Patent ID: 12201428

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described in detail below based on the drawings. Here,FIG.1(a),FIG.1(b), andFIG.1(c)are a plan view, a front view, and a bottom view schematically showing one embodiment of a biomedical electrode pad of the present invention.FIG.2is an exploded perspective view showing the configuration of the biomedical electrode pad of the embodiment along with the configuration of one embodiment of a biological signal processing device of the present invention that is combined with the biomedical electrode pad.FIG.3(a)andFIG.3(b)are plan views respectively showing an attachment sheet and a cover sheet of the biomedical electrode pad of the embodiment.FIG.4(a)andFIG.4(b)are a plan view and a bottom view showing an electrode sheet of the biomedical electrode pad of the embodiment.

The biomedical electrode pad of this embodiment is attached to the skin of a subject as a living body and used to detect electrocardiographic signals as biological electrical signals from the skin. This biomedical electrode pad includes: a resin attachment sheet1of a substantially elliptical shape bulging toward both sides at a central part that is elastically stretchable, contractible, and bendable, has an electrically insulating property, and has, on a back surface side, an adhesive surface suitable to be attached to the skin of a living body; an indifferent electrode2that is located at the central part on the back surface side of the attachment sheet1and exposed on the back surface side; two detecting electrodes3that are located at each end on the back surface side of the attachment sheet1, side by side with the indifferent electrode2on the same straight line, and exposed on the back surface side; two connecting parts4and two connecting parts5making pairs in intersecting directions, with the indifferent electrode2interposed between each pair of connecting parts, that are located at the central part on the back surface side of the attachment sheet1, near the indifferent electrode2, and covered with electrical insulation while being exposed toward the front surface side through openings1aof the attachment sheet1; and four electrode connecting wires6,7making two pairs that are located on the back surface side of the attachment sheet1and covered with electrical insulation, and that each electrically connect one of the indifferent electrode2and the two detecting electrodes3to one of the four connecting parts4,5making two pairs. The indifferent electrode2and the two detecting electrodes3are provided on the back surface side of the attachment sheet1as a plurality of electrodes that are located apart from one another. The electrode connecting wires6between the indifferent electrode2and the two connecting parts4extend in a straight line by obliquely crossing the central part on the back surface side of the attachment sheet1. The electrode connecting wires7between each of the two detecting electrodes3and the corresponding ones of the two connecting parts5are longer than the electrode connecting wires6, and extend by bending in a bellows shape along a back surface of the attachment sheet1in such a manner as to be stretchable and contractible as well as bendable in a direction perpendicular to the plane of the attachment sheet1.

Here, the indifferent electrode2and the two detecting electrodes3are formed by conductive layers on a back surface of a resin layer8that is elastically stretchable, contractible, and bendable and has an electrically insulating property. The four connecting parts4,5making two pairs and the four electrode connecting wires6,7making two pairs are each formed by a conductive layer on a front surface of the resin layer8. The indifferent electrode2is connected to the two connecting parts4by the two straight electrode connecting wires6that obliquely cross the central part on the back surface side of the attachment sheet1, a circular wire at the center that connects these electrode connecting wires6to each other, and a plurality of via-hole conductors (not shown) that are provided in this circular wire and extend through the resin layer8. The two detecting electrodes3are connected to the two connecting parts5by the two electrode connecting wires7and a plurality of via-hole conductors (not shown) that are provided at a leading end of each electrode connecting wire7and extend through the resin layer8. These components constitute an electrode sheet9.

The resin layer8may be formed by, for example, a polyimide sheet, and the conductive layers constituting the indifferent electrode2and the two detecting electrodes3on a back side of the resin layer8, and the conductive layers constituting the four connecting parts4,5making two pairs and the four electrode connecting wires6,7making two pairs on a front side of the resin layer8may be each formed by, for example, carbon printing, copper plating, copper foil application, silver plating, or silver foil application. Alternatively, the resin layer8may be formed by, for example, a polyethylene terephthalate (PET) film, and the conductive layers constituting the four connecting parts4,5making two pairs and the four electrode connecting wires6,7making two pairs on the front side of the resin layer8may be each formed by, for example, carbon printing, copper plating, or copper foil application, while the conductive layers constituting the indifferent electrode2and the two detecting electrodes3on the back side of the resin layer8may be formed by, for example, silver plating or silver oxide plating that makes these electrodes less prone to oxidation on contact with the skin.

In the biomedical electrode pad of this embodiment, the electrode sheet9is disposed on the adhesive surface of the back surface of the attachment sheet1, with a front surface side of the electrode sheet9facing the back surface of the attachment sheet1. Further, a cover sheet10is stuck on the adhesive surface of the attachment sheet1over the electrode sheet9, and the connecting parts4,5and the electrode connecting wires6,7are fixed to the attachment sheet1while being covered with the cover sheet10. The cover sheet10has smaller outside dimensions than the attachment sheet1such that the adhesive surface at a peripheral portion of the attachment sheet1is exposed, and has circular openings10athrough which the indifferent electrode2and the detecting electrodes3are respectively exposed.

In the biomedical electrode pad of this embodiment, the two detecting electrodes3are each provided with radial incisions to help them deform along the skin. A circular conductive gel sheet11larger than each of the indifferent electrode2, the two detecting electrodes3, and the openings10aof the cover sheet10through which these electrodes are exposed is disposed as a layer on each of the indifferent electrode2and the detecting electrodes3over the cover sheet10, and thus the indifferent electrode2and the detecting electrodes3are each covered with a conductive gel of the conductive gel sheet11.

Further, in the biomedical electrode pad of this embodiment, protrusions at four corners of a lower surface of a lower casing part21constituting a part of a casing20are positioned and adhesively fixed to the front surface side of the attachment sheet1, at positions corresponding to the four connecting parts4,5of the electrode sheet9, such that three through-holes21aof the lower casing part21respectively face three of the four openings1athrough which the four connecting parts4,5are respectively partially exposed toward the front side of the attachment sheet1. There is a gap left between the lower surface of the lower casing part21and the front surface of the attachment sheet1, except for the protrusions at the four corners that are bonded to the front surface of the attachment sheet1, to facilitate release of perspiration having been produced from the skin of a subject and passed through the attachment sheet1.

The casing20constitutes a part of the biological signal processing device of the embodiment, and the biological signal processing device of the embodiment is combined with the biomedical electrode pad of the embodiment to constitute a Holter electrocardiograph.

FIG.5is an exploded perspective view showing the configuration of the biological signal processing device of the embodiment, in a state where the lower casing part21of the biological signal processing device is anchored to the front surface side of the attachment sheet1of the biomedical electrode pad of the embodiment.FIG.6(a),FIG.6(b), andFIG.6(c)are a plan view, a front view, and a bottom view showing the lower casing part21constituting a part of the casing20of the biological signal processing device of the embodiment.FIG.7(a),FIG.7(b), andFIG.7(c)are a plan view, a front view, and a bottom view showing an upper casing part22constituting the casing20along with the lower casing part21.

As shown inFIGS.6(a) to (c), the lower casing part21has a substantially square trapezoidal shape with a circular depressed portion21bat a central part. The through-holes21aextending through the lower casing part21in an up-down direction are formed at three of the protrusions at the four corners surrounding the depressed portion21b, and an electrode plate (not shown) for connecting to a battery to be described later is provided at the other protrusion. A stepped portion21cextending along the entire circumference is formed around the lower casing part21, and a seal ring23made of an elastic material is fitted on the stepped portion21cas shown inFIG.2andFIG.5.

As shown inFIGS.7(a) to (c), the upper casing part22has a shape of a substantially square lid that is concave on a lower side. An inner circumferential surface of a lower portion of the upper casing part22is engaged with a lower portion of the lower casing part21including the stepped portion21cto form the casing20. The seal ring23is squeezed between the upper casing part22and the lower casing part21, and an inside of the casing20is liquid-tightly sealed by the seal ring23.

As shown inFIG.2andFIG.5, a biological signal processing circuit board24and a battery25of, for example, button type are housed inside the casing20. The biological signal processing circuit board24is a microcomputer composed of a substantially square printed wiring board and electronic components mounted thereon including IC chips and the like, such as a central processing unit (CPU), a memory, and an input-output circuit. The biological signal processing circuit board24acts as a Holter electrocardiograph based on a given program, and records electrocardiographic signals input from the indifferent electrode2and the detecting electrodes3by repeatedly rewriting them, for example, continuously for 24 hours or at few-hour intervals, while continuously analyzing the waveforms of these electrocardiographic signals. When a specific waveform occurs in the electrocardiographic signals, the biological signal processing circuit board24outputs an electrocardiogram of the electrocardiographic signals recorded for a certain period of time including that waveform, along with the time of recording, for example, by wirelessly transmitting it or recording it on a removable recording medium, such as a memory card, in order to notify of the occurrence. The battery25is disposed inside the casing20in a removable manner, and supplies the biological signal processing circuit board24with electricity that at least makes the above operation possible.

Here, to establish electrical connection between the input-output circuit of the microcomputer and the connecting parts5that are connected to the indifferent electrode2and the two detecting electrodes3through the electrode connecting wires6,7, three contact pins24aare provided so as to protrude on a lower surface of the biological signal processing circuit board24, respectively at three of the four corners thereof, as connecting members that extend through the lower casing part21and the central part of the attachment sheet1and are electrically connected to at least either the biological signal processing circuit board24or the connecting parts5in a separable manner. These three contact pins24aare respectively inserted in an extractable manner into the three through-holes21aextending through the lower casing part21in the up-down direction and pass through the openings1aof the attachment sheet1to come into contact with three of the four connecting parts5.

Of the three contact pins24a, the two contact pins24athat are located at the corners on a diagonal line of the biological signal processing circuit board24are electrically connected to the two connecting parts5that are connected to the two detecting electrodes3, while the one contact pin24alocated at another corner is electrically connected to one of the two connecting parts5that are connected to the indifferent electrode2.

The reason why two connecting parts5connected to one indifferent electrode2are provided is as follows: If the two through-holes21aon a diagonal line of the lower casing part21face the two connecting parts5connected to the two detecting electrodes3at the time of adhesively fixing the lower casing part21to the attachment sheet1, even when the lower casing part21is turned 180 degrees, the other through-hole21afaces one of the two connecting parts5connected to the indifferent electrode2. Therefore, housing the biological signal processing circuit board24into the casing20in such a direction that the three contact pins24aenter the three through-holes21aof the lower casing part21can reliably connect these three contact pins24arespectively to the predetermined connecting parts5.

In the biomedical electrode pad of the embodiment, when the attachment sheet1is stuck on and attached to an electrocardiographic signal detecting position in the skin of a subject through the adhesive surface on the back surface side of the attachment sheet1, the one indifferent electrode2that is located at the central part on the back surface side of the attachment sheet1and exposed on the back surface side, and the two detecting electrodes3that are located at each end of the attachment sheet1and exposed on the back surface side detect electrocardiographic signals from the skin of the subject. These electrocardiographic signals are transmitted by the electrode connecting wires6,7that are located on the back surface side of the attachment sheet1and covered with electrical insulation to the four connecting parts4,5making two pairs that are located at the central part on the back surface side of the attachment sheet1, near the indifferent electrode2, and covered with electrical insulation, and are then output toward the front surface side of the attachment sheet1by those portions of the connecting parts4,5that are exposed through the openings1aof the attachment sheet1.

Since the attachment sheet1of the biomedical electrode pad of the above embodiment is elastically stretchable, contractible, and bendable and has an electrically insulating property, the attachment sheet1remains in close contact with the skin by stretching, contracting, and/or bending so as to follow changes in shape of the limb due to body movement. Moreover, since the electrode connecting wires7between each of the two detecting electrodes3and the corresponding ones of the two connecting parts5extend by bending in a bellows shape in a stretchable, contractible, and bendable manner, the electrode connecting wires are less likely to break by undergoing excessive local deformation when the attachment sheet1stretches, contracts, and/or bends so as to follow changes in shape of the limb due to body movement.

Therefore, even when the attachment sheet1is expanded compared with the conventional one to broaden the range of detecting electrocardiographic signals, the biomedical electrode pad of the embodiment can continuously detect electrocardiographic signals from the skin by the indifferent electrode2and the detecting electrodes3for a long period of time, regardless of changes in shape of the limb due to body movement.

In the biological signal processing device of the above embodiment, when the elastically stretchable and contractible attachment sheet1of the biomedical electrode pad is attached to an electrocardiographic signal detecting position in the skin of a subject through the adhesive surface on the back surface side of the attachment sheet1, the biological signal processing circuit board24housed inside the casing20fixed at the central part on the front surface side of the attachment sheet1is electrically connected to each of the indifferent electrode2and the two detecting electrodes3provided on the back surface side of the biomedical electrode pad through the connecting pins24aextending through the casing20and the central part of the attachment sheet1and the electrode connecting wires6,7on the electrode sheet9. By being supplied with electricity from the battery25that is also housed inside the casing20, the biological signal processing circuit board24performs the process of analyzing and recording the electrocardiographic signals detected from the skin of the subject by the indifferent electrode2and the detecting electrodes3, and outputs the processing result to the outside by at least either recording it on a recording medium, such as a memory card, or wirelessly transmitting it.

Thus, in the biological signal processing device of the embodiment, the biological signal processing circuit board24is housed inside the casing20fixed to the front surface side of the elastically stretchable and contractible attachment sheet1of the biomedical electrode pad, supplied with electricity from the battery25, and electrically connected to each of the indifferent electrode2and the two detecting electrodes3on the back surface side of the attachment sheet1through the connecting pins24aextending through the casing20and the central part of the attachment sheet1, and through the connecting parts5and the electrode connecting wires6,7on the back surface side of the attachment sheet1. Since wires connecting the biological signal processing circuit board and the biomedical electrode pad to each other are not exposed to the outside, the biomedical electrode pad is unlikely to come easily off the skin due to body movement, such as movement of the arm or twisting of the body, and therefore can continuously detect electrocardiographic signals from the skin by the indifferent electrode2and the detecting electrodes3for a long period of time, regardless of changes in shape of the limb due to body movement.

The combination of the biomedical electrode pad of the embodiment and the biological signal processing device of the embodiment, despite using the biomedical electrode pad of which the attachment sheet1is expanded compared with the conventional one to broaden the range of detecting electrocardiographic signals, can continuously detect electrocardiographic signals from the skin by the indifferent electrode2and the detecting electrodes3for a long period of time, regardless of changes in shape of the limb due to body movement, by effectively preventing the biomedical electrode pad from coming off the skin.

Moreover, in the biomedical electrode pad of the embodiment, the conductive gel sheet11is disposed as a layer on each of the indifferent electrode2and the two detecting electrodes3. Thus, the electrical resistance between the electrodes2,3and the skin can be reduced by the conductive gel sheet11to raise the electrocardiographic signal detection level. In the biomedical electrode pad of this embodiment, either each of the indifferent electrode2and the detecting electrodes3or the conductive gel sheets11may be disposed on the skin side so as to come into contact with the skin.

Furthermore, in the biomedical electrode pad of this embodiment, the cover sheet10is stuck on the back surface side of the attachment sheet1, and the electrode connecting wires6,7and the connecting parts5are fixed to the attachment sheet1by being covered with the cover sheet10. The cover sheet10has smaller dimensions than the attachment sheet1such that the adhesive surface at the peripheral portion of the attachment sheet1is exposed, and has the openings10athrough which the indifferent electrode2and the two detecting electrodes3are respectively entirely exposed. Thus, the electrode connecting wires6,7and the connecting parts5can be easily covered with electrical insulation. At the same time, the electrode connecting wires6,7and the connecting parts5can be easily prevented from coming off or shifting over the attachment sheet1regardless of the attachment sheet1stretching and contracting according to changes in shape of the limb due to body movement.

In the biological signal processing device of the embodiment, the biological signal processing circuit board24has the contact pins24athat are erected on the lower surface of the biological signal processing circuit board24and extend through the casing20and the central part of the attachment sheet1in an insertable and extractable manner to electrically come into contact with the connecting parts5. Thus, the battery25and a recording medium can be easily replaced by attaching and detaching the biological signal processing circuit board24to and from the casing20.

In the biological signal processing device of the above embodiment, as shown at an upper part and a lower part ofFIG.10(a), the casing20has the lower casing part21that is fixed to the attachment sheet1and the upper casing part22that is mounted to the lower casing part21in a detachable manner, and the lower casing part21and the upper casing part22house the biological signal processing circuit board24. Alternatively, as shown at an upper part and a lower part ofFIG.10(b), the casing20of the biological signal processing device of the present invention may have a mounting holder26that is fixed to the attachment sheet1, and a casing main body27that houses the biological signal processing circuit board24and is mounted to the mounting holder26in a detachable manner, or, as shown at an upper part and a lower part ofFIG.10(c), the casing20may have a mounting holder28that is fixed to the attachment sheet1, a casing main body30that houses the biological signal processing circuit board24, and a casing cover29that covers the casing main body30and is mounted to the mounting holder28in a detachable manner.

FIG.11(a),FIG.11(b), andFIG.11(c)are views partially illustrating, as examples, three other types of configuration of the electrode connecting wires6,7of the biomedical electrode pad of the above embodiment. The electrode connecting wire ofFIG.11(a)employs a large number of linear fibrous conductors30, formed by copper wires or the like, that intersect one another and are electrically connected to one another at intersections by welding or the like to form a mesh. The electrode connecting wire ofFIG.11(b)employs a large number of ring-shaped fibrous conductors30, formed by copper wires or the like, that are combined with one another and electrically connected to one another at contact points by welding or the like to form a chain. The electrode connecting wire ofFIG.11(c)employs a large number of wavy fibrous conductors30, formed by copper wires or the like, that are coupled to one another by a large number of linear fibrous conductors30, also formed by copper wires or the like, and electrically connected to one another at coupling points to form a cloth, such as a woven cloth or a non-woven cloth. Electrode connecting wires of one of these types extend in a stretchable, contractible, and bendable manner as the electrode connecting wires6between the indifferent electrode2and the two connecting parts4and/or the electrode connecting wires7between the two detecting electrodes3and the two connecting parts5.

While the present invention has been described above based on the examples shown in the drawings, the present invention is not limited to these examples but can be changed as necessary within the scope of the description of the claims. For example, in the biomedical electrode pad of the present invention, only the two detecting electrodes at both ends may be provided by omitting the indifferent electrode, or the number of the detecting electrodes may be increased to three or more, and in that case, the indifferent electrode at the central part may be changed to a detecting electrode. The plurality of electrodes need not be disposed side by side on the same straight line. Further, at least either the electrode connecting wires6or7may be wires formed by, for example, a flake-shaped conductor made of a conductive rubber-like elastic material obtained by diffusing fibrous conductors, such as carbon nanotubes (CNTs), inside a rubber-like base material, instead of the examples shown inFIG.4orFIG.11(a)toFIG.11(c). The biomedical electrode pad of the present invention can also be used to detect myoelectric signals instead of or in addition to electrocardiographic signals. The biomedical electrode pad of the present invention may be connected to an ordinary biological signal processing device through a lead instead of being combined with the biological signal processing device of the present invention.

In the biological signal processing device of the present invention, for example, the connecting members may extend through and be fixed to the casing and the attachment sheet, and lower end portions of the connecting members may be always in contact with the connecting parts while upper end portions thereof may be in contact with a circuit pattern of the biological signal processing circuit board in a separable manner. The biological signal processing device of the present invention may be equipped with an IC chip constituting a wireless communication circuit based on standards of wireless LAN, such as Wi-Fi, and may transmit biological signals input from the biomedical electrode pad to an external transmission device through this wireless communication circuit, and a computer connected to this external communication device may perform processing including recording and analyzing the biological signals. The casing of the biological signal processing device of the present invention may be fixed to an attachment sheet of an ordinary biomedical electrode pad instead of being fixed to the attachment sheet of the biomedical electrode pad of the present invention.

INDUSTRIAL APPLICABILITY

As has been described above, even when the attachment sheet is expanded compared with the conventional one to broaden the range of detecting biological signals, the biomedical electrode pad of the present invention can continuously detect biological signals from the skin by the plurality of electrodes for a long period of time, regardless of changes in shape of the limb due to body movement.

In the biological signal processing device of the present invention, since the wires connecting the biological signal processing circuit board and the biomedical electrode pad to each other are not exposed to the outside, the biomedical electrode pad is unlikely to come easily off the skin due to body movement, such as movement of the arm or twisting of the body, and therefore can continuously detect biological signals from the skin by the plurality of electrodes for a long period of time, regardless of changes in shape of the limb due to body movement.

The combination of the biomedical electrode pad of the present invention and the biological signal processing device of the present invention, despite using the biomedical electrode pad of which the attachment sheet is expanded compared with the conventional one to broaden the range of detecting biological signals, can continuously detect biological signals from the skin by the plurality of electrodes for a long period of time, regardless of changes in shape of the limb due to body movement, by effectively preventing the biomedical electrode pad from coming off the skin.

REFERENCE SIGNS LIST

1Attachment sheet1aOpening2Indifferent electrode3Detecting electrode4,5Connecting part6,7Electrode connecting wire8Resin layer9Electrode sheet10Cover sheet10aOpening11Conductive gel sheet20Casing21Lower casing part21aThrough-hole21bDepressed portion21cStepped portion22Upper casing part23Seal ring24Biological signal processing circuit board24aConnecting pin25Battery26,28Mounting holder27,30Casing main body29Casing cover30Fibrous conductor