JPH073923B2 - Band type antenna device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a band-type antenna device that can be used for a wrist watch such as a radio watch or a television watch.

[Prior art]

With the advent of radio watches and television watches in recent years, wrist watches, which are usually the only electronic devices worn by humans on the skin, have become increasingly sophisticated.
However, the earphones and antennas that are the auxiliary devices are poor in portability or inconvenient. For example, in a radio watch, if it is AM broadcast, the antenna is omitted, and its reception is completely dependent on the tuning circuit, and if it is FM broadcast, an external antenna is prepared. It is normal. In the case of a television watch, most of the main circuit including the antenna may be used by another device, and the wristwatch part may be used as a simple display device.

Now, when a human walks in a city and receives a radio broadcast or a television broadcast, the noise in the city is a mixture of both noise and radio noise. Therefore, for the former, earphones
For the latter, the antenna plays an important role in removing the noise. In particular, the higher the reception frequency of the antenna, the stronger the radio wave becomes, so that the radio wave goes straight. Therefore, it is desirable that the antenna has directivity or a length close to the resonance wavelength. However, since the resonance wavelength is longer as the frequency is lower, it is difficult and extremely convenient to attach an antenna having a length close to the resonance wavelength to the wristwatch. For example, the frequency of 900MHz is 33cm per wavelength, and 33cm
It is impossible to attach the antenna of the to the wristwatch.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a band-type antenna device that can be installed in a wristwatch, has portability, and has sufficient resonance length and directivity. .

[Outline of Invention]

In order to achieve the above object, a band type antenna device according to the present invention has a resin band having a flexible metal plate embedded therein, and is electrically connected to the metal plate formed at one end of the resin band. It is characterized by comprising a connector and an antenna circuit connected to the connector.

Example of Invention

A band type antenna device according to an embodiment of the present invention is shown in FIGS. FIG. 1 shows a wristwatch equipped with a band type antenna device according to this embodiment, and one side of the band is omitted for the sake of explanation. FIG. 1 (a) is a rear view of this wrist watch, and FIG. 1 (b) is a side view. On the wristwatch body 1,
The band part 2 is attached.

The band portion 2 is formed such that its width becomes wider as it approaches the body 1. A plurality of holes 3 are formed to connect the band portions 2 to each other, and a hole (omitted) for passing the metal shaft 4 is mechanically connected to the main body 1 at one end so as to be movable. ing. Further, the main body 1 has a crown 5, a back cover 6, a female fitting 7 for a connector, and a recess 8 is further formed.

The band portion 2 has a sufficiently thin and flexible metal plate 9 forming a part of the antenna, and a metal plate 10 formed on the extension of the metal plate 10 so as to bypass the hole 3 and embedded at one end thereof. A male fitting 11 is formed. The main body 1 and the band portion 2 are preferably made of a material such as polystyrene which has a small dielectric loss. In particular, the band portion 2 has a sufficient flexibility, but even if it has a thin plate-shaped metal piece 9 in the center portion, it still retains sufficient flexibility so as not to impair the function as a band. Has been formed.

The tongue piece 12 formed at the end of the band portion 2 has a structure peculiar to the present invention, and has a plate-shaped metal piece 9 that is a part of the antenna and a male connector fitting 11 for terminating it. However, it is electrically and mechanically coupled to the antenna circuit formed inside the main body 1 and is detachable. The tongue 12 is
The wristwatch is half-filled in the recess 8 formed in the main body 1 so as not to hinder the wristwatch when it is worn on the arm. Further, the band portion 2 rotates smoothly with respect to the main body 1 as the tongue piece 12 expands and contracts.
That is, compared with the conventional technique in which the main body 1 and the band 2 are integrally formed, the mechanical load on the tongue 12 is reduced by having both the mechanical connection by the shaft 4 and the electrical connection by the tongue 12. It is accompanied by the effect of reducing and maintaining the advantage that the band can be rotated at an acute angle like the conventional wrist watch. The expansion and contraction of the tongue piece 12 means mechanical expansion and contraction, and means that the distance from the end of the tongue piece 12 changes.

As shown in FIG. 1 (b), a loading coil 13 and a high-frequency power supply or tuning circuit 14 are connected in series to the female connector metal fitting 7 as a main part of the antenna circuit inside the main body 1. The loading coil 13 is for extending the resonance length of the antenna. The ferrite 15 is loaded on the loading coil 13 and is used to lower the resonance frequency of the entire antenna.

FIG. 2 schematically shows, as an electric circuit, how the loop antenna is constructed when the wrist watch is actually worn on the wrist. The area indicated by reference numeral 16 in FIG. 2 indicates the area of the body 1 of FIG. First
The connection by the female-type metal fitting 7 and the male-type metal fitting 11 in the figure is in a state as indicated by reference numeral 17.

A plate-shaped metal plate 9 constituting the band type antenna device of FIG.
And 10 are represented as element 18 of the loop antenna in FIG.

The plate-shaped metal plate 10 of FIG. 1 constitutes a short-circuit portion 19 for high-frequency signals when a pair of bands are joined using the holes 3. That is, the two metal plates are spatially opposed to each other to form a capacitor, and the impedance thereof becomes very small with respect to a high-frequency signal. Therefore, a situation similar to a short circuit occurs. . As a result,
As compared with the case where the pair of arm bands are isolated from each other, the resonance frequency of the antenna can be significantly reduced. Therefore, the whole of FIG. 2 becomes a loop antenna according to the thickness of the arm, and its directivity has a gain perpendicular to the paper surface. The human body affects the resonance frequency as a lossy dielectric,
When the frequency is low, it does not matter so much. Ferrite 15
Can also be used as a fine adjustment of the resonance frequency of the antenna according to the thickness of the arm.

When the wristwatch is required to have a further function, for example, a function as a radio wave transmitting device, the band type antenna device according to the present embodiment plays an essentially important role. This is because the wristwatch is small and can only transmit weak radio waves, and the directivity and resonance characteristics of the antenna generate effective radiated power. The emission of weak radio waves from the wristwatch can be greatly reduced by consuming a small amount of power by intermittently transmitting the radio waves with a code.

Although the loading coil 13 and the ferrite 15 are provided in the main body 1 in the above embodiment, they may be provided in the band portion 2. Further, although the wristwatch band is used in the above embodiment, another band such as a headphone band may be used.

〔The invention's effect〕

As described above, according to the present invention, even when the wristwatch has a function of transmitting and receiving radio waves, it is possible to make the appearance of the wristwatch almost the same as that of the conventional wristwatch without using a separate accessory antenna. Therefore, it is possible to make the wristwatch multifunctional, for example, to add a personal identification function or a pager function.

[Brief description of drawings]

FIG. 1 is a diagram showing a band type antenna device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a state of forming a loop antenna when the band type antenna device is actually worn on an arm. 1 ... wristwatch body, 2 ... band, 3 ...
Connection hole, 4 ... Connection fitting, 5 ... Crown, 6 ... Back cover, 7 ... Female fitting, 8 ... Dimple, 9 ... Metal plate, 10
...... Metal plate, 11 ...... Male fitting, 12 ...... Tongue piece, 13 ...... Loading coil, 14 …… High frequency power supply or tuning circuit, 15
…… Ferrite.

Claims (1)

[Claims] 1. A wristwatch type portable device body (1), an arm band (2) having a metal plate (9, 10) therein, and a tongue piece (12) formed at one end of the arm band on the body side. An antenna circuit (13, 1) provided inside the main body (1), wherein the main body (1) and the arm band (2) are mechanically connected by a shaft (4) at one end on the main body side.
The metal fittings (7) electrically connected to the metal fittings (4, 15) and the metal fittings (11) electrically connected to the metal plates (9, 10) inside the tongue (12) are contacted and connected. A band type antenna device characterized by the above.