Patent Publication Number: US-2016248281-A1

Title: Cover For Converting Electromagnetic Radiation in Electronic Devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/489,641 filed May 24, 2011, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     At least certain embodiments of the invention relate generally to RF radiation, and particularly to converting RF radiation in electronic devices. 
     BACKGROUND 
     Electromagnetic radiation can include any form of electromagnetic waves at any frequency, including radio waves, microwaves, infrared, visible light, ultra-violet radiation, X-Rays and Gamma Rays. Of particular interest is electromagnetic radiation in the radio frequency (“RF”) range. RF radiation originates from a variety of electronic devices encountered in everyday life such as wireless phones, music players, microwave ovens, computers, PDAs, and so on. Consequently, exposure by a typical person to RF radiation continues to increase with the prevalence of these devices. Nowadays, the use of wireless phones and other RF radiation generating devices has become so pervasive that many users forego traditional hardline telephones in their homes for the convenience of wireless connectivity and mobility. 
     The continued and ever-increasing exposure by the population to RF radiation may have detrimental effects to users over time. It is already known that EM radiation in the very high frequency form of ultraviolet or X-rays can cause damage to Deoxyribonucleic Acid (“DNA”) in humans. It has lately been proposed that lower frequency RF radiation may also have an effect on DNA. As our understanding of RF radiation and its possible detrimental effects continues to develop, it is quite possible that a variety of yet unknown effects from exposure to RF radiation may also be uncovered in the future. This damage may likely be exacerbated by continued exposure at close proximity. For example, use of a wireless telephone or Bluetooth device held in proximity to a user&#39;s ear may increase RF radiation exposure and may in turn damage sensitive areas to the brain. 
     As previously observed with video display monitors, the biological effects of RF radiation are ascertainable, particularly when resonance conditions are met. It has been suggested that the focus of studies which have showed no harmful effects, and which have concluded that wireless telephone radiation is safe, depart from the fact that, in real-life, wireless users are exposed to this radiation numerous times during the course of a day and over the course of several years. Most scientific studies have not taken into account the chronic use of cell phones and other wireless devices. As devices and other sources that emit RF radiation become increasingly prevalent in our everyday lives, so too does the likelihood of exposure by users of these devices. Indeed, in current times it may be difficult, if not nearly impossible, for users to avoid this exposure such as through use of microwaves, interaction with personal computers, listening to portable music players, or using hand-held video games, and so on. 
     SUMMARY 
     Methods and apparatuses for capturing and converting radio frequency (“RF”) radiation emitted from electronic devices are disclosed. In at least certain embodiments, the method includes capturing at least a portion of the RF radiation emitted from an electronic device and converting it into electrical energy. This electric energy can be used for a number of different functional purposes such as to drive an indicator showing when the RF radiation emitted from the electronic device is being converted as well as what its relative intensity is. For example, the electrical energy captured from the electronic device can be used to drive a light-emitting diode (“LED”). In other embodiments, the electrical energy can perform additional functionality such as charging a battery of the electronic device. 
     The apparatus may include a cover for an electronic device. In at least certain embodiments, the cover includes an embedded circuit having an antenna adapted to capture at least a portion of the RF radiation emitted from the device, an RF conversion circuit to receive the captured RF radiation from the antenna and to convert it into electrical energy, and an indicator circuit. The electric energy can be used to drive the indicator circuit to provide users with an indication that at least some of the RF radiation emitted from the electronic device is being diverted away from a user&#39;s body and converted into electrical energy. The RF antenna can be positioned near the location where a user&#39;s body is in contact or close proximity to the electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of at least certain embodiments, reference will be made to the following Detailed Description, which is to be read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts a number of RF radiation sources according to one illustrative embodiment. 
         FIG. 2A  depicts an apparatus including a cover for converting RF radiation in an electronic device according to one illustrative embodiment. 
         FIG. 2B  depicts an apparatus including a cover for converting RF radiation in an electronic device according to one illustrative embodiment. 
         FIG. 3A  depicts an apparatus including a circuit for converting RF radiation in an electronic device according to one illustrative embodiment. 
         FIG. 3B  depicts example voltage output waveforms according to one illustrative embodiment. 
         FIG. 4  depicts an example of a preferred embodiment of an apparatus including a circuit for converting RF radiation in an electronic device. 
         FIG. 5  depicts a process for converting RF radiation in an electronic device according to one illustrative embodiment. 
         FIG. 6  depicts an apparatus including a circuit for converting RF radiation in an electronic device according to one illustrative embodiment. 
         FIG. 7  depicts an apparatus including a circuit for converting RF radiation in an electronic device according to one illustrative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout the description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent to one skilled in the art, however, that the embodiments described herein may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form to avoid obscuring underlying principles of embodiments of the invention. 
     A method and apparatus for capturing and converting RF radiation emitted from an electronic device are disclosed. In at least certain embodiments, the method includes capturing at least a portion of the RF radiation emitted from an electronic device and converting it into electric energy such as DC current. The DC current can then be used for a number of different functional purposes. For example, the DC current can be used to drive an indicator circuit to provide an indication when the RF radiation is being converted. The indicator circuit may include an LED that varies its brightness according to the relative power level of the RF radiation being absorbed. The electrical energy captured from the electronic device can be used to drive the LED to visually alert users during times when RF radiation is being converted and to allow users to observe the relative intensity of the captured RF radiation. 
     This is advantageous for several reasons. First, the LED can give a visual indication to a user showing the user when—and how much—RF radiation is being converted from their particular electronic devices. As the portion of RF radiation emitted from the users&#39; devices increases, the LED can be configured to flash more brightly and faster, indicating in a very palpable manner to users the amount of RF radiation that is being dissipated in the circuit described herein. This allows users to visualize and hence begin to understand the amount of RF radiation emitted from their devices that they are being exposed to at various times throughout the day, both at times during use and also when idle. This enables users to understand the amount of RF exposure their devices are subjecting them to, and to further understand in a very real sense their long-term exposure to these potentially harmful levels of RF radiation. Second, having provided an indication to users about the amount of RF radiation they are experiencing in their everyday lives, the techniques described herein are also advantageous in giving users the motivation to modify their behavior to avoid or at least moderate their exposure to this radiation. 
     The techniques described herein are not limited to any particular LED. The LED can be implemented on a flexible or rigid substrate. In addition, the LED can be made of any inorganic or organic materials, and can be of variable brightness. Organic composites or polymers such as light-emitting polymers (“LEPs”) or organic LEDs (“OLEDs”) can be used. The OLEDs and LEPs can be used to create a visual indication that is not limited to a flashing LED. For example, the LED can also be a display screen that lights up during times when the RF radiation is being converted. These display screens can be used to display any number of different displays such as a particular pattern, information such as date and time of day, a banner advertisement, or other display of information; or any other text or pictures. The electrical energy can also be used to drive other types of indicator circuits to provide a palpable indication to users. The indicator circuits can include sound or vibration, or any combination of these indications. The electrical energy captured from the RF radiation can also be used to perform additional functionality in the electronic device such as charging a battery. 
     In one embodiment, all the electrical power necessary to drive the indicator circuit such as an LED is derived from the captured RF radiation, and in other embodiments, the electrical power may be derived from additional sources such as the electronic device&#39;s battery. 
     The apparatus disclosed herein may include a cover for the electronic device. For the purposes of the present description, the term “cover” is to be interpreted broadly to include a hard or soft cover for the electronic device, a skin, or coating, etc. The cover may also be built into, or otherwise be an integral part of, the electronic device itself; and accordingly can be marketed and sold as a complete package of device and cover together. The cover may also be separate from the skin or outer shell of the electronic device, or can be any combination of these. In one embodiment, the cover can be a protective cover that may be in any form such as a protective case, shielding, article of clothing, a sticker or other adhesive material, or even a clip or clamp that can be secured to an electronic device for the purposes of capturing RF radiation emitted from the electronic device; or any combination of these embodiments. The cover can be fabricated of any material such as an insulating or conductive material, or metallic material, Velcro or related material, or even a single molded piece of material of any composition. 
     The cover may also include built-in electrical contacts configured to interface with corresponding electrical contacts of an electronic device such that the captured RF radiation can drive the interface of the device. In such an embodiment, the device software, hardware or combination of device software and hardware can be used in combination with the embodiments described herein to provide an indication originating from within the electronic device itself. For example, the contacts on the cover can be aligned with contacts built into the electronic device such as a device interface to provide an indication from the device itself. For example, the indication can be provided on the screen or other indication mechanism of the electronic device alerting users during times when RF radiation is being captured. In addition, the amount of RF radiation over time can be calculated by the device such as through the use of device software, hardware, or combination and can be provided to users from the electronic device such as on the screen or other output mechanism of the device. The contacts of the cover can be driven by the electronic current generated by the cover during RF radiation capture. 
     The apparatus can include a cover having an embedded antenna adapted to capture at least a portion of the RF radiation emitted from the device, a conversion circuit adapted to receive the captured RF radiation from the antenna and to convert it into electric current, and an indicator circuit to provide an indication to users during times when RF radiation is being converted. The indicator circuit can also provide an indication of the relative intensity of the RF radiation being absorbed by the described embodiments. As used herein, the term “antenna” refers to any electrical device or material that sends and/or receives electromagnetic waves. For instance, an antenna can be an RF antenna or other device or material of equivalent functionality. The antenna can be positioned at a location near where a user&#39;s body would come into contact or proximity to the electronic device. By capturing a portion of the RF radiation emitted from the electronic device, users can be protected from that portion of RF radiation which would otherwise be channeled into their bodies. 
       FIG. 1  depicts a number of RF radiation sources  100  according to one illustrative embodiment. There are many sources of RF radiation that people are exposed to in their everyday lives including wireless phones and headsets, computers, televisions, wireless routers and gateways, cable modems, microwaves, hair dryers, etc. One of the advantages of the techniques described herein is that users can be protected from the potential harmful effects of long-term exposure to the RF radiation emitted from electronic devices, particularly wireless phones and headsets, which are often held in close proximity to a user&#39;s body. A portion of the RF radiation emitted from users&#39; electronic devices can be converted and dissipated in the indicator circuit of the apparatus described herein. As such, these techniques can be used to avoid or mitigate the long-term effects of RF radiation exposure by allowing users to place a cover on his or her electronic devices that functions to convert some of the RF radiation into electrical energy. This electrical energy can be used to drive an indicator or to perform other useful work for users, or both. For example, the redirected electrical energy can be also used to drive various electronic functionality of the electronic device such as charging its battery. 
       FIG. 2A  depicts an apparatus including a cover for converting RF radiation in an electronic device according to one embodiment. In the illustrated embodiment, cover  201  is used to convert RF radiation emitted from electronic device  200 . Cover  201  includes an RF antenna  240  coupled with an RF conversion circuit  220 . The RF conversion circuit  220  is further coupled with an indicator circuit  210  via an interconnect  230 . Antenna  240  is adapted to capture at least a portion of the RF radiation emitted from the electronic device  200 . The RF radiation captured by antenna  240  is then output to RF conversion circuit  220  where it is converted into DC electric current supplied to indicator circuit  210 . As described above, indicator circuit  210  can include any visual, auditory, or other palpable indicator to alert users during times when the RF radiation emitted from their electronic device  200  is being captured and converted into electrical energy. Antenna  240  may be either a passive antenna, or a partially passive and partially active antenna. But a passive antenna is preferred as it avoids interference with the electronic device. Antenna  240  may be a dipole antenna, a meandering antenna, a monopole antenna, or any other directional or omni-directional antenna that can capture RF radiation. 
     In addition, antenna  240  may include multiple antennas such as would be used in an embodiment where it is desirable to capture multiple frequencies of RF radiation from an electronic device for versatility or compatibility purposes. The multiple antenna embodiment may be useful for capturing different frequencies known to be used by different manufacturers, or the same manufacturer. Table 1 lists a number of frequencies used by various current manufacturers of wireless telephones and cellular carriers in the U.S.: 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Carrier 
                 Frequencies 
                 Technology 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 AT&amp;T 
                 850  
                 MHz 
                 GSM/GPRS 
               
               
                   
                 1900  
                 MHz 
                 EDGE 
               
               
                   
                 1.7/2.1  
                 GHz 
                 UMTS/HSPA 
               
               
                   
                   
                   
                 LTE 
               
               
                 Metro PCS 
                 1900  
                 MHz 
                 CDMA 2000 1X Ev-Do 
               
               
                   
                 1.7/2.1  
                 GHz 
                 LTE 
               
            
           
           
               
               
               
            
               
                 Nextel 
                 See Sprint 
                 iDEN 
               
            
           
           
               
               
               
               
            
               
                 Qualcomm 
                 700  
                 MHz 
                 MediaFLO 
               
               
                 Sprint 
                 1900  
                 MHz 
                 CDMA 2000 1X Ev-Do 
               
               
                   
                   
                   
                 CDMA 
               
               
                 T-Mobile 
                 1900  
                 MHz 
                 GSM/GPRS 
               
               
                   
                 1.7/2.1  
                 GHz 
                 EDGE 
               
               
                   
                   
                   
                 UMTS 
               
               
                   
                   
                   
                 LTE 
               
               
                 Verizon 
                 850 
                 MHz 
                 CDMA 
               
               
                   
                 1900 
                 MHz 
                 CDMA 2000 1X Ev-Do 
               
               
                   
                 700 
                 MHz 
                 LTE 
               
               
                   
               
            
           
         
       
     
     The operation of the preferred embodiment of the apparatus will now be described with reference to  FIG. 2B . In the illustrated embodiment, the antenna  290  of device  200  is shown superimposed on top of cover  201 . During operation of the electronic device, antenna  290  emits an active RF waveform  270 . This can be during a phone call, for example, or at another active period of the electronic device, although enough RF radiation may be emitted even during passive periods of the electronic device. In addition, RF radiation may also come from other external sources such as a nearby cell tower (as depicted in  FIG. 1 ). For illustrative purposes, we will only refer to RF radiation that is generated from the electronic device. When the active RF wave  270  is generated by device antenna  290 , part of the wave is captured by antenna  240  of the cover  201  through electromagnetic induction. This captured part of the active RF wave is shown as passive RF wave  275  in the diagram. As described above, antenna  240  need not be limited to a passive antenna, but in the preferred embodiment, a passive antenna is used both for better cost efficiency and also so that it does not interfere with the active device antenna  290  of the device. Also as discussed above, antenna  240  can be a single or multiple antennas. In this embodiment, once passive RF wave  275  is captured by antenna  240 , it is driven through to RF conversion circuit  220  where it gets converted to an electric current  280 , and then driven out to indicator circuit  210 . 
       FIG. 3A  depicts an example embodiment of an apparatus including a circuit for converting RF radiation in an electronic device. Apparatus  300  includes antenna  340 , RF conversion circuit  320 , and an indicator circuit  310 . As discussed above, the antenna can be any antenna, material, or device that captures RF radiation. In the illustrated embodiment, RF conversion circuit  320  includes a clamp circuit followed by a rectifier circuit. The clamp circuit includes diode D 2 A in parallel with capacitor C 2 . The output of the clamp circuit is Node  1 . The rectifier circuit includes diode D 2 B and capacitor C 1 . The output of the rectifier circuit is Node  2 . Resistor R 1  is optional and can be configured by the circuit designer to adjust the flow of current at the output  307  from RF conversion circuit  320  to the indicator circuit  310 . In the illustrated diagram, indicator  310  includes a LED D 1 . 
     The operation of the apparatus  300  will now be described with reference to  FIG. 3B , which depicts example voltage output waveforms output according to one illustrative embodiment. As shown in the illustration, the input voltage  330  of the RF radiation received by antenna  340  is a normal sinusoidal wave signal that oscillates equally above and below zero volts (i.e., ground potential). The voltage waveform  331  at the output of the clamping circuit (Node  1 ) is also a sinusoidal wave signal, but it has been shifted up by some positive value according to the voltage present across capacitor C 2  and limited to the difference between ground and the forward bias voltage of the diode. The voltage waveform  332  after the rectifier circuit (Node  2 ) approximates a DC signal held in a steady-state by capacitor C 1  as shown in the diagram. According to this embodiment therefore an input sinusoidal signal associated with the RF radiation received at antenna  340  is converted to an output DC signal at Node  2  that is used to drive current through R 1  into the indicator circuit  310 . 
       FIG. 4  depicts an example of a preferred embodiment of an apparatus including a circuit for converting RF radiation in an electronic device. In this preferred embodiment, antenna  440  is a dipole antenna. RF conversion circuit includes three stages of clamping circuits followed by a rectifier circuit as shown in  FIG. 3A . Apparatus  400  shows a first stage (D 2 A, C 2 , D 2 B, C 1 ), a second stage (D 3 A, C 4 , D 3 B, C 3 ), and a third stage (D 4 A, C 6 , D 4 B, C 5 ). Embodiments however are not so limited as more or fewer stages can be used depending on several design choices such as the size of the circuit implementation, the size of the output resistor R 1 , the size and desired brightness of the LED D 1 , and the amount of DC current that drives the LED. In addition, other circuits known in the art to convert RF signals into an electric current can also be used. The techniques described herein are not limited to any particular configuration of the RF conversion circuit. In addition, the battery may be rechargeable and may be charged by the techniques described herein in addition to the normal battery charging mechanisms provided on the device itself such as conventionally through a wall plug or AC adapter. Solar panels, or any other energy harvesting methods may also be incorporated into the cover apparatus to provide additional battery charging, or may charge the battery independently of the battery charging mechanism discussed above. 
       FIG. 5  depicts a process for converting RF radiation in an electronic device according to one illustrative embodiment. Process  500  begins by capturing at least a portion of the RF radiation emitted from a particular electronic device (operation  501 ). As described above, this is done using an antenna or other equivalent mechanism to divert part of the RF radiation to an antenna through electromagnetic induction. The captured RF radiation is then converted to DC current (operation  503 ) and provided to an indicator circuit (operation  505 ). The indicator circuit provides the visual indication at operation  507 . In one embodiment, the visual indication provides both an indication as to when the absorption of RF radiation occurs and its relative intensity. This completes process  500  according to one embodiment. As discussed above, embodiments may include other types of indications and are not limited to visual indications. 
     The electric energy generated from the captured RF radiation can also be used to provide useful work. For example, the DC current can be used to charge a battery of the electronic device as shown in  FIG. 6 , which depicts an example apparatus including a circuit for converting RF radiation in an electronic device. In the illustrated embodiment, current  680  that is driven from the output of RF conversion circuit  620  is used to drive a battery charging circuit  698  that is output to a device battery circuit  699  of the electronic device (not shown) to charge the battery of the electronic device. Therefore the captured RF radiation  675  can be used to charge the battery of the electronic device. This can be accomplished by itself as shown in  FIG. 6 , or in combination with driving the LED. 
     In addition, a switch can be used to allow users to turn off the indication circuit during times when it is undesired, such as during a theater performance.  FIG. 7  depicts an example apparatus including a cover having a switch  770  that is adapted to selectively activate and deactivate the indicator  710 , although other embodiments are possible. In this embodiment, the switch  770  is located on the interconnect  730  between RF conversion circuit  720  and indicator circuit  710 . When the switch  770  is placed in the open position as shown in the diagram, interconnect  730  becomes an open circuit and no current flows through to drive the indicator  710 . When this happens, the indicator  710  will be shut off And during times when the switch  770  is placed in the closed position (not shown), interconnect  730  becomes a closed circuit, and current can flow through to drive the indicator  710 . When this happens, the indicator  710  will be turned on. This functionality provides users with a selection mechanism to turn on and off the indicator  710  as desired. Such a switch  770  can be actuated by any user input device in the field of art. This switch  770  can also be configured to interface with the electronic device such that it is actuated whenever a user switches their electronic device to silent mode, for example. 
     Various techniques described herein may also be used in combination with other RF radiation abatement techniques. For example, RF radiation absorption materials such as paramagnetic materials or other RF absorption materials or fabrics may be used to further limit users&#39; exposure to RF radiation emitted from their electronic devices. Throughout the foregoing description, and for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the described techniques. It will be apparent, however, to one skilled in the art that these techniques may be practiced without some of these specific details. Although various embodiments which incorporate these teachings have been shown and described in detail, those skilled in the art could readily devise many other varied embodiments or mechanisms to incorporate these techniques. 
     Also, embodiments may include various operations as set forth above, fewer operations, or more operations; or operations in an order. Accordingly, the scope and spirit of the invention should be judged in terms of the claims which follow as well as the legal equivalents thereof.