HK1012735B - Timepiece provided with an antenna - Google Patents

Description

The present invention relates to a watch part intended to be worn on the arm or wrist, which contains either a dipole antenna or a radiating slit antenna capable of picking up and/or emitting an electromagnetic field carrying radio broadcast messages, a case containing time display devices and a transmitter-receiver microphone which receives or transmits messages by means of the antenna.

Watch pieces already known to be equipped with a dipole antenna and a microreceptor to pick up radio signals. US Patent 5'317'326 in the name of Motorola, Inc., for example, describes a watch piece shaped like a wristwatch that has a folded dipole antenna housed in the wristband.

The installation of the antenna in the watch strap poses problems of connections between the transmitter-receiver which is located in the watch case and the antenna which is an integral part of the watch strap. The passage of conductive elements connecting the antenna to the receiver through the case therefore poses construction problems which lead to solutions which are never simple. In addition, at this passage, the conductive elements are mechanically applied in a nearly continuous manner when the watch is worn and break relatively quickly, if no means are put in place to prevent this break.

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However, placing the antenna in a watch case requires miniaturization of the antenna due to the very limited space available for mounting the antenna. If it is possible to reduce the antenna's dimensions to some extent for a given frequency, this will always be at the expense of its other characteristics, such as gain or bandwidth. At a fixed frequency, a miniature antenna will therefore have a lower gain and bandwidth than a normal-sized antenna placed in the bracelet.

Thus, the present invention is intended to provide a watchpiece of the type defined above which compensates for the disadvantages of the previous art.

The invention also aims to provide such a watchpiece whose antenna as such and its electrical dimensions are optimized.

The purpose of the invention is to provide a watch in which the construction of the antenna and its installation in the housing is simple and lightweight.

The invention relates to a watchpiece intended to be worn on the wrist, the part of which contains either a dipole antenna or a radiating slit antenna capable of picking up and/or emitting an electromagnetic field carrying radio broadcast messages, a first case comprising time-displaying devices and a micro-transmitter-receiver which receives or transmits messages by means of the antenna. The watchpiece is characterised by the first fact that it also includes a second case designed to receive the case so that the outer surface of the first bolt and the second inner surface of the case define a mounting, in that the mounting includes a radio-diode and a conductor element which is mounted in the antenna and a printed circuit board which is fixed on the mounting.

This combination of features allows the antenna to be manufactured independently of the other parts of the watch part and to be easily housed in the watch part when assembled in order to take advantage of the inherent dimensions of the watch part to optimise the electrical dimensions of the antenna.

According to one embodiment of the invention, the watch part also comprises a plane of mass located in the mounting groove between the antenna and the outer surface of the first case so that it surrounds this case.

Thus, the antenna can be electrically isolated from the disturbing elements inside the watch case.

Other features and advantages of the invention will be more clearly seen by reading the following detailed description, taken by reference to the attached drawings, which illustrates, by way of example, different modes of making the watch part of the invention and in which: Figure 1 shows a wrist wearing a watchpiece according to the present invention;Figure 2 is a plan view of the watchpiece in Figure 1;Figure 3 is a plan view of a first mode of making an antenna part of the watchpiece in Figure 1;Figure 4 is a plan view of a second mode of making an antenna part of the watchpiece in Figure 1;Figure 5 is a cut-out view of the watchpiece in Figure 2;Figure 6 is a perspective view of the antenna in Figure 3 wrapped around the case of the watchpiece in Figure 5;Figure 7 is a perspective view of a third mode of making the antenna part of the watchpiece in Figure 2;Figure 8 is a perspective view of the antenna in Figure 5;Figure 6 is a perspective view of the antenna in Figure 6 and the first mode of making the watchpiece in Figure 5;Figure 6 is a perspective view of the antenna in Figure 6;Figure 9 is a close-up view of a fourth antenna embodiment part of the watch movement in Figure 2.

Figure 1 shows a schematic of a forearm with a wristwatch 1 containing a case 2 and a bracelet 3.

Figure 2 is a plan view of the wristwatch 1 including case 2, wristwatch 3 and antenna 4. The wristwatch 1 also includes an additional case 5, which is arranged in the case 2. A transmitter-receiver microphone 6 is arranged in case 5 in addition to the time display organs including a movement 7, a dial 8, hands 9 and a power supply 10. The transmitter-receiver microphone 6 is connected to antenna 4 so that it receives or transmits messages using the latter and then transforms these messages into perceptible data by the wearer of the wristwatch 1, for example by emitting sound signals.

Referring now to Figure 3, it can be seen that antenna 4 comprises printed circuit elements 11 and 12 fixed to a dielectric substrate 13. Furthermore, to facilitate the assembly of the antenna in the watch case of the invention, substrate 13 is preferably flexible. For example, the commercially available materials Kapton® and Espanex® have been determined to be suitable in this respect.

The conductive element 11 defines a dipole. $\frac{\text{λ}}{\text{2}}$ The length of the arm is adjusted so that the impedance of the antenna is matched to a transmission line connecting the antenna 1 to the transmitter-receiver microphone 6 arranged in the housing of the watch piece of the invention.

The connection between antenna 4 and this transmission line is made at two excitation points 14 and 15, respectively, halfway along the conductive element 11 and on the conductive element 12.

Figure 4 shows a variant of the antenna in Figure 3. In this figure, we see that antenna 16 consists of printed circuit elements 17.1 and 17.2 mounted on a dielectric substrate 18.

The conductive element 17.1 forms a dipole. $\frac{\text{λ}}{\text{2}}$ The conductor 17.2 forms a compensating arm which is attached to this dipole. A relay of a capacitor 19 is connected to the end of the conductor 17.2 so as to form with the latter a gamma adaptive connection between the dipole 17.1 and the transmission line connecting antenna 1 to the microreceptor 6. The connection between antenna 16 and the transmission line is assigned to two excitation points, respectively half the length of the conductor 17.1 and the other relay of the capacitor 19.

Figure 5 is a cut-out view of the wristwatch 1. Watch part 1 includes the dipole antenna 4 of Figure 3 as well as the two boxes 2 and 5, the watch movement 7, the microreceptor 6 and the power battery 10 of Figure 2. Watch part 1 also includes a printed circuit board 20 mounted in the box 5, an ice pack 21, a bottom 22 and a transmission line 23. The microreceptor 6 is mounted on the printed circuit board 20.

Box 2 is designed to receive box 5 so that the outer surface of box 5 and the inner surface of box 2 define a mounting groove 25. As shown in Figure 6, the antenna 4 is located in mounting groove 25 so that it wraps around box 5.

The arrangement described above makes it possible to manufacture the antenna independently of the other parts of the watchmaking part, which facilitates the manufacture not only of the antenna but also of the watchmaking part itself.

In addition, this arrangement makes it easier to house the antenna when assembled in the watchmaking room in order to take advantage of the inherent dimensions of the watchmaking room and to optimise the electrical dimensions of the antenna.

Preferably, as shown in Figures 3, 4 and 5, the surface of the conductive elements 11 and 12 extends in the direction of the depth of the watch-wristwatch 1, i.e. in the direction between its bezel and its bottom. However, the optimization of the antenna 4 is related to this surface.

Antenna 4 is excited by means of transmission line 23 which connects antenna 4 to the microreceptor 6. The transmission line 23 is preferably a microrubane track. Alternatively, this transmission line could also be a coaxial cable.

Preferably, transmission line 23 passes through a cleared opening 26 in the side wall of the housing 5. By bringing the microreceptor 6 closer to antenna 4, this arrangement minimizes the length of transmission line 23 and thus losses due to it.

The wristwatch 1 could also include a mass plane 24. The mass plane 24 is located in the mounting groove 25 between the antenna 4 and the outer surface of the case 5 so that it surrounds the latter. The mass plane 24 has the advantage of electrically isolating the antenna 4 from the disruptive elements that are inside the watch 1 e.g. metal masses such as the movement 7, the microreceptor 6 and the power battery 10. Thus, the characteristics of the antenna 4 can be selected without consideration of the disruptive effects from inside the watch bracelets 1.

Figure 7 shows a third way of making the antenna of the watch part of the invention. This antenna 30 consists of a conductive printed circuit element 31 fixed on a dielectric substrate 32. As described above, the substrate 32 is preferably made of a flexible material. The conductive element 31 is preferably made by a metal deposit on the dielectric substrate 32.

A radiant slit 33 is formed in the conductive element 31. The professional knows that, according to Babinet's principle, this antenna is the dual of a conventional dipole antenna, such as the dipole formed by the conductive element 11. $\frac{\text{λ}}{\text{2}}$ , where λ is the wavelength of the electromagnetic signal that the antenna is intended to pick up.

The connection between antenna 30 and transmission line 23 is made at two excitation points 34 and 35, respectively, halfway along and on opposite sides of the radiating slot 33. If necessary, the adaptation of antenna 30 to the impedance of transmission line 23 may be made by means of a capacitor connected between one of the excitation points and one of the conductors of transmission line 23.

As shown in Figure 8, the antenna 30 is also located in the mounting groove 25 so that it is wrapped around the box 5.

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Finally, it should be noted that several modifications and/or improvements can be made to the object identification system according to the invention without going beyond the scope of the invention.

Claims (6)

1. Horlogical piece intended to be worn on the wrist, said piece including either a dipole antenna (4) or a radiating slot antenna (30; 40) able to receiver and/or emit an electromagnetic field bearing radio diffused messages, and a first casing (5) comprising

   - organs (7, 8, 10) for displaying the time of day,

   and

   - a micro emitter-receiver (6) which receive or emit messages detected by the antenna (4; 30; 40),

   characterized in that it further comprises a second casing (2) intended to receive said first casing (5) such that the exterior surface of said first casing and the interior surface of said second casing define a mounting slot or space 25, in that said antenna (4; 30; 40) comprises a dielectric subtract (13; 33; 43), and at least one printed circuit conductive element (11, 12; 31; 41) fixed to said subtract (13; 33; 43) and which definds a radiating element of said antenna (4; 30; 40), and in that said antenna (4; 30; 40) is located in said mounting slot or space (25) such that it is wound around said first casing (5).
2. Horlogical piece according to claim 1, characterized in that it further comprises a ground plate (24) located in said mounting slot between said antenna and the exterior surface of said first casing such that it surrounds this latter.
3. Horlogical piece according to either claims 1 or 2, characterized in that said dielectric subtract (13; 33; 43) is constituted by a flexible material.
4. Horlogical piece according to anyone of the preceding claims, characterized in that the surface of said conductive elements extend in the direction of the depth of said piece.
5. Horlogical piece according to anyone of the preceding claims, characterized in that it further comprises a transmission line (23) which connects said antenna (4; 30; 40) to said micro emitter-receiver (6), in that said first casing (5) includes an opening in its lateral wall, said transmission line (23) passing through said opening (26) to enable the approaching of said antenna (4; 30; 40) to said micro emitter-receiver (6)
6. Horlogical piece according to claim 5, characterized in that said antenna (16) is constituted by two conductive elements (17.1, 17.2) and a capacitor (19) connected to a first of said conductive elements so as to form a gamma adaptation connection between the second of said conductive elements and said transmission line (23).