Abstract:
A cell phone with radiation-free sound transmission system is the subject of this invention. By converting electric signals into sound waves that are transmitted through acoustical tubes, the exposure of user to hazardous electromagnetic radiation is significantly reduced, compared to ordinary cellular telephones.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to cellular telephones and, more particularly, to a system for using a cellular telephone without producing potentially hazardous radiation near the body of users. 
     2. Description of the Prior Art 
     Cellular phones are becoming omnipresent and necessary elements as society enters the new millennium. Unfortunately, operating on radio frequency transmission, these are also sources of electromagnetic radiation. Most phones include an antenna that is placed close to the user&#39;s head, emitted radiation and suspected to be hazardous to users. Attempts to reduce the emitted radiation by placing a shield around the antenna, have been found to be impractical and thus have not been commonly employed in cellular telephones. Another proposed solution is to avoid placing the antenna near the head of the user. Proposed and now commonly available is an electrical wire that is connected to the telephone at the input/output port of the cellular phone and terminating with an earpiece that is placed in the user&#39;s ear. A microphone is mounted on the wire near the earpiece, putting it at the level of the mouth of the user when the earpiece is placed in the ear. In such an arrangement, the telephone may be clipped to a user&#39;s belt or placed in a pocket or a purse, with the wire extending therefrom. The earpiece is placed in the user&#39;s ear. 
     When the user receives or makes a telephone call, the user merely activates the “send” or similar button on the cellular telephone to complete the call hands free. The user hears through the earpiece, the other party hearing the user through the signal picked up by the microphone which is in proximity of the mouth. Another configuration of cellular telephones in use includes a loudspeaker coupled directly to and mounted on a cellular telephone. The user can hear the emitted sounds with no need to hold the cellular telephone close to head. However, since a loudspeaker is used instead of a microphone, privacy is denied unless the user is alone. 
     Not only do these solutions provide for hands free operation of the telephone, they were also believed to have resolved the problem of unwanted radiation near the user&#39;s head, the telephone being remote therefrom. Unfortunately, recent studies conducted in Britain in 2000 have shown that such a wire configuration does not reduce radiation near the user&#39;s head. 
     There have been number of attempts aimed at solving the problem of potentially hazardous radiation emitted from cellular telephones. 
     U.S. Pat. No. 4,090,042 relates to acoustical communications headset including tubes for the transmission of sound. 
     U.S. Pat. No. 5,528,689 relates to a method for converting a cellular telephone into a headset telephone. U-shaped clips are used for attaching a mouth cup and an ear cup to the cellular telephone. However, there is still a problem that might evolve from disposition of these cups. Such disposition will interfere significantly with the smooth operation of the cellular telephone, since too much noise from the surroundings might be picked up by the microphone, or alternatively mask the sound coming from the earpiece. In addition, headset adjustment to user&#39;s head is done by a complicated mechanism that may easily dismembered. 
     U.S. Pat. No. 5,613,222 relates to a hands-free cellular phone that employ acoustical tubes. A receiving cup is attached to the speaker of the cellular telephone by loop type Velcro fasteners. However, Velcro straps can still be bulky and accidentally detached. Such disposition will interfere significantly with smooth operation of the cellular telephone, since too much ambient noise from surrounding might be picked up by the microphone. 
     While these devices fulfill their particular objectives and requirements the aforementioned devices are not effective when the telephone has to be located more than ten feet away from the user, since longer acoustical tubes absorbs too much noise from surroundings. 
     In addition, receiving and transmitting of sound waves between the cellular phone and the user is not mediated by any apparatus capable of amplifying, coding, decoding, filtering, or conferring any other change on the sounds heard or spoken. Such apparatus, hereafter called a conversion device, is required especially when using the cellular phone near a source of loud noise. There is therefore a need for producing a cellular telephone employing acoustical tubing that can be employed in a noisy environment. 
     SUMMARY OF THE INVENTION 
     The present invention relates to cellular phone systems which use acoustical tubes for the transmission of sound. The present invention successfully addresses the shortcomings of the prior art by transmitting sound signals between the telephone and earpiece or microphone via a combination of electrical wire and acoustical tube connected end to end by a novel conversion device. 
     This conversion device may be connected to any kind of electrical output of mobile telephones and other apparatus. Hence, there is no need to make any changes in the configuration of existing mobile telephone in order to use this system. 
     In these respects, the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of communicating near loud noise sources. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
     In the drawings: 
     FIG. 1 shows a prior art cellular telephone coupled to an earpiece and a microphone via an electrical wire; 
     FIG. 2 shows a cellular telephone system in which a telephone is coupled to acoustical tube. The acoustical tube is coupled to a conversion device, which is coupled to the cellular telephone via electrical wire. The acoustical earpiece is coupled to the acoustical tube. The electric microphone is coupled to the cellular telephone by an electric wire; 
     FIG. 3 shows a cellular telephone system in which a telephone is coupled to acoustical tube. The acoustical tube is coupled to a conversion device, which is coupled to the cellular telephone via electrical wire; 
     FIG. 4 shows a cellular telephone system in which a telephone is coupled without wires to acoustical tube. The acoustical tube is coupled to a first conversion device. A second conversion device is coupled to the cellular telephone via electrical wire. The two conversion devices exchange electromagnetic signals; 
     FIG. 5 shows a configuration of cellular telephone system having two conversion devices, one on each side of an acoustical tube. The two conversion devices exchange signals of mechanical waves; 
     FIG. 6 shows a cellular telephone system in which a telephone is coupled to two acoustical tubes. Two acoustical tubes are coupled to a conversion device, which is coupled to the cellular telephone via electrical wire; 
     FIG. 7 shows a cellular telephone system in which a telephone is coupled to two acoustical tubes. The acoustical tubes are coupled to a first conversion device, which is coupled to the cellular telephone via electrical wire. One tube is coupled to a second conversion device, which is coupled to an electrical microphone by an electrical wire. A second tube is coupled to an earpiece; 
     FIG. 8 is a cross sectional view of two acoustical tubes fused alongside; 
     FIG. 9 is a cross sectional view of two acoustical tubes fused alongside and separated by a web; 
     FIG. 10 is a cross sectional view of two concentric acoustical tubes with fins between their walls; 
     FIG. 11 is a diagram of a conversion device including a full-wave rectifier; 
     FIG. 12 is a diagram of a conversion device including a half-wave rectifier; 
     FIG. 13 is a diagram of a conversion device including an amplifier connected to the earpiece and another amplifier connected to the microphone. A power supply is connected to both amplifiers; 
     FIG. 14 is a diagram of a power supplier circuit coupled to a charger. 
     FIG. 15 is a diagram of a conversion device including one amplifier connected to the earpiece and one amplifier connected to the microphone. Power to the amplifiers is supplied from the mobile telephone; 
     FIG. 16 is a diagram of a power supply system including two power supplies and a charger. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of better understanding of the present invention, as illustrated in the drawings, reference is first made to the construction and operation of a conventional prior art cell phone as illustrated in FIG.  1 . Such a conventional cell phone  6  may be connected to a microphone  2  and an earpiece  3  via an electrical wire  8 . Such wire, like the antenna  5 , is a source of electromagnetic radiation which present potential health hazards to the user. 
     The principles and operation of a system according to the present invention may be better understood with reference to the drawings and accompanying descriptions. 
     As shown in FIG. 2, a cellular telephone  6  may be connected to conversion device  7  via an electrical wire  8  and electrical coupler  9 . Conversion device  7  converts electrical signals into sound waves that in turn are transmitted to an acoustical earpiece  10  via an acoustical tube  11 . Electrical microphone is coupled to cellular telephone  6  via an electrical wire  8  and electrical coupler  9 . 
     Referring is now made to FIG. 3, a cellular telephone  6  is connected to conversion device  7  via an electrical wire  8  and electrical coupler  9 . Conversion device  7  converts electrical signals into sound waves that in turn are transmitted to an acoustical earpiece  10  via an acoustical tube  11 . Speech is transmitted from an acoustical microphone  12  to the conversion device  7 . 
     Referring is now made to FIG. 4. A cellular telephone  6  is connected to a proximal conversion device  14  via an electrical wire and electrical coupler  9 . Conversion device  7  converts electrical signals into sound waves that in turn are transmitted to an acoustical earpiece  10  via an acoustical tube  11 . Speech is transmitted from an acoustical microphone  12  to the conversion device  7 . Conversion devices  7  and Referring is now made to FIG. 3. A cellular telephone  6  is connected to conversion device  7  via an electrical wire  8  and electrical coupler  9 . Conversion device  7  converts electrical signals into sound waves that in turn are transmitted to an acoustical earpiece  10  via an acoustical tube  11 . Speech is transmitted from an acoustical microphone  12  to the conversion device  7 . 
     In an alternative embodiment, the cellular telephone system of the present invention may contain two conversion devices as illustrated in FIG.  5 . In such a case, the telephone  6  is connected to a proximal conversion device  7  via an electrical wire  8 . Conversion device  7  is connected to a distal conversion device  16  with an acoustical tube  11 . Distal conversion device  16  is connected to electrical earpiece  3  and electrical microphone  2  with electrical wires  15  and  17 . Proximal conversion device  7  may be connected directly to telephone  6  or may be an integral part of telephone  6 . 
     Referring now to acoustical tube  11 , it is made of (electrically) non-conducting, optionally flexible, material such as polyethylene, polypropylene, polyvinylchloride (PVC), etc., filled with a medium capable of conducting sound waves, such as plasma, gas, liquid, or solid. Instead of one tube, two tubes can be employed, one for receiving sound and another for transmission. Tubes may be separated by a web or fused with one another, wrapped together side by side or one inside the other as concentric tubes. 
     Branching may appear at any position along a tube. A tube with multiple branching tubes may be used as an announcement system for internal communication among the crew of a vehicle, an airplane, a vessel or any other need of internal communication. 
     The cross-section of tube  11  may be round, square or of any other geometry. One or more acoustical fittings such as quarter wavelength plate, a membrane or a funnel may be installed or embedded in a tube. 
     Conversion devices  7  and  16  are an essential part of the invention. They contain at least one transducer, which is a device capable of converting electrical signals into sound waves and/or vice versa. Conversion devices  14  and  20  contain a transceiver for exchanging electromagnetic signals. In addition, conversion devices  7 ,  14 ,  16 , and  20  may contain any of the following: 
     An encryption device. 
     A decoder. 
     An amplifier circuit. 
     A filter circuit. 
     An internal power supplier, redundantly operated. 
     A micro controller. 
     A wireless transmitter/receiver. 
     A device for sending a signal to any entrance or any exit of the conversion device. 
     A device for changing a signal to any entrance or any exit of the conversion device. 
     A device that can control transmission of any signal to any entrance or any exit of the conversion device. 
     Some examples for possible configurations of conversion devices are shown in FIGS. 11,  12 ,  13  and  15 . 
     In a specifically preferred embodiment shown in FIG. 11, the invention is related to a conversion device  7  including a full-wave rectifier  54  with an amplifier  52  connected to the speaker  50 , and an acoustical tube  11  for the microphone  51  and the speaker  50 . 
     In another embodiment shown in FIG. 12, the invention is related to conversion device  7  including a half-wave rectifier  55  with an amplifier  52  in the path of speaker  50 , and acoustical tubes  11  for the microphone  51  and the speaker  50 . 
     Further, the invention is related to a conversion device  7  as shown in FIG.  13 . Conversion device  7  comprises one amplifier  52  connected to earpiece  50 , and one amplifier  53  connected to microphone  51 , with separate acoustical tubes  11  for the microphone  51  and the earpiece  50 . A power supplier  56  is connected to amplifiers  52  and  53 . A momentary switch  74  may be installed for the purpose of controlling microphone  51 . A switch  75  may be installed for the purpose of controlling the conversion device from the cellular telephone. 
     As shown in FIG. 14, a removable charger  58  may be installed, for charging of the power supplier  57 . A switch  76  is used for coupling the amplifier  52  to the power supplier  57 . 
     Still Further, the invention is related to a conversion device  7  as shown in FIG.  15 . Conversion device  7  comprises a first amplifier  52  in the path of earpiece  50 , and one amplifier  53  in the path of the microphone  51 , with separate acoustical tubes  11  for a microphone  51  and an earpiece  50 . Power to the amplifiers is supplied from the mobile telephone via electrical wires  60  and  61 . 
     An example of a power supply system that can be utilized in the construction of conversion devices is shown in FIG.  16 . The system comprises two power suppliers  56 ,  57  and a charger  58  controlled by a micro switch  62 . The micro switch  62  selects the suitable power supplier for the amplifier  52  of the conversion device. 
     The use of an amplifier improves the transmission of sound waves and especially required for the transmission of sound wave to long distances. 
     The internal power supplier may be a battery, a solar cell, a wind vane, an apparatus for coupling kinetic energy to conversion device, or any other energy source. The power supplier may be connected to an amplifier. 
     Typical amplifiers are described in the following publications: 
     Ralph J. Smith, Circuits, Devices and Systems, second edition (1971), pp. 365, fig. 11.21 and pp. 376, fig. 11.31(a) 
     305 Circuits, Elcktor Elecktronice publishing (1995), ISBN 090570536x, pp. 19, fig. 924053-11. 
     Typical microphone amplifier circuit configurations are described in: 
     305 Circuits, Elcktor Elecktronice publishing, ISBN 090570536x, pp. 33, fig. 934039-11. 
     Typical filter circuit configurations are described in: 
     Ralph J. Smith, Circuits, Devices and Systems, second edition (1971), pp. 404, figs. 12.15(a), and 12.16(a). 
     305 Circuits, Elcktor Elecktronice publishing, ISBN 090570536x, pp. 31, Fig. 924095-11. 
     Typical wave rectifier circuit configurations are described in: 
     Ralph J. Smith, Circuits, Devices and Systems, second edition (1971), pp. 393, fig. 12.3(a). 
     305 Circuits, Elcktor Elecktronice publishing, ISBN 090570536x, pp. 14, fig. 914122-11; page 137, fig. 934024-11. 
     Typical relay circuit configurations are described in: 
     305 Circuits, Elcktor Elecktronice publishing, ISBN 090570536x, pp. 14, fig. 914122-11. 
     Typical charger circuit configurations are described in: 
     305 Circuits, Elcktor Elecktronice publishing, ISBN 090570536x, pp. 96, fig. 914004-11; pp. 103, fig. 914047-11. 
     An electrical microphone is defined as a device for the conversion of sound waves into an electrical signal. An electrical earpiece is defined as a device for the conversion of an electrical signal into sound waves. 
     Acoustical microphone and earpiece may optionally be unified in one device. 
     An electrical coupler is a device at one end of a wire or a conversion device with which it is attached to an input/output port of a cellular telephone. 
     Instead of a telephone, there may be a cell phone, a wireless transmitter/receiver, a computer, a CD player, a tape recorder, a DVD, a video camera or any other means of communication. When data is transmitted, electrical signals are converted into sound waves and vice versa. 
     In addition, the transmission of sound waves is insensitive to surrounding electromagnetic field. 
     Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the figures, which are not intended to be limiting.