Abstract:
A mobile phone comprises an car-piece for transmitting sound in a first direction a transducer for converting electrical signals into speech sound, and a dielectric member having an acoustic duct that extends in a direction that is normal to the first direction, the acoustic duct guiding sound generated by the transducer to the ear-piece. By this arrangement all radiating parts of the mobile can be kept away from the ear. The earpiece is movable relative to the casing of the mobile phone.

Description:
FIELD AND BACKGROUND OF THE INVENTION  
         [0001]    The present invention is concerned with reducing radiation from a mobile phone into the brain of its user. There is concern that such radiation may possible be harmful to parts of the brain.  
           [0002]    Currently available mobile phones comprise a housing that includes a set of operating keys, a display at a top portion of the mobile phone, a radio frequency transceiver, an aerial at the top portion of the mobile phone, a microphone, a speaker at the top portion of the mobile phone that converts electrical speech signals into sound, and wiring for interconnecting these items. In use, the speaker is placed at the ear, with the aerial also close to or at the ear. The speaker, being a wired electrical part, radiates radio waves straight into the car and, therefore, into the brain. All metallic parts in the mobile phone reflect or re-radiate radio waves emanating from the aerial Also, the aerial itself is very close to the brain and therefore transmits strong radio waves into the brain.  
           [0003]    In order to reduce the risk of radiation into the brain many users of mobile phones have resorted to using a hands-free kit, the conventional hands-free kit consists of a cable having a plug that fits into the mobile phone. The cable has a microphone part Ad ax along its length, and terminates in an earphone that is fitted to the ear. It has been supposed that the hands-free kit provides protection against radiation into the brain, since the mobile phone casing containing the transmitter can be placed away from the head, for example in a pocket. However, some tests that have been carried out indicate that the cable of the hands-free kit can guide radio staves into the brain via the ear, in some cases causing higher radiation in portions of the brain than when the kit is not resorted to.  
         SUMMARY OF THE INVENTION  
         [0004]    A mobile phone according to the present invention comprises an ear-piece for transmitting sound in a first direction; a transducer for converting electrical signals into speech sound; and a dielectric member having an acoustic duct that extends in a direction that is normal to the first direction, the acoustic duct guiding sound generated by the transducer to the ear-piece. By this, all metallic parts of the mobile phone (which parts are sources of radio frequency radiation or re-radiation) can be kept well away from the ear and brain. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 illustrates schematically a mobile phone according to a first embodiment of the invention.  
         [0006]    [0006]FIG. 2 illustrates schematically a second embodiment of the invention, using a telescopic sound guide.  
         [0007]    [0007]FIG. 3 illustrates schematically a third embodiment of the invention comprising a hands-free kit. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0008]    [0008]FIG. 1 illustrates schematically the first embodiment of the invention. As shown, mobile phone assembly  1  includes a lid  3  of dielectric material that can rotate about a hinge  4 , a display screen  5 , a microphone  2 , and operating keys  6 . Included in lid  3  is a transducer  7  that is close to hinge  4  and that converts electrical energy into sound. Speech sound from transducer  7  is transmitted via a duct  8  in lid  3  to exit from lid  3  at an opening  9  in the direction of arrow  15  into the user&#39;s ear. Opening  9  is in a dished portion  10  of lid  3  that services as the earpiece of the mobile phone. By this arrangement all electrical parts of the mobile phone can be kept several centimeters away from the ear. The length of the lid can range from 7 cm to 15 cm or more, consequently hole  9 , opposite the car, can be about 5 cm to 13 cm areas from all metal parts of the phone. Transducer  7  is connected to circuits in mobile phone I by a flexible cable not shown. Sound duct  8  can have a cross section of any shape, for example the cross section can be a 2 millimeter diameter circle. Lid  3  can be made wholly or partly transparent so as to allow display  5  to be seen even if lid  3  is in the folded position, i.e. covering the display. Mobile phone casing includes an aerial and a radio frequency transmitter and receiver (not shown) for communication with base stations. The aerial may be wholly or partly inside casing  11 .  
         [0009]    During talking using mobile phone  1 , earpiece  10  is pressed against the user&#39;s car. The direction  12  in which sound is guided by duct  8  is normal to the direction of arrow  15 .  
         [0010]    If desired, transducer  7  can be placed inside casing,  11  it shown location  14 , in which case holes are provided at the top of casing  11  and the bottom of lid  3  so as to provide unobstructed transmission of sound from transducer  7  to duct  8 .  
         [0011]    [0011]FIG. 1 shows lid  3  hinged to casing  11  so that it can swing to cover the front face of casing  11  when not in use. It is possible to re-arrange lid  3  so that It is hinged to casing  11  so as to cover the back of casing  11  when not in use.  
         [0012]    [0012]FIG. 2 illustrates schematically a second embodiment of the invention. As shown, mobile phone assembly  20  includes the transducer  7  arranged to deliver speech sound into the bottom of a cylindrical tube  21 . Contained in cylindrical tube  21  is a cylindrical tube  22  of non-metallic material, and inside tube  22  is a cylindrical tube  23 , also of nonmetallic material. The top end of tube  23  terminates in a non-metallic earpiece  24  having an opening  25 . By this arrangement, speech sound from speaker  7  is transmitted through hollow tubes  21 ,  22 ,  33  in succession to pass through opening  25  in earpiece  24 . The arrangement of the tubes is telescopic. Tube  22  is prevented from sliding right out of tube  21  by stop means not shown. Tube  23  slides in tube  22 , and tube  22  slides in tube  21 . Thus when mobile phone  20  is not in use tubes  22 ,  23  can be nested in casing  11  of mobile phone  20 , with earpiece  25  nesting in pocket  26 . By this arrangement, during talking on the phone, all electrical parts of the phone can be positioned away from earpiece  24  by more than the length of the phone. Thus, for example, if the length of the phone is 10 cm, the distance between ear-piece  24  and the electrical parts in the phone can be greater than 15 cm. Optionally, there can be more than two sliding tubes acting as sound ducts. A switch  27  is provided which disables transducer  7  when tube  22  is not pulled out.  
         [0013]    [0013]FIG. 3 illustrates another embodiment of the invention. Mobile phone assembly  30  includes a main unit having a casing  11  and a hands-free kit  31 . The main unit can be a conventional mobile phone complete with a radio frequency transceiver, an aerial, a microphone, a speaker, display operating keys, etc., and a socket  32  for connection to a hands-free kit.  
         [0014]    In the assembly of FIG. 3, hands free kit  31  comprises a small housing unit  33  containing a speaker  7  and a microphone  2 . Speaker  7  delivers speech sound into a bent dielectric tube  34  which in turn passes the sound via a hollow in dielectric earpiece  35  into the ear of the user. A cable  36  with a plug  37  electrically connects microphone  2  and speaker  7  to circuits in casing  11 . The inside of tube  34  provides the acoustic duct  8 . Tube  34  is can be 2-20 centimeters long and can include soft flexible material. The direction  15  of sound emanating from earpiece  34  is normal to the direction of sound travel in tube  34  indicated by arrow  12 . Microphone  2  picks up the user&#39;s speech though an aperture  38  in housing  33 . In all of the arrangements that have been described all electrical parts can easily be kept  10  centimeters or more away from the ear and brain. The arrangements of FIGS. 1.  2  have the advantage that they provide protection against phone radiation without using a hands-free kit. The advantage of the arrangement of FIG. 3 is that the kit  31  can be used with most of the existing mobile phones.