CN1215303A - Radio telephone electromagnetic radiation shielding cover and its production method - Google Patents

Abstract

The present invention relates to an electromagnetic radiation protection cover for wireless telephone and its production method. It is characterized by that said protection cover is made up by using an electromagnetic radiation protection plastic layer prepared with polymer as base material whose interior contains uniformly suspended electroconductive, magnetic conductive, polarity and absorbent material particles, and covering the plastic layer with a metal-shielded layer and adopting the processes of plastic-pressing and forming. Said protection cover possesses low electromagnetic wave reflectivity, high electromagnetic wave absorption capacity and wide electromagnetic wave frequency absorption range, can be cover-mounted on the upper portion of display screen of wireless telephone so as to protect human body against the electromagnetic radiation harm from antenna, emitter and earphone,and can obtain good shielding effect.

Description

Radio telephone electromagnetic radiation shielding cover and production method thereof

The present invention relates to the electromagnetic radiation protection material, relate in particular to ELECTROMAGNETIC RADIATION SHIELDING overcoat, cover and screen and method for making thereof such as equipment such as radio telephones.

Radio telephone in the information age, advantage such as takes in various countries' fast development with its light urine.Yet its harm to user's health is also paid close attention to day, becomes the hot issue of scientific research institution, and this also is reflected in the patent application of various countries.

CN92114605.1 discloses Mr.'s Huang Xianli " radio telephone electromagnetic radiation protective cover " patented technology, and its electro-magnetic screen layer is that metallic fiber and textile fabric blending are made, and insulating protective layer is arranged outward; CN94116907.3 discloses Mr.'s Yang Zaitian antimagnetic ray conductive plastics of magnetic conduction and manufacturing process, powdery metal, metal oxide, slaine and graphite, carbon black is added in the plastics make.Above-mentioned two Mr.s provide the useful scheme that can use and inspire for society from different perspectives, and what still dislike deficiency is not select soft magnetic materials such as ferrite, rare earth for use, and having in mind from the loss of increasing tape increases shield effectiveness.Noticeable this patented technology of CN92114605.1 " housing " of on the contrary inventing by Mr.s such as the uncommon families of U.S. Edward Alan with multilayer electromagnetic armouring structure; consider all sidedly both with the conductive powder material; again the magnetic conduction dusty material is added in the plastics as inserts; the branch three-decker is made screening can, and its shield effectiveness is better than the former.What but the latter's three-decker was that the intermediate layer mixes is the magnetic conduction powder, the conductive powder that ectonexine is mixed, the way of this completely layering its to electromagnetic scattering property not as good as conduct electricity and the magnetic conduction powder is the good of one deck.

For this reason, the object of the present invention is to provide a kind of double-deck, to electromagnetic radiation protection effective, be suitable for doing the protective materials and the method for making thereof of radio telephone overcoat or screen sheet especially.

Should, this protection is two-way, so another object of the present invention is the interference of protection stray electrical magnetic radiation to electrical equipment such as radio telephones.

Purpose of the present invention can realize by following measure: its base material is a polymer, mixing conduction, magnetic conduction dusty material in it equably, the polymer that yet be mixed with simultaneously polar material and other absorbing material, will be mixed with above-mentioned four kinds of dusty materials equably is one deck, its outer layer of metal screen again again.

Described conductive powder material is preferably selected copper, aluminium, nickel, gold, silver etc. for use; The magnetic conduction dusty material selects the ferroxplana of hexaplanar bodies such as MnZn, ambrose alloy zinc, magnesium copper zinc, nickel magnesium zinc, SmCo ₅Deng spinels soft magnetic materials such as terres rares and NiAlFe; Polar material selects metallic salts such as metal oxides such as aluminium oxide and barium sulfate; Other absorbing material selects graphite and carbon fiber etc.

Production method of the present invention is that granularity is mixed less than the absorbing material of 80 μ m less than 100 purpose conductions and permeability magnetic material, technical pure or analytically pure polar material, granularity, amount by 10-60% (volume) is dosed in the polymer, press plastics conventional method processing already through plastic pressure forming, outside it, electroplate the genus screened film again or answer the layer of metal thin layer earlier with the working of plastics punch forming.

Powdered conduction and the permeability magnetic material dosed in the said method account for the 60-85 weight portion, and Powdered polar material and other absorbing material account for the 15-40 weight portion.

Below, further illustrate intension of the present invention: during radio telephone work, its electronic circuit component sends electromagnetic radiation, especially with earphone, antenna and reflector for the strongest, move to the brain side during use, very big to the human injury, take into account protection effect, do not affect the appearance and small-sized requirement easily, can make cover shape with the upper part in wireless phone display, the rear side of antenna exposes; Reveal after also can making the above front shroud of display screen; Easier is the above screen sheet of display screen, does not take the shielding of antenna into account, and another kind is to make a ring plate and standing part in antenna part, blocks the electromagnetic radiation of antenna to brain.Electroplate behind these all available mould plastic compressions and realize, but also the multiple metal film of flat plastic again mold pressing form, also moldable, metal level is compound again after the moulding respectively.

Select copper for use, that aluminium is made electric conducting material is more inexpensive than gold and silver, select for use soft magnetic materials such as ferrite, rare earth, spinelle as permeability magnetic material be because of its to super 500MH _zHigh frequency absorption can force rate carbonyl iron strong.When this body of electromagnetic wave directive, by reflection of the metal particle that conducted electricity and scattering, and form current vortex, the electromagnetic wave of magnetic field that is formed by current vortex and reflection, scattering is concentrated in the permeability magnetic material, has reduced the reflection, the scattering electromagnetic wave that are formed by current vortex.Electromagnetic wave is in the reflection of metal particle, in the absorption of soft magnetic material particulate, under the acting in conjunction of polar material and other absorbing material particulate, the modes such as loss, magnetic hysteresis loss, high-frequency dielectric loss, residual loss of leading with electricity mainly are converted into heat energy, play very significant shielding action.

Double-decker of the present invention, can understand like this: the polymeric layer that is mixed with conduction, magnetic conduction, polarity, absorption particulate is called for short plastic layer, metal screen layer is called for short metal level, then when electromagnetic wave is injected plastic layer, major part is reflected, absorbs, enter metal level after the partial penetration, a part of reflected back plastic layer in metal level, another part is led the mode loss by this metal level with electricity.

At present; commercially available radio telephone electromagnetic radiation protector is many to be made with materials such as wire netting paper tinsel, fibrous braid, coated fibers; can only lead the loss mode by reflection and electricity and weaken electromagnetic radiation; this structure that relies on metallic reflection not have soft magnetism to absorb; not only shield effectiveness is not good enough; to the protection deficiency of human body, and reflected wave plays interference effect to the electronic device of radio telephone inside, influences the work and the life-span of parts.

Be embodiments of the invention below.

Earlier with choose any one kind of them in the metal materials such as copper, aluminium, nickel, silver, gold, two or more, strong and cost hangs down preferably with conductivity, it is standby to be ground into granularity and to be 100 orders even more small powder.Again with choose any one kind of them in the materials such as ferrite, rare earth, spinelle carbonyl iron, two or more, ferrite is preferred with the plane hex crystal soft magnetic material of the Z, the Y that contain cobalt and W type structural formula, it is standby to be ground into granularity and to be 100 orders even more small powder.Make the high-frequency dielectric material with barium sulfate, aluminium oxide polar materials, select analysis pure during purchase, get final product with technical pure in enormous quantities.Non-metal particle such as graphite, carbon fiber, granularity is grasped at 5-80 μ m, makes inserts with it, has both increased the absorption of electromagnetic wave performance, can also improve the antistatic and anti ageing property of plastics.The optional engineering plastics of condensate, promptly thermoplastic resin such as ABS also can be selected thermosetting resins such as phenolic resins for use, and both are that processing method is slightly different, and this is that the colleague is known, does not carefully state.

Present key is the proportioning problem of the conduction dosed, magnetic conduction, polarity, four kinds of dusty materials of absorption, generally say, the ratio of the weight portion of the amount of filling that amount of filling and polarity utmost point material, the absorbing material that conduct electricity, permeability magnetic material lumps together lumps together is 70-90: 10-30.If distinguish the weight portion of dosing separately again, can be: electric conducting material 35-45 part, permeability magnetic material 35-45 part, polar material 5-15 part, other absorbing material 15-25 part.

After above-mentioned four kinds of materials mix by weight portion proportioning separately, dose among the ABS or in the phenolic resins by 5-60% (volume), as use thermoplastic resin, then add other processing aid through mix, granulation, drying, plastic compression, plating form, or multiple behind the extrusion board with any electric good conductor thin metal layers such as copper, aluminium, magnesium, silver, gold, be molded into goods again.If thermosetting resins such as phenolic resins then need solubilizer and other processing aid, through ball milling, drying, sieve, plastic pressure forming, plating or compound getting final product.The thickness 0.4-2mm of plastic layer, plated metal layer thickness be less than 0.05mm, the about 0.1mm of composition metal bed thickness.

Above the mold pressing mentioned of several places; refer to by mold pressing system; the unsuitable complete machine of radio telephone coats; can only suitably cover in earphone, radiated element, antenna place more than display screen, then can make the upper half cover, expose at the rear of antenna; both to protect the person; can not influence again and transmit and receive signal, or the upper half cover is clipped again latter half of, or the clear-cut one grade of screen etc. of only before earphone, radiated element, doing.In a word, with the protection human body, block electromagnetic wave, do not influence the transmitting-receiving of radio telephone working signal, attractive in appearancely, light design and produce for principle.

The present invention has lower reflection of electromagnetic wave rate compared to existing technology, reduces back wave To the dried sorrow of element in the radio telephone, higher electro-magnetic wave absorption performance and wider frequency are arranged The rate absorption region, shielding action is remarkable, easily machine-shaping, the advantage such as corrosion-resistant.

Claims (7)

1. radio telephone electromagnetic radiation shielding cover, base material is a polymer, conduction, magnetic conduction dusty material are equably suspending in it, it is characterized in that in the described polymeric substrate, still be suspended with polar material and other absorbing material equably, the polymer that contains these four kinds of dusty materials is one deck, outside it metal screen layer is arranged again again, and mold pressing is compound to be the double-deck enclosure.

2. as the said shielding cover of claim 1, it is characterized in that described conductive powder material is a metal powder material.

3. shielding cover as claimed in claim 1 is characterized in that described magnetic conduction dusty material is soft magnetic materials such as ferrite, rare earth, spinelle.

4. shielding cover as claimed in claim 1 is characterized in that said polarity dusty material is metal oxide and salt.

5. shielding cover as claimed in claim 1 is characterized in that said other absorbing material is graphite and carbon fiber.

6. the production method of shielding cover as claimed in claim 1, it is characterized in that particle size is mixed less than 80 μ m absorbing materials less than 100 purpose conductions and permeability magnetic material, technical pure or analytically pure polar material, granularity, dose in the polymer by the conventional processing method of plastics industry behind plastic pressure forming by the amount of 10-60% (volume), the composition metal screen gets final product outside it again.

7. method as claimed in claim 6 is characterized in that Powdered conduction and the permeability magnetic material dosed are the 60-85 weight portion, and Powdered polar material and other absorbing material are the 15-40 weight portion.