watch comprising said case component. Prior art examples relating to a watch case component comprising a photovoltaic cell are disclosed by patent DE 697 35 159 T2. Technological background

[0003] Beyond a certain surface area, typically a few tenths of a square centimeter or a few square centimeters, photovoltaic cells made of semiconductor material have an upper electrode in the form of a network of metallic lines formed in a grid and a lower electrode arranged on either side of an elementary solar cell.

[0004] The top electrode is positioned on the side of the photovoltaic cell exposed to incident light and its function is to collect the charge carriers generated by the elementary solar cell. The arrangement of the top electrode on the surface of the solar cell results from a compromise between the degree of shading of the face of the solar cell on which it is deposited and the optical absorption of the elementary solar cell.

[0005] In the case of a photovoltaic cell intended for use on a watch face, for aesthetic reasons, the top electrode is usually positioned so as not to be seen by the user, leaving only the individual solar cell visible. This significantly reduces the efficiency of the photovoltaic cell, particularly in bright sunlight, due to the electrical resistance induced by the hidden electrode, which is less efficient than that of a visible electrode.

[0006] To overcome this drawback, watches have been designed to feature a dial with holes invisible to the naked eye or a translucent dial superimposed on a photovoltaic cell, this type of approach allowing the electrode arranged on the cell to be hidden.

[0007] The photovoltaic cell is therefore not or barely visible to a user, but these solutions are not satisfactory insofar as the dial blocks part of the light radiation likely to reach said photovoltaic cell, which negatively impacts its efficiency. Summary of the invention

[0008] The invention resolves the aforementioned drawbacks and relates, for this purpose, to a watch casing component comprising a photovoltaic cell including an elementary solar cell interposed between two electrodes, one of which, called the "upper electrode", is arranged on a face of the elementary solar cell intended to be subjected to incident light radiation and intended to be visible to a user.

[0009] The upper electrode is formed by segments connected to each other and arranged according to a predetermined pattern, for example, conforming to a graphic representation of a constellation, the photovoltaic cell being intended to be electrically connected to an electronic clock movement.

[0010] The upper electrode has a peripheral portion arranged around the periphery of the face of the elementary solar cell, designed to receive incident light radiation. The peripheral portion defines an area within which the segments extend, these segments being connected to the peripheral portion.

[0011] Advantageously, the upper electrode can thus generate a decoration while allowing the photovoltaic cell to have improved efficiency without detracting from the aesthetics of the room.

[0012] In particular embodiments, the invention may further include one or more of the following features.

[0013] This characteristic helps to increase the efficiency of the photovoltaic cell by improving the collection of charge carriers and lowering the resistance of the upper electrode.

[0014] According to the claimed invention, the casing component comprises a dial with an aperture facing which the photovoltaic cell is configured to be positioned. The casing component further includes a movable display interposed between the dial and the photovoltaic cell and intended to be driven by the watch movement so that at least a portion of its travel is visible through the aperture.

[0015] Thanks to the features of the invention, the photovoltaic cell can be integrated, for example, into a moon phase module, and in particular, the elementary solar cell can form the background of the moon phase.

[0016] According to another aspect, the present invention relates to a watch comprising an electronic watch movement and a casing component as described above, in which the load-bearing structure is formed by a bridge or plate of the watch movement.

[0017] In particular embodiments, the watch includes the casing component, and the photovoltaic cell materializes a moon phase background and represents a celestial vault, the movable display including at least one representation of a moon.

[0018] The present invention makes it possible, by means of the segments of the upper electrode, to generate a graphic representation of a constellation in order to generate a decoration while increasing the efficiency of the photovoltaic cell. Brief description of the figures

[0019] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings in which: there figure 1 schematically represents a front view of a photovoltaic cell of a housing component according to a preferred embodiment of the invention; the figure 2 schematically represents a perspective view of part of a trim component according to a preferred embodiment of the invention; the figure 3 represents a cross-sectional view of a casing component installed on a watch movement. Detailed description of the invention

[0020] There figure 1 This shows a watch case component 10 according to an embodiment of the invention. The watch case component 10 comprises a photovoltaic cell 20 having an elementary solar cell 21 interposed between two electrodes. The photovoltaic cell 20 is intended to be electrically connected to an electronic watch movement 30 of the watch.

[0021] The watch movement 30 includes an electricity storage unit, such as a battery, intended to supply energy, via an electronic circuit 32, to at least one electric motor which drives an hour display and a minute display via gears.

[0022] An electrode called the "upper electrode" 22 is intended to be visible to a user and is arranged on one face of the elementary solar cell 21 intended to be subjected to incident light radiation. A lower electrode, for example in the form of a thin metallic film (not shown in the figures), is arranged opposite the upper electrode 22 on the elementary solar cell 21.

[0023] The upper electrode 22 is formed by segments 220 connected one after the other, made of an electrically conductive material, for example a metallic material, such as gold or silver. These segments 220 are arranged according to a predetermined pattern of a graphic representation of at least one constellation, such as can be seen on the figures 1 and 2 .

[0024] Thus, the trim component 10 includes representations of stars, one representation of a star being arranged at the junction between two segments 220. The representations of stars can be made in the same material as that in which the segments 220 are made.

[0025] More specifically, as seen on the figures 1 and 2 The upper electrode 22 comprises a peripheral portion 221 connected to the segments 220 and arranged around the periphery of the face of the elementary solar cell 21, intended to receive incident light radiation. In other words, this peripheral portion 221 forms an area within which the segments 220 extend from said peripheral portion 221.

[0026] The peripheral portion 221 is connected to a connecting tab 23 intended to be connected to the clock movement 30 so as to transmit the electricity collected by the elementary solar cell 21 to the electricity storage unit. More specifically, the connecting tab 23 is intended to be connected to the electronic circuit 32, for example, by means of an anisotropic conductive heat-adhesive film, a zero-insertion-force connector, or a flexible printed circuit board portion fixed to the electronic circuit 32, for example, by means of an anisotropic conductive adhesive.

[0027] In a preferred embodiment of the invention, the casing component 10 comprises a dial 11, as shown in the figure 3, equipped with a window 110 towards which the photovoltaic cell 20 is configured to be arranged. Thus, a user can see the photovoltaic cell 20 through the window, and said photovoltaic cell 20 can be subjected to light radiation.

[0028] In the example implementation shown on the figures 2 and 3 The photovoltaic cell 20 is intended to be rigidly fixed, that is, fixed without any degree of freedom, for example by gluing, onto a supporting structure 31. Such a supporting structure 31 can be formed, for example, by a bridge, as shown in the figures 2 and 3 , or by a plate of the watch movement 30.

[0029] The casing component 10 further preferably includes a movable display 12 interposed between the dial 11 and the photovoltaic cell 20. The movable display 12 is intended to be driven in movement by the clock movement 30 so that at least part of its travel is visible through the window 110.

[0030] In particular, the movable display 12 includes at least one representation of a moon and is intended to be moved in front of the window 110 so that its movement corresponds with a lunar phase. In the embodiment shown in the figure 3The movable display 12 comprises at least one eccentric disc 120 representing a moon, fixed to the end of a rod 121 intended to be driven in rotation by the clockwork mechanism 30 such that said eccentric disc 120 moves along a circular path. Alternatively, the movable display 12 may comprise a disc made of a transparent material, on which at least one moon is represented in an off-center position. The disc is arranged to be driven in rotation by movement around an axis passing through its center, so that the representation of the moon moves along a circular path.

[0031] The moon can be represented by printing, such as pad printing, by engraving, or by any other suitable means known to a person skilled in the art.

[0032] The photovoltaic cell 20 materializes a moon phase background and represents a celestial vault whose background is the color of the elementary solar cell 21, and including at least one constellation represented by the upper electrode 22.

[0033] The elementary solar cell 21 comprises, in the preferred embodiment of the invention, at least one layer made of a semiconductor material, for example gallium arsenide or silicon, on which an anti-reflective layer is superimposed.

[0034] Advantageously, the upper electrode 22 of the photovoltaic cell 20 can be made by photolithography on a substrate consisting of the elementary solar cell 21.

[0035] Tests have demonstrated that a photovoltaic cell 20 according to the invention, having an elementary solar cell 21 of 0.3 cm², is capable of supplying sufficient electricity to the clock movement 30 to ensure its continuous operation, under an illumination of 1 W / m² and in a configuration of the upper electrode 22 as schematically represented in the figures 1 and 2 .

[0036] In another embodiment not covered by the wording of the claims, the photovoltaic cell 20 can be arranged on the dial 11, so that the upper electrode 22 represents a constellation on the face of the dial 11 intended to be visible.

Claims

1. An external part component (10) of a watch comprising a photovoltaic cell (20) including an elementary solar cell (21) interposed between two electrodes, one of which so-called "upper electrode" (22) is arranged over a face of the elementary solar cell (21) intended to be subjected to an incident light radiation, said upper electrode (22) being formed by segments (220) connected together and arranged according to a predetermined pattern, said upper electrode (22) including a peripheral portion (221) arranged at the periphery of said face of the elementary solar cell (21), the segments (220) extending within an area defined by said peripheral portion (221) and being connected to the latter, the photovoltaic cell (20) being intended to be electrically connected to an electronic horological movement (30), the external part component (10) being characterised in that it comprises a dial (11) provided with an aperture (110) opposite which the photovoltaic cell (20) is configured to be arranged, the external part component (10) further including a movable display (12) interposed between the dial (11) and the photovoltaic cell (20) and being intended to be driven in motion by the horological movement (30) so that at least one portion of its travel is visible through the aperture (110).

2. The external part component (10) according to claim 1, wherein the predetermined pattern matches with a graphical representation of a constellation3. A watch including an electronic horological movement (30) and an external part component (10) according to one of claims 1 or 2, wherein the photovoltaic cell (20) is fastened without any degree of freedom on a carrier structure (31) formed by a bridge or a plate of the horological movement (30).

4. The watch according to claim 3, including an external part component (10) according to claim 1 or 2, wherein the photovoltaic cell (20) materialises a lunar phase background and represents a sky vault, the movable display (12) including at least one representation of a moon.