JPH1065427A - Tube for antenna guide for communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain shielding effect against external noises, smoothness in antenna extension/retraction and to prevent damages due to thermal stress by adhering and integrating an electromagnetic shield layer composed of a metallic foil to the outer face if a plastic tube. SOLUTION: A plastic tube A is formed of a wrap winding of a plastic film 1. A polytetra fluoroethylene film is suitable for the plastic film 1 because a friction coefficient is small. An electromagnetic shielding layer B adhered and integrated to an outer face of the plastic cube A is formed of a winding of a metallic foil 2. An aluminum is preferred for the metallic foil 2. It is preferable that the thickness of the metallic foil 2 is 5 to 50μm and the thickness of the plastic film 1 is 5 to 200μm preferably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless portable communication device, and more particularly to a tube for an antenna guide of a PHS or a portable telephone.

[0002]

2. Description of the Related Art Recently, two-way mobile communication has been put to practical use in pocket telephones, and portable telephones have spread widely. Also, at the beginning of practical use, a relatively high-power PHS (Personal Handy Phone System) enables a weak power type cordless phone intended for home use only to communicate within a range of 50 to 100 m from a relay base. ), And is spreading more rapidly than mobile phones.

In a mobile communication device, an antenna, a transceiver, and a rechargeable battery are integrated. Conventionally, the antenna is provided with an antenna guide tube made of aluminum in a housing of the communication device, and the antenna is used for communication. A so-called whip antenna is often used in which an antenna is pulled out from the tube and, when communication is completed, the drawn-out antenna is pushed into the tube and stored.

[0004]

However, in the above-mentioned metal antenna guide tube, the friction coefficient of the inner surface thereof is considerably high, and there is a problem in the slidability with the antenna. There are often things that are difficult to do smoothly. By the way, there are many kinds of plastic tubes which have low friction coefficient and excellent slidability in terms of material, and it is considered that the above-mentioned metal antenna guide tube is replaced with a plastic tube. Can be

However, when a plastic tube is used, the external electromagnetic noise, which has been shielded by the metal antenna guide tube, is not shielded, but penetrates the plastic tube and enters the receiving circuit of the equipment housing. There is a fear that noise noise may be caused by intrusion.

Accordingly, the present applicant has already proposed an antenna guide tube for a portable telephone or the like in which an electromagnetic wave shield layer of a metal foil is provided on the outer surface of a plastic tube (Japanese Patent Application No. Hei 7-1995). 274658).

However, in this electromagnetically shielded plastic tube, the coefficient of thermal expansion of plastic is remarkably large (approximately one order of magnitude) as compared with that of metal. When exposed, a large thermal stress is generated due to the difference in the amount of thermal expansion between the electromagnetic wave shield layer and the plastic tube. And mobile phones and P
Since the HS is used in various temperature environments and is exposed to a very severe temperature change, the generation of thermal stress in the electromagnetically shielded antenna guide tube is inevitable.

In the present invention and the like, in order to examine the influence of this thermal stress, a heat cycle test (85 ° C. for 1 hour) was conducted on an aluminum foil wound fluororesin tube.
Cooling / heating cycle test with one cycle of -30 ° C for 1 hour)
As a result, cracks were observed in the electromagnetic wave shield layer.

SUMMARY OF THE INVENTION It is an object of the present invention to satisfactorily achieve both a shielding effect against external noise, a smoother sliding in / out of a sliding antenna, and prevention of thermal stress damage in an antenna guide tube for communication equipment. To provide an antenna guide tube that can be used.

[0010]

An antenna guide tube for a communication device according to the present invention is a sliding antenna guide tube attached to a housing of the communication device, and a metal tube is provided on an outer surface of a plastic tube. An electromagnetic wave shield layer made of a foil is bonded and integrated, and the plastic tube is formed of a plastic film. The plastic tube is formed by, for example, wrapping a plastic film in a wrap. Can be formed. The thickness of the metal foil is usually 5 μm to 50 μm, and the thickness of the plastic film is usually 5 μm to 200 μm.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an antenna guide tube according to the present invention. In FIG. 1, A
Denotes a plastic tube, which can be formed by wrapping a plastic film 1 in a wrap. The plastic film 1 has a small coefficient of friction in the plastic film, for example, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl-ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer And a film of ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride or the like is used, and a polytetrafluoroethylene film is particularly preferable because it has the smallest coefficient of friction. In addition, films of polyethylene, polypropylene, polyester (for example, polyethylene terephthalate), polyimide and the like can be used.

[0012] B plastic Ju - Bed electromagnetic bonded and integrated to the outer surface of A sheet - indicates shield layer, the metal foil 2, for example, typically a volume resistivity of the winding of 10 ⁰ [Omega] cm or less of the metal foil Is formed. It is preferable to use aluminum for the metal foil 2 from the viewpoints of easiness of forming a foil, oxidation resistance, light weight, and the like, but metal foil such as copper, silver, nickel, and stainless steel can also be used. The metal foil is usually wrapped, but can be longitudinally attached so as to have seams in the longitudinal direction.

The electromagnetic shield layer B is formed of a plastic tube.
In order to adhere / integrate with the outer surface of the tube A, for example, a metal foil coated with an epoxy resin adhesive, a hot melt adhesive or a pressure-sensitive adhesive on one surface is placed on the plastic tube A with the one surface inside. Wrap or vertical wrapping, wrap a plastic film with epoxy resin adhesive, hot melt adhesive or adhesive applied on one side, wrap it around a core with one side outside, and wrap metal foil on the outer surface A method of winding or vertically attaching can be used. In any case, when the plastic tube is made of fluororesin, it is preferable to bond one surface of the plastic film so that the outer surface of the tube is used as the bonding surface. Chemical treatment with metallic sodium, deposit treatment with inorganic sintering and the like can be used.

The antenna guide tube according to the present invention is used by being attached to a PHS housing. At the time of communication, the antenna is pulled out of the tube, and when the communication is completed, the antenna is pushed into the tube.・ It is stored. The antenna can be pulled out and pushed in smoothly because the inner surface of the plastic tube, especially the fluororesin tube, has a low coefficient of friction and excellent slidability. Also, due to the electromagnetic shielding effect of the antenna guide tube, external electromagnetic noise can be reduced as much.

In the tube for an antenna guide according to the present invention, the plastic tube is formed from a plastic film, and the thickness of the plastic tube can be reduced as compared with the case where the plastic tube is extruded. Therefore, the thermal stress acting on the electromagnetic wave shield layer B can be sufficiently reduced, and cracks can be effectively prevented from occurring in the electromagnetic wave shield layer. That is, the antenna guide tube
The radius of the probe r, electromagnetic waves - t ₁ the thickness of the shield layer, plastic Ju - the thickness of the probe t _2, the electromagnetic wave sheet - ₁ thermal expansion coefficient of the shield layer alpha, electromagnetic waves - E the elastic modulus of the field layer ₁ , if the thermal expansion coefficient of the plastic tube is α ₂ , the elastic modulus of the plastic tube is E ₂ , and the temperature change is Δt, the tensile force δx ₁ of the electromagnetic wave shielding layer is δx ₁ = (α ₂ − α ₁ ) E ₁ t ₂ E ₂ Δt / (t ₂ E ₂ + t ₁ E ₁ ) Since the thickness t ₂ of the plastic tube is small, the stress is small and the electromagnetic wave shielding layer is formed. Cracks can be effectively prevented.

In the antenna guide tube according to the present invention, as shown in FIG. 2, a plastic film 1 is wrapped around a release-treated core C (in the case of a fluororesin film, one surface is bonded. And the metal foil 2 provided with the adhesive layer 20 on one side is wrapped with the one side facing inward to form a metal foil wound layer and a plastic film wound layer. Are integrated by fusion of an adhesive layer by heating, and then a method of removing the core C or wrapping a plastic film on a wrapped core (in the case of a fluororesin film, Wrap the film with the adhesive treatment on one side wrapped with the adhesive treatment surface facing out), wrap the film adhesive on top of it, further wrap the metal foil, wrap the metal foil winding layer and plastic film Integrating the layers by fusion of the adhesive by heating, after 而Ru can be produced by a method in which pulled out of the core. In any of the manufacturing methods, the wrapping direction of the plastic film and the wrapping direction of the metal foil can be either the same direction or the opposite direction.

[0017]

【Example】

Example 1 One side was treated with a metal sodium-based surface treatment agent (manufactured by Junkosha Co., Ltd., tetra-etch).
A 0 mm polytetrafluoroethylene film is wound around a metal core having an outer diameter of 4.0 mm with a half flap with the treated surface facing outward, and a modified polyolefin hot melt film having a thickness of 15 μm is provided on one surface, and a thickness of 10 μm and a width of 1 mm
A 0 mm aluminum foil was wound with a half flap with the hot melt film facing inward, the two winding layers were integrated by heating at 180 ° C., and after cooling, the metal core was pulled out to obtain a tube for an antenna guide. .

Comparative Example 82% by weight of polytetrafluoroethylene (fine powder, polyflon F-201 manufactured by Daikin Industries, Ltd.) and a hydrocarbon extrusion lubricant [odorless solvent, Isopar-E manufactured by Exxon Chemical Co., Ltd.] 18% by weight, preformed, ram extruded, dried and sintered to obtain a polytetrafluoroethylene tube having an inner diameter of 4.0 mm and an outer diameter of 4.3 mm. To metal sodium based surface treatment agent (Junkosha, Tetra-etch)
And subjected to an external surface bonding treatment. Furthermore, one side has a thickness of 15μ.
m, a 10 μm-thick, 10 mm-wide aluminum foil provided with a modified polyolefin hot-melt film is wound with a half flap with the hot-melt film facing inward.
The two winding layers were integrated by heating at 180 ° C. and cooled to obtain an antenna guide tube. .

The product of this example and the product of the comparative example (the number of samples was 10 each) were subjected to 100 cycles of a thermal cycle test in which 1 cycle of 85 ° C./1 hour of −30 ° C. was performed. No abnormality such as cracking or peeling of the aluminum foil was observed. When a sheet-like sample having the same configuration in the thickness direction as that of the embodiment was used and the electromagnetic shielding effect was measured after 100 cycles of the cooling / heating cycle test, it showed 55 dB or more (generally 40 dB or more).
Materials exhibiting attenuation of more than dB exhibit a shielding effect),
It was also confirmed that it had an excellent shielding effect.

On the other hand, in the comparative example, cracks were generated in the aluminum foil in all of the ten cases, and electromagnetic wave shielding was observed.
Reduced to less than 40 dB.

[0021]

In the tube for antenna guide of communication equipment according to the present invention, a plastic tube having extremely small sliding resistance, particularly a fluororesin tube, is used for the inner surface layer. Smooth sliding antenna in and out
Can be done. Further, since the thickness of the plastic tube can be sufficiently reduced, the thermal stress acting on the electromagnetic wave shield layer can be reduced, and the generation of cracks and the like in the electromagnetic wave shield layer can be prevented well. The shield effect can be guaranteed, and a decrease in receiving sensitivity due to external noise can be well eliminated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an antenna guide tube of a communication device according to the present invention.

FIG. 2 is an explanatory view showing a method of manufacturing a tube for an antenna guide of a communication device according to the present invention.

[Explanation of symbols]

 A plastic tube 1 plastic film B electromagnetic shielding layer 2 metal foil

Claims (3)

[Claims] A sliding antenna guide tube to be mounted on a housing of a communication device, wherein an electromagnetic wave shield layer made of a metal foil is adhered to and integrated with an outer surface of the plastic tube. An antenna guide tube for a communication device, wherein the tube is formed of a plastic film. 2. The antenna guide tube according to claim 1, wherein the plastic tube is formed by wrapping a plastic film in a wrap. 3. The metal foil has a thickness of 5 μm to 50 μm,
3. The antenna guide tube according to claim 1, wherein the thickness of the plastic film is 5 to 200 [mu] m.