RU2396890C1 - Mobile (radio) telephone case - Google Patents

Abstract

FIELD: personal use articles.

SUBSTANCE: invention is related to the items for protection from electromagnetic emission effect and concerns the case for mobile (radio) telephone electromagnetic emission protection. Case consists of individual protective screen, rectangular in shape, with side dimensions, corresponding to the dimensions of cell telephone. Screen of protective device is made in the form of flat multilayer solid construction containing parallel layers with different features. Lower layer of protective screen material is made of metal foil, upper layer is uniform rubber compound, containing dispersion of ferrum and metal intermetallic compound, selected from the group: W, Cr, Co, Mn, Mo, Al, Ni, dispersed in synthetic rubber or thermoplastic elastomer with relative permittivity 2.8-12.0 on radio frequency. It has the dimension of protective screen, exceeding the dimensions of telephone in 1.05-1.25 times, and 10-100 is a proportion of metal foil and rubber compound layer thickness, that are tight connected without using glues and other adhesion materials.

EFFECT: protection against mobile telephone electromagnetic emission is provided.

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Description

The technical field to which the proposal relates

The proposal relates to the field of protecting a person from the potentially harmful effects of electromagnetic radiation from household appliances, and more particularly to the device of a cover (case) for a radiotelephone made of composite materials.

State of the art

A device is known for protecting a human body from potentially dangerous electromagnetic radiation from a cell phone tube, consisting of cell phone body elements facing the human body made of materials containing ferromagnetic powder [Pat. RF 2237376, H04M 1/03, published. 2004.09.27].

A disadvantage of the known device is the influence of housing elements containing ferromagnetic powder on the characteristics of the transmitter and receiver of a cell phone, accompanied by a deterioration in the quality of telephone communications, as well as the possibility of using the device only in those models of cell phones where the use of ferromagnetic powder is provided for by the technology for manufacturing their bodies.

Shielding cases are known for protecting the user of cordless telephones from microwave radiation, comprising a housing with closed and open ends. A layer absorbing electromagnetic energy is deposited on the inner surface of the housing. A hole is made in the closed end so that the working end of the radiating element (antenna) can be placed in it. [US Patent No. 5336896, cl. N05K 9/00, NKI 250-515.1, published. 08/09/1994 and US patent No. 5438333, CL. H01Q 17/00, NKI 342-4, published. 08/01/1995].

Known devices protect only from radiation of the intercom itself, but the bulk of the radiation from the receiving and radiating antenna element directly hits the user's head, exerting its negative effect on the brain.

Known protective cover for a radiotelephone containing a housing made in the form of a rectangular parallelepiped with a screen mounted on the front wall of the housing with the possibility of vertical movement [Witness. RF for utility model No. 14750, class. H01Q 17/00, application. 02/29/2000, published. 08/20/2000]. In this device, an electromagnetic absorber is applied to the surface of the screen walls facing the housing.

This device protects the user from short-wave radiation of the antenna and radiation passing through the window, but at the same time it is inconvenient and unreliable to use, since as you use the coating, the material absorbing electromagnetic radiation applied to the surface of the screen walls facing the case is gradually worn away, and the protective properties of the screen are lost.

Closest to the proposed device is a device for protection against electromagnetic radiation from mobile telephones, including an electromagnetic wave absorber made of a rubber mixture filled with carbonyl iron powder pretreated in attritors with an iron content of up to 80 wt.% With an average particle size 0.5 ÷ 3.0 μm, providing a fraction of the reflection of the radiation of the cell phone from the screen surface of less than 0.05 in the frequency range 1.8 ÷ 1.9 GHz and less than 0.35 in the frequency range 850 ÷ 950 MHz.

The disadvantages of the known device is the significant thickness of the screen and the uncertainty of the composition of the rubber compound, the properties of which depend on the processing regime of iron in the attritors - devices of uncertain design. Low protection efficiency in the long-wave range of radio frequencies (850 ÷ 950 MHz).

The essence of the proposal

Solved technical problem is:

- ensuring greater stability and technological reproducibility of the protective properties of the device while maintaining a given level of communication quality in the long-wave range of radio frequencies.

The problem is solved in that the protective cover for a radiotelephone containing a case in the form of a case repeating the outline of the telephone, and a two-layer metal-polymer protective screen made of foil and a homogeneous rubber mixture containing metal powder, according to the proposal, contains a dispersion of an intermetallic compound of iron with metal as a powder selected from the group: W, Cr, Co, Ml, Mo, Al, Ni dispersed in synthetic rubber or thermoplastic elastomer with a relative dielectric constant of 2.8 ÷ 12.0 at frequencies Radiocommunication shield has dimensions that exceed the dimensions of the phone in time 1.05 ÷ 1.25 and thickness ratio of the layers of metal foil and the rubber mixture of 10 ÷ 100 which are firmly connected without using adhesives or other adhesive layers.

Case for mobile radiotelephone is used as follows. The mobile phone is placed in a case so that the metallized side of the protective screen is directed towards the human body, and the layer of the electromagnetic radiation absorber, which includes an intermetallic compound of iron, is directed towards the phone.

Protective functions are implemented as follows. Potentially dangerous telephone radiation in the base station search, standby, call or connection modes is shielded by a metallized layer of a protective screen, and the alignment of the impedance jump at the screen border from the telephone antenna side is compensated by the absorber layer. The radiation absorber layer enhances the protective properties of the screen by suppressing resonances between the metallized layer of the screen and the antenna of the mobile phone.

The cover guarantees a reduction in the radiation of mobile phones of all types to levels that ensure their safe use in accordance with sanitary and epidemiological rules and SanPin 2.1.8 / 2.2.4.1190-03 standards.

In talk mode, the case is effective only if you use a “hand-free” headset.

The proposal is illustrated by the device’s schematic diagram, an example of the design of the device for carrying Nokia 6120c-1 and Sony Ericsson T650i mobile phones, test results tables showing the attenuation efficiency of electromagnetic radiation from cell phones in the case at frequencies 850 ÷ 950 MHz; 1.8 ÷ 1.9 GHz.

Scheme of a general view of a case for carrying a mobile phone. 1 - leather bag; 2 - absorber of electromagnetic waves; 3 - metal foil (screen - reflective substrate) (see drawing).

Example 1. A case for protecting a person from electromagnetic radiation of cellular mobile phones is made of leather, consists of a bag and a rectangular-shaped protective screen with side dimensions of 100 × 50 mm exceeding the size of the phone by 1.2 times. The screen of the protective cover is made in the form of a flat multilayer non-separable structure containing parallel layers of materials with different characteristics. The lower (directed towards the human body) layer of material of the protective shield is made of metal (copper) foil with a thickness of 0.05 mm. The top layer of the rubber mixture is 1.95 mm thick, and dispersed filler, an intermetallic compound of iron with Co (90 wt.%), Is introduced into its composition. Layers of materials having a thickness ratio of 39 are bonded to each other by hot pressing without the use of adhesives or adhesive layers. Together, the layers of the materials used provide absorption of electromagnetic waves with a reflection coefficient of radio waves from the side of the polymer layer from 0.05 to 0.2, thereby eliminating the effect of the protective screen on the characteristics of the receiver and transmitter of the cell phone.

Table 1

The results of the experimental radiation power of Nokia 61 20c-1 and Sony Ericsson T650i cell phones using the proposed device *

No. p / p Phone type Mode The density of the power flux of electromagnetic radiation, μW / cm ² Using a protective case Without cover one Nokia 6120s-1 GSM 900 1,58 2.18 GSM 1800 0.8 1,03 2 Sony Ericsson T650i GSM 900 0.99 5.27 GSM 1800 0.45 2.60 ) ^* Note In this case, the protective cover does not affect the parameters of the transmitter and receiver, the quality of communication within the error of the measuring equipment.

Example 2-7. A case for protecting a person from electromagnetic radiation of mobile phones according to Example 1 for Nokia, Samsung and Sony Ericsson models, but made using screens of various sizes made of different synthetic rubbers and thermoplastic elastomers with a relative dielectric constant of 2.8 ÷ 12.0 per frequency close to the radio frequency.

Table 2. Materials for the manufacture of a protective screen cover Example No. Polymer name 10 GHz dielectric constant 2 Styrene butadiene rubber SKD 2,8 3 Butyl rubber SKB 3.6 four Silicone rubber SKTN 3.0-3.9 5 Polyester Resins (PN-2) 3.0-4.5 6 Chloroprene rubber 6.0-6.5 7 Nitrile butadiene rubber SKN-40 10 ÷ 12

The specific dimensions of the protective screen, exceeding the size of the phone by 1.05 ÷ 1.25 times, and the ratio of the thicknesses of the layers of metal foil and polymer mixture 10 ÷ 100, respectively, according to examples 2-7 are shown in tables 3 and 4.

Table 3. Overall dimensions of the elements of the device (different types of phones and sizes of covers) When measures Phone type Dimensions: screen / phone dimensions (mm) Aspect Ratio: Screen and Phone The density of the power flux of electromagnetic radiation, μW / cm ² With case Without cover 2 Nokia N96 129 × 58/103 × 55 over 1.25 length over 1.05 width 1,58 2.18 3 Nokia N82 127 × 58/112 × 50 1.13 length 1.16 wide 0.8 1,03 four Soni Ericsson K660i 109 × 58.6 / 104 × 47 1.05 length 1.25 wide 0.99 5.27 5 Samsung F490 127 × 62.5 / 116 × 54 1.09 length 1.16 wide 0.45 2.60

Table 4. Overall dimensions of the elements of the device. The metal layer (Me) thickness is 25 ÷ 200 microns. Layer of polymer composition - 2 ÷ 2.5 mm) When measures Phone type Thickness Me (μm) / Polymer Thickness (mm) Thickness ratio Flux density
electromagnetic radiation power, μW / cm ² With case Without cover 6 Samsung F490 25 / 2.5 one hundred 1,53 2.14 7 Nokia N82 200 / 2.0 10 0.75 1.05 Nokia N96 100 / 2.0 fifty 0.82 1,11

Claims (1)

A protective cover for a radiotelephone, comprising a case in the form of a phone repeating outline, and a two-layer metal-polymer protective screen made of foil and a homogeneous rubber mixture containing metal powder, characterized in that the powder contains a dispersion of an intermetallic compound of iron with a metal selected from the group: W, Cr, Co, Mn, Mo, Al, Ni dispersed in synthetic rubber or thermoplastic elastomer with a relative dielectric constant of 2.8 ÷ 12.0 at a radio frequency, has the dimensions of a protective screen by 1.05 ÷ 1.25 times greater than the size of the phone, and the ratio of the thicknesses of the layers of metal foil and rubber compound 10 ÷ 100, which are tightly joined without the use of adhesives or other adhesive materials.

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