U.S. patent number 3,565,059 [Application Number 04/735,394] was granted by the patent office on 1971-02-23 for biological electrode and method of making same.
This patent grant is currently assigned to Hauser Research and Engineering Co., Boulder, CO. Invention is credited to Marlin S. Liles, Ray L. Hauser.
United States Patent |
3,565,059 |
|
February 23, 1971 |
BIOLOGICAL ELECTRODE AND METHOD OF MAKING SAME
Abstract
Electrode for application to the skin of the human anatomy for
use with electromedical devices, such as electrocardiograph
apparatus, which employs a normally dry electroconductive material,
which, when wetted with a solvent, has adhesive properties for
maintaining it firmly affixed to the skin. The electroconductive
material is also bonded to a lead wire, minimizing electrical
resistance between them in contradistinction to juncture contact
between metallic electrical conductors.
Inventors: |
Ray L. Hauser (Boulder, CO),
Marlin S. Liles (Boulder, CO) |
Assignee: |
Hauser Research and Engineering
Co., Boulder, CO (N/A)
|
Family
ID: |
24955600 |
Appl.
No.: |
04/735,394 |
Filed: |
June 7, 1968 |
Current U.S.
Class: |
600/391; 600/396;
445/35 |
Current CPC
Class: |
A61B
5/259 (20210101) |
Current International
Class: |
A61B
5/0408 (20060101); A61b 005/04 (); A61n 000/00 ();
H01i 009/00 () |
Field of
Search: |
;128/414--417,1.5,303.13--303.19,(PickupElectrod,404,419,419(P),419(D),(PickupDigest),2.06,172.1,418,410--413
;29/(Inquired),25.17 ;128/303.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Argyle; A. S. Aloe Company; 1831 Olive Street, St. Louis, Missouri;
page .
10.
|
Primary Examiner: Richard A. Gaudet
Assistant Examiner: J.B. Mitchell
Attorney, Agent or Firm: Sheridan, Ross & Burton
Claims
We claim:
1. In apparatus of the type for establishing an electrical
connection between electromedical apparatus and the skin of the
human anatomy, including an electrode adapted to be attached to the
skin at a desired position thereon, and a lead wire extending
between the electrode and the electromedical apparatus, the
improvements wherein said electrode comprises: a. a flexible
sheetlike base member having a body face and an exposed face; b. an
uninsulated wire terminal portion having structural securement to
the base member and having at least one leg portion disposed
contiguous with the body face; c. a layer of normally dry
electroconductive adhesive embedding said leg portion therein and
bonding same to said body side; and d. said adhesive being of a
type adapted to be wetted with a liquid solvent to render its
exposed surface semiliquid and sticky, whereby it will adhere to
the skin.
2. Apparatus in accordance with claim 1 wherein said terminal
portion comprises a first portion extending through the base member
from the exposed side to the body side, the leg portion aforesaid
forming a continuation thereof, and another continuing portion
extending from an end of the leg portion through the base member to
the exposed face and therealong, thus forming said structural
securement.
3. Apparatus in accordance with claim 2, including a sheetlike
electrical insulating member adhesively secured to said exposed
face and over the uninsulated wire lying adjacent thereof.
4. Apparatus in accordance with claim 3, including a plurality of
electrodes, the electrical insulating members on the various
electrodes being suitably coded to visually distinguish
therebetween.
5. Apparatus in accordance with claim 4, wherein the exposed faces
of said insulating members are of different color.
6. Apparatus in accordance with claim 1, including a plurality of
series connected leg portions disposed contiguous with said body
face.
7. Apparatus in accordance with claim 1, wherein said uninsulated
wire terminal portion is an integral part of an insulated lead wire
extending between the electrode and electromedical apparatus, thus
forming a continuous electrical conductor, without junctures,
between the electroconductive adhesive and the electromedical
apparatus.
8. Apparatus in accordance with claim 7, wherein the terminal end
of the uninsulated wire is twisted about the lead wire.
9. The method of making an electrode for use in transmitting an
electrical signal between the skin of the human anatomy and
electromedical apparatus, comprising the steps of: a. forming a
base member from flexible sheet material to a desired flat shape,
thus providing a body face and an opposite exposed face; b. forming
at least two spaced apertures through the base member; c. threading
an uninsulated wire through one of the apertures from the exposed
face to the body face, thence therealong to another aperture, and
therethrough back to the exposed face, and thence therealong, to
thus provide a leg portion contiguous with the body face,
structurally secured to the base member; d. coating said leg
portion and said body face with a sheetlike coating of liquid
electroconductive adhesive of a type adapted to dry but again
become adhesive when wetted with a solvent, thus embedding the leg
portion in the adhesive; and e. drying the adhesive, forming a
dried bond between same and the wire and also a bond to the base
member.
10. The method of claim 9 including the further steps of threading
the wire through the base member, alternately from one face to the
other, to provide a plurality of leg portions contiguous with the
body side.
11. The method of claim 9 including the further step of twisting
the terminal end of the wire about an intermediate portion thereof.
Description
In the prior medical art it has been well known practice to attach
electrodes to the skin to provide contact and through which
electrical signals are transmitted between the anatomy and
electromedical apparatus. U.S. Pat. to Baum, No. 3,187,745 and
Berman, No. 3,085,577 are exemplary of such electrodes, employed in
the art of electrocardiography wherein electrical heart signals are
received, and the U.S. Pat. to Alderman, No. 2,872,926, is
exemplary of an electrode employed in the art of
electroencephalography wherein electrical brain signals are
received. The signals, in either event, are suitably recorded or
charted and are a measure of a body function or functions under
known conditions, such as rest, exercise, mental stress, intensive
care, and the like. Also, with the advent of space travel and radio
monitoring, or with the use of small portable electromedical
recording devices, it is now possible to biologically monitor body
functions of pilots under conditions encountered in fulfilling
their missions. The importance of maintaining a low resistance
contact with the anatomy is well recognized and the patents
referred to are exemplary of obtaining the desired results by
utilizing electroconductive pastes through which an electric signal
is transmitted. The U.S. Pat. to Howell, No. 2,943,628 is exemplary
of another approach wherein contact is made with metal foil
surrounded by a pressure sensitive adhesive.
As the relatively recent art referred to has advanced, certain
improvements appear desirable, including the need for more rapid
and expedient application of the electrodes, simplification of
their construction, together with its attendant reduction of cost,
and elimination of protective coverings or the like previously
employed with pressure sensitive adhesives or similar protective
coverings for conductive pastes. Additionally, a light weight
electrode is desirable to minimize or obviate inertial movement
relative to a predetermined position on the skin. The principal
objective of this invention is to fulfill such needs.
An uninsulated leg portion of an insulated lead wire is
structurally connected to a flexible base member on its body facing
side and coated with electroconductive adhesive, the adhesive
embedding such portion and also bonding it to the base member. The
opposite or exposed side of the base member may be provided with a
color or otherwise coded insulating member, covering other
uninsulated portions of the wire. When wetted with a solvent, the
normally dry adhesive becomes sticky and will adhere to the skin.
When it is desired to remove the electrode assembly, the base
member may be engaged by human fingers or forceps and peeled from
the skin, a solvent again being applied, if adhesion is unduly
severe.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 depicts the general manner in which an electrocardiograph is
recorded:
FIG. 2 is a side elevation, or exposed face, of the subject of the
invention, an element being omitted;
FIG. 3 is a reverse side elevation, or body face, of FIG. 1, other
elements being omitted;
FIG. 4 is a central cross section through FIG. 2 and 3, showing the
omitted elements in exploded relationship;
FIG. 5 is an elevation, like FIG. 2, showing an omitted element
superimposed thereon; and
FIG. 6 is an elevation, like FIG. 3, showing other omitted elements
superimposed thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, FIG. 1 depicts the well-known manner
of recording a chart 10 on electrocardiograph apparatus (not
shown), the apparatus being connected to a subject 12, by insulated
lead wires 14, terminating in electrodes 16 affixed to desired
points on the skin of the subject.
Referring now to FIGS. 2 to 6, the construction of each electrode
can best be described by the manner in which it is fabricated.
Starting with FIG. 2, a suitable length of insulation is stripped
from a lead wire 14 and its end threaded through aperture 18,
extending through disc 20, thence in sequence through like
apertures 22, 24, 26, its end terminating in a twist 28 around the
standing part of the lead wire. As will be apparent from FIGS. 2
and 3, this now provides a pair of parallel spaced series connected
uninsulated wire portions or legs 30 disposed adjacent the face of
the disc which is to be in contact with the subject, an uninsulated
connecting portion 32 adjacent the opposite or exposed face of the
disc, and another uninsulated portion 34 adjacent the exposed
face.
The uninsulated portions 32, 34 may be covered with an insulating
disc 36, FIGS. 4 and 5, having an adhesive on one face of same,
such disc being particularly desirable when these uninsulated
portions might contact clothing of the subject and produce
erroneous signals. Discs 36 of the various electrodes are
preferably colored on their exposed surfaces, or otherwise coded,
so that they may be applied to predetermined portions of the skin
in order that chart 10 may be interpreted in accordance with the
various signal sources. To attain this end, the remote ends of the
conductors terminate at a multiple connector jack or plug 38, which
connects with the circuitry of the electromedical apparatus in a
predetermined manner.
Referring now to FIGS. 4 and 6, the body face of disc 20 is coated
with an electroconductive adhesive 40 over an area sufficient to
cover and embed at least the exposed portions 30 of the wire. If so
desired, the surrounding area may be coated with an adhesive 42 of
the same type to obtain a larger bonding area. Adhesives 40, 42 are
preferably of a type which may be softened with readily available
solvents, such as water or alcohol, when it is desired to remove
the electrodes from the skin. It is not essential, however, that
adhesive portion 42 be electroconductive since its principal
function is to improve bonding to the skin rather than to transmit
an electrical signal through it.
Discs 20 may be constructed from any suitable flexible material
which will conform to the shape of the skin area to be covered, a
paper, cloth or wire fabric material, being exemplary. It is
preferably porous to obtain a strong structural bond with the
applied adhesive. In one manner of fabrication, the entire disc may
be coated with a liquid adhesive and allowed to dry to thus provide
both faces with calenderlike surfaces. As previously referred to,
this need not be an electroconductive material. The uninsulated end
of the lead wire is then threaded through the various apertures, or
stapled or soldered or otherwise attached and terminated to provide
structural securement with the disc. Uninsulated portions 30 are
then coated with an electroconductive adhesive embedding them
within the adhesive which also bonds them to the disc, the adhesive
then being allowed to dry, in which process its volatile solvent or
solvents evaporate. Either prior or subsequent to this step, gummed
insulating disc 36 is applied to the exposed face, thus insulating
portions 32, 34.
As will now be apparent, the adhesive of principal importance is
adhesive 40. This must have the characteristics of flexibility,
electroconductivity, and strong adhesive affixity to the human skin
when wetted with a solvent, as previously referred to, which may be
applied with a sponge or the like, or the human tongue if water is
the solvent.
Insulating disc 36 may be cut from conventional insulating paper,
gum coated on one side and rewettable and having a colored opposite
side. Rather than being colored, as just described, other coding
may be employed.
An exemplary adhesive 40 comprises the following formulation
proportions: Polyvinylpyrollidone (Plasdone) 7.50 gr. Camphor 0.75
gr. Ethanol 8.00 gr. Ether 6.00 gr. 12 percent Silvered
polyethylene 15.00 gr.
Another example is: Polyvinylpyrollidone (Plasdone) 7.5 gr.
Dimethylphthalate 0.75 gr. Water 10.00 gr. 12 percent Silvered
Polyethylene 10.00 gr.
Other examples of electroconductive materials include various
plastic micro spheres coated with metals and forming inclusions in
the adhesive to provide electrical conductive paths through their
points of contact. A further example is disclosed in my copending
application for Low Density Electrically Conductive Particulate
Material, Ser. No. 639,530, filed May 18, 1967. In view of the
various examples referred to, it is now believed apparent that the
inventive concept is not dependent upon a specific
electroconductive inclusion or material, but rather, upon the
general characteristics as hereinbefore set forth.
Obviously many modifications and variations of the present
invention are possible in the light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims the invention may be practiced otherwise than as
specifically described.
* * * * *