IES68343B2 - An electrode - Google Patents

Abstract

An electrode (10) comprises a substrate (13) having an obverse (8) and a reverse face (9) and incorporates two spaced apart electrical contacts (15). An electrically conductive layer (14) has an obverse and a reverse face. The obverse face of the layer is applied to the reverse face of the substrate thereby providing a first electrical impendence through said layer between the electrical contacts. The reverse face of said layer is, in use, applied to the skin of a patient providing a second lower impedence between the electrical contacts.

Description

An Electrode The present invention relates to an electrode. In particular, the invention relates to an electrode which is, in use, applied to a patient's skin and through which trans-epidermal muscle stimulation can be administered.

According to the present invention there is provided an electrode comprising a substrate having an obverse and a reverse face and incorporating two spaced apart electrical contacts, and an electrically conductive layer having an obverse and a reverse face, the obverse face of said layer being applied to the reverse face of the substrate thereby providing a first electrical impedence through said layer between the electrical contacts, and the reverse face of said layer, in use, being applied to the skin of a patient providing a second lower impedence between the electrical contacts.

Preferably, said electrical contacts comprise a male part located on the reverse face of the substrate which passes through said substrate and a cooperable female part located on the obverse face of the substrate and electrically connectible to said male part. Ί Preferably, said second layer is a hydrogel layer.

* A method of manufacturing an electrode including the -steps Of: applying a substrate, incorporating a plurality of spaced apart electrical contacts, to an electrically conductive layer, to electrically connect said conductive layer to said contacts, said conductive S68343 4 layer being removably adhered to a carrier layer, and t . punching said substrate and conductive layers to define a plurality of electrodes removably adhered to said ,4 carrier layer and each including a pair of said electrical contacts.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of an electrode according to the invention; Figure 2 is a cross-sectional view of the electrode 15 through the line II-II in Figure 1 of the drawings; Figure 3 is a more detailed cross-sectional view of the electrode of Figure 2; Figure 4 illustrates a plurality of electrodes according to .the invention in use; and Figure 5 is a schematic illustration of a fabrication process for electrodes according to the invention.

Referring now to the drawings wherein similar numerals have been used to indicate like parts, there is shown an electrode generally indicated at 10 according ϋ to the invention. The electrode 10 comprises a ' curvaceous figure-of-eight shaped body having ends 11 separated by a narrowed waist portion 12. The electrode 10 includes a substrate of electrically insulating backing material 13 having an obverse face 8 and a reverse face 9 to which a continuous hydrogel layer 14 is applied as will be described later, Figure 3.

A hole (not shown) is formed in each end 11 of the backing material 13. The electrode 10 includes two electrical contacts each comprising a standard dot snapper 15, formed of inter-engageable female and male parts 16 and 17 respectively. Each male part 17 comprises a circular base 18, having a diameter greater than the diameter of the holes formed in the backing material 13, and a stud 19 projecting from the base 18, having a diameter approximately equal to the diameter of the holes formed in the backing material 13. Each female part comprises an annular base 20, approximately equal in diameter to the base 18, and a narrower cylindrical socket 21 located over the centre of the base 20. Thus, part of the backing material 13 is sandwiched between the base 18 located on the reverse face 9 and the base 20 located on the obverse face 8.

The stud 19 is inserted from the reverse face 9 of the backing material 13 into the socket 21 of the female part 16, thus fixing the snapper or contact 15 in place on the backing material 13. The hydrogel layer 14 is applied to the reverse face 9 of the backing material 13. Electrical signals applied through one of the contacts 15 from a muscle stimulator apparatus (not shown) travel a relatively short distance through the hydrogel layer 14 into a patients skin in comparison to the distance along the hydrogel layer 14 towards the other contact 15.

The equivalent impedence between the contacts 15 through the patients skin is lower than the impedence of the hydrogel layer 14 between the contacts. Thus, the continuous hydrogel layer 14 does not present a short-circuit between the two contacts 15.

The electrode according to the invention is particularly useful in the application of f trans-epidermal muscle stimulation to a patients facial muscles, as shown by some of the possible in-use positions of the electrode in Figure 4.

The electrodes can be fabricated in a continuous process as shown in Figure 5. Hydrogel 14 is supplied to the process in a continuous layer sandwiched between an upper and lower acetate sheet 22, 23 respectively. The upper sheet 22 is removed during the first stage before the exposed hydrogel layer 14 is fed into a second stage. In the second stage, the layer of backing material 13, pre-populated with a plurality of contacts 15, is applied to the exposed surface of the hydrogel layer 14. The continuous sheet is then fed to a third stage where a punch 24 is used to cut the figure-of-eight shaped outline for a plurality of electrodes 10 from the backing material and hydrogel layer 13, 14. The punch 24 does not penetrate the lower sheet 23 so that the sheet 23 can be drawn through the process while carrying the electrodes 10-1, 10-2, 10-3 etc.

In the fourth stage, waste material 25, which should preferably form a continuous sheet of backing material and hydrogel, is removed from the sheet 23 containing the now discrete electrodes. The electrodes 10 can then be divided up and packed for shipping as required.

It will be seen that the backing material 14 can be * pre-populated in such a pattern and the punch 24 so shaped that a minimum of waste material is produced. * Use of a continuous layer of hydrogel thus simplifies the fabrication of the electrodes 10, as well as providing greater adhesion between the patients face Ί and the electrode than if discrete small area electrical contacts are used. It will be seen that while the hydrogel layer 14 in the area of the waist 12 provides the greater adhesion to the patients face, the narrowed waist also increases the resistance of the hydrogel layer 14 between the contacts 15.

It will be seen that in more complex variations of the embodiment, the electrode may include more than two contacts. It will also be seen that variations of the contact 15 are possible. The contact could be fabricated from a single piece, which when pushed through the backing material 13 momentarily stretches the material before allowing the material to flex back to normal and retain the contact within the material 13. The contact does not need to be fabricated entirely from metal, rather it could, for example, be fabricated from metal coated plastic which has the advantage of being lighter than an all metal contact.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

CLAIMS: e

1. An electrode comprising a substrate having an obverse arid a reverse face and incorporating two spaced & apart electrical contacts, and an electrically conductive layer having an obverse and a reverse face, the obverse face of said layer being applied to the reverse face of the substrate thereby providing a first electrical impedence through said layer between the electrical contacts, and the reverse face of said layer, in use, being applied to the skin of a patient providing a second lower impedence between the electrical contacts.

2. An electrode as claimed in Claim 1 wherein said electrical contacts comprise a male part located on the reverse face of the substrate which passes through said substrate and a cooperable female part located on the obverse face of the substrate and electrically connectible to said male part.

3. An electrode as claimed in Claim 1 or 2 said second layer is a hydrogel layer.

4. An electrode substantially as hereinbefore described with reference to the accompanying drawings.

5. A method of manufacturing an electrode including the steps of: applying a substrate, incorporating a plurality of spaced apart electrical contacts, to an electrically conductive layer, to electrically connect said conductive layer to said contacts, said conductive layer being removably adhered to a carrier layer, and * punching said substrate and conductive layers to define a plurality of electrodes removably adhered to said carrier layer and each including a pair of said electrical contacts.