GB2546263A

GB2546263A - Isolation device

Info

Publication number: GB2546263A
Application number: GB1600543.1A
Authority: GB
Inventors: Lewis Marcus
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-01-12
Filing date: 2016-01-12
Publication date: 2017-07-19
Also published as: WO2017122003A3; GB201600543D0; WO2017122003A2

Abstract

An isolation device comprises an audio plug electrically connected to a first end of an isolation unit 30. The plug is connectable to the audio socket of a mobile phone (12, Fig 1). A second end of the isolator is connectable to an electrically conductive cable 42, the other end of which is connected to a speaker 40, such as a headphone or earpiece speaker. The isolation unit may use optical transmission and preferably takes the form of an opto-coupler comprising an LED 36 and a photodiode 38. Alternatively the isolation device may use acoustic transmission. The isolation device reduces a users exposure to secondary microwave radiation from headphone cable. The isolation device may include a battery 16. The isolation device may be housed within a case for a mobile phone (see e.g. Fig. 1). The isolation unit may include a microwave screen (34a, Fig. 3c). In the case of stereo headphones there is a separate isolation unit for each audio channel.

Description

ISOLATION DEVICE

This invention relates to an isolation device, and in particular to an isolation device whereby the transmission or conduction of microwave frequency signals to earpieces can be reduced or avoided.

The use of, for example, in ear type earpieces or other style of headphones when listening to music or other sound signals output from an electronic device such as a cell phone, portable mp3 player or the like is commonplace. Whilst the use of such equipment often allows adequate sound reproduction, one problem associated with such equipment is that the cables by which the earpieces or speakers of the headphones are connected to the device can act as conductors or waveguides along which microwave frequency signals can travel towards the users head. It is thought that this may carry health risks, and so should be avoided if possible. By way of example, exposure to microwave frequency radiation is thought to increase the risk of cancers and carcinomas, or to increase the risk of the formation of eye cataracts.

Where the electronic device used as the sound signal generation source takes the form of a cell phone, since cell phones use microwave frequency signals in communication with the cell phone network in normal use, there is a concern that such signals generated by the cell phone may be conducted along the cables to the earpieces. The signals may be conducted upon the electrical conductors of the cables, or may skitter along the outer sheath of the cables.

It is an object of the invention to provide an arrangement whereby the transmission of such signals along a cable from a cell phone to the earpieces can be avoided or reduced.

According to the present invention there is provided an isolation device comprising a plug to be connected to an audio output of a cell phone, in use, an isolation unit electrically connected to a conductor of the plug and, in use, to a conductor of a cable, the opposite end of which is connected to a speaker for outputting a sound signal generated, in use, by the cell phone, wherein the isolation unit is operable to prevent or restrict the transmission of microwave frequency signals from the cell phone to the cable and speakers.

Conveniently, separate isolation units are provided to provide isolation to respective channels of a stereo signal output from the cell phone, in use.

The plug and the isolation unit are conveniently mounted within or upon a single housing. The housing may take the form of a case for the cell phone. The housing may further house a battery or other power source for the isolation unit. A plug and socket connection may be used to connect at least part of the cable to the isolation unit. At least part of the cable, and the speakers, may thus take the form of a conventional set of headphones or earpieces. In some arrangements, the battery may also be used as an auxiliary power source for the cell phone. However, such use may potentially negate some of the benefits of the invention and so it may be preferred to only use the battery as an auxiliary power source when the cable and speakers are not in use.

The isolation unit is preferably an optical isolation unit, for example comprising a housing containing an optical light transmitter arranged to transmit or emit light pulses in response to receipt of an electrical signal, and an optical receiver arranged to output electrical signals in response to the incidence of light pulses thereon, the optical light transmitter and optical receiver being held in a spaced relation by the housing of the isolation unit. Between the transmitter and receiver, a microwave screen is preferably provided. The microwave screen may take the form, for example, of a region of housing of small inner diameter, for example in the region of 1mm diameter. The housing may be of metallic form.

The distance by which the optical transmitter and receiver are spaced is preferably of the order of several millimetres, but it will be appreciated that the invention is not restricted in this regard.

Between the transmitter and the receiver, the transmitted light pulses may be transmitted through air, through a vacuum, through other selected gases or fluids, or through transparent solid materials such as optical fibres.

The light pulses may take the form of pulses of visible light. Alternatively, for example, infrared frequencies may be used.

As an alternative, the isolation unit may take the form of an audio isolation unit, for example comprising a housing within which is located an audio speaker operable to output sound signals in response to the receipt of an electrical signal, and a microphone operable to output electrical signals in response to receipt of a sound signal, the housing holding the speaker and the microphone in a spaced relationship. Between the speaker and the microphone, a microwave screen is preferably provided. The microwave screen may take the form, for example, of a region of housing of small inner diameter, for example in the region of 1mm diameter. As with the optical isolation unit, the signals may be transmitted through air or, for example, through another gas or mix of gases, or through a liquid. It is thought that the use of a pressurised liquid may be preferable in this regard.

The speakers may comprise the speakers of an in-ear type headphone arrangement, or may comprise the speakers of a traditional headphones arrangement.

The invention further relates to an isolation unit suitable for use in an isolation device of the type described hereinbefore.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic view illustrating part of an isolation device in accordance with an embodiment of the invention;

Figure 2 is another view illustrating part of the device of Figure 1;

Figure 3 is an illustration of a component that may be used in the device of Figures 1 and 2;

Figures 3a, 3b and 3b are schematics illustrating variants of the component shown in Figure 3;

Figures 4 to 6 are a series of schematic views illustrating various embodiments of the invention; and

Figure 7 is another view illustrating the device of Figure 1.

Referring firstly to Figures 1 and 2, an isolation device is illustrated, the device taking the form of a housing 10 shaped to define a recess or cavity within which a cell phone 12 can be received. The material of the housing 10, and shape of the cavity formed therein are such that the cell phone 12 can be snap fitted into position, and once positioned within the recess or cavity, the housing 10 serves to retain the cell phone 12 in position. It will be appreciated that the housing 10 serves as a protective cover, providing protection to at least the underside of the cell phone 12. Although not illustrated, the housing 10 could include a flap adapted to hinge, pivot or otherwise move to allow the flap to cover the front of the cell phone, providing protection to the screen thereof, or the like, when desired. The housing 10 is conveniently of a flexible elastomeric material.

Within the housing 10 is formed a void 14, conveniently located between the rear of the cell phone 12 and the housing 10, in use, in which a battery 16 is located. By way of example, the battery may take the form of a 3A lithium polymer power cell. However, this need not always be the case, and other forms of battery may be used.

The housing 10 further defines a component receiving compartment 18 (illustrated in Figure 1 with a cover thereof removed to show the interior of the compartment 18). Within the compartment 18 are located circuit boards 20, 22 carrying conductive tracks and the components necessary for the device to function. These components include, for example, a plug 26 (not shown in Figures 1 and 3), for example in the form of a 3.5mm jack plug, to be plugged into an audio output socket 24 of the cell phone. The plug 26 is axially fixed within the housing 10, and to fit the cell phone 12 into the housing 10, the plug is introduced fully into the socket 24, some flexing of the housing 10 being required in order to achieve this, and the housing 10 and cell phone 12 are then manipulated to fully locate the cell phone 12 within the recess of the housing 10.

The board 20 carries a socket 28 whereby a jack plug associated with a conventional set of headphones comprising a cable 42 and speaker 40 can be received.

Electrically connected between the plug 26 and the socket 28, the circuit boards 20, 22 carry a pair of isolation units 30, for example of the form shown in Figure 3, one for each signal channel as shown in Figure 4.

The isolation unit 30 comprises a housing 32 of generally hollow cylindrical form, the interior of the housing 32 including a partition 34 in which one or more small openings, for example of diameter in the region of 1mm, are formed. The partition is of tapering form. The housing 32 is conveniently of metallic form, provided with a plastics material coating. An optical transmitter device 36, for example in the form of an LED or other controllable light transmitting or emitting device is located within, and closes, one end of the housing 32. A receiver device 38, for example in the form of a photodiode, is located at, and closes, the opposite end of the housing 32. The transmitter device 36 is electrically connected to the plug 26 so as to receive power and a signal representative of one audio channel from the cell phone 12, and to an analogue to digital converter (not shown) operable such that the transmitter device 36 outputs a series of light pulses representative of said audio channel supplied from the cell phone 12 via the socket 24 to the plug 26. The receiver device 38 is positioned so that the light pulses are incident thereon. It is connected to a circuit, powered by the battery 16, including a digital to analogue converter arranged to generate an electrical signal that substantially conforms with the respective signal supplied to the plug 26 from the cell phone. The circuit is connected to the socket 28 such that a set of headphones including speakers 40 and a cable 42 connected to the socket 28 can output a sound signal.

As shown in Figure 3 and Figure 3b, the housing 32 may be of multi-part form including end sections 32a in which the transmitter device 36 and receiver device 38 are located, the end sections being interconnected by a sleeve 32b. Alternatively, as shown in Figure 3a, the housing 32 may be of one piece form. Figure 3c illustrates a variant in which a separate microwaves screen 34a is provided.

It will be appreciated that the presence of the isolation units 30 results in the cable 42 and speakers 40 of the headphones being electrically isolated from the circuits of the cell phone 12, despite being able to output a sound signal substantially conforming with that generated by the cell phone 12. The risk of microwave signals being conducted from the cell phone 12 along the conductors of the cable 42 to the speakers 40 is thus reduced. Furthermore, the presence of the partition 34 within the housing 32 of the isolation unit reduces the risk of such signals being able to by-pass the isolation unit to skitter along the sheathing of the cable 42 towards the speakers 40 thereof. The housing 32 serves effectively as a Faraday cage preventing microwave signals from entering the housing 32.

Whilst the partition 34 illustrated defines a single opening, the partition could, if desired, take the form of a metallic sheet formed with a plurality of small openings.

As shown in Figure 4, and as described above, where a stereo signal is to be supplied, then two isolation units 30 are provided, one for the left hand channel and one for the right hand channel.

The optical signals used in the isolation unit 30 may be modulated in any suitable way. The light pulses transmitted may be in the visible wavelengths or alternatively could be in the infrared wavelengths.

In the arrangement shown in Figure 3, the housing 32 is air filled. However, this need not always be the case. If desired, other gases or liquids, or mixes of gases or liquids may be located therein. Furthermore, if desired, a short length of an optical fibre or the like may be located therein to optically couple the output of the transmitting 36 to the receive 38.

It will be appreciated that the isolation device described hereinbefore may be used to reduce or prevent microwave frequency signals from being carried from the cell phone 12 to the cable 42 and speaker 40 of a set of headphones. The health associated risks arising from the use of headphones in conjunction with a cell phone 12, for example when listening to music output from the cell phone 12 or when making or receiving telephone calls whilst using the headphones can thus be reduced. Conveniently, the housing 10 houses a microphone 44, for example for use where the device is being used during telephone calls.

As shown in Figure 7, the tip 26a of the plug 26 is conveniently shaped to include a flat 26b, and the plug 26 is conveniently angularly moveable about its axis between a position in which a pair of contacts within the socket 24 both bear against the tip, and so are electrically connected to one another, and a position in which only one of the contacts bears against the tip. When the angular position of the plug is such that both contacts bear against the tip, then the cell phone 12 will mute its internal speaker (as is the usual case when headphones are being used). Rotation of the plug 26 to a position in which only one of the contacts engages therewith results in the internal speaker of the cell phone 12 not being muted, and so allows use of the cell phone in the conventional manner, with the headphones disconnected. When used in this manner, if desired, the battery 16 may be connected to circuits of the cell phone, providing an auxiliary power source for the cell phone 12. A manually operable lever or the like is conveniently provided to permit control over the angular position of the plug 24.

Figure 5 illustrates a modification to the arrangement shown in Figure 4 in which the isolation unit 30, instead of being of optically based form, is of audio based form. As illustrated in Figure 5, each isolator unit 30 includes an audio speaker 36a and an associated audio microphone 38b. Operation of the arrangement of Figure 5 is substantially as hereinbefore described with the exception that instead of light pulses being transmitted and received within the isolation units 30, audio signals are transmitted and received. The arrangement of this embodiment has the benefit that there is no need to undertake any analogue to digital conversion, and so the number of components required in the device may be reduced.

As with the arrangement of Figure 4, the housing 32 may be air filled. Alternatively, it may contain another fluid. It is thought that slightly pressurising the fluid above ambient pressure may be beneficial.

The arrangement of Figure 6 is similar to that of Figure 5 in function, but rather than having the isolation units 30 located within a housing 10 in the form of a case for a cell phone 12, the isolation units 30 are instead located within a housing 10 located part way along the cable extending between the plug 26 and the speakers 40. In this arrangement, the housing 10 contains a microphone 44 as in the arrangements described hereinbefore, and a further isolation unit 30, including a speaker 44a and a microphone 44b is provided to provide isolation for the microphone channel. It will be appreciated that the arrangement of Figure 6 may be incorporated into a set of headphones, if desired.

It will be appreciated that a range of styles of housing 10 may be required to fit cell phones of different sizes and designs.

Whilst specific embodiments of the invention are described hereinbefore, it will be appreciated that a wide range of modifications and alterations may be made thereto without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. An isolation device comprising a plug to be connected to an audio output of a cell phone, in use, an isolation unit electrically connected to a conductor of the plug and, in use, to a conductor of a cable, the opposite end of which is connected to a speaker for outputting a sound signal generated, in use, by the cell phone, wherein the isolation unit is operable to prevent or restrict the transmission of microwave frequency signals from the cell phone to the cable and speakers.

2. A device according to Claim 1, wherein separate isolation units are provided to provide isolation to respective channels of a stereo signal output from the cell phone, in use.

3. A device according to Claim 1 or Claim 2, wherein the plug and the isolation unit are mounted within or upon a single housing.

4. A device according to Claim 3, wherein the housing takes the form of a case for the cell phone.

5. A device according to Claim 3 or Claim 4, wherein the housing further houses a battery or other power source for the isolation unit.

6. A device according to any of Claims 3 to 5, wherein a plug and socket connection is used to connect at least part of the cable to the isolation unit.

7. A device according to Claim 6, wherein at least part of the cable, and the speakers, take the form of a conventional set of headphones or earpieces.

8. A device according to any of the preceding claims, wherein the isolation unit is an optical isolation unit.

9. A device according to Claim 8, wherein the isolation unit comprises a housing containing an optical light transmitter arranged to transmit or emit light pulses in response to receipt of an electrical signal, and an optical receiver arranged to output electrical signals in response to the incidence of light pulses thereon, the optical light transmitter and optical receiver being held in a spaced relation by the housing of the isolation unit.

10. A device according to Claim 9, wherein, between the transmitter and receiver, a microwave screen is provided.

11. A device according to Claim 9 or Claim 10, wherein the housing is air filled, houses other selected gases or fluids, houses an optical fibre, or accommodates a vacuum.

12. A device according to any of Claims 9 to 11, wherein the optical light transmitter transmits or emits light pulses in the visible or infrared frequencies.

13. A device according to any of Claims 1 to 7, wherein the isolation unit takes the form of an audio isolation unit.

14. A device according to Claim 13, wherein the isolation unit comprises a housing within which is located an audio speaker operable to output sound signals in response to the receipt of an electrical signal, and a microphone operable to output electrical signals in response to receipt of a sound signal, the housing holding the speaker and the microphone in a spaced relationship.

15. An isolation unit suitable for use in an isolation device of the type claimed in any of the preceding claims.