JPH08125418A - Antenna - Google Patents

Abstract

PURPOSE: To obtain an antenna for mobile communication equipment with an excellent radio wave radiation efficiency without losing flexibility by winding a conductive wire to at least a part of an outer circumference of a core wire made of a superelastic alloy in spiral and connecting one terminal of the winding to a wave transmission reception electronic circuit. CONSTITUTION: A thin wire such as a copper wire, a phospor bronze wire, a stainless wire is wound on a core wire 1 made of a superelastic alloy as a conductor wire 2 whose conductivity is 30 times or over than that of a conventional superelastic alloy to form the antenna. The conductor wire 2 with excellent conductivity is wound in spiral onto the surface to improve the conductivity of the antenna without losing the property of superelasticity having flexibility in this way. As the winding method, close winding or winding with slight gap may be adopted. Then one terminal of the conductive wire 2 at the lower end of the antenna is connected to a wave transmission reception electronic circuit. Moreover, a chromium with excellent corrosion proof whose conductivity is higher by 5 times or over than that of a superelastic alloy is plated to the surface of the core wire 1 of the superelastic alloy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible antenna used for so-called mobile communication devices such as mobile phones.

[0002]

2. Description of the Related Art The recent development and popularization of mobile communication devices have been remarkable, and in particular, the popularization of mobile phones and the like has been remarkable. The widespread use of mobile phones has greatly contributed to the improved performance of the mobile phones, that is, the sensitivity, and the reduction in size and weight.

[0003] Currently, the frequency of the radio wave used in a mobile phone generally used is from 0.7 GHz to 1.6 GHz, and the antenna has a simple structure, a length of about 10 cm, and a thickness of 1φ mm to 1 mm. A rod antenna with a diameter of about 0.5 mm is generally used.

At present, for this rod antenna, a thin tube or wire having an outer diameter of about 1φ mm made of a superelastic alloy having superelastic characteristics is used because of its flexibility, and its surface is protected against corrosion. A heat-shrinkable tube made of a resin material is wound to keep the appearance beautiful.

[0005]

However, while the antenna using the above-mentioned conventional rod-shaped superelastic alloy has excellent flexibility, its surface resistance in the GHz band is several thousand Ω to tens of thousands Ω. It has a problem that the radiation efficiency of the antenna is low because the high frequency current is difficult to flow when receiving and transmitting the radio wave to the antenna.

Further, there is a problem that the superelastic alloy is difficult to be solder-welded, and it is difficult to attach and fix the antenna to the body of the mobile phone.

Therefore, an object of the present invention is to provide an antenna having good radio wave radiation efficiency and good workability when mounted on the body of a mobile phone without impairing good flexibility and flexibility as an antenna. Especially.

[0008]

In order to solve the above technical problems, the present invention provides an antenna in which the core wire is made of a superelastic alloy, and at least the outer circumference of the core wire is made of the superelastic alloy. An antenna is formed by wrapping a super-elastic alloy core wire in a part and winding a conductive wire in the form of a stranded wire.

Further, in an antenna in which the core wire is made of a superelastic alloy, the surface of the core wire of the superelastic alloy, which is the core wire of the antenna, is chemically activated by anodizing and has a higher electric conductivity than that of the superelastic alloy. The antenna is plated with metal and dehydrogenated so that the antenna has good radio wave radiation efficiency without impairing the flexibility of the antenna.

That is, according to the present invention, a conductive wire is wound around at least a part of the outer circumference of a core wire of a superelastic alloy composed of a thin wire of a superelastic alloy, and one end of the conductive wire is fed. An antenna characterized by being connected to a wave receiving electronic circuit.

Further, according to the present invention, an outer peripheral surface of a superelastic alloy core wire made of a superelastic alloy fine wire is anodized, and the surface is plated, dehydrogenated, and then surface-finished. The antenna is characterized in that a plated film is formed, and the core wire of the plated superelastic alloy is connected to a transmitting / receiving electronic circuit.

[0012]

[Function] A thin wire made of a material having good conductivity is wound around the surface of an antenna made of a superelastic alloy having poor conductivity which has been conventionally used as a conductor of the antenna, or a metal having good conductivity is provided on the surface of the superelastic alloy. By plating the antenna, the antenna can be made to have a good radio wave radiation efficiency without impairing the flexibility of the antenna, and the antenna can be attached to the body of a mobile phone by using a base or a joint. This can be done by soldering or screwing using, so that it becomes easy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the above-mentioned antenna according to the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is an external view of an antenna according to the present invention. That is, according to the present invention, a copper wire, a phosphor bronze wire, or the like is used as the conductive wire 2 in which the conductivity value of the superelastic alloy core wire 1 is 30 times or more that of the conventional superelastic alloy.
A thin wire such as a brass wire or a stainless wire is wound to form an antenna. The conductive wire 2 may be wound tightly, but may be provided with a slight gap. The mobile phone is attached to the body 9 by soldering using the pedestal 3.

The material of the core wire 1 of the superelastic alloy is a Ni-Ti alloy having a Ni composition of 50.4% to 51% in atomic%,
Alternatively, it is a thin wire made of Cu-Zn alloy and having a wire diameter of 0.8 mm to 1.0 mm.

Superelasticity means that the stress-induced martensitic transformation causes an apparent plastic deformation of several to several tens of percent when stress is applied, and the original size and shape are restored by reverse transformation when the stress is unloaded. It is a characteristic of returning.

In order to improve the conductivity of the antenna without impairing the superelastic property having flexibility, the conductive wire 2 having good conductivity is spirally wound around the surface of the antenna, and the lower end of the antenna of the conductive wire is wound. One end of the is connected to the transmitting and receiving electronic circuits. Conductive wire with good conductivity (hereinafter referred to as wire)
A material having high conductivity as described above is suitable for 2, and a fine wire having a diameter of 0.2 mm or less is suitable for the wire diameter.

The method for winding the wire 2 such as copper wire, phosphor bronze, brass wire, stainless wire, etc., is to make the wire 2 into a spring and pass it through a core wire, or, as shown in FIG. 2, use a superelastic alloy. There is a method in which both ends of the core wire 1 are sandwiched between the chucks 5 and are rotated while being pulled, and the wire rod 2 is wound. The super-elastic alloy core wire 1 has a high tensile strength and is a wire that can withstand the above-mentioned tensile strength. In the antenna in which the conductive wire 2 is wound in this way, the resin film 4 of FIG. 1 is applied to the surface of the antenna to prevent the wire 2 from separating. Also, by covering the surface with the resin film 4, the appearance can be improved.

(Embodiment 2) FIG. 3 shows chromium on the surface of the core wire of the superelastic alloy according to the present invention, which is excellent in corrosion resistance and has a conductivity 5 times higher than that of the superelastic alloy. It is an external view of the plated antenna. In the antenna of the superelastic alloy wire 7 in which the chromium plating film 6 is applied to the superelastic alloy core wire 1 of the present invention, the terminal portion 10 connected to the superelastic alloy core wire 1 by soldering or caulking is a joint portion. It is mechanically fixed to the body 9 by being connected via screws 8 or the like. The joint 8 is
It has a screw hole 12 and is fixed with a screw 11 so that the outer frame is fixed to the body 9 of the mobile phone.

The core wire of the antenna is composed of the core wire 1 of a superelastic alloy, and generally, a Cu-Zn alloy or a Ni-Ti alloy is used. In this embodiment, the composition of Ni is atomic%
50.4% to 51% Ni-Ti based alloy was used.

FIG. 4 is a manufacturing process drawing showing a part of the process of plating the core wire 1 of the superelastic alloy. The manufacturing process of the antenna of the present invention is as follows. That is, first, the degreased superelastic alloy core wire 1 is anodized. this is,
In a bath of chromic acid aqueous solution or sulfuric acid aqueous solution, an electric current of the opposite polarity to that during plating is applied to electrolytically remove the superelastic alloy core wire that forms the anode surface to completely degrease it Activate. This strengthens the adhesion between the Ni-Ti alloy base and the electrodeposited chromium. The anodic treatment was performed at a current value of 20 A / dm ² and an energization time of 1 to 3 minutes. By this anodic treatment, the surface of the core wire of the superelastic alloy is etched and activated.

The plating treatment was carried out at a current value of about 25 A / dm ² per surface area of the superelastic alloy core wire. The core wire 1 of the superelastic alloy in the bath was slowly rotated so that the plating thickness was uniform. The super-elastic alloy core wire 1 generates a large amount of hydrogen on its surface during the plating process, so that hydrogen gas is enclosed in the attached layer of the chromium plating.
The hydrogen gas may corrode the Ni—Ti based alloy of the core wire of the superelastic alloy and exerts a bad influence, so a dehydrogenation treatment for removing the hydrogen gas by heating is required.

In the dehydrogenation treatment of this embodiment, the heating temperature is 15
The temperature is 0 ° C. to 180 ° C., and the heating time is 2 hours to 4 hours. The heating time varies greatly depending on the plating thickness and plating conditions, and it is necessary to experimentally obtain the heating time.

Since the thickness of the plating also affects the conductor resistance when it is used as an antenna, it is preferable that the thickness of the chromium plating is thick, but in the present embodiment, the thickness of the plating is 80.
μm to 250 μm. If the thickness is further increased, the surface condition deteriorates and the dehydrogenation treatment takes time.

Next, it is necessary to form a slight unevenness on the surface after the plating treatment, which adversely affects the reliability and the radiation efficiency of radio waves, and it is necessary to finish the surface smooth from the viewpoint of aesthetics. . Surface finishing machining is buffing,
Alternatively, sandblasting is suitable. Excessive machining is
Since the plating thickness is reduced, the processing time can be short.
This is also experimentally determined, but in one embodiment of the present invention, buffing for about 5 minutes was sufficient.

The super-elastic alloy core wire whose surface is chromium-plated in this manner is connected to the terminal portion 10 which is the input / output end of the electronic circuit in the center of the joint portion 8. In the portion where the surface is chrome-plated, nickel plating is applied to the chrome-plated surface, so that connection such as soldering can be easily performed. As described above, the antenna in which the surface of the core wire of the superelastic alloy is plated with chromium has a good conductivity on the surface, has a low surface resistance to a high frequency current, and allows a high frequency current to flow uniformly.

[0027]

As described above, the antenna of the present invention is inserted into the superelastic alloy fine wire of the core wire of the antenna in the form of a coil wound like a spring material, or the fine wire is made of copper. A conductive wire with high conductivity such as a wire is wound, and the antenna is formed by forming a resin film on the surface of the wound conductive wire, or on the surface of the superelastic alloy core wire, excellent corrosion resistance, or Compared to the conductivity of superelastic alloys, the antenna is plated with chromium, which has a much higher value. Therefore, it is possible to improve the radiation efficiency when transmitting and receiving radio waves, and to make the antenna flexible. It becomes easy to attach and fix the antenna to the body of the mobile phone without impairing its flexibility and appearance, and it is possible to provide the antenna with good workability.

[Brief description of drawings]

FIG. 1 is an external view of an antenna according to an embodiment in which a conductive wire is wound around the core wire of a superelastic alloy of the present invention.

FIG. 2 is a conceptual diagram of a method of winding a conductive wire around a core wire of a superelastic alloy.

FIG. 3 is an external view of an antenna according to an embodiment in which the surface of the core wire of the superelastic alloy of the present invention is plated with chromium.

FIG. 4 is a chrome plating process drawing of a core wire of the superelastic alloy of the antenna shown in FIG.

[Explanation of symbols]

 1 Super-elastic alloy core wire 2 (conductive) wire 3 Base 4 Resin film 5 Chuck 6 Chromium plating film 7 Super-elastic alloy wire 8 Joint 9 Instrument 10 Terminal 11 Screw 12 Screw hole

Claims (2)

[Claims] 1. A conductive wire is wound around at least a part of the outer circumference of a core wire of a superelastic alloy made of a thin wire of a superelastic alloy, and one end of the conductive wire is transmitted / received by a receiving / transmitting electron. An antenna characterized by being connected to a circuit. 2. An outer peripheral surface of a superelastic alloy core wire made of a superelastic alloy fine wire is anodized, and the surface is plated, dehydrogenated, and then surface-finished to form a plating film. An antenna characterized in that the core wire of the superelastic alloy coated with a plated film is connected to a wave transmitting / receiving electronic circuit.