Abstract:
Devices and methods to reduce or attenuate electromagnetic radiation emitted by an electronic device such that the electromagnetic radiation does not impinge on a user of the electronic device include one or more layers of material. The one or more layers of material have properties including one or both of absorption and/or reflection of electromagnetic radiation in frequency ranges used for wireless telephonic communication. The one or more layers of material are arranged to be disposed near the back side of the electronic device. Use of the one or more layers of material attenuates the electromagnetic radiation as measured at or near the front of the electronic device during use by about 75%.

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Patent Application Ser. No. 61/687,026, entitled “NEW METHODS IN REDUCING CELL PHONE RADIATION,” and filed Apr. 16, 2012. This application is hereby incorporated by reference into the present application in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a device to shield electromagnetic radiation from cell phones and other electronic devices so that the electromagnetic radiation does not impinge on the user of those electronic devices. The invention also relates to methods of operation or manufacture of these devices. 
     BACKGROUND OF THE INVENTION 
     It is known that electronic devices, including cell phones, emit electromagnetic radiation during operation. It is known that at least some emitted electromagnetic radiation impinges on the users of the electronic devices. It is known that impingement of electromagnetic radiation may be undesirable under certain circumstances. It is known that electromagnetic radiation may be attenuated by various mechanisms, including absorption, deflection, and/or other mechanisms. 
     SUMMARY 
     One aspect of the invention relates to a device configured to shield a user from electromagnetic radiation by an electronic device. The electronic device may include a mobile telecommunications device, such as a cell phone, and/or the functionality thereof. The electronic device may include other wireless (local area) networking functionality, such as Wi-Fi™. The electronic device may be integrated, combined, embedded, and/or operating conjunctively with a mobile telephone. 
     In the context of this disclosure, “shield,” “shielding,” and variations thereof refer to a reduction in the amount of electromagnetic radiation impinging, e.g., on a user. This reduction may be quantified as an attenuation of a particular number of decibels, as a percentage, and/or in other ways. The attenuation may vary within a range of frequencies of the electromagnetic radiation. In other words, the specific attenuation may depend on characteristics of the electromagnetic radiation, including frequency or frequency range. The specific attenuation may be measured under various operating conditions, including but not limited to stand-by mode, telephonic usage, data transfer, and/or other modes of operation. The specific attenuation may be measured in different positions, including but not limited to at or near the front of the electronic device, at or near the back of the electronic device, at a predetermined distance from the front or back of the electronic device, and/or other positions. For example, the predetermined distance may correspond to the average distance users hold a telephone from their ear, face, and/or head, or in other words, about 1 inch, about 2 inches, about 3 inches, about 4 inches, about 6 inches, about 8 inches, about 10 inches, about 12 inches, and/or other predetermined distances. 
     The pertinent range of frequencies of the electromagnetic radiation targeted for shielding depends on the specific telecommunication services and/or telecommunication standards used by the electronic devices. The predominant range of frequencies to shield may be between about 450 MHz and about 2.5 GHz. In the context of this disclosure, a “predominant” range of frequencies refers to a frequency range that includes the intended telecommunications signal, and/or a frequency range that includes the majority of the amount of energy within the emitted electromagnetic radiation. Any one particular telecommunications standard may only cover a portion of this range. For example, the Universal Mobile Telecommunications System (UMTS) frequency band as used in the United States may be 1710-1755 MHz and 2110-2155 MHz for uplink and downlink, respectively. Note that the specific frequency bands used may vary across operators/carriers, and may vary between different geographic locations. 
     Reduction of electromagnetic radiation emitted by an electronic device may be viewed in relation to the amount of electromagnetic radiation that impinges on a user of the electronic device. Reduction of electromagnetic radiation may be accomplished through various mechanisms, including but not limited to absorption, deflection, and/or other mechanisms to reduce the amount of electromagnetic radiation that impinges on the user of the electronic device. 
     Reduction of emitted electromagnetic radiation may be accomplished through a body that includes one or more layers of material arranged at or near at least a portion of the back of the electronic device. In some embodiments, the body may include peripheral portions that may be arranged at or near one or more lateral sides (or segments thereof) of the electronic device. In some embodiments, the body may include holes, gaps, cut-outs, and/or other open spaces for one or more components of the electronic device. For example, these components may need to be accessible and/or unblocked, such as, by way of non-limiting example, buttons, switches, screens, control interface components, speakers, cameras, antennas, and/or other components. It is noted that the number of these components and the placement thereof varies between models and brands of electronic devices, such that, e.g., a newly-released model of a particular smartphone would need a device configured to shield a user from electromagnetic radiation having specific dimensions, peripheral portions, cut-outs, holes, and/or other device-dependent characteristics. 
     In some embodiments, one or more peripheral portions may be arranged and/or folded such that a portion of the front side of the electronic device may be covered. It is noted that the portion of the front side of the electronic device that is used for user interaction may need to remain uncovered by the body. For example, if the electronic device includes a touch screen that substantially covers the entire front side, then the body may be arranged to be disposed at or near the back side and one or more lateral sides rather than the front side. 
     The one or more layers of material may include a first layer of material having the property of attenuating electromagnetic radiation through absorption by at least 25 dB in a particular range of frequencies, a second layer of material having the property of attenuating electromagnetic radiation through deflection by at least 25 dB in a particular range of frequencies, and/or one or more other layers. The particular range of frequencies may be the predominant range of frequencies between about 450 MHz and about 2.5 GHz, between about 700 MHz and about 1.5 GHz, between about 2.0 GHz and about 3.0 GHz, and/or ranges of frequencies. The attenuation of the first, second, and/or other layer of material may be about 30 dB, about 40 dB, about 50 dB, about 60 dB, about 70 dB, about 80 dB, between about 25 dB and 35 dB, between about 30 dB and about 50 dB, between about 40 dB and about 60 dB, and/or other amounts of attenuation. The attenuation of multiple layers of material may be different, and/or may be specified for different frequency ranges. 
     In some embodiments, the layer of material having the predominant property of attenuating electromagnetic radiation through absorption may have an attenuation of about 25 dB, about 30 dB, about 40 dB, about 50 dB, about 60 dB, and/or another amount of attenuation. In some embodiments, the layer of material having the predominant property of attenuating electromagnetic radiation through deflection may have an attenuation of about 25 dB, about 30 dB, about 40 dB, about 50 dB, about 60 dB, about 70 dB, about 80 dB, and/or another amount of attenuation. It is understood that attenuation may be frequency-dependent. It is understood that materials may have multiple properties. For example, a material that has the property of attenuating electromagnetic radiation through absorption may also have, to some extent, the property of attenuating electromagnetic radiation through deflection, and/or vice versa. In the context of this disclosure, a “predominant” property refers to the highest level of attenuation that is contributed to a particular mechanism for attenuation, for a particular type of material. In other words, if the property of attenuating electromagnetic radiation through deflection is about 25 dB and the property of attenuating electromagnetic radiation through absorption is about 40 dB for the same material, this particular material may be referred to as having a predominant property of attenuating electromagnetic radiation through absorption. 
     These and other objects, features, and characteristics of the present disclosure, as well as the methods of operation and functions of the related components of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the any limits. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  illustrate isometric views of a device configured to shield electromagnetic radiation emitted from an electronic device. 
         FIGS. 4-6  illustrate views of a device configured to shield electromagnetic radiation emitted from an electronic device. 
         FIG. 7  illustrates a method to shield a user from electromagnetic radiation emitted by an electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     Impingement (on users) of electromagnetic radiation emitted by electronic devices, including mobile telephones, may be undesirable under certain circumstances. 
       FIG. 1  illustrates an isometric view of a device  10  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 1 ). The electronic device may have a front side, back side, and multiple lateral sides. By way of non-limiting example, device  10  may be configured to shield a user from electromagnetic radiation emitted by an iPhone™ 4S™ or similar mobile telephone/smartphone. Device  10  includes a body  11  including one or more layers of material. The one or more layers of material have properties including absorption and/or deflection of electromagnetic radiation in a particular range of frequencies. The particular range of frequencies may be from about 450 MHz to about 2.5 GHz, and/or any subset thereof. The attenuation of electromagnetic radiation in the particular range of frequencies may be about 25 dB, at least 25 dB, about 30 dB, about 40 dB, about 50 dB, about 60 dB, and/or other amount of decibels of attenuation per layer of material or per combination of multiple layers of material. Body  11  may be arranged to be disposed at or near the back side of an electronic device. 
     One or more layers of material may have the predominant property of attenuating electromagnetic radiation through absorption by about 25 dB, about 30 dB, about 40 dB, about 50 dB, about 60 dB, and/or another amount of attenuation. In some embodiments, such a layer may include carbon-based fabric, such as the carbon-based microwave-absorbing fabric described in U.S. Patent Application Ser. No. 61/687,026, entitled “NEW METHODS IN REDUCING CELL PHONE RADIATION,” and filed Apr. 16, 2012, which is hereby incorporated by reference into the present application in its entirety. This application is hereinafter referred to as “the &#39;026 application.” The described level of attenuation ranges between at least 25 dB and about 35 dB for the frequency range between 1 GHz and 10 GHz. In some embodiments, body  11  may include multiple layers of such carbon-based fabric. 
     One or more layers of material may have the predominant property of attenuating electromagnetic radiation through deflection by about 25 dB, about 30 dB, about 40 dB, about 50 dB, about 60 dB, about 70 dB, about 80 dB, and/or another amount of attenuation. In some embodiments, such a layer may include radio-frequency (RF) shielding fabric, such as the cobalt-alloy-coated RF-shielding fabric described in the &#39;026 application as fabric provided by CobalTex™. The thread of this fabric includes a polyester core covered by nickel, copper, nickel, and a cobalt alloy. The described level of electric field attenuation for this material ranges between about 40 dB and about 100 dB for frequencies ranging from 0.1 MHz to 1000 MHz. The described level of magnetic shielding attenuation for this material ranges between about 25 dB and about 80 dB for frequencies ranging from about 10 MHz and 1000 MHz. In some embodiments, body  11  may include multiple layers of such RF-shielding fabric. 
     In some embodiments that include multiple layers of material, e.g. at least one layer of carbon-based (microwave-absorbing) fabric and at least one layer of (cobalt-alloy-coated) RF-shielding fabric, one or more layers of a first type of material, e.g. carbon-based fabric, may be arranged to be disposed closer to the back side of the electronic device than one or more layers of a different type of material, e.g. RF-shielding fabric. The opposite order may be used. The order may be dependent on the number, location, and/or type of antennas used for a particular type of electronic device, and/or on the selected type of electronic device, e.g. the model of smartphone. Other ways to order, arrange, organize, and/or place in a pattern multiple layers of material are contemplated within the scope of this disclosure. 
     In some embodiments, multiple layers of material, e.g. of carbon-based (microwave-absorbing) fabric, may be combined for enhanced effects. 
     Individual layers of body  11  and/or a combination of multiple layers may be laminated (e.g. with a polyethylene finish) and/or pressure-treated to reduce the thickness of body  11 . A combination of between 2 and 4 layers may have a thickness between about 30 mils and about 60 mils, responsive to being pressure-treated. Prior to being pressure-treated such a combination may have a thickness between about ⅛ and ⅙ of an inch. In some embodiments, an adhesive may be applied to one or more sides of body  11  to (removably) fix body  11  in place against the back of an electronic device and/or within a case or cover of the electronic device. 
     Body  11  of device  10  as depicted in  FIG. 1  may include one or more peripheral portions  13 . The one or more peripheral portions  13  may be folded at substantially transverse angels with the center of body  11  in such a manner that the one or more peripheral portions  13  may be arranged to cover and/or be disposed at or near one or more lateral sides of an electronic device. In other words, a peripheral portion  13  may be folded around the side of the mobile telephone/smartphone. In some embodiments, one or more lateral sides of the electronic device may be covered by one or more peripheral portions  13  in a manner such that predetermined types of components of the electronic device are uncovered, such as, by way of non-limiting example, buttons or antennas. 
     In some embodiments, body  11  may include a cut-out  12  (and/or other open spaces) for one or more components of the electronic device. In the example depicted in  FIG. 1 , cut-out  12  may be configured to accommodate a camera of the mobile telephone/smartphone. 
     In some embodiments, the dimensions, shapes, sizes, and/or number of peripheral portions  13  of body  11  of device  10  may be configured such that at least a predetermined threshold of attenuation of emitted electromagnetic radiation is accomplished. In other words, the predetermined threshold may correspond to a maximum attenuation such that the electronic device can still operate as intended. For example, since 100% attenuation may prohibit telecommunication services, the predetermined threshold may be about 75%, about 80%, about 85%, about 90%, and/or another level of attenuation. 
     Measurements of the attenuation may include specific absorption rate (SAR) testing, such as a direct method SAR test. Measurements may be specific to a particular operating band, such as GSM850. Measurements may pertain to electromagnetic radiation emitted by the front of an electronic device, by the back of an electronic device, at different distances from a user&#39;s head or ear (ranging from 1 inch, ½ inch, 15 mm, to zero inch), at varying levels of relative ambient humidity or ambient temperature, and/or taking other variable operating conditions into account. For example, detailed results of such measurements are included with the &#39;026 application. Using an iPhone™ 4S™ as the electronic device, a device similar to device  10  as depicted in  FIG. 1  and  FIG. 4  has been measured using SAR testing to attenuate radiation emitted through the front side by 62.89% using the GSM850 band, 83.98% through the front side using Band V, 94.65% through the back side using Band V and 95.32% through the back side using Band II. 
       FIG. 2  illustrates an isometric view of a device  20  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 2 ). By way of non-limiting example, device  20  may be configured to shield a user from electromagnetic radiation emitted by a Motorola™ RAZR™ or similar mobile telephone/smartphone. Device  20  includes a body  21  including one or more layers of material. In some embodiments, the one or more layers of material may be similar to the one or more layers as described herein with regard to body  11  of device  10  in  FIG. 1 . Referring to  FIG. 2 , body  21  of device  20  may include one or more peripheral portions  23 . The one or more peripheral portions  23  may be folded at substantially transverse angels with the center of body  21  in such a manner that the one or more peripheral portions  23  may be arranged to cover and/or be disposed at or near one or more lateral sides of an electronic device. In other words, a peripheral portion  23  may be folded around the side of the mobile telephone/smartphone. In some embodiments, one or more lateral sides of the electronic device may be covered by one or more peripheral portions  23  in a manner such that predetermined types of components of the electronic device are uncovered, such as, by way of non-limiting example, buttons or antennas. Note that the description of peripheral portions  13  in  FIG. 1  also applies to peripheral portions  23  in  FIG. 2 . 
       FIG. 3  illustrates an isometric view of a device  30  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 3 ). By way of non-limiting example, device  30  may be configured to shield a user from electromagnetic radiation emitted by a Samsung™ Galaxy™ S2 or similar mobile telephone/smartphone. Device  30  includes a body  31  including one or more layers of material. In some embodiments, the one or more layers of material may be similar to the one or more layers as described herein with regard to body  11  of device  10  in  FIG. 1 . Referring to  FIG. 3 , body  31  of device  30  may include one or more peripheral portions  33 . The one or more peripheral portions  33  may be folded at substantially transverse angels with the center of body  31  in such a manner that the one or more peripheral portions  33  may be arranged to cover and/or be disposed at or near one or more lateral sides of an electronic device. In other words, a peripheral portion  33  may be folded around the side of the mobile telephone/smartphone. In some embodiments, one or more lateral sides of the electronic device may be covered by one or more peripheral portions  33  in a manner such that predetermined types of components of the electronic device are uncovered, such as, by way of non-limiting example, buttons or antennas. Note that the description of peripheral portions  13  in  FIG. 1  also applies to peripheral portions  33  in  FIG. 3 . In some embodiments, body  31  may include one or more cut-outs  32  or holes  32  (and/or other open spaces) for one or more components of the electronic device. In the example depicted in  FIG. 3 , one or more cut-outs  32  may be configured to accommodate a speaker, camera, and/or one or more control-buttons of the mobile telephone/smartphone. 
       FIG. 4  illustrates views and dimensions of device  10  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 4 ).  FIG. 4  includes two flat views of device  10 , including peripheral portions  13  as described in relation to  FIG. 1 . Dimensions in  FIGS. 4-6  are annotated in inches unless noted otherwise. 
       FIG. 5  illustrates views and dimensions of device  20  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 5 ).  FIG. 5  includes two flat views of device  20 , including peripheral portions  23  as described in relation to  FIG. 2 . 
       FIG. 6  illustrates views and dimensions of device  30  configured to shield electromagnetic radiation emitted from an electronic device (not shown in  FIG. 6 ).  FIG. 6  includes two flat views of device  30 , including peripheral portions  33  and cut-outs  32  (or holes  32 ) as described in relation to  FIG. 3 . 
       FIG. 7  illustrates a method  700  to shield a user from electromagnetic radiation emitted by an electronic device. The operations of method  700  presented below are intended to be illustrative. In certain embodiments, method  700  may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method  700  are illustrated in  FIG. 7  and described below is not intended to be limiting. 
     At an operation  702 , a first layer of material is provided that has properties of absorption of electromagnetic radiation. The absorption may pertain to a predominant range of frequencies between about 450 MHz and about 2.5 GHz. The first layer of material attenuates the electromagnetic radiation by at least 25 dB. In one embodiment, operation  702  is performed by a first layer of material of a body similar to or substantially the same as body  11  (shown in  FIG. 1  and described above). 
     At an operation  704 , a second layer of material is provided that has properties of deflection of electromagnetic radiation. The deflection may pertain to a predominant range of frequencies between about 450 MHz and about 2.5 GHz. The second layer of material attenuates the electromagnetic radiation by at least 60 dB. In one embodiment, operation  704  is performed by a second layer of material of a body similar to or substantially the same as body  11  (shown in  FIG. 1  and described above). 
     At an operation  706 , a combination of the first layer and the second layer is arranged to be disposed near the back side of an electronic device. In one embodiment, operation  706  is performed by a body similar to or substantially the same as body  11  (shown in  FIG. 1  and described above). 
     Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.