WIRELESS TELEPHONES

The present invention concerns a system for shielding radio frequent electromagnetic radiation for a wireless phone.

BACKGROUND OF THE INVENTION

With the background of a worldwide public discussion on health hazards caused by electro-magnetic radiation from mobile phones and other telephones with a radio transmitter, as well as the evaluation of mobile phones connected to the Specific Absorption Rate (SAR-value), shielding technologies for wireless phones may provide a competitive advantage in the market.

Contemporary radio frequency (RF) shielding technology for mobile phones is based on different shielding systems where shielding materials with high conductivity cover the whole phone, or parts or components of it.

For example, US 6624432B1 discloses an apparatus for shielding of electromagnetic interference (EMI) caused by electronic components. The shielding is preferably metal coated plastic, and may comprise several chambers to prevent electronic components from interfering with each other, and from emitting electromagnetic radiation to the atmosphere. The compartments are shielded and cover different components of the phone's circuit board.

In WO 9531048A2 a flat battery covers the total length and width of the mobile phone. The battery itself has a certain shielding ability and shielding function, and is used directly as shielding material. Use of separate backup batteries is also disclosed.

Other examples of shielding technology can be found in US 2004/0212520A1 , US 6855883B1 , EP 1244223A1 , WO 9740655, EP 949052A2 and DE 9113382U.

All mentioned solutions have a major disadvantage. RF energy is induced upon shielding material and all metallic components of the phone. In this way, RF energy is more or less transmitted to the front side of the mobile phone and further towards the head of the user. This happens even though RF energy is partly reflected by or absorbed by shielding material built into the phone.

Further, RF signals generated from the electronic components may, if unshielded, contribute to the RF radiation in the direction toward the user, and even disturb the RF-transceiver used to send and receive radio signals while communicating.

The objective of the present invention is to overcome the problems of prior art and improve shielding against radiation in the direction of the user caused by radio transmitters in wireless phones.

SUMMARY OF THE INVENTION

This is achieved by providing a system for shielding radio frequent electromagnetic radiation for a wireless phone, the system comprising: a first chamber containing an RF transceiver, a second chamber containing the main electronic elements of the phone, a third chamber containing input and output devices, wherein each chamber has a separate shielding from RF radiation, the chambers are electrically insulated from each other; and optical transceivers are adapted to communicate information between the chambers.

By separating the major components of the mobile phone into three independently RF shielded and dielectrically insulated chambers, the above-mentioned induction problem and transmission of RF radiation via shielding material and metallic components of the phone to the front side are reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the following detailed description with reference to the accompanying drawing, in which:

FIG. 1 is a schematic side view of a wireless phone according to the invention DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic view of a wireless phone, e.g. a mobile phone, viewed from the side with its front facing left.

The phone is divided into three different chambers.

The first chamber 8 includes the RF transceiver unit 2. The second chamber 9 includes the major electronic parts 3. The third chamber 10 includes display, keyboard, microphone, speaker, camera, etc. The three different chambers are individually shielded against RF energy with a material of high conductivity 4.

The RF shielding 4 of the three chambers is provided in accordance with the individual need of each chamber. While the first chamber 8 has an opening 11 in the RF shielding towards the back of the phone to allow radio signals to pass to and from the transceiver unit 2, the second chamber 9 is totally covered by the shielding material 4. The third chamber 10 is only shielded towards the second chamber and towards the frame of the mobile phone 1 , but remains unshielded 11 towards the front side of the phone. In this way it is avoided that shielding material influences the design of the phone.

There are no electrical connections between the shielding materials 4 of the different chambers, because a dielectric material 5 is placed between them and against the frame 1 of the mobile phone.

The chambers communicate with each other through optical signal paths 6 and 7.

For example, electronic signals from the RF transceiver unit 2 are converted into optical signals before they are transmitted to the second chamber 9, where they are converted back to electrical signals for processing within the chamber.

Because the second chamber is completely shielded, RF-signals from the electronic components cannot escape and disturb the transceiver unit 2 or be emitted into the atmosphere.

In a similar manner optical signals from the second chamber are converted to electronic signals in order to communicate with the RF transceiver 2 in the first chamber. Optical signals are transmitted from chamber to chamber via fiber-optic cable or optical channel 7.

An optical signal transceiver and an opto-electric signal converter 6 are positioned at each end of each optical channel where signals are sent through a fiber-optic cable or optical channel 7.

In order to maintain integrity of the electromagnetically separated three chamber system, each chamber can be individually supplied with energy by its own battery 12. The batteries 12 can be charged simultaneously through connectors 13 and are adapted to the energy requirements of the respective chamber. A headset 16 can optionally be connected via an optical connector 14 and an electro optical transducer 15. The mobile phone headset 16 is built in accordance with the same principles. Between the signal converter 6 in the phone and the signal converter of the headset 15, signals are transmitted optically.