EP1014231B1 - Wrist watch with capacitive coupling - Google Patents

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 the figure 1 of this description, the EP 0 186 804 describes a wristwatch 1 comprising a housing 3 and a bracelet 5 associated with this housing. The housing 3 comprises an electric circuit 7 provided with an integrated circuit (not shown in FIG. figure 1 ) and a display device 9, the housing 3 being closed by a lens 11. The bracelet 5 comprises two strips 12a and 12b formed in a flexible plastic material, and a conductor 24a disposed between these two strips. The lamella 12a comprises a thick zone 26 of curved shape in which is arranged a transverse opening 27 intended to receive an axle 28 by means of which the bracelet 5 is articulated to the casing 3.

A problem encountered in the wristwatch 1 lies in the achievement of an electrical connection between the electrical circuit 7 of the housing 3 and the conductor 24a of the wristband 5.

The solution according to this EP 0 186 804 consists in making an electrical connection by mechanical contact between the electric circuit 7 and the conductor 24a. Thus, the wristwatch 1 comprises a junction 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 produce the electrical connection between the conductor 24a and the integrated circuit 7.

US 5,159,713 describes another watch with the same type of electrical connection.

However, such an electrical connection has several disadvantages. Indeed, an alteration of this electrical connection can occur for sealing reasons (in particular an oxidation of the components of the junction device) and reasons for maintenance of the wristwatch (especially when replacing the bracelet with a new bracelet ).

Another disadvantage of the wristwatch 1 lies in the fact that the rotation of the bracelet 5 around the axis 28 of the housing 3 is limited, because of the presence of the junction device 13 which is fixed with respect to this housing, which limits the comfort of the wearer of the wristwatch 1.

Another disadvantage of the wristwatch 1 lies in the fact that the choice of materials used to form the housing 3 is limited to achieve electrical isolation 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 an 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 to each other, while overcoming the aforementioned drawbacks.

Another object of the present invention is to provide such a wristwatch arranged to prevent alteration of 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 it easy to replace the bracelet.

Another object of the present invention is to provide such a wristwatch whose arrangement of the electrical connection limits the movement of the bracelet relative to the housing, 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 housing.

Another object of the present invention is to provide such a wristwatch answering the usual concerns in a clock application of size and rationality.

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

These and other objects are achieved by the wristwatch of claim 1.

One advantage of the arrangement of the first and second conductors of such a wristwatch is to provide an electrical connection without mechanical contact and, more specifically, by a capacitive coupling between the first conductor of the case and the second conductor of the wristband, which does not require any additional external hardware arrangement in addition to the conventional articulation between the bracelet and the housing.

Another advantage of such an arrangement of the first and second conductors is to avoid a limitation of the movement of the bracelet relative to the case, as is the case in conventional wristwatches, due to the presence of a mechanical contact or galvanic between the first driver of the housing and the second conductor of the bracelet.

Another advantage of such an arrangement of the first and second conductors is to facilitate the replacement of the bracelet by another similar bracelet, without there being, after this replacement, a material deterioration of the electrical connection between the first driver of the housing 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 and other objects, features, and advantages of the present invention will become more apparent upon reading the detailed description of two preferred embodiments of the invention, given by way of example only, in connection with the attached figures, among which:

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

Referring to the figure 2 , the wristwatch 30 comprises a housing 32 and a bracelet 34 associated with this housing. The housing 32 comprises an electric circuit 36 provided with an integrated circuit (not shown in FIG. figure 1 ), the housing 32 being closed by an ice 38. The bracelet 34 comprises a blade 40 formed in a flexible plastic material. The blade 40 comprises a thick zone 44 having an outer surface 41 of rounded shape in which is arranged a transverse opening 46 able to receive an axis 48 by means of which the bracelet 34 is articulated to the housing 32. The bracelet 34 also comprises an electrical conductor, or second conductor 42, incorporated in the strip 40, in the outer portion of its rounded shape.

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

The outer surface 49 of the housing 32 is disposed facing the outer surface 41 of the bracelet 34, so that the conductors 42 and 50 form the two electrodes of a coupling capacitor, which provides a capacitive coupling between the bracelet 34 and the housing 32. It follows from this provision that an electrical connection is made without mechanical contact and, more precisely, by capacitive coupling, between the conductor 42 and the electrical circuit 36.

Typically, each of the conductors 42 and 50 are preferably formed by forming a metal layer having a surface area of 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 tightness of the wristwatch 30.

In the example shown in figure 2 the wristwatch 30 further comprises a conductor 51 arranged to form an electrical connection between the conductor 50 and the electrical circuit 36.

By way of example, the bracelet 34 may also comprise an antenna 52, one of the electrodes of which is formed by the conductor 42, as represented by FIG. 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 bulk of the housing 32.

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

Referring again to the figure 2 , and in the particular case where the housing 32 is formed of a metallic material, the housing 32 may comprise two zones 54 and 56 formed of an electrically insulating material, and arranged on either side of the conductor 50, so as to realize the electrical insulation between the conductor 50 and the metal case of the wristwatch 30. The zones 54 and 56 can be formed by forming a single annular piece arranged around the conductor 50.

An advantage of this arrangement of the insulating zones 54 and 56 is to provide electrical insulation of the electrical circuit made in the wristwatch 30, vis-à-vis external disturbances of electrical and magnetic nature.

Another advantage of this arrangement of the insulating zones 54 and 56 is to avoid the formation of a parasitic coupling, especially in the case where the housing 32 is arranged to form the ground of the electric circuit 36.

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

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

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

It is obvious to those skilled in the art that the detailed description above may undergo various modifications without departing from the scope of the present invention as defined in the claims. For example, one can achieve a capacitive coupling between the bracelet and the housing, at each of the two joints of the bracelet to the housing.

Claims (7)

1. Wristwatch (30) including:

   - a case (32) provided with a first electric conductor (50) and an electric circuit (36) connected to said first electric conductor (50), and

   - a wristband (34) including a second electric conductor (42), characterized in that said first (50) and second (42) electric conductors are arranged in order to realize an electric connection without mechanical contact.
2. Wristwatch (30) according to claim 1, characterized in that : said case (32) and said wristband (34) have respectively first and second outer surfaces (49, 41); in that said first and second electric conductors are respectively arranged in the vicinity of said first and second outer surfaces; and in that said second outer surface is arranged opposite said first outer surface, so that said first and second electric conductors form the two electrodes of a coupling condensator, in order to realize said electric connection by a capacitive coupling between said first and second electric conductors.
3. Wristwatch (30) according to claim 2, characterized in that said second electric conductor (50) is arranged to have a shape suited to said second outer surface, so that, once said wristband is mounted onto said case, there is the same distance between said first and second electric conductors, whatever the angular position of said wristband with respect to said case.
4. Wristwatch (30) according to claim 2, characterized in that said wristband (34) incorporates an antenna (52) whose one of the electrodes is formed by said second electric conductor (42), so that, once said wristband is mounted onto said case, said antenna is electrically connected to said first electric conductor, via said capacitive coupling.
5. Wristwatch (30) according to claim 2, characterized in that it also includes an electric circuit (36) connected to said first electric conductor, so that, once said wristband is mounted onto said case, said electric circuit is electrically connected to said second electric conductor, via said capacitive coupling.
6. Wristwatch (30) according to claim 1, characterized in that each of said first and second electric conductors (42, 50) is formed of a metal layer covered with an electrically insulating material.
7. Wristwatch (30) according to claim 1, characterized in that said case is formed of a metallic material, and in that said case includes first and second zones (54, 56) formed in an electrically insulating material, and arranged on either side of said first electric conductor, so as to achieve electric insulation of said wristwatch.

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