EP1014231A1 - Wrist watch with capacitive coupling - Google Patents

Abstract

The watch and wrist strap (30) include: - a housing (32) fitted with a first electrical conductor (50) and an electrical circuit (36) connected to the first conductor (32), and; - a strap (34) including a second electrical conductor (42). The first and second electrical conductors (50,42) are arranged to form a non mechanical contact electrical connection. The housing (32) and the strap (34) have respectively first and second external surfaces (49,41). The first and second conductors (50,42) are arranged near to the external surfaces (49,41). The second external surface (41) is arranged near to the first external surface (49) so that the first and second conductors (50,42) form the two electrodes of a capacitor so that capacitive coupling is formed between the two conductors.

Description

The present invention relates to the technical field of wristwatches and, more particularly, that of wristwatches comprising a housing provided with a first electrical conductor, and an electrical circuit connected to the first electrical conductor, and a bracelet comprising a second electrical conductor.

Referring to Figure 1 of this description, the patent EP 0 186 804 describes a wristwatch 1 comprising a case 3 and a bracelet 5 associated with this case. The housing 3 includes an electrical circuit 7 fitted with an integrated circuit (not shown in Figure 1) and a device display 9, the case 3 being closed by a glass 11. The bracelet 5 comprises two strips 12a and 12b formed in a plastic material flexible, and a conductor 24a disposed between these two strips. Lamella 12a comprises a thick zone 26, of convex shape in which is arranged a transverse opening 27 intended to receive a pin 28 by means of which the bracelet 5 is articulated to the case 3.

A problem encountered in wristwatch 1 lies in the making an electrical connection between the electrical circuit 7 of the housing 3 and the strap 24a driver 5.

The solution according to this patent EP 0 186 804 consists in making a connection electrical by mechanical contact between electrical circuit 7 and the conductor 24a. Thus, the wristwatch 1 comprises a joining device 13 comprising a contact set 15 consisting of a rigid conductive element 17, an elastic conductive element 19, and a cylindrical pin 21, these components being arranged to make the electrical connection between the conductor 24a and the integrated circuit 7.

However, such an electrical connection has several drawbacks. In indeed, an alteration of this electrical connection can occur for reasons sealing (in particular an oxidation of the components of the junction) and reasons for maintaining the wristwatch (especially when replacement of the bracelet with a new bracelet).

Another disadvantage of wristwatch 1 is that the rotation of the bracelet 5 around the axis 28 of the case 3 is limited, due to the presence of the joining device 13 which is fixed relative to this case, which limits the comfort of the wearer of the wristwatch 1.

Another disadvantage of wristwatch 1 is that the choice of materials used to form the housing 3 is limited to achieve electrical insulation of the electrical connection between the integrated circuit 7 and the conductor 24a.

An object of the present invention is to provide a wristwatch comprising a housing provided with a first electrical conductor and a electrical circuit connected to the first electrical conductor, and a bracelet comprising a second electrical conductor, this case and this bracelet being arranged to make an electrical connection between them, while overcoming the disadvantages mentioned above.

Another object of the present invention is to provide such a wristwatch arranged to prevent damage to the electrical connection between the first and second electrical conductors.

Another object of the present invention is to provide such a wristwatch whose arrangement of the electrical connection makes replacement easy of the bracelet.

Another object of the present invention is to provide such a wristwatch whose arrangement of the electrical connection does not limit the movement of the bracelet in relation to the case, to improve the comfort of the wearer of the wristwatch.

Another object of the present invention is to provide such a wristwatch whose arrangement of the electrical connection does not limit the choice of materials used to form the case.

Another object of the present invention is to provide such a wristwatch addressing common concerns in an application timepiece of size and rationality.

Another object of the present invention is to provide a wristwatch responding to a common concern in the cost industry.

These and other goals are achieved by the wristwatch according to claim 1.

An advantage of the arrangement of the first and second conductors of such a wristwatch is to make a contactless electrical connection mechanical and, more specifically, by a capacitive coupling between the first conductor of the case and the second conductor of the bracelet, which does not requires no additional external hardware arrangement in addition to the classic joint between the bracelet and the case.

Another advantage of such a provision of the first and second is to avoid limiting the movement of the bracelet by compared to the case, as is the case in wristwatches due to the presence of a mechanical or galvanic contact between the first conductor of the case and the second conductor of the bracelet.

Another advantage of such a provision of the first and second conductors is to facilitate the replacement of the bracelet by another similar bracelet, without there being, after this replacement, deterioration material of the electrical connection between the first conductor of the case and the second conductor of the bracelet.

• la figure 1 déjà citée représente une vue de coupe partielle d'une montre-bracelet classique;
• la figure 2 représente une vue de coupe partielle d'une montre-bracelet selon la présente invention; et
• la figure 3 représente une variante de réalisation du bracelet de la montre-bracelet de la figure 2.

These objects, characteristics and advantages, as well as others, of the present invention will appear more clearly on reading the detailed description of two preferred embodiments of the invention, given by way of example only, in relation to the attached figures, among which:

• Figure 1 already cited shows a partial sectional view of a conventional wristwatch;
• Figure 2 shows a partial sectional view of a wristwatch according to the present invention; and
• FIG. 3 represents an alternative embodiment of the bracelet of the wristwatch of FIG. 2.

Referring to Figure 2, the wristwatch 30 includes a case 32 and a bracelet 34 associated with this case. The housing 32 includes a circuit 36 with an integrated circuit (not shown in Figure 1), the housing 32 being closed by a crystal 38. The bracelet 34 includes a strip 40 formed in a flexible plastic material. Lamella 40 includes a zone thick 44 having an external surface 41 of rounded shape in which is arranged a transverse opening 46 which can receive an axis 48 by means from which the bracelet 34 is articulated to the case 32. The bracelet 34 comprises also an electrical conductor, or second conductor 42, incorporated in the strip 40, in the external part of its rounded shape.

The housing 32 further comprises an external surface 49 and a electrical conductor, or first conductor 50, connected to the circuit electric 36, and disposed in the vicinity of the external surface 49.

The external surface 49 of the housing 32 is arranged opposite the outer surface 41 of the strap 34, so that the conductors 42 and 50 form the two electrodes of a coupling capacitor, which achieves a capacitive coupling between bracelet 34 and case 32. It emerges from this provision that an electrical connection is made without mechanical contact and, more precisely, by capacitive coupling, between the conductor 42 and the circuit electric 36.

Typically, each of the conductors 42 and 50 by forming a metallic layer having an area equal to a few square millimeters, and covered with an electrically insulating material.

An advantage of the arrangement of such an insulating material on the conductors 42 and 50 is to prevent the oxidation of these conductors.

Another advantage of the arrangement of such an insulating material on the conductors 42 and 50 is to improve the water resistance of the wristwatch 30.

In the example shown in Figure 2, the wristwatch 30 includes in addition a conductor 51 arranged to form an electrical connection between the conductor 50 and electrical circuit 36.

By way of example, the bracelet 34 can also include a antenna 52, one of the electrodes of which is formed by conductor 42, as shown in Figure 2.

An advantage of this arrangement of the antenna 52 in the bracelet 34 is to connect the antenna 52 to the electronic circuit 36, without making a galvanic electrical connection between these two components.

Another advantage of this arrangement of the antenna 52 in the bracelet 34 is to reduce the size of the housing 32.

As an alternative embodiment, Figure 3 shows a view partial of a bracelet 60 of a wristwatch according to the present invention. Note that the case (not shown) of this watch is similar to the box 32 of Figure 2. We also note that objects of Figure 3 similar to those described in connection with Figure 2 have been designated by same references. As shown in Figure 3, the '60 patent includes a coil 62 provided with two conductors 52 arranged to form two respective couplings similar to that described in connection with FIG. 2, which makes two electrical connections between the case and the bracelet 60.

Referring again to Figure 2, and in the particular case where the case 32 is formed from a metallic material, case 32 can comprise two zones 54 and 56 formed in an electrically material insulator, and arranged on either side of the conductor 50, so as to realize the electrical insulation between the conductor 50 and the metal box of wristwatch 30. Zones 54 and 56 can be produced by forming a single annular part arranged around the conductor 50.

An advantage of this arrangement of the insulating zones 54 and 56 is that electrically isolate the electrical circuit made in the wristwatch 30, with respect to external disturbances of an electrical nature and magnetic.

Another advantage of this arrangement of the insulating zones 54 and 56 is to avoid the formation of a parasitic coupling, in particular in the case where the box 32 is arranged to form the mass of electrical circuit 36.

As an improvement, the conductor 42 is arranged in the bracelet 34, to have a rounded shape suitable for the rounded shape of the bracelet 34, so that, once the bracelet 34 is mounted on the case 32, the same distance is present between conductors 42 and 50, whatever the position of the bracelet 34 relative to the case 32.

An advantage of this arrangement of conductors 42 and 50 (in particular of the equal distance between these two conductors) is to ensure a constant capacity of the coupling capacitor formed by these conductors, whatever the position of the bracelet 34 relative to the case 32.

Another advantage of this arrangement of conductors 42 and 50 is to facilitate the adaptation of the wristwatch 30 to the different sizes of wrist, without any influence on the electrical connection between the circuit 36 and the conductor 42.

It goes without saying for those skilled in the art that the detailed description above may undergo various modifications without departing from the scope of this invention. For example, a capacitive coupling can be made between the bracelet and case, at each of the two joints of the bracelet to the case.

Claims (7)

Wrist watch (30) comprising: a housing (32) provided with a first electrical conductor (50) and an electrical circuit (36) connected to said first electrical conductor, and a bracelet (34) comprising a second electrical conductor (42), characterized in that said first and second electrical conductors are arranged to make an electrical connection without mechanical contact. Wrist watch (30) according to claim 1, characterized in that: said case (32) and said bracelet (34) respectively have first and second external surfaces (49, 41); in that said first and second electrical conductors are disposed respectively in the vicinity of said first and second external surfaces; and in that said second surface external is arranged opposite said first external surface, so that said first and second electrical conductors form the two electrodes of a coupling capacitor, for making said connection electric by capacitive coupling between said first and second electrical conductors. Wrist watch (30) according to claim 2, characterized in that said second electrical conductor (50) is arranged to have a shape suitable for said second external surface, so that, once said bracelet mounted on said case, the same distance is present between said first and second electrical conductors, whatever the position of said bracelet with respect to said case. Wrist watch (30) according to claim 2, characterized in that said bracelet (34) incorporates an antenna (52), one of the electrodes of which is formed by said second electrical conductor (42), so that a once said bracelet mounted on said case, said antenna is connected electrically to said first electrical conductor, via said capacitive coupling. Wrist watch (30) according to claim 2, characterized in that it also includes an electrical circuit (36) connected to said first electrical conductor, so that once said bracelet is mounted on said said electrical circuit is electrically connected to said second electrical conductor, through said capacitive coupling. Wrist watch (30) according to claim 1, characterized in that each of said first and second electrical conductors (42, 50) is formed of a metallic layer covered with an insulating material electrically. Wrist watch (30) according to claim 1, characterized in that said housing is formed from a metallic material, and that said housing includes first and second zones (54, 56) formed in a electrically insulating material, and arranged on either side of said first electrical conductor, so as to achieve electrical insulation of said wristwatch.

Images