GB2532189B

GB2532189B - Phototherapy apparatus

Info

Publication number: GB2532189B
Application number: GB1417821.4A
Authority: GB
Inventors: Dumbreck Glass Iain
Original assignee: APPLIED MATERIALS Technology; Applied Materials Technology Ltd
Current assignee: APPLIED MATERIALS Technology; Applied Materials Technology Ltd
Priority date: 2014-10-08
Filing date: 2014-10-08
Publication date: 2019-07-03
Anticipated expiration: 2034-10-08
Also published as: GB201417821D0; GB2532189A

Description

PHOTOTHERAPY APPARATUS

Field of the Invention

The present invention relates to wearable garments, in particular wearable garments comprising optical fibre.

Background to the Invention 720,000 babies are born in the UK each year (5 million across the EU). 60% have jaundice and 6% require urgent medical treatment to prevent brain damage. Hospital treatment is in the form of phototherapy, consisting of powerful lights shining on the baby's skin. The light helps break down bilirubin in their blood. Current treatment methods require large, fixed location devices, and the mother and baby to be separated. The babies are put in a fixed position to expose as much of the body as possible but due to the directional light source it is not possible to expose all the body. Babies also require eye protection. Tanning side effects can occur and equipment is expensive, so treatment only occurs in hospitals. The accepted methods for phototherapy treatment in the NHS include overhead phototherapy units, a Bilibed® unit which provides treatment from below, and a slightly more portable but cumbersome Biliblanket® comprising a small pad to allow light treatment. Although these forms of treatment are used to treat neonatal jaundice they all suffer from the drawbacks that the patient is required to stay in hospital, the patient is required to wear eye protection, there is a necessity to keep the patient uncovered in a fixed position to allow maximum exposure (unidirectional light) and because a wide spectrum of light is used, heat is produced, which not only heats the patient, but means frequent replacement of expensive bulbs. US4885663 and EP1147786 discloses an illumination devices in which a plurality of optical fibres are woven or plaited together to form a strip material. Light is encouraged to leave each fibre through its side wall by the relatively sharp bends imposed upon the fibre by the act of weaving/platting the material. A portion of the light incident upon each bend exceeds the critical angle for internal reflection and escapes from the fibre. However, the weaving/platting op- eration is mechanically demanding on the fibres, often causing breakages which result in portions of the material remaining 'dark'. Furthermore, as the material depends on the transmitted light exceeding the critical angle for internal reflection at the bends of the weave/plait, light is emitted in all directions at once. In addition, the material, by its very nature, cannot lie flat and is only marginally flexible, thereby limiting its potential applications. In EP1147786, light which is directed upwards, away from the body against which the fabric is placed, is reflected back down towards the body by an external mirrored layer to the fabric. Unfortunately this increases the insulative capacity of the fabric and can significantly heat body areas over which the fabric is covered. FR2626381 discloses an illumination device comprising a plurality of optical fibres, ordinarily of elliptical or rectangular cross-section, in which the cladding of the fibre is stripped at periodic intervals to expose the fibre core. Light is leaked through the exposed regions of the fibre since the critical angle for internal reflection is changed at those points with regard to the clad portion and any light rays exceeding that angle can escape from the fibre. The light is emitted from the fibre at a very shallow angle and is non-directed. US5432876 discloses an optical fibre having a light emitting region along at least a portion of its length, the light emitting region comprising a plurality of optical elements spaced along the fibre, the optical elements comprising at least one reflecting surface arranged such that a portion of light propagated through the fibre and impinging upon the surface(s) of an optical element is reflected across the fibre and through the wall of the light emitting region. The installation of these so called optical elements within a fibre is not only time consuming but expensive.

There has now been devised a wearable garment which overcomes and/or substantially mitigates the above mentioned and/or other disadvantages associated with the prior art.

Summary of the Invention

In a first aspect of the invention there is provided a wearable garment comprising a length of optical fibre embedded within a light diffusing fabric ma- terial, and a light source adapted to connect to an end of the optical fibre, the optical fibre being adapted to emit light along its length and from only the portion of its surface which faces inwardly when the garment is worn, wherein the fabric comprises two layers of the fabric material superimposed on top of one another and the optical fibre is sandwiched between the two layers, the two superimposed layers of material being connected to one another by portions of the two materials which are bonded together to define channels in which the optical fibre is received and the optical fibre being bent around said portions.

The garment according to the first aspect of the invention is advantageous because substantially all of the light emitted from the garment illuminates the skin of the wearer of the garment. This means that the light source can be made less powerful than conventional light sources. This increases the portability of the light source which means that the subject can be continuously treated in hospital, at home, elsewhere or on the move. Being of relatively simple construction the garment is also disposable. Also, being a wearable garment means that the periods and area coverage of the phototherapy can be maximised without the requirement for the patient to remain motionless. No eye protection is required as the light is emitted towards the subject only.

The fabric is a light diffusing material. This means that the subject is illuminated uniformly. Preferably the light diffusing material is a non-woven fabric material. Typically, the non-woven fabric is a polypropylene based material. The light diffusing material may be a sheet or web structure bonded together by entangling fibers or filaments (and by perforating films) mechanically, thermally or chemically. For the purposes of the invention other types of light diffusing material are considered suitable, such as clear plastics, foams, and woven fabrics.

The fabric comprises two layers of the material superimposed on top of one another and the optical fibre is sandwiched between the two layers. This makes it easier to construct the garment. In such an arrangement preferably only the layer in contact with the skin when the garment is worn is light diffusing.

Preferably the optical fibre is held in a substantially fixed orientation within the fabric material. This means that the optical fibre cannot rotate or move significantly. As such the portion of its surface which emits light and faces inwardly when the garment is worn is maintained as facing inwardly in use.

Preferably the optical fibre is held in a substantially fixed orientation by stitching or adhesive applied around or onto the optical fibre.

The garment comprises two layers of the material superimposed on top of one another and the optical fibre is sandwiched between the two layers, the two superimposed layers of material being connected to one another by portions of the two materials which are bonded together. Such bonds may be created by heat sealing, glueing, stitching or welding. The portions of the two materials which are bonded together define channels in the garment in which the optical fibre is received. The optical fibre is bent around said portions. Preferably the optical fibre forms a plurality of loops around said portions within the fabric. Preferably the optical fibres are evenly distributed over the area of the garment. In this arrangement, the optical fibre is prevented from twisting or rotating or moving significantly, which would otherwise mean that the light emitting side of the optical fibre is not directed inwardly when the garment is worn. The arrangement of the fibres throughout the fabric as described above also means that light is emitted uniformly from the garment inwardly during use.

Preferably, the light is emitted from substantially one side of the garment only. This means that energy is not wasted and thus an efficient transportable light source can be used with the garment. It will be appreciated that due to internal reflection from the fabric a very small proportion of light will be emitted outwards of the garment. Also, it will be appreciated that the optical fibre may not 100% efficient at transporting light along its length, and inherently loses some light uncontrollably any way.

Preferably, the said substantially one side is the side of the garment that faces inwardly when the garment is worn. This is because only the portion of the surface of the optical fibre which faces inwardly when the garment is worn emits light. This means that the subject gets the full effect of the light, rather than some light being lost away from the subject.

Preferably, the light is emitted from the entire one side or a portion of the one side of the garment. This means that the whole body of the subject/patient can be treated, or a particular area. The latter is particularly useful when treating wounds.

Preferably, the light is emitted uniformly along the length of the optical fibre. This means that all the light from the light source is not lost over the first few inches of the fibre, and is emitted throughout the garment.

The light source can emit light at any wavelength. Preferably, the light source emits light in the region of 440-450 nm peak wavelength. Most preferably the light source emits light in the region of 445 nm peak wavelength. This wavelength is known for the treatment of jaundice or hyperbilirubinemia. Using light of limited peak wavelengths means that there is no redundant energy and this means that heating effect of the garment is minimal. The garment according to the invention is particularly suitable for use in the treatment of the skin of subjects suffering from jaundice or hyperbilirubinemia, or other photosensitive skin conditions. The garment according to the invention is also particularly suitable for the use in the treatment of wounds.

Preferably the light source is a laser. Most preferably the light source is a gallium nitride laser. Preferably the light emitted from the optical fibre along its length is laser derived light.

Preferably the garment comprises a receiver connected to the end of the optical fibre opposite the first end, the receiver being adapted to measure changes in light intensity.

Preferably, a controller is connected to the receiver and the light source.

Preferably the controller is adapted to vary the light emitted from the light source in response to light received by the receiver.

The optical fibre is fibre is adapted to emit light along its length, preferably by changing the refractive index of the optical fibre along one edge of the optical fibre during manufacture of the garment according to the invention. This means that light which hits the inside of the optical fibre is allowed to escape the fibre in the regions where refractive index has been changed. The degree of change to the refractive index may be varied along the length of the fibre in order to regulate the intensity of light emitting from the optical fibre. Thus the refractive index may be changed in order to allow a controlled intensity of light to be emitted along the length of the fibre. Such a controlled intensity may be a constant intensity, but also may be varied according to the treatment regime required. Alternatively the refractive index of the fibre may be changed in areas of the garment such that portions of the garment emit light but not others. Preferably the refractive index is changed by the action of a laser on the optical fibre during manufacture. Thus intensity of the laser may be varied along the length of the optical fibre such that a controlled intensity of light is emitted from the optical fibre. Alternatively, where treatment of particular areas is required, the laser may change the refractive index of only a portion of the optical fibres in the garment thereby enabling only a portion of the garment to emit light. This is particularly useful when the garment is used for wound therapy.

The refractive index may be alternatively changed mechanically by physical abrasion along one edge of the optical fibre. This preferably removes the surface layers of the optical fibre and allows light out of the axis of the fibre. Such abrasion may be carried out using abrasive paper or the like. As with the laser described above, the intensity of the abrasion may be altered along the length of the fibres, or in a region of the garment.

The refractive index may be alternatively changed by introducing a plurality of optical elements spaced along the fibre. This is similar to the elements described in US5432876. Such optical elements encompass any controlled interruption or discontinuity formed in the core of the optical fibre, which defines one or more surfaces capable of reflecting at least a portion of light impinging thereon through the opposing wall of the fibre. Such optical elements are to be distinguished from scratches and other interruptions, as well as imperfections and other surface irregularities, which occur from time to time in optical fibres.

The garment may be formed into a blanket, a covering, a suit, a wrap or sleeping bag.

Brief Description of the Drawings

The invention will now be described by way of example only with reference to the drawings of which:

Figure 1 shows a plan view of an embodiment of the garment according to the invention and

Figure 2 shows a cutaway of a portion of the garment in figure 1.

Detailed Description of the Illustrated Embodiment

In figure 1 there is a shown a garment according to the invention generally designated 1. The garment is a shirt or the like to be worn over a baby’s torso. The garment 1 comprises two superimposed layers of light diffusing fabric material 2, and a length of optical fibre 10 sandwiched between the two layers (shown in dotted lines). The optical fibre is a continuous loop with each end of the loop terminating in a control box 30. The control box 30 comprises a receiver connected to one end of the optical fibre 10, a light source connected to the other end of the optical fibre 10, and a controller which is connected to both the receiver and the light source. Further detail of the garment shown in figure 1 is described further with reference to figure 2 which shows a cutaway portion the garment 1.

In the garment 1 there are two superimposed layers of light diffusing material 3. The light diffusing material is non-woven fabric, such as fleece. The light diffusing material has a thermal resistance per unit area of 1 tog. This is beneficial in order to prevent the baby from over-heating and to allow for sufficient diffusion of the light from the optical fibre. The optical fibre 10 is sandwiched between the two superimposed layers 3 and is looped backwards and forwards in an even pattern so as to be distributed evenly through the material and cover the garment evenly. The two superimposed layers of material are bonded together at bonded areas 5 between the optical fibres. Bonding is by heat sealing the two layers together. The bonded areas 5 serve at least two purposes. The first is to hold the two layers of material together so that the garment forms a consistent shape. The second is to form channels in which the optical fibre extends in, and as the optical fibre is looped backwards and forwards within the material the bonded areas serve to hold the optical fibre in substantially the same orientation though out the garment. Thus the optical fibre is not allowed to twist or rotate substantially within the garment. In the example shown each run of optical fibre is approximately 20mm from an adjacent run.

Each end of the optical fibre is connected to the control box 30. In the control box 30 there is a light source 32, a receiver 34 and a controller 36. The light source 32 is connected to one end of the optical fibre. The receiver 34 is connected to the opposite end of the optical fibre. The controller 36 is connected to both the receiver 34 and the light source 32. The light source is a gallium nitride laser which emits light at a wavelength of 445nm. The light source is powered by a power source (not shown), comprising a battery and a voltage regulator and associated circuitry. The receiver 34 is adapted to measure the intensity of the light returning from the light source via the optical fibre. The measured intensity information is sent to the controller, which controls the light source such that a constant light intensity is maintained throughout use. Alternatively the controller may be programmed in order to deliver a pattern of light intensities over time, for example if different treatment regimes are required. The control box 30 is made of a small, manageable size, so that the patient can be treated with the garment at all times, when mobile and when stationary. It will be appreciated though that even if a large box were provided, as the garment is flexible and designed to be worn it allows for movement of the patient whilst treatment is in progress. The control box 30 constantly measures the light intensity of the laser and the passage of the light through the fibre. If at some point the optical fibre is cut, then the controller 36 shuts off the light source 32. This prevents the laser from shining in the wrong direction and into areas such as eyes etc, in which it could cause damage.

In order to manufacture the garment 1 firstly a single layer of light diffusing material is laid down and cut to shape. Then a length of optical fibre is placed on top of said layer in a looping pattern as described above, evenly over the surface of the material. The optical fibre is then pinned to the material in order to temporarily retain it in place. A short wavelength pico second laser is then targeted at the optical fibre and tracked along its exposed edge. The pico laser changes the refractive index of the optical fibre along the exposed edge of the optical fibre. The intensity of the laser is varied around the bends and along the length of the fibre in such a manner that once the garment is manufactured, light is emitted at a constant intensity along the length of the fibre but only from the edge that was exposed to the pico laser. This makes for a garment where light is emitted evenly over its surface. In another example however the intensity and duration of the pico laser is varied in such a manner that light is not emitted at a constant intensity along its length, but is for example varied such that light is emitted from particular regions of the garment. This may be useful in treating particular trauma areas or wounds. The second layer of material is then placed on top of the first layer and the optical fibre is consequently sandwiched between. The second layer is then heat sealed to the first layer at positions between the optical fibre. This prevents the optical fibre from rotating. The pins are then removed and the material is trimmed for use. The garment manufactured as detailed above is portable, disposable and cheap to produce. It can also be manufactured to any shape or size. The garment described above is suitable for use in the treatment of jaundice. The garment according to the invention may also be formed into a blanket, a covering, a suit, a wrap or sleeping bag.

As the garment according to the invention is made of limited numbers of materials, it is more readily and easily disposed of at the end of treatment.

Claims

1. A wearable garment comprising a length of optical fibre embedded within a light diffusing fabric material, and a light source adapted to connect to an end of the optical fibre, the optical fibre being adapted to emit light along its length and from only the portion of its surface which faces inwardly when the garment is worn, wherein the fabric comprises two layers of the fabric material superimposed on top of one another and the optical fibre is sandwiched between the two layers, the two superimposed layers of material being connected to one another by portions of the two materials which are bonded together to define channels in which the optical fibre is received and the optical fibre being bent around said portions.

2. A wearable garment according to claim 1, wherein only the layer in contact with the skin when the garment is worn is light diffusing.

3. A garment according to any preceding claim, wherein the optical fibre is held in a substantially fixed orientation within the fabric material.

4. A garment according to claim 3, wherein the optical fibre is held in a substantially fixed orientation by stitching or adhesive applied around or onto the optical fibre.

5. A garment according to any preceding claim, wherein the length of optical fibre forms a plurality of loops within the fabric.

6. A garment according to any preceding claim, wherein the light is emitted from substantially one side of the garment only.

7. A garment according to claim 6, wherein the said substantially one side is the side of the garment that faces inwardly when the garment is worn.

8. A garment according to claim 6 or 7, wherein light is emitted from the entire one side or a portion of the one side of the garment.

9. A garment according to any preceding claim, wherein the light is emitted uniformly along the length of the optical fibre.

10. A garment according to any preceding claim, wherein the light source emits light in the region of 440-450 nm peak wavelength.

11. A garment according to any preceding claim, wherein the light source is a laser.

12. A garment according to claim 11, wherein the laser is a gallium nitride laser.

13. A garment according to any preceding claim, comprising a receiver connected to an opposite end of the optical fibre, the receiver being adapted to measure changes in light intensity.

14. A garment according to claim 13, wherein a controller is connected to the receiver and the light source.

15. A garment according to claim 14, wherein the controller is adapted to vary the light emitted from the light source in response to light received by the receiver.

16. A garment according to any preceding claim, wherein the garment is formed into a blanket, a covering, a suit, a wrap or sleeping bag.