EP1887921A2

EP1887921A2 - Multipurpose light source

Info

Publication number: EP1887921A2
Application number: EP06744349A
Authority: EP
Inventors: John Dingley; David Williams
Original assignee: Individual
Current assignee: Shakerscope Ltd
Priority date: 2005-06-10
Filing date: 2006-06-09
Publication date: 2008-02-20
Also published as: WO2006131770A3; WO2006131770A2

Abstract

A light source which can be used in a range of medical applications, has a handle in which a magnet moves inside a coil of wire to generate an electric current in the coil to power an LED. The handle can be attached to a range of instrument head devices such as a laryngoscope, ophthalmoscope, otoscope etc. to provide light from the LED for the instrument head via a light guide.

Description

MULTIPURPOSE LIGHT SOURCE

FIELD OF THE INVENTION

The present invention relates to a light source which can be used in a range of medical applications, such as in inspections of the body and in carrying out medical procedures.

BACKGROUND TO THE INVENTION

In many medical procedures a bright light source is required for a short period of time, for example inspection of organs such as the ears, eyes, nose etc. and in carrying out procedures such as tracheal intubation using a laryngoscope.

Two of the requirements in tracheal intubation are (i) the necessity to observe the larynx, and (ii) the necessity to introduce a tube through the larynx and into the trachea. In order to observe the larynx there is the need to illuminate the larynx and conventional laryngoscopes have a light source which is provided by the means of a handle containing batteries which operate an incandescent bulb such as a tungsten filament bulb in the laryngoscope blade. The use of an incandescent bulb can lead to excess temperatures in the laryngoscope blade and consequent patient harm.

Other instruments such as ophthalmoscopes and otoscopes use a light source which shines directly into the eyes or ears when examining a patient and are specifically designed for such a purpose and such instruments have a handle containing batteries which operate an incandescent bulb to provide the light required.

The use of batteries can be convenient enabling the device to be used under a range of conditions and in a variety of environments, however in some applications the use of batteries suffers from serious disadvantages. For example there has to be a supply of batteries available at all times in order that the device can be used and, in remote areas, suitable batteries are not always available and, even if they are available, they are an extra expense. Batteries can gradually discharge over time and there is the risk that the device may not work when it is required, which can be very serious under emergency conditions. Thus existing devices need regular checking to make sure they are operational. The batteries have to be ready for immediate use and this necessitates that the batteries are stored in the device. These problems with batteries are exacerbated under adverse conditions such as high humidity where batteries can corrode and leak. Conventional incandescent bulbs have a finite life and can fail unexpectedly and they are also susceptible to damage or breakage in handling.

Small portable Faraday generators are well known in which an electromotive force is generated by moving a permanent magnet in a fixed coil and torches utilising Faraday generators to power Light Emitting Diodes (LEDs) and incandescent bulbs are known and such devices are described in US Patents 4114305, 5975714 and 6729744. However, there is no disclosure or suggestion in any of these specifications that a Faraday generator could be incorporated into an optical medical instrument.

SUMMARY OF THE INVENTION

We have now devised a device based on a Faraday generator and LEDs for use in medical applications which does not use batteries and incandescent bulbs with their inherent problems. The invention provides a medical instrument with a self-contained means for generating power/light which does away with the need for batteries.

According to the invention there is provided a device for use in medical procedures which comprises (i) a handle (ii) an attachment means whereby the handle can be detachably attached to a head (iii) an electricity generating means mounted in the handle and (iv) a light emitting diode connected to the electricity generating means in which the electricity generating means generates electricity by the relative movement of at least one magnet and an electrically conductive wire to generate an electric current in the wire to power the light emitting diode. DESCRIPTION OF PREFERRED FEATURES

The electricity generating means can comprise at least one substantially spherical or cylindrical magnet which moves inside a coil of wire mounted in the handle. Shaking or otherwise moving the handle causes the magnet to move inside the coil and thus generate an electric current in the coil. In order to provide light when the device is not being shaken there is preferably a current or electrical field storage means which is charged up, for example, a capacitor or rechargeable cell can be used.

The attachment means can be any connector such as a screw connector, a snap fit or bayonet fit but is preferably of the type which is conventionally used in medical applications such as a hook mount and, in one embodiment, the light emitting diode (LED) is mounted in the handle and light is conducted from the LED by means of a light guide, such as a fibre optic bundle or transparent plastic moulding, to the attachment means. The head has a corresponding light guide so that, when the head is attached to the handle via the attachment means there is a light path from the LED to the head. The head can then be operated in the conventional way. The head can be a laryngoscope blade, an ophthalmoscope, an otoscope, illuminated tongue depressor for mouth examination, illuminated dental examination mirror, nasendoscope, proctoscope, and gynaecological speculum or any other instrument which needs a localised light source. Suitably modified instrument heads may be used for applications in veterinary medicine.

To use the device the head is attached to the handle and the handle is shaken to generate an electric current which is stored in a storage device. Alternatively the head can be attached to the handle after the device is charged. The device is then placed in position and the LED is turned on which provides the required illumination.

A capacitor is a suitable storage device and Electric Double Layered capacitors, known as 'gold capacitors' are particularly useful in the present invention as they combine very large charge storage with miniature size. They are commonly used as temporary 'back up' power supplies in computers and personal organisers to maintain memory function in - A -

case of power failure, and can handle repeated charge-discharge cycles without loss of capacity, unlike conventional rechargeable cells. Alternatively the gold capacitor may be replaced by a small rechargeable cell.

High intensity white LEDs are now readily available which are capable of producing illumination of 500OmCd with a current requirement of only 2OmA. With an average lifespan of over 100,000 hours, LEDs are impervious to electrical and mechanical shocks, vibrations, and environmental extremes. The inherently robust and long life times of LEDs compared with incandescent bulbs means that the unit can be sealed with no need for access to the LED. The Correlated Colour Temperature (CCT) of a white LED light source gives a more realistic appearance of tissue than an incandescent bulb and, although normally used with a white LED, different colour LEDs can be used for particular applications if required.

It has been found that thirty seconds of shaking can, with a suitable electrical field storage means, provide five minutes of light, which is what is required for a range of procedures.

In order to deliver a more constant current to the LED there can be a controller such as a micro-processor controller which restricts the current from the capacitor at the beginning of the discharge and boost it as the current decays. In this way a more constant current is delivered to the LED from the storage means, which improves brightness duration and efficiency.

There is preferably a means incorporated so that the user is warned when the stored charge is about to run out so the user can recharge the storage means by shaking the device. The warning may be visual (e.g. flashing of the LED), audible or other. There any also be a means for indicating when the device is fully charged and ready for use. That may be audible, visible or other.

The optical fibres used may be Polymer Optical Fibres (POFs) which are cheaper, more robust and more flexible than their traditional silica counterparts. Single core polymethylmethacrylate (PMMA) POFs have acceptable optical properties and are thermoplastic (softening temperature 70 - 8O⁰C) and so can be readily moulded as required. Recently developed microstructured POFs have superior optical properties.

For ease of use an ergonomic non-slip handle is used, which allows the device to be used in an upright or inverted orientation by left or right-handed users. A suitable handle is illustrated in UK Registered Designs Application No.3022429. The handle may be made of any material, however it should ideally be robust to withstand physical damage, unaffected by the sterilisation process (which may involve high temperatures or chemical agents), and non-ferromagnetic to prevent the generation of eddy currents which would impair the efficiency of the electrical generator.

The device can be used with a range of different interchangeable heads such as laryngoscopes, ophthalmoscopes, otoscopes, illuminated tongue depressor for mouth examination, illuminated dental examination mirror, nasendoscope, proctoscope, and gynaecological speculum etc. thus avoiding the need for separate devices. The device can also be in the form of a medical pen torch for examination of body cavities including, but not restricted to, the mouth cavity and pupillary reflexes. In contrast to conventional medical instruments in which each instrument has its own separate (battery/mains) power

& light source, the present apparatus enables multiple different instrument heads to be used with a single hand held generator/light source, thereby saving cost, size and weight.

The electricity generating means may be protected from mechanical vibration or shock by suitable material (eg a layer of expanded foam and/or springs), and may be securely fixed within the handle of the device. Alternatively, to prevent transmission of infection between patients, the electricity generating means may be removable so that it can be removed from the handle and the handle can then be disposed of or sterilised in a conventional way e.g. by steam sterilisation or immersion in a sterilising liquid. The invention provides a device which is a robust kinetically powered light source which provides illumination for a range of essential medical instruments. This avoids the need for separate instruments for each application as all that is required is a single handle and separate interchangeable heads or attachments.

The invention is particularly useful under adverse conditions such as in developing countries, military and disaster conditions, can be used in aviation, maritime and exploration medicine, and is convenient for resuscitation trolleys, paramedic equipment and operating theatres.

It is a feature of the invention that it can be a sealed unit so that it is water-proof, dust- proof, humidity-proof etc. and has potentially a very long or infinite shelf life and so can be stored for occasional use or stockpiled for major incidents. There are no batteries to leak or run out of power, no bulbs to burn out, break or malfunction or to drop out of the holder. The invention provides a free, potentially everlasting light source which has only one moving part and because it has no disposables such as batteries or bulbs is therefore more environmentally friendly.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by way of example in the drawings in which: -

Figure 1 shows a schematic view of the device (external and internal views).

Figure 2 shows the handle and head separated. Figure 3 shows the device and a range of interchangeable instrument heads.

Figure 4 shows an electrical circuit.

Figure 5 shows the device with a removable electricity generating means and LED.

Figure 6 shows the device with a removable electricity generating means.

Figure 7 shows a conventional incandescent bulb in a bulb holder and an LED mounted in an identical bulb holder. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to fig. 1, the device consists of a handle (1) in which there is a coil of wire (2) having a pathway down which cylindrical permanent magnet (3) can move. There is a light emitting diode (LED) (4) connected to the coil via an electric circuit shown in more detail in fig. 4. There is an attachment means (5) connected to the handle to which instrument heads can be detachably attached. There is a light guide from the LED (4) through the attachment means (5) so that there is a continuous light path from the LED to a head attached to (5).

Referring to fig. 2 this shows a laryngoscope blade (14) and the handle (1) separately. The handle (1) has a conventional hook mount connector (5) which may also incorporate a light guide (7) which leads to the LED in the handle. The blade (14) contains a light guide (6), unlike a conventional laryngoscope blade which would contain an incandescent bulb connected to batteries in the handle. The laryngoscope blade (14) is connected to (5) by means of cooperating components (10) and (11) as in the conventional hook mount connectors. The light guide (7) is then connected to the light guide (6) which provides light from the LED to the blade.

Referring to fig. 3 this shows the device and a range of interchangeable instrument heads (14,15) which are each fitted with fibreoptic ligt guides and which attach to the handle (1) by means of cooperating components (10,11) via the attachment means (5).

Referring to fig. 4 the circuit in its simplest form comprises the light emitting diode (16), on/off switch (17), capacitor, rechargeable cell or charge storage means (18), Zener diode (19) to prevent over-charging, bridge rectifier (20) to convert AC to DC and coil

(21) in which the cylindrical magnet (22) moves. This circuit may be modified with a microprocessor or other device(s) to give the user warning of when the stored charge is running low and to ensure a constant delivery of current to the LED to improve efficiency as described above. The switch may be mechanically or magnetically operated

(e.g. reed switch), and may be mounted on the handle (1) of the device as a discreet component, or incorporated into the attachment means (5) as an integral part of the device such that when an instrument head (14, 15) is attached to the device it causes the switch to close and the LED to illuminate.

Referring to fig 5. this shows the electricity generating means, circuit and LED combined as a single sealed unit (23) which may be removed from the handle (1) to allow disposal or sterilisation of the handle as described above.

Referring to fig 6. this shows a means by which a conventional instrument handle may be readily adapted to combine the device. The electricity generating means with or without the circuit but without the LED (16) are combined into a single sealed unit (24) which may be removed from the handle (1) to allow sterilisation or disposal of the handle. The external dimensions of the sealed unit (24) are identical to those of the conventional batteries or power source. The electricity output from the sealed unit is connected to electrical contacts on the exterior of the sealed unit which correlate with the electrical contacts of the conventional power source and make contact with the existing electrical connections in the handle (1). The conventional light source (eg. incandescent bulb) in the handle or instrument head (14, 15) is replaced by an LED and is connected to the sealed unit by existing electrical connections in the handle.

Referring to fig 7. this shows a conventional miniature incandescent bulb (26) in a bulb holder (27) which makes electrical contact with the batteries or conventional power source as described above. If a conventional instrument handle is adapted to incorporate a Faraday generator as described above, the incandescent bulb and holder are replaced by an LED (16) mounted in an identical bulb holder (27).

In use the handle (1) is shaken for about thirty seconds which charges up capacitor (18). The laryngoscope blade (14) or other instrument head (15) is connected to the handle (1) via hook mount (5) (if it has not already been done). The switch (17) is turned on, the LED (16) illuminates and light is conducted from the LED via light guide (7) to (6). The Part of the body to be examined is then illuminated by light coming from (6). Thirty seconds shaking of the handle (1) provides enough power for powering the LED for five minutes.

After use the laryngoscope blade (14) or other instrument head (15) can be removed from the handle and the device is ready to be re-used or used with another head attached to attachment means (5).

Claims

1. A device for use in medical procedures which comprises (i) a handle (ii) an attachment means whereby the handle can be detachably attached to a head (iii) an electricity generating means mounted in the handle and (iv) a light emitting diode connected to the electricity generating means in which the electricity generating means generates electricity by the relative movement of at least one magnet and an electrically conductive wire to generate an electric current in the wire to power the light emitting diode.

2. A device as claimed in claim 1 in which the electricity generating means comprises a magnet which is able to move inside a coil of wire mounted in the handle.

3. A device as claimed in claim 1 or 2 in which there is an electrical current or electrical field storage means in which electricity generated by the movement of the magnet can be stored.

4. A device as claimed in claim 3 in which the electrical current or electrical field storage means is a capacitor or rechargeable cell.

5. A device as claimed in claim 4 in which there is an electronic current controller which restricts the current from the electrical field storage means at the beginning of the discharge and/or boosts it as the current decays.

6. A device as claimed in any one of the preceding claims in which the attachment means is a hook mount.

7. A device as claimed in any one of the preceding claims in which the light emitting diode (LED) is mounted in the handle and light is conducted from the LED by means of a light guide.

8. A device as claimed in claim 6 in which the light guide is a fibre optic bundle or transparent plastic moulding.

9. A device as claimed in claim 8 in which the optical fibres used are polymer optical fibres.

10. A device as claimed in claim 8 or 9 together with a head able to be attached to the attachment means, in which the head has a light guide so that, when the head is attached to the handle via the attachment means there is a light path from the LED to the head.

11. A device as claimed in any one of the preceding claims in which the head is a laryngoscope blade, an ophthalmoscope, an otoscope, illuminated tongue depressor for mouth examination, illuminated dental examination mirrors, nasendoscope, proctoscope, and gynaecological speculum or any other instrument which needs a localised light source.

12. A device as claimed in any one of the preceding claims in which there is a means incorporated so that the user is warned when the stored charge is about to run out.

13. A device as claimed in any one of the preceding claims in which the electricity generating means with or without the attached circuit and LED is removable from the handle.

14. A device as claimed in any one of the preceding claims in which the electricity generating means with or without attached circuit is packaged as an insertable unit or cartridge which replaces a conventional power source.

15. A device as claimed in any one of the preceding claims in which the source of illumination is an LED which is packaged in a bulb holder which replaces a conventional incandescent bulb and bulb holder.