HK1109559A - Sensory arrangement - Google Patents

Abstract

The English abstract will be submitted.

Description

Sensing device

The present invention relates to a sensing device. In particular, the invention relates to a novel sensor for measuring physiological signals of the skin. The sensor typically includes a substrate, signal electrodes, and a means of transmitting an electrical signal. Furthermore, the invention relates to a method of manufacturing a sensor, to a heart rate belt and to a garment (aparel).

Conventional heart rate meters, heart rate belts and heart rate belts typically comprise a body made of plastic on the surface of which two local electrodes are placed close to the chest. The electronic device that transmits the heart rate signal is typically a wriston device built into a plastic body. Conductors from the electrodes to the electronics also run inside the body, which is usually attached to the chest by means of a flexible strap.

Heart rate belts and sensors using fabric materials have been developed in particular recently, as plastic heart rate belts are relatively thick and feel uncomfortable in use. One of which has been disclosed in WO 2005/032366. In the solution described therein, the conductor material in the textile material is used to directly provide the surface for the electrodes and the transmission conductors. The transmission conductor may then be coated with an insulating material so that only the electrodes remain in contact with the skin and the signal quality is improved. However, the laminate material (laminate) then remains on the surface of the product at the conductors, so that the breathability of these parts is reduced and they may feel uncomfortable against the skin.

WO 2002/071935(FI 110925) discloses a heart rate sensor having electrodes comprising conductive fibres with a moisture retaining layer at their ends to improve the electrical contact of the electrodes with the skin. This solution also presents the problem of the placement of the signal-transmitting conductors with respect to the fibrous material, in particular of producing a reliable contact between them and the electrodes while producing a good electrical insulation.

WO 2003/082103 discloses a heart rate sensor whose electrodes are moulded from a fabric material. Electrical conductors may be added to the mold to securely attach them to the electrode molding. However, the electrical conductors remain loose on the fabric surface and are subject to mechanical stresses acting thereon. They can also be adhered as part of the fabric by means of heat and pressure, but then strong interfering signals can be connected to them by the skin through fibers.

WO 2005/0043641 discloses a device intended to measure heart rate, which is detachably attached to a flexible belt or garment by means of hooks in the interior thereof. Although attachable to multiple garments, it does not eliminate the problem of discomfort when using a conventional heart rate belt.

The present invention aims to eliminate the drawbacks of the prior art disclosed above and to this end invent a new type of flexible sensor, which is made on a flexible substrate and which is reliable and easy to manufacture.

In the sensor for measuring physiological signals according to the present invention, the outer layer is a flexible and moisture-permeable substrate having an outer surface (first surface) and an inner surface (second surface) opposite thereto. The signal transmission conductors are arranged in a watertight manner on the inner surface of the substrate so that the interference signals cannot communicate directly from the skin through the substrate. The signal surface of the electrode is facing the same as the outer surface of the flexible substrate, and the electrode is in turn electrically connected to the transmission conductor.

In a method of manufacturing a sensor according to the invention, a flexible substrate is used, which has an inner surface and an opposite outer surface. The signal transmission conductor is electrically connected with the electrode and attached to the second surface of the substrate. The electrode is placed opposite the substrate in such a way that the signal surface is facing the same as the outer surface of the substrate.

The substrate is preferably a fabric material or other fibrous article. The electrodes may be made of, for example, metal, or conductive plastic, elastomer, single fibers, or of fibrous materials such as woven or knitted fabrics. The material of the transmission conductor may be metal, conductive plastic, conductive rubber, conductive elastomer, conductive ink, conductive polymer, paint with metal-particle content, conductive fiber, fiber bundle (a packof fibers), or fiber product such as conductive fabric.

The sensor typically comprises a structure of at least three layers, among which a substrate layer to be held against the skin, a first insulating layer and a conductor layer. Furthermore, another insulating layer is typically arranged on the second surface of the conductor layer as a fourth layer. The purpose of the insulating layer is to prevent liquid, such as sweat, from accumulating in the substrate and reaching the conductor layer during movement and thus to prevent electrical contact with the signal conductors and undesired interference with the electrode signal connections.

More specifically, the sensor according to the invention is characterized by what is stated in the characterizing part of claim 1.

The method according to the invention is characterized in part by what is stated in the characterizing part of claim 20.

Significant advantages are realized by the present invention. In the structure according to the invention, the flexibility of the structure and the reliability of the signal can be combined with the comfort of use of the sensor. In particular, it allows the use of a comfortable durable textile substrate tested, completely or almost completely, directly against the skin over the entire area of the sensor. The signal transmission conductors are protected from stress, moisture and electrical interference on the second side of the fabric.

The structure according to the invention can also be produced entirely from the inner surface of the substrate, in which case the outer surface remains stationary against the user, except for the electrode openings. Thus, for example, the comfort and breathability of the textile substrate remain good, even at the conductors. The conductor is also held behind the fabric layer and is well protected from mechanical stress.

By means of the invention, the structure of the sensor product can also be implemented in such a way that the conductor structure is held in a position in the finished sensor product such that no tensile forces act on it when the product is bent, or at least such forces are relatively small in the outer layer of the product. Thus, non-stretchable and less stretchable conductor materials can also be used, which was not possible in the previous solutions.

In particular, a structure in which the substrate, the first insulating layer, the conductor/electrode layer, and the second insulating layer are bonded together as a combined body (pack) is advantageous in terms of manufacturing technique and use. If the insulating layers adhere to each other at the edges, a conductor structure will be obtained which prevents moisture from propagating parallel to the surface or at a suitable angle to the surface, and which is thin and flexible. Such a structure can be used in both heart rate belts and in clothing.

In the following sections, embodiments of the invention will be described in more detail with reference to the accompanying drawings, in which

Figures 1-3 show exploded views of structures according to preferred embodiments of the present invention,

figures 4a-4c show cross-sections of various sensor configurations in an environment closer to the electrodes,

figure 5 shows a cross-section of a sensor structure protected on both sides,

FIG. 6 shows the use of a sensor in combination with a detachable electronic module, an

Fig. 7 shows in more detail the contact with the detachable electronic module according to one embodiment.

In fig. 1, a substrate is indicated by reference numeral 10. Openings 11 are provided therein for electrode contacts. The moisture resistant intermediate layer 12 is permanently attached to the top of the substrate. An opening 13 may also be provided in the intermediate layer, which opening 13 may substantially coincide with the opening 11. Of course, the openings 11 and 13 can also be made in a separate process step later. The electrodes 15 are arranged opposite the openings 11 in the substrate and the openings 13 in the intermediate layer so that there is a contact connection from the outer surface of the substrate 10 (from the skin) to the signal surface. A signal transmission conductor 14 is attached to the intermediate layer 12. The signal-transmitting conductor 14 is thus attached to the substrate 10 by means of an electrically insulating and water-tight layer 12, said layer 12 being located between the strip-shaped signal-transmitting conductor 14 and the substrate 10. At one end, the conductor is electrically connected to the electrode 15. And at the other end to the electronic module or the mounting means 19 of the module.

The substrate may be a woven material made of natural and/or man-made fibers. The material may be woven or non-woven. It is preferably self-breathing, i.e. permeable to air and water vapour, and often also to water. Thus creating a comfortable feel against the skin of the user.

In fig. 2a, the structure is further extended by the addition of a second intermediate layer 16 and a surface layer 18. The layer 16 ensures that the second side of the transmission conductor 14 is also impermeable to water. Layers 12 and 16 are adhered to each other directly on each side so that conductor layer 14 remains water-tight therebetween.

According to one embodiment, the substrate is continuous throughout from the side of the sensor facing the skin to the side opposite the sensor. The substrate can thus enclose the assembly of signal transmission conductor and intermediate layer or layers from all sides, in which case both surfaces of the sensor will be formed of the complete material. Applied to the embodiment of fig. 2a (and fig. 2b, described in more detail below), layers 10 and 18 are thus composed of the same unitary material, which is bent at the sides of the sensor so that the other layers are encapsulated therein. For example, sensor surface elements arranged in a tube shape may be used, in which other layers of the sensor are placed. The other layers may be laminated to a ready-made assembly before being placed in the tubular surface layer. Optionally, after the application of the further layers, the planar substrate layer may be bent over the layers to the other side of the sensor and form a bond at that side, for example by means of an adhesive. The openings of the electrodes and the connection of the electronic module are made in a tubular surface element. By means of the described embodiment, a clean appearance is created at the edges of the sensor and the use of separate surface layer elements is avoided.

According to a preferred embodiment, the second intermediate layer 16 is electrically insulating. A second conductor structure may then be applied on top of it. Such a second conductor structure may be used to create a second signal path, or an electrical shield. Therefore, by means of such a structure, the induction channel can be increased, or the electromagnetic interference from the direction of the second surface can be effectively eliminated. The intermediate layers 12 and 16 are preferably of the same material. Depending on the thickness of the intermediate layer and the conductor structure, several such layers may be present without a significant increase in the thickness of the sensor. More conductors may also be fabricated in a single layer and/or they may overlap in different layers.

According to a preferred embodiment, a conductor layer shielding against electromagnetic interference is placed below or on top of the signal transmission path 14 by means of the insulator-conductor lamination technique as described above. The two shield layers may further be electrically connected to each other at the edges to form a complete jacket for the signal conductor.

According to one embodiment, the intermediate layers 12 and/or 16 consist of an electrically insulating laminate. The necessary conductors are applied to the substrate 10 and/or stacked on top of each other on top of the laminate before they are laminated. Such a manufacturing method is very easy to implement, cheap and maintains its flexibility after the application of several layers. The laminate is preferably of the flexible material type (barrier type), typically a thin layer, attached by heat, pressure, heat pressure, or adhesive. For example, many seam laminates (seam laminates) used in the apparel industry are suitable for this purpose. The laminate may also be extended simultaneously to the environment of the electrode 15 as shown in figures 1 and 2 a. It reinforces the area of the substrate 10 adjacent to the electrode and may even prevent abrasion of the substrate around the hole 11 made therein.

According to one embodiment, the signal transmission path is composed of a conductive substance, such as a conductive ink, a conductive polymer, or a paint with a metal-particle content, which may be dispersed in a fluid form. Such a conductive substance is dispersed on the support layer, preferably the intermediate layer 12 and/or 16 serves as said support layer. In this case, the surface of the intermediate layer is preferably directly printable thereon, i.e. the surface is easily printable (print-ready). According to one aspect of the invention, a laminate attached to a textile substrate is really provided with a new use, namely as a basis (base) for a conductor material applied in liquid form.

The signal transmission conductors may also include conductors applied in solid form, such as rubber or elastomeric conductors, metal conductors, conductive fibers, or conductive fabrics. In this case, the conductor is also preferably attached to the above-described support structure or intermediate layer. In particular, TPU elastomers may be well suited for this purpose.

According to a preferred embodiment, the signal-transmission conductor is non-metallic, in which case its conductivity may be, for example, 10^-10～10^-2% metal (copper) conductivity. Permanent bonding of non-metallic conductors to existing laminated structures is generally simpler than that of metallic conductors, for example, by processes used in the textile industry.

The electrode 15 and the signal transmission conductor 14 may form an integral structure and/or consist of the same material, in particular a conductive substance produced in solid form application.

As with the laminate described above, the intermediate layer attached to the substrate may be arranged such that the sensor is not stretchable or is poorly stretchable. The flexibility of the structure is advantageously kept good also in this case. In particular, if a signal conductor with poor stretchability is used, a non-stretchable intermediate layer would be suitable. This situation is achieved by the described assembly structure, wherein the laminated layer (single or multiple layers) may, together with the fabric layer, withstand the forces acting on the sensor.

Fig. 2b shows a structure that is particularly suitable for the heart rate belt. There is a further layer 17 which is arranged on top of the electrodes 15 and the signal transmission conductors 14, but below the electronic module or its mounting area 19. It thus forms the basis of the mounting area. In the layer 17 there is an opening 171 through which the overlapping of the layers can be carried out in such a way that the transmission conductor 14 passes through the opening 171 or that the transmission conductor 14 makes contact with the mounting region 19 at the location of the opening 171. At the same time, the layer 17 may also serve as a moisture protection layer for the signal transmission conductor 14 and thus replace the intermediate layer 16 for this purpose. In the illustrated construction, for example, the fabric-like surface layer 18 of the laminate 16 is used to attach the surface layer 18 to the sensor. However, it also protects and covers opening 171, thus preventing contact with moisture.

As can be seen from fig. 4a-4c, the electrode 45 is arranged on the substrate 40 in the following manner: there is a direct contact connection from the side of the first surface of the substrate 40 to the signal surface 47. The signal surface 47 is preferably at least at the same level as the first surface of the substrate 40, as shown in fig. 4a and 4 c. In some applications, the signal surface 47 may also be deeper than the surface level of the substrate 40 in the manner shown in fig. 4b, especially in case the substrate is very thin and/or when electrodes with a very large surface area are used. In these figures, the laminate or other intermediate layer is indicated by reference numeral 42, and the signal carrying conductors connected to the electrodes and located directly on top of the laminate 42 are indicated by reference numeral 44.

The electrode openings are preferably formed in the substrate. The electrodes can be arranged at the location of the openings through the openings of the substrate or through the surface of the substrate using several different techniques. It may be provided as a prefabricated anchor, in which case it is usually attached directly to the substrate, or to an intermediate layer on top of it, with preferably also openings. If necessary, an adhesive may be used. The electrodes may also be hardened or sewn to the substrate. Portions of the substrate may also be treated to be electrically conductive, such as fibers that are impregnated with a conductive substance or that coat the substrate with a conductive substance. Suitable conductive substances are conductive polymers, inks and adhesives. The electrode may also be insulated on all sides so that it is either partially or completely out of electrical contact with the substrate, in which case the signal will only connect to the electrode through the signal surface, even when the substrate is wet.

With reference to fig. 5, after application of the electrodes 55 and the signal transmission conductors 54, the structure of the sensor may advantageously be extended in such a way that the signal transmission conductors 54 remain in the inner layers of the sensor structure. This preferably takes place in the following manner: when the finished structure is bent, the transmission conductor 54 has a substantially smaller extension than the outer layers 50, 56 of the structure. Accordingly, such material layers 50, 52, 56, 58, or layer structures, having relatively similar elongation and bending properties are preferably on both sides of the conductor layer 54. Their elongations usually differ from each other by a maximum of 30%, preferably less than 15%. In this case, the signal transmission conductor will essentially remain on the zero axis (zeroaxis) of the bending elongation of the structure. Such an embodiment would protect the conductors from unnecessary elongation and contraction when the sensor is in use and allow the sensor to be packed into a small space without damage, such as a roll. Washing of the sensor, in particular machine washing, will also exert mechanical stress on the conductor layer if the conductor layer is erroneously arranged with respect to the sensor layer.

The sensor according to the invention is particularly suitable for monitoring heart rate from the skin, for example from the chest. The sensor thus typically also comprises a second electrode as described before and a corresponding second signal conductor, which is to be placed on a different side of the chest. The sensor may also be used to measure other electrical functions or properties of the body, such as measuring the conductivity and percentage of fat of the skin, and measuring muscle activity (muscle activity).

The sensor may be made as part of a heart rate belt or as a fixed part of, for example, underwear, sportswear, head band or brassiere, in which case the fabric material of these substances may serve as the substrate of the sensor. Due to its structure, it can be made very thin and dense and can be washed without moisture penetrating into the interior of the sensor.

For placement on the skin, one layer of the above-mentioned layered structure may extend outside the actual sensing area. When incorporated into a garment, this layer is typically a backing layer, but when used in a heart rate belt, for example, an elastic belt to be stretched around the chest may also be made to continue from some other layer of the structure. Typically, in such a configuration there are at least three layers permanently stacked on top of each other, one of which forms the signal conductor layer and one of which extends as a textile-like or elastic structure so that it can be arranged around parts of the body so as to bring the signal surface of the electrode substantially against the skin. As mentioned above, at least one layer and preferably two layers additionally form a moisture barrier to protect the transmission conductor.

One particular embodiment that may be referred to is the use of a heart rate belt, in which the sensor structure described is combined with an elastic belt (belt) or band (band), which is made "extra long" at the factory, this part being cut off so that the remaining length of the belt fits the user's body. A connector may be attached to the end of the strap that is capable of mating with a counter element (counter piece) attached to the sensor. The tape may also be sewn or glued to form an integral ring, in which case plastic components would not be required. The individual fittings of the strap (referred to as individual fittings) may be made by an agent, such as at a sporting goods store. In particular, a separately mounted heart rate belt makes it possible to avoid the use of plastic length adjusters, since they are typically thicker than the actual belt (belt) or band, which may be uncomfortable in operation.

Furthermore, in addition to electrode-signal transmitting conductors, other conductors may also be laminated into the sensor structure. Examples of this are antennas and other electrical/optical conductors associated with other electrical/optical functions incorporated into the garment/device as a whole.

By means of the described sensor structure, medical sensors, such as sensors for electroencephalogram (EEG) or Electrocardiogram (ECG), can be manufactured. There may be tens or even hundreds of measurement channels. Such sensors are economical to manufacture, durable, washable, and comfortable for the patient. The fear of the test for the patient can be reduced by the following facts: the signal paths of the individual channels can be reliably and unnoticed integrated into the fibre construction, thus giving the measuring device a pleasant appearance.

Referring to fig. 6, the sensor may further include a mounting area 69 for an electronics module 610 to which the signal transmission conductor 64 may be connected. In this case, the transmission conductor 64 is electrically connected with a contact region located within the mounting region 69. The mounting region may include a ring structure 79, such as that shown in fig. 7, into which a metal contact ring 720 is incorporated. Fig. 7 also shows one possible method of achieving the joint 730 between the signal carrying conductor 74 and the contact wire 720. Bond 730 is preferably made using a bond molding technique that produces a durable bond with good electrical conductivity. Molding techniques may also be used to assist in creating the durable joint 730, such as when an output conductive substance is used in the transmission conductor 14. The electronic module can advantageously be mounted in a manner that can be removed afterwards. Typically, the contact members in the mounting area or the electronic module are flexible when mounting the module to produce good contact. Such a sensing device would also be able to withstand machine washing. The electronic module can also be connected to the transmission conductors in other ways, for example by means of press studs (pressstuds).

The electronic module typically includes a means to transmit, record or display the measured physiological signal. Typically, it comprises a wireless signal transmitter, the terminal device of which is for example a wristop computer, a computer, or some other heart rate monitor.

Claims (25)

1. A sensor for measuring physiological signals from outside a body, the sensor comprising:

-a flexible substrate permeable to moisture and having a first surface and a second surface opposite to the first surface,

-at least one electrode having a signal surface facing the same as the first surface of the flexible substrate, an

-a signal transmission conductor electrically connected with the electrode,

wherein the signal transmission conductor is attached to the second surface of the substrate in a watertight manner.

2. Sensor according to claim 1, characterized in that the signal transmission conductor is attached to the substrate by means of a water-tight and preferably at the same time electrically insulating layer, which is located between the signal transmission conductor and the substrate.

3. A sensor according to claim 2, characterized in that the intermediate layer is permanently attached to the substrate.

4. A sensor according to claim 2 or 3, characterised in that the intermediate layer is arranged such that the sensor is not stretchable or poorly stretchable but at the same time retains its flexibility.

5. A sensor according to any of claims 2 to 4, wherein the signal carrying conductor is permanently attached to the intermediate layer.

6. A sensor according to any preceding claim, wherein the signal transmission conductor comprises a conductive substance dispersed in a fluid form, such as a conductive ink, a conductive polymer, or a paint with a metal-particle content.

7. A sensor according to any of the preceding claims, wherein the signal transmission conductor comprises a conductor applied in solid form, such as a rubber or elastomer conductor, a metal conductor, a conductive fibre, or a conductive fabric.

8. A sensor according to any one of the preceding claims, wherein the electrodes are arranged on the substrate in such a way that: such that there is a direct contact connection with the electrode signal surface from the first surface side of the substrate.

9. A sensor according to any preceding claim, wherein the electrodes extend across the entire substrate in the direction of their thickness.

10. A sensor according to any preceding claim, wherein the electrodes and the signal transmission conductors are formed from a single layer or sheet, the single layer or sheet being formed from substantially the same material.

11. Sensor according to any one of the preceding claims, characterised in that the transmission conductor is located between two watertight layers, which are adhered to each other in a watertight manner.

12. A sensor according to any one of the preceding claims, characterized in that it comprises at least one second conductor layer arranged below or on top of the signal transmission conductor in such a way that: such that an insulator laminate is interposed between the conductor layers.

13. A sensor according to any of the preceding claims, characterized in that it further comprises at least one protective layer placed on top of the signal transmission conductors, such that the signal conductors are held in an inner layer of the sensor structure, the elongation of the signal conductors being substantially smaller than the elongation of the outer layer of the structure when the structure is bent.

14. A sensor according to any preceding claim, wherein the substrate is a textile material.

15. A sensor according to any one of the preceding claims, further comprising a mounting area for an electronic module, wherein the signal transmission conductor is electrically connected to a contact area located within the mounting area.

16. Sensor according to claim 15, characterized in that the contact area contains a metal conductor with which an electronic module which is brought to the mounting area in a subsequently detachable manner is arranged to form an electrical contact.

17. A sensor according to claim 15 or 16, wherein the electronic module comprises means for transmitting, recording or displaying the measured physiological signal.

18. A sensor according to any one of the preceding claims, characterised in that it comprises a layer structure with at least three layers detachably superposed on each other, one of which forms the signal-transmitting conductor and one of which extends as a textile-like or elastic structure so that it can be arranged around parts of the body so that the signal surface of the electrode rests substantially against the skin.

19. A sensor according to any preceding claim, wherein the substrate extends in a unitary manner from a surface on the signal surface side of the electrode to the counter surface of the sensor, such that the signal transmission conductor is substantially retained within a tubular structure formed by the substrate material.

20. A method of manufacturing a sensor for measuring physiological signals, in which method:

-using a moisture permeable flexible substrate having a first surface and a second surface opposite to the first surface, and

-arranging further electrodes in the sensor, the electrodes being in electrical contact with the signal transmission conductors, the signal surfaces of the electrodes being oriented in the same direction as the first surface of the substrate,

it is characterized in that the preparation method is characterized in that,

-the signal transmission conductor is attached to the second surface of the substrate in a watertight manner.

21. A method according to claim 20, characterized in that the signal-transmitting conductor is attached to one surface of a layer of electrically insulating and water-tight material, and that the layer of material is laminated to the substrate from its free surface.

22. The method of claim 21, wherein a second layer of electrically insulating and water-tight material is further disposed on a free surface of the signal transmission conductor.

23. A method according to any of claims 20-22, characterized in that an opening is made in the substrate, and the electrode is fitted in relation to the opening such that there is a direct contact connection to the electrode signal surface from the first surface side of the substrate.

24. A heart rate belt comprising a sensor according to any one of claims 1 to 19.

25. A garment, characterized in that it comprises a sensor according to any one of claims 1 to 18, wherein the innermost fabric layer of the garment forms the substrate.