GB2532058A - Finger dressing - Google Patents

Abstract

A surgical dressing for applying to an injured finger has electrical properties which permit the operation of a capacitive touch screen or pad. A selected outer surface of the dressing may be electrically conductive. An electrically conductive region may also be provided on the inner surface of the dressing and may be electrically connected to the conductive outer surface. The outer surface of the dressing may be formed from a fabric having electrically conductive filaments in its warp or weft. The dressing may be self adhesive or may be in the form of a tubular bandage.

Description

Finger Dressing

Field of the invention

The present invention relates to a surgical dressing, also known as a plaster or a bandage, for fitting to the tip of a digit.

Background of the invention

Adhesive dressings are commonly formed as rectangular self-adhesive strips with a sterile gauze covering the central region of each strip. Such dressings are well suited for application to a flat or cylindrical surface, such as around a digit.

An inconvenience experienced when applying such a dressing to a finger or thumb is that the thickness of the fabric or of the gauze is such that it prevents the finger tip from registering when using a capacitive touch screen.

Summary of the invention

According to the present invention, there is provided a surgical dressing for applying to an injured finger having electrical properties to permit a finger to which the dressing is applied to be used to operate a capacitance touch pad.

Preferably, a selected region proximate or on the outer surface of the dressing is electrically conductive.

To be able to operate a touch pad, the capacitor plate formed by the finger need not have very high, metal-like, conductivity. Indeed, the plate need have a conductivity no higher than that of a human body.

In a capacitance touch pad, a high frequency electrical is capacitatively coupled between two electrodes of the touch pad when a finger is placed on the tough pad, the finger acting as a plate of a coupling capacitor. As is well known, the capacitance value of a capacitor increases in proportion to the area of the plates and in inverse proportion to their separation. For this reason, the conductive region need not be on the surface and it could even be covered by an insulating film, provided only that the film thickness does not reduce the capacitance to such as level as to prevent the capacitative coupling between the electrodes.

Advantageously, the electrically conductive region of the outer surface has an area in excess of 5, 10, 15, 20 or 25 mm2.

Additionally, an electrically conductive region may be provided on the inner surface of the dressing and electrically connected to the conductive region on the outer surface of the dressing.

Advantageously, the outer surface of the dressing may be made of a fabric having electrically conductive filaments in its warp or its weft.

Alternatively, the electrically conductive region of the outer surface may be embroidered using an electrically conductive thread.

Preferably, the dressing is a self-adhesive dressing.

Alternatively, the dressing may be in the form of a tubular bandage.

Detailed description of the preferred embodiment(s) The appearance of the bandage according to the present invention may be identical to that of a conventional fingertip plaster or bandage. These vary between manufacturers and application.

Non-waterproof adhesive plasters for use in covering a cut or wound are typically made of a woven fabric strip having a self adhesive inner surface for adhering to the skin of a patient. Additionally they include a non-adhesive padded area for overlaying the wound to prevent removal of the plaster from pulling at or even tearing open the healed wound. After a desired period of time the plaster is removed by pulling against the adhesive sticking the plaster to the skin. In the case of a waterproof bandage, a plastics strip is used in place of a the woven fabric.

Alternative surgical dressings for digits are in the form of a tubular fabric. These may be used to secure a splint when nursing a broken finger. Such tubular bandages are applied by means of a tubular applicator over which the fresh bandage is stretched. The hollow interior of the applicator is placed over the relevant finger to the desired length. A loose end of the bandage is then allowed to contract directly on to the finger. The applicator is then separated from the digit allowing more of the length of the tubular bandage to contract around the finger until it is fully covered. Typically the applicator and hence the bandage is then twisted to seal the end of the finger inside the tubular bandage and then repositioned over the finger causing the bandage to be doubled over.

When either of the above dressing types are applied to a finger, it becomes impossible to operate a capacitive touch screen. This is due to the thickness of the fabric reducing the capacitative coupling, preventing the touch screen from detecting the presence of the fingertip.

The solution proposed by the present invention is to provide a conductive element, representative of the position of the fingertip close enough to the touch screen to act as a capacitor plate, so that the fingertip position remains detectable by the capacitive touch screen. This may be achieved by providing a large enough conductive element that the magnitude of the induced charge is sufficient for its detection by the touch screen, or by providing a conductive element in physical contact with the finger increasing the amount of charge that may be induced in what would otherwise be too small a conductive element.

Either of these solutions may be achieved by incorporating a suitable conductive element within the construction of the bandage.

In the case of a dressing comprising a fabric, it is proposed to incorporate a conductive thread into the weave of the fabric or gauze from which the bandage is made.

Such conductive threads exist and have similar physical properties to cotton. They would therefore not affect the overall physical properties of the bandage, and could potentially remain invisible to the user. An alternative construction could use a metal foil as an internal layer of the bandage though this may be more expensive and affect the mechanical properties of the bandage.

Best results are achieved when the conductive element is electrically coupled to the skin. This is achieved in the case of the non-adhesive tubular bandage described above, as by virtue of the twisting and doubling over of the bandage, the inner surface in contact with the skin of the finger is the same as the outer surface of the bandage that would engage the touch screen.

In the case of the self adhesive plaster it is possible for a conductive thread to be woven through the entire thickness of the fabric, joining the inner and outer surfaces of the plaster, or for a specific contact to engage with the conductive element present in (not necessarily woven in) the outer engaging surface of the plaster and the skin of the user.

This can be achieved by arranging the contact to overlap a portion of the adhesive of the plaster, securing the contact immediately adjacent the skin.

Another important consideration, highlighted previously, is that the conductive element need not be arranged at the outermost layer of the fabric. As noted above, the critical consideration is the separation of the conductive element from the touch screen.

The minimum separation is a function of the capacitance of the conductive element and the strength of the electric field within the touch screen that is inducing a charge within the conductive element. It is entirely possible for the outer surface of the plaster to be coated with a thin electrical insulator whilst still allowing a fingertip encased within a bandage according to the present invention, to be detectable by a capacitive touch screen.

Thus in the case of a waterproof self-adhesive dressing, an electrically conductive adhesive may be used both to adhere the dressing to the finger and to adhere a gauze to the plastics strip. The plastics strip may in this case be very thin, allowing the adhesive to act as a large area conductor in contact with the skin of the finger.

An alternative would be to metallise the side of the plastics strip to which the adhesive is applied instead of providing a conductive adhesive. The metallisation coating will in this case be capacitively coupled both to the skin and to the touchscreen.

Claims (9)

1. CLAIMS1. A surgical dressing for applying to an injured finger having electrical properties to permit a finger to which the dressing is applied to be used to operate a capacitance touch pad.
2. 2. A dressing as claimed in claim 1, wherein a selected region of the outer surface of the dressing is electrically conductive.
3. 3. A dressing as claimed in claim 2, wherein the electrically conductive region of the outer surface has an area in excess of 5, 10, 15, 20 or 25 mm2.
4. 4. A dressing as claimed in claim 2 or 3, wherein an electrically conductive region is provided on the inner surface of the dressing and is electrically connected to the conductive region on the outer surface of the dressing.
5. 5. A dressing as claimed in any preceding claim, wherein the outer surface of the dressing is made of a fabric having electrically conductive filaments in its warp or its weft
6. 6. A dressing as claimed in any of claims 2 to 5, wherein the electrically conductive region of the outer surface is embroidered using an electrically conductive thread.
7. 7. A dressing as claimed in any preceding claim wherein the dressing is a self-adhesive dressing.
8. 8. A dressing as claimed in any of claims 1 to 6, wherein the dressing is in the form of a tubular bandage.
9. 9. An adhesive bandage substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.