JPH0715214Y2 - Arm-type receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an antenna of an arm-mounted receiver.

[Conventional technology]

Although various types of antennas have been used in conventional arm-mounted receivers, the small loop antenna is particularly effective when the antenna is present near the human body as in arm-mounted receivers.

A receiving apparatus in a conventional example will be described below with reference to the drawings.

2 and 3 each show a conventional arm-mounted receiver equipped with a conventional micro loop antenna. FIG. 2 is an external perspective view, and FIG. 3 is a side view of FIG. As shown in FIG. 2, 1b is a small loop antenna, 2 is a band, and 3 is a case of an arm-mounted receiver. The micro loop antenna
1b has extremely poor reception characteristics when it is close to parallel to the arm surface as in the arrangement C in FIG. 3, but the reception characteristics are practically used when the angle is about 30 ° with respect to the arm surface as in the arrangement B. When the level is reached and the arrangement A is perpendicular to the arm surface, the best reception characteristics are obtained.

[Problems to be solved by the device]

In the conventional arm-mounted receiver, it is necessary to make the micro loop antenna 1b form an angle of 30 ° or more with respect to the arm surface due to the problem of reception characteristics. However, when the arm-mounted receiver is used in such a state by being worn on the arm, the micro loop antenna 1b bumps against another object, such as when deformed by an external force, and the reception characteristics deteriorate, or Case 3
There was a problem that the mounting part of the micro loop antenna of 1 may be damaged.

An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide an arm-mounted receiver having a stable antenna shape and a minute loop antenna in which the case is unlikely to be damaged even when an external force is applied to the antenna. .

[Means for Solving the Problems]

The structure of the present invention for achieving the above object is as follows.

That is, in a portable receiving device including a receiving circuit and a receiving antenna, a shape memory alloy exhibiting superelastic properties at room temperature is used as a material of the receiving antenna.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external view of an arm-worn receiver according to an embodiment of the present invention, where 1 is a small loop antenna made of a shape memory alloy that exhibits superelasticity at room temperature, 2 is a band, and 3 is arm-worn. It is a case of a type receiver.

In FIG. 1, since the micro loop antenna 1 is made of a shape memory alloy having superelasticity, it deforms very flexibly when an external force is applied. Therefore, since the minute loop antenna 1 absorbs the applied external force, the antenna mounting portion of the case 2 will not be damaged. When the external force is removed, the shape of the shape memory alloy quickly returns to its original shape due to its superelastic property. Therefore, it is possible to prevent the deterioration of the reception characteristic due to the change of the antenna shape.

The properties of the shape memory alloy used in the micro loop antenna 1 of the present invention will be briefly described below with reference to the drawings.

FIG. 4 is a characteristic diagram showing a stress-strain curve of a shape memory alloy showing superelastic properties, and FIG. 5 is a characteristic diagram showing a stress-strain curve of an ordinary metal.

Shape memory alloys are alloys composed of several kinds of metals, but if they are manufactured under certain conditions, it is possible to make those that exhibit superelastic properties at room temperature. As shown in Fig. 5, ordinary metal undergoes plastic deformation when a large load exceeding the proportional limit is applied, and the strain corresponding to this remains as permanent deformation even if the load is unloaded.
It does not return to its original shape. On the other hand, in a shape memory alloy exhibiting superelastic properties, when a large strain exceeding the proportional limit is applied as shown in FIG. 4, superelastic deformation occurs due to stress-induced martensitic transformation. This deformation disappears by unloading the stress and returns to the original shape.

[Effect of device]

As is clear from the above description, according to the present invention, by using a shape memory alloy that exhibits superelasticity at room temperature for a micro loop antenna, even if an external force is applied to the antenna, it will return to its original shape if the external force is removed. However, good reception characteristics can be obtained. Also, even if external force is applied to the antenna, the antenna flexibly deforms to absorb the force,
It is possible to prevent damage to the case.

[Brief description of drawings]

FIG. 1 is an external perspective view of an arm-mounted receiver according to an embodiment of the present invention, FIG. 2 is an external perspective view of a conventional arm-mounted receiver, and FIG.
2 is a side view of the arm-mounted receiver of FIG. 2, FIG. 4 is a characteristic diagram showing a stress-strain curve of a shape memory alloy showing the superelastic property of the present invention, and FIG. 5 is a stress of ordinary metal. -Is a characteristic diagram showing a distortion curve. 1, 1b …… Small loop antenna, 2 …… Band, 3 ……
Case.

Claims (1)

[Scope of utility model registration request] 1. A wrist-worn receiver comprising a case, a band for wearing, a receiving circuit, and a loop antenna for receiving,
An arm-wearing type characterized in that a loop antenna for receiving is erected on the surface of the case to form a loop, and a shape memory alloy exhibiting a superelastic property by martensitic transformation at room temperature is used as a material of the loop antenna Receiver.