GB2340691A - Mobile phone arrangement for limiting high frequency radiation exposure - Google Patents

Abstract

A mobile telephone in which the electronic circuits of the telephone are separated into two units, one unit 1 being a handset containing the earpiece and microphone, the other unit 2 containing the transmitter, and any other circuit elements which generate large amounts of electromagnetic radiation. During operation, the transmitter unit is located at some suitable distance from the- head of the user to minimise the amount of radio energy impinging on the user's head, thereby reducing user health concerns. Further more, if the user is wearing a hearing aid, interference in the hearing aid caused by the telephone's emissions are reduced to an acceptable level. Speech and control signals are exchanged between the handset and the transmitter unit via a wire link or a wireless link consisting of an infra red link, a low power radio link, or some other arrangement which does not produce unacceptable levels of electromagnetic emissions.

Description

2340691 A MOBILE TELEPHONE This Invention relates to a mobile telephone in

which the various elements of the telephone are arranged so that the transmitter and other parts of the telephone which emit significant amounts of electromagnetic energy are not located in close proximity to the head of the user, but are located at some appropriate distance from the users head. This arrangement minimises the effect of the radio transmissions and other electromagnetic radiation on the brain of the user and reduces interference with any hearing aid which the user might be wearing.

There are a number of problems associated with the common design of mobile telephone in which the radio transmitter, receiver, earpiece and microphone are incorporated in a single unit which is held to the car of the user. The first is that there are suspicions that the high frequency radio energy which radiates from the transmitt er could have an adverse effect on the brain function or on the long term health of the brain of the user. Even_ if medical evidence eventually shows these fears to be unfounded, mobile telephone users are likely to continue to worry about a telephone arrangement which requires a radio transmitter to be held in close to their heads and are likely to prefer a telephone arrangement which minimises the exposure of the brain to radio frequency energy. The second problem is that the radio transmissions and other electromagnetic emissions from some forms of mobile telephones particularly those employing digital technology - cause interference in hearing aid circuits to such a degree that hearing aid wearers are unable to use these types of mobile telephone.

An object of this invention is to overcome both user health concerns and interference in hearing aids by dividing the mobile telephone into two units. The first unit contains the radio transmitter and other circuit elements which generate high levels of electromagnetic radiation. This unit is hereinafter referred to as the transmitter unit. This unit is may also contain the receiver used to connect to the mobile telephone network. The second unit contains the earpiece, the microphone and any other circuit elements (such as the dialling keypad and display panel, and possibly the mobile telephone receiver) which do not produce significant electromagnetic radiation. This unit is hereinafter referred to as the handset. The two units are linked so that voice signals and data can be transmitted between the transmitter unit and the handset. The handset is held to the head in the normal manner of use of a telephone handset, while the transmitter unit is held or located at a distance from the head of the user which is sufficient to allay the users concerns regarding the possible health effects of the telephones emissions or for a user's hearing aid to function in a satisfactory manner. The two units may be designed to be brought together to form a single unit during storage or may be designed as two separate units which are operated and stored as separate units.

A variety of link arrangements can be used between the two units. Some forms of link, for example a cable, will permit power to be transferred between the two units. The link will convey voice and data signals between tne handset and the transmitter unit. The link may use one or several of the following 2 well known voice and data transmission systems: - cable link (wires), radio link, infra red link, ultrasonic link, inductive loop link, acoustic tubes. These link arrangements generally require electronic circuits in both the transmitter unit and the handset to process the signals but in the case of the acoustic tube, the sound transmitted through the tube may require amplification at each end or sufficient sound may be carried through the tube to obviate the need for electronic circuits in the handset. In the case of a cable link the audio signals may be sufficiently large for no electronic processing to be required in the handset. If R is advantageous a system may incorporate more than one kind of link. When the link is not capable of transferring significant power to the handset., the transmitter unit and the handset may both contain batteries. Where power can be transferred by the link between the transmitter unit and the handset (for example in the case of a cable) the link can carry both signals and power permitting only one battery to be used. The battery may be located either in the transmitter unit or the handset, but advantageously in the transmitter unit since this unit- can be placed on a table, carried on the belt of the user or carried in a briefcase and represents a convenient location for the heavier components of the telephone. Where a cable link is not used, electrical contacts can be located on the surfaces of the transmitter unit and the handset so that when the two units are brought together for storage, power can be transferred between the two batteries through the contacts, so that, for instance, the transmitter unit could contain a large battery and the handset a small battery, with the small battery being recharged from the big battery. Alternatively, power can be transferred in the storage configuration by transformer action between a coil located in the transmitter unit and a coil located in the handset.

When the telephone is not in use, the transmitter unit and handset may be united to form a single compact unit for storage. If so desired, the telephone may be constructed in a way which permits R to be used in the storage configuration in the manner of a conventional, single unit telephone, although in this mode of use the transmitter will be close to the user's head and the benefits which the two unit configuration provides will be lost.

If the link does not employ a cable or other arrangement which requires a physical connection between the handset and the transmitter unit, the transmitter link or the handset link can be directed to a third unit to increase the usefulness of the invention. This third unit when connected to a port of a laptop computer allows the computer to be linked to the transmitter unit, rather than, or as well as, the handset, for the purposes of data transfer via the mobile telephone system in the well known manner. Similarly, the link arrangements between the handset and the transmitter unit also permit a link to be established between the handset and a third unit. A use for this third unit is as a base station which can be connected to a conventional wired telephone system to form a base station so that the handset can be used as a cordless telephone with the conventional telephone network. The cordless telephone handset may communicate with its base station or with a base station contained within the transmitter unit which may be a specially adapted mobile telephone. Alternatively the cordless telephone may communicate with its base station or a base station which is connected to a conventional mobile telephone through a socket commonly provided on mobile telphones for the purposes of allowing the telephone to operate with a "hands-free" microphone and loudspeaker arrangement.

3 Where a radio link is used between the transmitter unit and the handset, the transmitter unit may be located at some considerable distance from the handset, determined by the range of this radio link. The transmitter could also be located out of sight of the user, for example in a pocket of the user, in the users briefcase, or even in another room from that occupied by the user. The radio link used to connect the handset and the transmitter could use a transmitter power much lower than that used by the mobile telephone transmitter to connect to the mobile telephone network, so that the transmitter in the handset would be at a power level which would not raise significant concerns about as effect on the brain and would permit hearing aids to perform satisfactorily. The frequency of the link transmissions could also be chosen to minimise health concerns and interference in hearing aids. The type of radio link conventionally used in cordless telephones would be one possible arrangement which could form the link between the handset and the transmitter unit. Alternatively, the radio link could utilise that part of the radio spectrum assigned to citizen's band radjo, or any other part of the radio spectrum assigned for wireless communication. A further advantage of a cordless telephone type radio link or any other type of radio link is that the handset can be very small and light since much of the mobile telephone circuitry and battery can be contained in the transmitter unit which can be carried in a pocket or briefcase and which is therefore not subject to the same weight constraints and considerations. Freed from weight constraints, the transmitter unit can incorporate a large battery, permitting the telephone to operate for long periods without recharging the battery. Similarly, the transmitter unit can incorporate features and systems which might not be practical in a conventional (one-piece) mobile telephone because of weight and power consumption considerations.

A further object of the invention is to permit the handset unit of the two-unit mobile telephone to make connection not only to the transmitter unit of the two unit mobile telephone system of which h is part but also with any other telephone lines - for instance the conventional wired telephone network. In this embodiment a mobile telephone arrangement is combined with a cordless telephone arrangement so that the user can enjoy the full benefits of a mobile telephone system without needing to locate close to the brain of the user a transmitter which transmits at a power level or at a frequency which causes health worries or which interferes with hearing aids.

The incorporation of the cordless telephone base station into the transmitter unit of the mobile phone transmitter unit permits a number of handsets to use the same mobile telephone transmitter unit. The handset can be used either with the mobile telephone and the cordless base station which it contaips, or with another similar base station which is connected to the conventional (wired) telephone service in the users home or office. The cordless base station can be separate from but connected to the transmitter unit. The transmitter unit may be a complete mobile telephone, which is connected to the cordless telephone base station through the electrical connector which is a common feature of mobile telephones and which permits the mobile telephone to be, for instance, connected to "hands-free" microphone and loudspeaker arrangements. Thus a brief case could contain a mobile telephone, which could if necessary be used on its own as a conventional mobile telephone, a cordless base station 4 connected to the mobile telephone, and, if required, a laptop computer which is also connected to the mobile telephone for the purposes of data communication.

Preferred embodiments of the invention will now be described in which:

Figures la, 1b and lc show the telephone with the two units together for storage or for use as a conventional mobile telephone.

Figure 2 shows the telephone comprising two units with a cable (wires) link between the two units, Figure 3 shows the telephone comprising two units with a wireless (no wire) link between the two units Figure 4 shows the telephone comprising two units plus a third unit linked to a computer.

Figure 5 shows the telephone comprising two units plus a third unit through which the handset may be connected to a conventional wired telephone network.

Figure 6 shows the telephone comprising two units, with the transmitter unit containing a cordless radio base station and the cordless handset.

Figure 7 shows the telephone comprising a transmitter unit or conventional mobile telephone connected to a separate cordless base station and the handset (cordless) together with a base station connected to the conventional wired telephone network.

As shown in Figure la and Figure 1b the two units which comprise the telephone may be brought together for storage to form a single entity. In Figure l a the earpiece, microphone, keypad and display of the handset 1 face inwards towards the transmitter unit 2 for protection. The transmitter unit may include an external antenna 3. If it is required that the telephone should be capable of use in the storage configuration, a more convenient arrangement may be that shown in Figure 1b in which the earpiece, microphone, ke ypad and display of the handset face outwards. Figure lc shows how the handset 1 may be carried inside a compartment which is part of the transmitter unit. The holster section 4 is an integral part of the transmitter unit 2 and holds the handset when not in use. If the holster section has appropriate cutouts, the holster construction permits the telephone to be used in the storage configuration as a conventional single unit mobile telephone which may be held to the head if the user is not concerned about electromagnetic radiation from the telephone. The handset may be activated automatically when removed from the holster or may require an action by the user to activate it. A telephone based on this type of construction may be worn on the users belt if the user is not concerned about the effect of transmissions on the middle part of the body. Alternatively the holster type of construction may be a convenient means of storing the handset regardless of how the telephone is carried. It will also be clear that many other shapes of transmitter unit and handset can be used. In subsequent diagrams the shape of telephone shown in Figure la is used but it will be clear that the arrangements shown in Figure lb and Figure lc could equally well be employed. Alternatively, the telephone may be designed so that the two parts of the telephone need neyer be brought together and may be used and stored separately.

Figure 2 shows how the telephone is used in the preferred manner, with the transmitter unit held or located at some distance from the handset and therefore from the head of the user. Voice signals, data signals and possibly electrical power are exchanged between the handset and the transmitter unit via the connecting cable 5. The cable can be made to retract into the body of one of the units as the two units are brought together.

Figure 3 demonstrates an arrangement in which the handset and the transmitter unit are not connected by a cable but by some other link 6 which permits the exchange of voice and data signals between the handset and the transmitter unit. As set out earlier, this link may be a radio. link, and infra;red link, an ultrasonic link, inductive loop link or some other convenient form of link.

Provision of an extra unit enhances the utility of the telephone system. Figure 4 shows how the transmitter may also communicate with a computer 7 via an extra unit 8 which connects to a socket of the computer. A link 9 of the type described above passes data between the transmitter unit and the computer receiveltransmit unit 8. The computer link 9 may be operated in preference to the handset link 6 or the system may be arranged to permit both to operate simultaneously. Link 6 and link 9 may be handled by a single set of components at the transmitter unit end.

An extra unit may also be employed to allow the handset to communicate with the conventional wired telephone network as well as with the transmitter unit. As Figure 5 shows, the handset can communicate with the mobile telephone network through link 6 and the transmitter unh 2 but by use of an extra unit 11 the handset may also be connected to the an outlet of the conventional Wred telephone network 12 via link 10. Links 6 and 10 may be handled by a single set of components in the handset 1.

One of the ways in which the link between the handset and the base station may be established is through a radio link, the power and frequency of which do not lead to concerns over health. The power and frequency may also be chosen so as to minimise interference in hearing aids. One type of radio link which could be used beneficially is the type of radio link used in cordless telephones (telephones usually used with the conventional wired network in which there is a wireless (cordless) connection between the handset and the base station which is connected to the Wired telephone network). Hence the links used in the system shown in Figure 5 could be of the cordless telephone radio link type and the extra unit 11 could be a cordless base station connected to the wired telephone network 12.

The arrangment described above and illustrated in Figure 5 would require the transmitter unit 2 to contain a cordless base station as shown in Figure 6. In Figure 6 the mobile telephone transmitter and 1 6 receiver unit 13 is connected to a cordless transmitter and receiver unit 15 by an electrical link 14, permitting signals to be exchanged between the mobile telephone network and the cordless telephone radio system which links the handset 1 and the transmitter unit 2. The frequency and power used in the cordless link to the handset may be those presently employed in cordless telephone technology or the frequency and power may be completely different from those presently employed in cordless telephones.

Figure 7 illustrates a way in which a conventional mobile telephone can be employed as the transmitter unit 16. Voice. and possibly control signals and power, are exchanged with the handset via a link unit 18. This unit 18 establishes a link 19 with the handset 1. The link unit 18 is connected to the mobile telephone via a cable 17 and the socket which is available on most mobile telephones to permit connection to a hands- free or car microphone and loudspeaker arrangement. Alternatively the link unit 18 plugs directly onto the. mobile telephone 16. The link 19 may be any of the types mentioned earlier including a radio link of the type used in cordless telephones. The handset 1 can be a conventional cordless telephone handset capable of communicating in the normal manner through a radio link 20 with its base station 21, while unit 18 is an additional unit provided with the cordless telephone system which, when connected to a mobile telephone, permits the cordless telephone handset to be used as the handset for the mobile telephone as well as with its own base station 21 connected to the conventional wired telephone network 12. This arrangement has the advantage that the mobile telephone 16 which is used as the transmitter unit may be used as a mobile telphone in the conventional way, as well as forming the transmitter unit a two unit telephone.

Another way in which a conventional mobile telephone may be employed as the transmitter unit is by adaptation of that type of mobile telephone which has built into it apparatus for forming an infra-red link with a laptop computer or other data processing equipment. Referring to Figure 3, the mobile telephone with built-in infra-red link takes the place of the transmitter unit 2 while the link 6 is an infra-red link using the builtin infra-red link facility of the mobile telephone. The handset 1 has a built-in infra-red link apparatus to complete the transmission of voice and control signals between the transmitter unit 2 and the handset 1. The voice signals may be transmitted in either analogue or digital form. This arrangement has the advantage that the mobile telephone which is used as the transmitter unit 2 may be used as a mobile telephone in the conventional way, as well as forming the transmitter unit of a two unit telephone.

7

Claims (17)

1 A mobile telephone in which the electronic circuit elements of the telephone are divided between two units, one of the said units containing the radio transmitter which communicates with the mobile telephone system and also containing any other electronic circuit elements which generate inconvenient levels of electromagnetic radiation, and the other said unit containing the earpiece, microphone and other components which constitute a telephone handset but not containing elements'which generate inconvenient levels of electromagnetic radiation, the said units having between them a link which permits the exchange of the necessary signals for the transfer of the voice signals and any command signals necessary for the operation of the telephone, with this link having sufficient range of operation so as to permit the second unit containing the earpiece and microphone to be held to the head of the user in the manner of a telephone handset while the first unit containing the transmitter is held or located during operation of the telephone at a distance from the head of the user at which radio and other electromagnetic emissions from the first unit on reaching the head of the user have been attenuated sufficiently by the physical separation of the two units to a level at which these emissions do not cause the user significant concerns about their effects on the users health or at which level they do not cause serious interference in any hearing aid which the user may be wearing.

2. Apparatus according to claim 1 in which the link between the two units is a radio link.

3. Apparatus according to claim 1 in which the link between the two units is an infra-red light link.

4. Apparatus according to claim 1 in which the link between the two units an inductive loop link.

5. Apparatus according to claim 1 in which the link between the two units is a radio link.

6. Apparatus according to claim 1 in which the link between the two units is an ultrasonic link.

7. Apparatus according to claim 1 in which the link between the two units is an acoustic tube link.

8. Apparatus according to claim 1 in which the link between the two units is a cable containing at least one wire.

9. Apparatus according to claim 1 and claim 8 in which there is a sufficient number of wires in the cable to permit the transmission of electrical power between the two units as well as the transmission of voice signals and control signals.

10. Apparatus according to claim 1 in which power is transferred by transformer action between the said units in the storage mode.

11. Apparatus according to claim 1 and claim 5 in which the radio link is a cordless telephone link.

12. Apparatus according to claims 1,5 and 11 in which the base station of the cordless telephone link is contained within the unit containing the mobile telephone transmitter.

13. Apparatus according to claims 1,5 and 11 in which the unit containing the mobile telephone transmitter is a conventional mobile telephone and the base station unit of the cordless telephone is connected to the said conventional mobile telephone via a socket on the mobile telephone which is commonly provided for the exchange of voice and control signals between the mobile telephone and external apparatus.

14. Apparatus according to claims 1 and 3 in which the unit containing the transmitter used for communicating with the mobile telephone network is a mobile telephone with infra-red link apparatus built into the telephone for the purpose of communicating with a computer, said infrared link apparatus being adapted to communicate with a telephone handset unit containing similar infra-red link apparatus.

15. Apparatus according to claim 1 and 2, or claim 1 and 3, or claim 1 and 4, or claim 1 and 5, or claim 1 and 6, or claim 1 and 8, in which a third unit is provided to permit communication between the unit containing the mobile telephone network transmitter and any other apparatus as well as with the telephone handset unit.

16. Apparatus according to claim 1 and 2, or claim 1 and 3, or claim 1 and 4, or claim 1 and 5, or claim 1 and 6, or claim 1 and 8, in which a third unit is provided to permit communication between the telephone handset unit and any other apparatus as well as with the unit containing the mobile telephone network transmitter.

17. Apparatus substantially as described with reference to any one of the accompanying drawings.