EP1393408A1

EP1393408A1 - Safety shield

Info

Publication number: EP1393408A1
Application number: EP02771671A
Authority: EP
Inventors: Lance Harold Rayner
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-19
Filing date: 2002-05-16
Publication date: 2004-03-03
Also published as: GB0328802D0; GB2393387B; GB2393387A; WO2002095867A1

Abstract

Disclosed is a mobile telephone or a mobile telephone or radio case comprising means for receiving a mobile telephone or radio which has a speaker, display and keypad on a face thereof; the case having a first face for holding towards a user's head; the first face of the case having a radiation shield layer thereon, therein and/or thereunder, for shielding the user from reflecting and/or absorbing mobile phone or radio radiation; the case further comprising means for receiving sound or signals corresponding to sound from the mobile phone or radio and means for emitting sound located on, in or under the first face of the mobile telephone or radio configured to output sound from the mobile telephone or radio whilst the radiation shield layer is interposed between the mobile telephone or radio and the user's head.

Description

Title: Safety Shield

The present invention relates to safety shields and in particular, but not exclusively, to safety shields including one or more radiation shielding components to at least partially protect wearers of the shields from potentially harmful effects of mobile telephone and radio radiation exposure.

Background to the Invention

In operation, contemporary mobile telephones emit pulsed radiation at a frequency of substantially 900 MHz at an average power level in a range in the order of 200 mW to 1 W. The radiation is pulsed to allow telephone network operators to implement time division multiple access (TDMA) so that a plurality of mobile telephone users can be simultaneously supported from each mobile telephone tower.

It is estimated that 60% of radiation emitted by mobile telephones is absorbed in users' brains. On account of such absorption, there is widespread concern regarding potential health risks arising from exposure to mobile telephone radiation.

It is generally known that microwave radiation of 2.45 GHz frequency is capable of heating water molecules, for example as occurs in domestic microwave ovens when cooking food. Although mobile telephones emit radiation at a somewhat lower frequency than 2.45 GHz, measurable heating of mobile telephone users' brains occurs when making telephone calls. Whereas such thermal heating is not generally considered to pose any health risk, it has been suggested that microwave radiation emitted from mobile telephone can cause subtle biological changes not associated with the aforesaid thermal heating. Such subtle changes are believed to include:

(a) genetic damage to chrosomes and hence increased risk of tumours and cancer, for example increased occurrence of acoustic neuromas or Schwannovas;

(b) reduced selectively of users' blood-brain barrier enabling toxins to cross the barrier into users' brains and thereby causing neurone damage and premature ageing;

(c) demyelination of nerve sheaths; and

(d) modification of synaptical transmission between nerve cells manifest as memory loss, fatigue and disturbed neurone response.

Health risks associated with pulsed mobile telephone radiation, for example as generated by digital GSM mobile telephones, is suspected to be potentially more dangerous than radiation emitted from earlier analogue-type mobile telephones because biological molecules are thought to be affected within a period of each pulse during which the peak radiation power emitted from mobile telephones can approach in the order of 10 W, namely above average safe radiation power thresholds stipulated by governments. Although numerous research programs have collated evidence that there may be health risks associated with exposure to mobile telephone radiation, no conclusive proof presently exists that mobile telephone radiation is definitely a serious health risk. However, current research activities may soon identify such proof.

Concerns regarding potential health risks associated with mobile telephone use has resulted in numerous mobile telephone radiation protection products becoming commercially available. For example, a Microshield radiation protection case for use with mobile telephones is manufactured in the United Kingdom, Microshield being a registered trade mark. The Microshield case is fabricated from layers of leather between which a specialised layer comprising woven polyester and nickel is incorporated. The Microshield case includes a substantially transparent window for viewing a mobile telephone encased therein, the window being fabricated from clear polished PVC laminated around an ultra- fine metal wire mesh. The Microshield case further comprises an adjustable polyester- coated metal antenna guard which physically touches an antenna of the telephone and preferentially absorbs by induction radiation given off by the antenna which would normally be absorbed by a user of the telephone. Other manufacturers provide alternative types of mobile telephone radiation shield cases.

The inventor has appreciated that these radiation shield cases, in some circumstances, are relatively ineffective at reducing user exposure to mobile telephone radiation. For example, some types of mobile telephone determine received signal strength and regulate their output radiation power correspondingly. Thus, encasing such telephones in radiation shield cases merely causes them to radiate at increased power level. In some situations, use of such shield cases can increase user exposure to mobile telephone microwave radiation depending upon orientation of the cases to the nearest mobile telephone towers.

Similar concerns apply relating to digital radio systems such as Terrestrial Trunk Radio (TETRA) designed for use by the emergency services in the United Kingdom. The signal, at around 400MH∑ is pulsed at 17.6HI. The UK Independent Expert group on Mobile Phones (IEGMP) recommended in May 2000 that amplitude modulation around 16H_* should be avoided, if possible, in future developments in signal coding as amplitude modulation around that frequency is thought to lead to a leakage of calcium from nerve cells. The shield disclosed herein may also be applied to blocking this type of pulsed radiation and other radiation emissions from radios.

Summary of the invention

According to a first aspect of the invention, there is provided a mobile telephone or radio case comprising means for receiving a mobile telephone or radio which has a speaker, display and keypad on a face thereof; the case having a first face for holding towards a user's head; the first face of the case comprising a radiation shield for shielding the user from mobile phone or radio radiation; the case further comprising means for receiving sound or signals corresponding to sound from the mobile phone or radio and means for emitting sound located on, in or under the first face of the mobile telephone or radio configured to output sound from the mobile telephone or radio whilst the radiation shield is inteφosed between the mobile telephone or radio and the user's head.

By providing a means for emitting sound which is configured to output sound from the mobile telephone or radio, it becomes possible to provide an effective radiation shield between the mobile telephone or radio and the user's head. As there is no need to provide a screen on the face away from the user's head, the mobile telephone can still send signals without having automatically boost its power output by a substantial amount, which is a feature that obviates the benefit of many prior art shields.

The means for receiving sound may be a microphone locatable so as to receive sound from the mobile telephone or radio speaker, but is preferably an electrical connection to an external loudspeaker connector provided on a mobile telephone or radio. Such connectors are provided on the majority of mobile telephones or radios at the present time for use with 'hands-free' kits. By removing the need for the sound heard by the user to originate from the built in loudspeaker on the mobile telephone or radio, the configuration of the radiation shield is not limited by the constraints of the layout of any particular mobile telephone or radio.

Preferably, the means for emitting sound is a loudspeaker disposed in, on or under the rear face. The loudspeaker may be underneath the radiation shield. In this configuration, the rear face preferably has an aperture with the radiation shield extending across the aperture.

The case may be in the form of one or more detachable fascia for a mobile telephone or radio.

An amplifier may also be provided. The case may comprise means for cooperating with a power supply connector on the mobile telephone or radio or may be battery-powered. The case may comprise two separable parts having mutually cooperating electrical connectors. The radiation shield is preferably in the form of a radiation shield layer. Preferably the radiation shield absorbs and/or reflects radiation.

Preferably, the radiation shield also extends around one or more of the top, bottom, or side faces of the mobile telephone or radio. We have found that this substantially improves the radiation shielding.

The case may also comprise a microphone located on the first face of the case or another face of the case, having means to supply received sound to the mobile telephone or radio. This may be in the form of a loudspeaker positioned over the mobile telephone or radio internal microphone but is preferably a connection to an electrical connector (such as a 'hands free kit connector') on the mobile telephone or radio.

Preferably, the case is configured so that the mobile telephone or radio can be inserted therein with the front face of the mobile telephone or radio (ie the face with any display and keypad) facing away from the first face of the case. Thus, there is no need for the screening material to extend across the display and keypad, enabling a user to conveniently use their mobile telephone or radio display and keypad without obscurement. However, an openable cover may also be provided and the cover could contain a further radiation shield if desired.

In the foregoing, it is preferable that the radiation shield comprises a shielding means such as at least one of metal conductive sheet, metal conductive film, and metallic conductive wire mesh. Such sheet, film and mesh are capable of both absorbing and reflecting mobile telephone radiation, thereby protecting the wearer.

Preferably, such a sheet, film or mesh is embedded in a fabric or other textile, for example leather. It may also be embedded in a hard material, such as a plastic. The fabric, textile or hard material may have one or more apertures therein but across which the shielding means extends. The inventor has found that the mesh performs especially well to protect the wearer whilst allowing for the transmission of sound and remaining flexible and compliant. Such properties are most effectively provided when the mesh has certain ranges of dimensions. Thus, preferably, the mesh has a mesh wire diameter in a range of 0.1 mm to 0.5 mm and a mesh wire pitch in a range of 0.6 mm to 3.0 mm. Most preferably, the wire diameter is in a range of 0.15 mm to 0.3 mm and the wire pitch is in a range of I mm to 2 mm.

In order to obtain a most appropriate compromise between reflectivity and absorption, the mesh is preferably fabricated from one or more of aluminium, copper, brass, nichrome and stainless steel. Aluminium and copper are especially good conductors and hence good reflectors whereas nichrome and stainless steel are more resistive and therefor capable of providing a relatively greater degree of radiation absorption.

When metallic sheet is used for the shielding means, the metal conductive sheet and metal conductive film preferably have a thickness in a range of 20 μm to 0.2 mm.

Preferably, the sheet is fabricated from one or more of copper and aluminium.

According to a second aspect of the invention therefore, there is provided a mobile telephone or radio comprising a housing with a loudspeaker associated with the telephone or radio on a first face, and a display and keypad associated with the telephone or radio located on the opposite face (the second face), the housing further comprising a radiation shield for shielding the user from radiation emanating from circuits associated with the mobile telephone or radio within the housing. Preferably, the radiation shield extends at least over the first face.

The screening layer may conveniently comprise shielding means as hitherto described, such as a screening mesh. Preferably, the first face has an aperture for the speaker but the screening mesh extends across that aperture. A mobile phone case for use in this aspect of the invention may comprise a shield as described herein, except that it is not essential for the shield to be hinged.

Thus, in this aspect if the invention, the screening layer can if required remain permanently in place. Viewing and keypad operation take place on the second face, with the phone held remote from the head, while to listen and speak the phone is turned over and the first face held close to the head.

According to a further aspect of the present invention, there is provided a safety shield for protecting a wearer thereof from radiation emissions from a mobile telephone or radio held in close proximity to the wearer's head, the shield comprising radiation shielding means for at least one of reflecting and absorbing mobile telephone or radio radiation incident thereupon, and mounting means for mounting in use said shielding means on the wearer's head.

The invention is of advantage in that the shield is capable of at least partially shielding the wearer from the potentially harmful effects of mobile telephone or radio radiation.

The phrase "in close proximity" is defined as being a separation distance of 10cm or less between the mobile telephone or radio and the wearer.

The radiation shielding means may comprise a radiation shield layer. Preferred features are as discussed above.

Preferably, the mounting means is in the form of a head cap wearable on the wearer's head, and the shielding means is at least attached in use to the cap. Implementing the safety shield in combination with the cap is of advantage in that the shield does not need to be tailor made to fit the mobile telephone. New models of mobile telephone are being launched for sale each week hence it is difficult to provide safety shields which fit around every type of mobile telephone or radio. In contradistinction, implementing the safety shield in the form of a cap to suit the wearer means that all types of mobile telephone and radio can be catered for. Moreover, there is less variation in size of mobile telephone user' heads than in the constantly changing range of mobile telephone sizes.

Preferably, the shielding means is implemented as one or more shielding components covering at least ear regions of the cap. Mobile telephones and radios are normally held in use in close proximity to users' ears resulting in the ears, their auditory nerves and associated brain temporal lobes being primarily irradiated by the mobile telephone radiation. Thus, as these regions are subject to such direct irradiation, it is advantageous that these regions are at least partially protected.

Preferably, the one or more shielding components extend unitarily from one side of the wearer's head to the other side thereof. Forming a complete unitary shield from one side of the wearer's head to the other side thereof reduces the formation of a fluctuating electric field at the frequency of the mobile telephone or radio radiation across the wearer's brain, thereby improving protection for the wearer.

Preferably, the one or more shielding components extend in use below a height of a lower end of the mobile telephone or radio. The inventor has appreciated a suφrising characteristic that a typical contemporary mobile telephone functions effectively as an unbalanced dipole, a body region of the telephone functioning as one of the dipoles and a stub antenna of the telephone functioning as another of the dipoles, the body region thereby capable of emitting microwave radiation as well as the stub antenna. Thus, the inventor has appreciated that it is just as important to shield the wearer from the body region as well as the antenna. Conventional forms of mobile telephone shielding devices have tended to concentrate on antenna emissions. For most effective protection, it is preferable that the one or more shielding components extend in use at least 2 cm below the height of the lower end of the mobile telephone.

Preferably, in order to take account of edge effects, the one or more radiation components are more extensive in area than the area of the telephone or radio presented in use towards the wearer. Although safety shields according to the invention can be supplied as complete items, the inventor has appreciated that the safety shield can be retrofitted to existing carriers such as caps. Thus, preferably, the one or more shielding components are retro fittable to an existing cap. In order to achieve such retrofittability, the one or more shielding components are preferably attachable by Velcro strips to the existing cap.

Other carriers are possible, for example the mounting means is preferably in the from of spectacles wearable on the wearer's head, and the shielding means is attached at least in use to the spectacles.

As elucidated above, wearer's ear regions are potentially most at risk from mobile telephone or radio radiation damage. Thus, for the spectacles, the shielding means is implemented as one or more shielding components covering in use at least ear regions of the wearer.

Preferably, in order to reduce a high frequency alternating electric field being generated across the wearer's brain, one or more of the shielding components extend unitarily in use from one side of the wearer's head to the other side thereof. More preferably, in use the one or more shielding components extend below a height of a lower end of the mobile telephone or radio. Most preferably, the one or more shielding components extend in use at least 2 cm below the height of the lower end of the mobile telephone or radio. Such extension of the safety shield is capable of providing enhanced degrees of protection.

The one or more radiation components are preferably more extensive in area than the area of the telephone presented in use towards the wearer. As radiation field fringing occurs around peripheral edges of the shield hence, for enhanced wearer protection, the shield should preferably be made of greater area in comparison to the telephone or radio.

The inventor has appreciated that wearers will prefer to affix the safety shield to their spectacles. Thus, preferably, the one or more shielding components are retrofittable to existing spectacles. Such fixing can be achieved in a number of different ways. For example, the one or more shielding components are preferably attachable by one or more of resiliently deformable clips and Velcro strips to the existing spectacles.

The safety shield can be implemented as a retrofit item. Thus, in a further aspect of the present invention, there is provided a shielding attachment for at least partially protecting a wearer thereof against radiation from mobile telephones or radios, the attachment including shielding means for at least one of reflecting and absorbing radiation from mobile telephones or radios incident in use thereupon, the attachment being retrofittable in use to one or more of head wearable caps and spectacles.

According to another aspect of the present invention there is provided a safety shield for protecting a user from radiation emissions from a mobile telephone or radio held in close proximity to the user's head, the shield comprising radiation shielding means capable of reflecting and/or absorbing radiation from the mobile telephone and hinging means enabling the shield to be moved between a closed position in which it covers at least part of the face of the mobile telephone or radio, and an open position in which the display and keypad of the mobile telephone or radio are accessible to view and use.

The invention is based on the realisation that the main danger to the user from radiation emanating from use of a mobile telephone or radio is when the telephone or radio is held close to the head during communication and that at this time it is not necessary to be able to see or read the display or to access the keypad.

The shield may be hinged by the hinging means either to the mobile telephone or radio itself or to an independent telephone or radio casing.

In either case, but in the former case especially, the hinging means may simply comprise strips of hooked pile material respectively fixed at appropriate positions to the shield and to the telephone or to the telephone casing. Alternatively, in the case of a casing especially, the shield may be more integrally hinged to the cover. The invention therefore also extends to a telephone or radio casing to which the shield is hingedly fixed.

The shield may be formed in one piece to hinge over the face of the telephone or radio from one side, or be formed in two parts, preferably equal parts, to hinge over the face of the telephone or radio from two opposite sides.

As previously stated the shielding means may conveniently comprise metal conductive sheet, metal conductive film or metallic conductive wire mesh, the last mentioned being generally preferred. The mesh may be formed of aluminium, copper, brass, nichrome or stainless steel, preferably with a wire diameter of 0.1 to 0.5 mm, most preferably 0. 15 to 0.3 mm and a mesh pitch in the range 0.6mm to 3mm, most preferably Imm to 2mm.

The inventor has also appreciated that, when holding the electronic device, in this case in particular a mobile telephone or radio, only the speaker requires exposure to the head.

Description of the drawings

Embodiments of the invention will now be described, by way of example only, with reference to the following diagrams in which:

Figure I is perspective and cross-sectioned views through a mobile phone case according to the invention;

Figure 2 is a perspective drawing of modified version of the mobile phone case of

Figure I;

Figure 3 is a modified version of the case of Figure 1 in the form of front and back covers; Figure 4 is a modified version of the case of Figure 2 in the form of front and back covers;

Figure 5 shows a mobile phone layout in accordance with a further aspect of the invention;

Figure 6 is a perspective and cross-sectional views of a case having an aperture with a screening layer extending thereacross;

Figures 7 and 8 respectively show two embodiments of a hinged radiation shield in accordance with the invention;

Figure 9 shows a modification;

Figure 10 is an illustration of a safety shield according to the invention bearing a radiation shield for extending around (a) a rear area or (b) the top of a wearer's head;

Figure 11 is an exploded view of fabric layers having a shielding component therebetween;

Figure 12 is a schematic diagram of a mobile telephone represented as a dipole held directly against a user's head;

Figure 13 is an illustration of a user wearing a safety shield according to one aspect of the invention together with a mobile telephone adjacent thereto;

Figure 14 is an illustration of a user wearing a safety shield according to one aspect of the invention wherein a radiation shielding component extends from a first side of the user's head to a second side thereof, a mobile telephone placed adjacent to the shield; Figure 15 is an illustration of safety shields according to one aspect of the invention implemented as an accessory for spectacles;

Figure 16 is a further illustration of a safety shield according to one aspect of the invention implemented as a side feature of spectacles;

Figure 17 is a further illustration of a safety shield according to one aspect of the invention implemented on both sides of spectacles; and

Figure 18 is a further illustration of a safety shield according to one aspect the invention contoured to the user's head to provide enhanced protection.

Referring first to Figure 1 , there is shown a schematic illustration of a safety case for a mobile telephone 1. The safety case encloses a volume 2 with in which a mobile telephone can be fitted. The rear wall 3 of the case, has means for emitting sound in the form of a loudspeaker 4 and a microphone 5 which are powered by a jack 6 for connecting to the jack typically provided on a mobile phone for use with hands free kits. The rear wall 3, contains a radiation shield layer 50 which extends across the rear wall 3, top 10, bottom 1 1 and side 12, 13 walls of the case.

The radiation shield layer 50 can be fabricated from a number of different materials. As a first example, the layer 50 can be fabricated from aluminium wire mesh. The mesh preferably has a wire diameter in a range of 0.1 mm to 0.5 mm and a mesh wire pitch in a range of 0.6 to 3.0 mm. More preferably, the wire diameter is in a range of 0. 15 mm to 0.3 mm and the mesh wire pitch is in a range of 1 mm to 2mm. Aluminium wire mesh is especially preferred as it is inexpensive, lightweight and relatively easy to sew onto woven fabric. Alternatively, the layer 50 can be fabricated from aluminium foil having a thickness in a range of 20 μm to 0.2 mm. More preferably, the foil has a thickness in a range of 50 μm to 0.1 mm.

As further alternatives, the layer 50 can be fabricated from one of more of copper mesh, brass mesh and stainless steel mesh. If desired, meshes of different materials can be stacked together to form the layer 50.

Figure 6 illustrates how the radiation shield layer 50 is disposed within the case I . It can be seen from the figures that the loudspeaker 4 is disposed underneath an apermre 14 in the case 1. However, the aperture 14 is simply a gap in the casing 3, and the radiation shield layer extends. This allows sound to be emitted by the loudspeaker, whilst ensuring that the radiation shield layer extends across the aperture 14 providing uninterrupted radiation shielding.

In use, a mobile phone is inserted into the enclosed volume 2, with its front face, being the side with the display and keyboard, facing outwards, towards the user, and its rear face against the rear wall 3 of the case. The jack 6 is inserted into the hands free socket.

Now, when a user makes a mobile telephone call, they can hold the mobile telephone with the rear wall 3, against their head. The loudspeaker 4 and microphone 5 enable them to carry on a telephone conversation. However, the presence of the radiation shield layer 50, along the rear wall 3 and top, bottom and side panels 10, 11, 12 and 13, means that they will be protected from the radiation emitted by the mobile telephone. However, the front face of the mobile telephone is still free for them to use when dialling new telephone calls.

A flap 20, and button, hook and loop fasteners 21 or other fixings materials 21 may be used to secure the case around the telephone and, optionally, over any external antenna which is present. The back top bottom and sides panels 3, 10, 11, 12 and 13 are made from leather or a similar soft fabric, which can be prepared in two layers encasing the radiation shield layer 50.

Figure 2 illustrates an alternative embodiment in which an additional microphone 24 is provided at the front. This microphone can be used when the mobile telephone does not have a socket for a hands free kit, and picks up sound emitted by the microphone 14, which it then outputs through a loudspeaker 4 at the back of the telephone. A power supply may be taken from the recharge socket on the mobile telephone, or an independent power source, for example batteries.

Figure 3 shows an alternative embodiment in which the mobile phone case 100 is made from a hard material. The radiation shield layer 50 is present as before (not shown). In particular, it is provided in the form of changeable front and rear fascias for a mobile telephone. Such covers may clip on to formations already provided on mobile telephones for use with detachable fascias, or may join on to each other. Here, the hard casing material, such as a plastic, or a metal laminate, may be formed as a mould around the case 100. Again apertures 14 may be provided for the loudspeaker, and also correspondingly for the microphone 5.

Figure 4 illustrates a case 110 adapted particularly for use with a mobile telephone which does not have a hands free jack, but does have a connector for supplying external power 120. A microphone 121 picks up sound emitted by the microphone on a mobile telephone and it is rebroadcast through a speaker 122 on the back face after appropriate amplification by an amplifier (not shown). Power is supplied by the connector 120 through wires 121 and the microphone 125 and loudspeaker 122 are connected by way of electrically interconnectable engaging formations 123, 124.

In each of the embodiments of Figures 1, 2, 3 and 4, the aerial may be included within the case 1 , 60, 100, 1 10. It is important that the radiation shield layer 50 extends around the top, bottom, and side panels 10, 11, 12, 13, as well the back face 3. We have found that in this case, much better radiation protection is achieved than when the radiation shield layer 50 is only present on the back face 3.

Figure 5 illustrates a mobile telephone 150 according to a further embodiment in which only the display 152 and keypad 154 are positioned on a front face of the phone, the speaker 156 being located on the back face. This phone, together with its antenna 158 are retained within a case 160 which incoφorates a radiation shield layer comprising radiation reflecting and/or absorbing material such as the mesh material described above. The radiation shield layer extends in particular over the entire back face of the phone and, preferably also, the sides of the phone. This screen layer is particularly effective when the antenna 158 is contained within the body of the mobile phone, as with many modern mobile telephones.

Turning to another aspect of the invention. Figure 7 shows a tray shaped radiation shield 200 which attaches by means of hooked pile strips 201 to a mobile telephone or independent case 202, so as to be able to hinge between a closed postion covering the face of the telephone and an open position in which the display and keypad (not shown) of the telephone are exposed for viewing and access.

Figure 8 shows a modified embodiment in which the shield is formed in two parts 204 and 206.

In use, the shield is first hinged back to enable the user to initiate communication and then closed over the face of the telephone when the user brings the telephone close to the side of his/her head in order to listen and talk. At the latter time, the user does not need access to the display and keypad on the face of the telephone.

Figure 9 shows a modification in which a battery powered small illuminating strip light 203 is added to the shield to assist use of the phone in poor lighting conditions. The technology disclosed herein is applicable with minimal or no amendment to use with radios.

Referring to Figure 10, there is shown in Figure 10 (a) another safety shield according to the invention indicated by 300, the shield 300 being in the form of a wearable head-cap comprising a cloth head-piece 310, a rounded visor 320 and a lateral ear protector 330 for covering a wearer's ears and extending around a back rear part of the wearer's head. The protector 330 includes substantially over its entire area a conductive shielding component fabricated from the aforesaid aluminium mesh of the a aforementioned aluminium foil. The shielding component in operation reflects mobile telephone microwave radiation incident thereupon and also assists to ensure similar instantaneous potentials at right and left hand sides of the wear's head, thereby substantially avoiding the formation of an electric field at microwave frequencies across the wearer's brain. If desired, the headpiece 310 can also comprising a conductive radiation shielding component fabricated from the aluminium mesh or aluminium foil, thereby more completely shielding the entire wearer's head. A variant of this is illustrated in Figure 10 (b) which shows another safety shield according to the invention indicated by 350. The wearable head cap comprises a cloth head-piece 360 and rounded visor 370. Cloth head piece 360 comprises a radiation shielding layer fabricated from the aforesaid aluminium mesh or the aforementioned aluminium foil in the form of a strip centred over the ears passing either over a user's head or, on either side extending as far as (a) or, preferably (b) as illustrated within shielded region 340.

Figure 11 illustrates the provision of the radiation shielding layer 50 within the fabric of the shielded region 340.

The shields 300, 350 are woven and assembled in a conventional manner except that the radiation shielding layer 50 is incorporated into the muffs 330 or other shielded region 340 during manufacture. In order to describe how the safety shields 300, 350 are capable of reducing radiation exposure to a user thereof, reference is made to Figure 12. In Figure 12, a user 400 holds a mobile telephone indicated by 420 to his or her left ear 430. The telephone 420 comprises a stub antenna 422 and a body section 424. When the telephone 420 is in operation, a microwave oscillator 426 included as part of an electronic circuit of the telephone 420 causes the potential of the antenna 422 to fluctuate at microwave frequencies in the order of 900 MHz relative to the body section 424. It will be appreciated that the telephone 420 is not connected to an earth potential on account of it being a portable handheld unit. Thus, when the telephone 420 is in operation emitting microwave radiation, both the antenna 422 and the body section 424 have rapidly fluctuating potentials relative to earth potential, and hence relative to the user 400 who is substantially at earth potential.

The user 400 is therefore exposed when the telephone is emitting radiation to a fluctuating electrical field, for example as represented by an electrical field line 440, and propagating microwave radiation represented by R. Part of the radiation propagating towards the user's head Ri is absorbed in the user's skull but a proportion in the order of 40% of radiation emitted from the telephone 420 is absorbed in the user's brain.

Users of mobile telephones have reported jaw pains as well as ear pains and loss of memory which supports a theory that microwave emission occurs from the body section 424 as well as the antenna 422 as these two items effectively function as an unbalanced dipole.

When the user 400 wears any one of the safety shields 300, 350 the shielding component 50 provides two benefits:

(a) it provides electrostatic shielding of the user's brain; and

(b) it reflects at least part of the microwave radiation R. away from the user's brain thereby increasing the strength of radiation emitted in a left direction relative to the user 400. Thus, unlike radiation protection cases known in the prior art which substantially enclose mobile telephones reducing their radiation output, the safety shields 300, 350 not only provide protection for the user 400 but also do not attenuate radiation output from the telephone directed away from the user 400. Clearly, the shields 300, 350 provide greatest benefit when the user 400 orientates the side of his head to which the telephone 420 is held towards his nearest telephone repeater tower.

Whereas mobile telephones are manufactured in a variety of sizes requiring aforesaid radiation cases to be tailored to each size of telephone, the shields 300, 350 are compatible with all types of mobile telephone provided the shields fit users' heads satisfactorily to be retained thereon. Such compatibility of the shields potentially renders them less expensive to manufacture than the aforesaid radiation cases.

In order to investigate performance of the shields 300, 350 a dummy head was constructed onto which the shields could be mounted. Within the dummy head, a microwave probe was centrally installed, the probe being connected to a digital voltmeter remote from the head. A standard proprietary mobile telephone manufactured by Nokia operating at substantially 900 MHz was employed as a source of microwave radiation when testing safety shields according to the invention on the head.

Experiments performed using the dummy head identified that the material from which the shield component 50 is fabricated and the area of the component 50 both have an influence on the effectiveness of the component 50 to protect the user 400. Surprisingly, the aforesaid aluminium foil and aluminium mesh were found to be especially effective at reflecting radiation and rendering a greatly reduced radiation level within the dummy head. Reductions in radiation level within the dummy head of more than an order of magnitude are achievable. In some situations, especially when the component 50 is made relatively large, namely substantially corresponding to a lateral area of the user's head, radiation reductions of up to 40 times could be achieved using the shields 300, 350 compared to unprotected exposure. These reductions take into account any effect of dynamic compensation applied by the mobile telephone and its nearest telephone tower resulting from radiation attenuation arising due to the presence of the shields 300, 350. Such dynamic compensation is believed to render relatively ineffective contemporary mobile telephone shields which substantially enclose their mobile telephones.

Referring now to Figure 13, there is illustrated the user 400 wearing the shield 350. The shielded part 340 has an area defined by a width "a" and a length "b" as illustrated.

When the radiation shield layer 50 and its associated muff 330 have dimensions a =25 cm and b=25 cm and the aluminium foil is employed, an order of magnitude reduction in radiation within the dummy head is achievable, the layer 50 extending 25 mm below a bottom edge 450 of the telephone 420. It has been found that in some circumstances a 12 mm diameter hole within the layer 50 aligning to the user's ear 420 further attenuates radiation transmitted to the dummy head by 40 times relative to no protection. Moreover, reducing the dimension "b" to 160 mm does not substantially degrade performance of the layer 50.

The aforesaid aluminium mesh is preferably employed for the radiation shield layer 50 rather than the aforesaid aluminium foil because greater levels of radiation attenuation can thereby be achieved. When such a mesh is employed for the radiation shield layer 50 and the dimension "b" is chosen so that the radiation shield layer extends 50 mm below the bottom edge 450 of the telephone 420, attenuation factors of 300, 18, and 8 are achievable for component dimensions "a" of 18.75 cm, 11.25 cm and 6.25 cm respectively. Thus, preferably, the dimension "a" is greater than substantially 10 cm.

In particular, the radiation shield layer 50 should preferably extend from the apex 445 of the headpiece 350 to about 50 mm below the lower edge 450 in use to provide best protection for the user 400. When the layer 50 is made smaller, shielding performance of the safety shields 300, 350 is reduced but is still of benefit.

When the radiation shield layer 50 extends from the apex, it is especially desirable to implement the component as a continuous strip as illustrated in Figure 14, the strip preferably extending in use below the bottom edge 450 by a distance in excess of 2 cm. Such a continuous strip provides a benefit that differential electric fields cannot be created across the user's head as the strip ensures that potentials at left and right hand sides of the user's head are substantially similar. The absence of such differential electric fields renders the shield illustrated in Figure 14 especially effective at protecting the user 400 from exposure to mobile telephone radiation.

It will be appreciated that the shields 300, 350 can be implemented as shielding pads including the radiation shield layer 50 which are retrofitted to existing standard cloth caps. The shielding pads are preferably attached to existing caps by means of Velcro strips, press-stubs, buttons or similar.

The safety shields 300, 350 can also be modified to become effectively an attachment 500 for spectacles 510 as illustrated in Figure 15. The radiation shield layer 50 can be shaped into a round form component 500a, a rectangular form component 500b, trapezoidal form components 500c, 500d, an ovoid form component 500e or a contoured rectangular form component 500f depending upon the degree of protection desired and preferred aesthetic style. The components 500a, 500b, 500c, 500d, 500e, 500f can be mounted on one or more of right and left-hand sides of the spectacles 510 depending upon users' requirements. In order to render the spectacles 510 wearable, the components 500a, 500b, 500c, 500d, 500e, 500f are preferably mounted by using a spacer member 520 a distance "c" in a range of 1 cm to 2 cm from a lateral extremity of the spectacles 510 as illustrated in Figure 16. If desired, the components 500a, 500b, 500c, 500d, 500e, 500f can be implemented as an accessory retrofittable to standard spectacles and retained thereon by means of Velcro strip, metal clips or similar forms of attachment.

Figure 17 illustrates spectacles 510 with a radiation shield 500g mounted at both sides. Equally, only one side may suffice.

Referring next to Figure 18, the spectacles 510 preferably have mounted at one or more sides thereof a radiation shield layer 500h contoured to a wearer's head at an upper region of the component 500h as illustrated. The radiation shield layer 500h is preferably fabricated from the aforesaid aluminium wire mesh although other aforementioned mesh materials can be employed, for example copper mesh.

It will be appreciated that the safety shields and cases 1, 25, 100, 110, 150, 200, 204, 206, 300, 350, and the spectacles 510 including the shielding components 500a to 500h can be modified without departing from the scope of the invention. For examples, conductive materials used for the radiation shield layers and the dimensions of the components can be varied depending upon a degree of protection desired. The shielding components can be sewn onto an exterior exposed surface of their associated pieces of cloth or cases rather than being embedded between the pieces of cloth. Such exterior mounting is desirable where the metallic appearance of the radiation shield layer is an aesthetic feature of the shield.

Claims

1. A mobile telephone or radio case comprising means for receiving a mobile telephone or radio which has a speaker, display and keypad on a face thereof; the case having a first face for holding towards a user's head; the first face of the case comprising a radiation shield for shielding the user from mobile phone or radio radiation; the case further comprising means for receiving sound or signals corresponding to sound from the mobile phone or radio and means for emitting sound located on, in or under the first face of the mobile telephone or radio configured to output sound from the mobile telephone or radio whilst the radiation shield is inteφosed between the mobile telephone or radio and the user's head.

2. The case of claim 1 wherein a layer of material to comprise the radiation shield is supported on, in or under the first face of the case.

3. The case of claim I or claim 2 wherein the means for receiving sound is an electrical connection to an external loudspeaker connector provided on a mobile telephone or radio.

4. The case of any one preceding claim wherein the means for emitting sound is a loudspeaker.

5. The case of claim 4 wherein the radiation shield extends across the louspeaker.

6. The case of claim 5 wherein the case includes an aperture through which sound from the loudspeaker can escape and the radiation shield extends across the aperture.

7. A case according to any one preceding claim wherein the radiation shield also extends around one or more of the top, bottom, or side faces of the mobile telephone or radio

8. A case according to any one preceding claim configured so that the mobile telephone or radio can be inserted therein with the front face of the mobile telephone or radio (ie the face with any display and keypad) facing away from the first face of the case.

9. A case according to any one preceding claim wherein the radiation shield comprises at least one of a metal conductive sheet, a metal conductive film, and a metallic conductive wire mesh.

10. A case according to claim 9 wherein the film or mesh is embedded in a fabric or other textile, or a hard material.

11. A mobile telephone or radio comprising a housing with a loudspeaker associated with the telephone or radio on a first face, and a display and keypad associated with the telephone or radio located on the opposite face (the second face), the housing further comprising a radiation shield for shielding the user from radiation emanating from circuits associated with the mobile telephone or radio within the housing.

12. A mobile telephone or radio as claimed in claim 11 wherein the radiation shield extends at least over the first face.

13. A safety shield for protecting a wearer thereof from radiation emissions from a mobile telephone or radio held in close proximity to the wearer's head, the shield comprising radiation shielding means for at least one of reflecting and absorbing mobile telephone or radio radiation incident thereupon, and mounting means for mounting in use said shielding means on the wearer's head.

14. A mobile telephone or radio case constructed, arranged and adapted to shield a user of the telephone or radio from radiation emitted therefrom, substantially as herein disclosed and with reference to the accompanying drawings.

15. A mobile telephone or radio housing constructed, arranged and adapted to shield a user from radiation emitted by circuits within the housing; constructed and arranged substantially as herein disclosed and with reference to the accompanying drawings.

16. A safety shield to protect a user from radiation from a mobile telephone or radio used in close proximity to a user's head, constructed, arranged and adapted to be used as herein described and with reference to the accompanying drawings.