Biological information measurement device

In this biological information measurement device, the following are provided within a shield frame 315 in which the interior is shielded from the outside when attached to a sensor sheet 100: a terminal (a spring probe 312) that is connected to a sensor (an electrode 133) of the sensor sheet 100; and an external terminal (a USB terminal 313) for connection to an external device.

TECHNICAL FIELD

The present invention relates to a biological information measurement apparatus that measures biological information using a sensor sheet applied to the skin of a subject.

BACKGROUND ART

Conventionally, there are apparatuses that measures biological information of a subject by a sensor sheet with a sensor incorporated therein applied to the body surface of the subject. For example, in the case of electrocardiographic measurement apparatuses, an electrocardiogram of a subject is obtained via electrodes incorporated in a sensor sheet (see Patent Literatures 1 and 2).

In the sensor sheet (biological electric signal recording device) disclosed in Patent Literature 1, electrodes are provided in a sheet-like base material that is flexible enough to follow movements of a living body, and the electrodes are surrounded in a watertight manner by the sheet-like base material, such that measurement of electrocardiograms can be made even during bathing in addition to walking, eating and sleeping.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

A terminal for recording or transmitting information sensed by a sensor sheet is connected to the sensor sheet. Generally, the terminal is provided with contacts for connection to the sensor sheet, a memory that stores information input from the sensor sheet through the contacts, and an external contact. The external contact is used to output biological information stored in the memory to an external device or make settings of the terminal via an external device. When the terminal is a terminal having a wireless function such as a telemeter, biological information stored in the memory is wirelessly output to the outside without an external contact, but settings of the terminal may be configured by an external device through an external contact. Therefore, even if the terminal is a terminal having a wireless function such as a telemeter, the terminal may include an external contact.

Here, biological information measurement is performed in a state in which a terminal is connected to a sensor sheet. During the biological information measurement, it is very dangerous if an external device is connected to the external contact and a current from the external device flows into the subject via the terminal and the sensor sheet, and thus, countermeasures for preventing such dangerous current flow are necessary.

One of such countermeasures may be a floating mechanism, a floating mechanism has a complicated configuration and has the drawback of causing an increase in size of the apparatus.

The present invention provides a biological information measurement apparatus that can more reliably prevent a current from an external device from flowing into a subject via a terminal and a sensor sheet during biological information measurement, with a simple configuration.

Solution to Problem

An aspect of the present invention provides a biological information measurement apparatus including: a sensor sheet to be applied to a skin of a subject; and a terminal to be attached to the sensor sheet, in which the terminal includes a shield frame that shields an inside of the terminal from an outside when the terminal is attached to the sensor sheet, and inside the shield frame, in addition to a sensor connection contact to be connected to a sensor of the sensor sheet, an external contact to be connected to an external device is provided.

Advantageous Effects of Invention

According to the present invention, upon attachment of a terminal to a sensor sheet, a sensor of the sensor sheet and a sensor connection terminal are electrically connected inside a shield frame. Also, in this state, the inside of the shield frame is shielded from the outside, and thus, an external contact inside the shield frame cannot be connected to an external device. Therefore, it is possible to more reliably prevent a current from an external device from flowing into a subject via the terminal and the sensor sheet during biological information measurement, with the simple configuration.

DESCRIPTION OF EMBODIMENTS

FIG. 1is an exploded perspective view illustrating an overall configuration of a sensor sheet according to Embodiment of the present invention.FIG. 2is a top view of the sensor sheet with a terminal attached thereto. The sensor sheet is attached to the chest region of a subject and used to obtain an electrocardiogram.

The present embodiment will be described in terms of a case where a terminal to be attached to a sensor sheet is a recording terminal including a memory and a coin cell housed inside a case thereof; however, the terminal to be attached to the sensor sheet is not limited to this type of terminal. For example, the terminal may be a terminal that includes a wireless transmission section inside a case and wirelessly transmits biological information measured by the sensor sheet. Also, the terminal may be, for example, a telemeter.

As illustrated inFIG. 1, before use, sensor sheet100is held between liner210and top separator220. Then, in use, liner210and top separator220are removed and sensor sheet100is applied to the chest region, and as illustrated inFIG. 2, terminal300is attached to the front surface side.

Sensor sheet100includes lower sheet110and upper sheet120. Electric circuit section130, which serves as a measuring element, is disposed between lower sheet110and upper sheet120. An adhesion layer is provided on a surface on the skin side of each of lower sheet110and upper sheet120, and consequently, lower sheet110is to be applied to the skin of a subject and upper sheet120is stuck to the front surface side of lower sheet110. Electric circuit section130is held between lower sheet110and upper sheet120as a result of upper sheet120being stuck to the front surface side of lower sheet110.

Upper sheet120is smaller in area than lower sheet110. The area of upper sheet120is large enough to cover electric circuit section130. More specifically, as can be seen fromFIG. 2, which illustrates upper sheet120stuck to lower sheet110, peripheral edge portion110a, which is formed of lower sheet110alone, is formed over an entire circumference of sensor sheet100while electric circuit section130is fully covered by upper sheet120.

Electric circuit section130includes tongue piece131, a plurality of wires132extending from tongue piece131, and a plurality of electrodes133formed at terminal ends of respective wires132.

Holes111are formed at positions in lower sheet110that correspond to respective electrodes133, and gels134are disposed at positions corresponding to respective holes111. Consequently, electrodes133are electrically connected to the skin via gels134, and electric conductivity between the skin and electrodes133is enhanced by gels134.

Connector140to be connected to terminal300is provided on the front surface side of tongue piece131. Hole121is formed at a position in upper sheet120, the position corresponding to tongue piece131. Consequently, in a state in which upper sheet120is stuck to lower sheet110, tongue piece131is exposed on the front surface side of upper sheet120via hole121.

Furthermore, hole221is formed at a position in top separator220, the position corresponding to connector140. Consequently, connector140is exposed on the front surface side of top separator220via hole221.

Here, lower sheet110includes a base material formed of polyurethane and the adhesion layer formed on the surface on the skin side of the base material. Likewise, upper sheet120includes a base material formed of polyurethane and the adhesion layer formed on the surface on the skin side of the base material. As described above, sheets110,120are each formed of polyurethane having a high moisture vapor permeability, enabling suppression of a skin rash caused by sweating and thus enabling suppression of itching caused by a rash.

For further information, polyurethane has the characteristic of transmitting water vapor and not transmitting collected water (that is, transmitting small particles such as water vapor, but not transmitting a large mass of water such as collected water or a water droplet), and thus, when the subject takes a bath, there is almost no permeation of water from the front surface side to the skin side of upper sheet120. Therefore, entry of water from the front surface side of upper sheet120to wires132and electrodes133can be suppressed, enabling prevention of a short in the electric circuit even when the subject takes a bath with sensor sheet100applied.

Although in the present embodiment, lower sheet110and upper sheet120are both formed of polyurethane, itching is likely to occur particularly at a peripheral edge portion of a sheet, and thus, it is possible that: only lower sheet110including peripheral edge portion110ais formed of polyurethane; and upper sheet120is formed of a material other than polyurethane. Furthermore, for materials of lower sheet110and upper sheet120, any of various materials other than polyurethane can be used as long as such materials are ones that can prevent entry of water that causes a short in wires132and electrodes133while transmitting moisture resulting from sweating. For example, foamed polyethylene or a non-woven material may be used. Also, lower sheet110and upper sheet120are not necessarily formed of polyurethane alone, and may be formed of a material containing polyurethane as a main component.

However, the inventors found out that polyurethane is most excellent for materials of lower sheet110and upper sheet120. Here, for lower sheet110and upper sheet120, for example, almost no permeation of water from the front surface side to the skin side of upper sheet120when the subject takes a bath (that is, waterproof property), the capability of being used for a long period of time without being torn (that is, durability), a flexibly enabling following movements of the skin (that is, stretchability), and the capability of being thinned are required. Polyurethane is desirable in all of waterproof property, durability, stretchability and the capable of being thinned. On the other hand, foamed polyethylene is poor in durability and the capability of being thinned. Non-woven fabric is poor in waterproof property.

Lower sheet110in the present embodiment has a thickness of 15 [μm]. This thickness is much smaller than a thickness of around 50 [μm], which is a thickness of a conventional sheet of this type. On the other hand, upper sheet120has a thickness that is larger than that of lower sheet110. In the case of the present embodiment, upper sheet120has a thickness of 50 [μm]. In other words, in the case of the present embodiment, while peripheral edge portion110aformed of lower sheet110alone has a thickness of 15 [μm] and thus, is very thin, a center area in which electric circuit section130is held has a thickness of 65 [μm] including the thicknesses of lower sheet110and upper sheet120. Consequently, even if peripheral edge portion110ais very thin, the center area in which electric circuit section130is held is thick, enabling a measurement accuracy decrease to be prevented without a decrease in reliability of electric circuit section130.

In particular, it is desirable that upper sheet120be made to be thicker than lower sheet110. In other words, it is only necessary to form upper sheet120so as to be higher in strength than lower sheet110. For example, upper sheet120may be formed of a material having a strength that is higher than that of lower sheet110.

The reason why a conventional sheet has a large thickness including a peripheral edge portion thereof is that a priority is placed on suppression of damage of the sheet and highly reliable holding of electric circuit section130, which serves as a measuring element, and no sufficient consideration is given to itching caused when the sheet is continuously applied for a long period of time.

In the present embodiment, paying attention to the point that itching can substantially be reduced if peripheral edge portion110afollows the skin, lower sheet110was studied in terms of material and thickness. As a result, it has been found that if lower sheet110is formed of polyurethane in consideration of moisture vapor permeability, itching is less likely to occur even if lower sheet110is continuously applied for around two weeks as long as lower sheet110has a thickness of no more than 20 [μm]. In other words, in the present embodiment, forming lower sheet110from polyurethane and making lower sheet110have a thickness of no more than 20 [μm] are proposed.

Also, as described above, lower sheet110is made to have a very small thickness of no more than 20 [μm] and is thus superior in following the skin, which provides the advantage of enabling provision of a sheet that is less likely to come off in addition to suppression of itching. In other words, a sheet almost always starts coming off at a peripheral edge portion and thus, can be prevented from coming off by the configuration provided by the present embodiment.

Wires132and electrodes133are configured by forming a metal layer on a base material formed of, e.g., PET (polyethylene terephthalate) or PEN (polyethylene naphthalate). The base material has a thickness of, for example, around 50 to 100 [μm]. It is also possible that wires132and electrodes133are formed directly on upper sheet120or lower sheet110; however, in the case of the present embodiment, wires132and electrodes133are formed on, e.g., the base material formed of, e.g., PET (polyethylene terephthalate) or PEN (polyethylene naphthalate), enabling prevention of occurrence of, e.g., disconnection.

Here, the base material formed of, e.g., PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) is less flexible than polyurethane, which is the material of lower sheet110and upper sheet120. Therefore, in the case of the present embodiment, wires132have a pattern including a meandering pattern. Consequently, wires132follows movements of the body surface (skin) well. As a result, the capability of following the skin can be enhanced also in the area of electric circuit section130, as well as peripheral edge portion110a, enabling further suppression of occurrence of itching.

Tongue piece131is thicker than the base material of wires132and electrodes133. Terminal300is detachably attached to connector140provided on tongue piece131. A structure of the attachment of connector140to terminal300will be described later.

Next, a procedure for applying sensor sheet100to the chest region of a subject will be described.

When sensor sheet100is applied to a predetermined position in the chest region, first, liner210is removed and sensor sheet100is pressed against the predetermined position in the chest region together with top separator220to apply lower sheet110to the predetermined position in the chest region.

Top separator220is rubbed from above in this state, whereby lower sheet110is firmly applied to the skin of the subject. For further information, an adhesion layer having a small adhesive force enough to hold sensor sheet100is formed on a lower surface of top separator220.

The provision of top separator220enables prevention of twisting of peripheral edge portion110aof very thin lower sheet110. Hole221for avoiding connector140is formed at a center of top separator220. A user holds areas in the periphery of hole221between his/her fingers and separates and peels back top separator220so as to be separated and removed outward like opening a double door, whereby top separator220is removed from sensor sheet100. As described above, as a result of top separator220being removed from sensor sheet100from the center to the edge side of sensor sheet100, rather than from the edge side, lower sheet110is strained by top separator220, enabling reduction in possibility of the edge of lower sheet110peeling off and wrinkling.

After sensor sheet100is applied to the chest region to the subject in this way, the user attaches terminal300to connector140of sensor sheet100.

FIGS. 3A, 3B and 3Care diagrams illustrating a configuration of terminal300;FIG. 3Ais a perspective view,FIG. 3Bis a side view andFIG. 3Cis a bottom view.

Terminal300includes, e.g., a coin cell and a memory incorporated therein. Upon power supply button301being pressed, terminal300starts an electrocardiographic measurement and recording operation, and records an electrocardiogram based on an electrocardiographic signal from the sensor sheet100. This measurement and recording operation is a known technique and thus, description thereof will be omitted.

As illustrated inFIG. 3C, attachment section310to be detachably attached to connector140provided in sensor sheet100is provided in a back surface of terminal300.

FIGS. 4A and 4Bare cross-sectional views for description of an attachment structure in terminal300for attaching terminal300to sensor sheet100.FIG. 4Ais a cross-sectional view before attachment, andFIG. 4Bis a cross-sectional view after attachment.

FIGS. 5A and 5Bare perspective views for description of an attachment structure in terminal300for attaching terminal300to sensor sheet100,FIG. 5Ais a perspective view before attachment, andFIG. 5Bis a perspective view after attachment.

Here, connector140provided on the sensor sheet100side includes packing141having an oval shape in plan view. Terminal ends of wires132, other ends of which are connected to respective electrodes133, are disposed on an area in tongue piece131, the area being surrounded by packing141.

Also, insertion opening311having a size that allows packing141to be just fitted therein is formed in the back surface of terminal300. Inside insertion opening311, spring probes312and USB port313are disposed. More specifically, as illustrated inFIGS. 4A and 4B, shield frame315is formed in the back surface of terminal300, and shield frame315forms insertion opening311. Inside shield frame315, in addition to contacts (spring probes312) to be connected to sensors (electrodes133) of sensor sheet100, an external contact (USB port313) for connection to an external device is provided. The external contact is used to output biological information stored in the memory to an external device or make settings of the terminal via an external device. Upon attachment of packing141, the inside of shield frame315in which the contacts are provided is shielded from the outside.

Consequently, as illustrated inFIG. 4B, upon insertion of packing141to insertion opening311in the back surface of terminal300, spring probes312are brought into abutment with the terminal ends of wires132, the terminal ends being exposed on tongue piece131, at a predetermined pressure, whereby the spring probes312and the wires132are electrically interconnected, respectively. Also, in this state, the inner side surrounded by packing141is prevented from entry of water from the outside. In other words, the plurality of spring probes312and the plurality of wires132are electrically connected without short-circuiting caused by water.

Furthermore, inside insertion opening311, USB port313is disposed in addition to spring probes312, and thus, when electrocardiographic measurement is being performed with terminal300attached to sensor sheet100, USB port313cannot be used. Consequently, the risk of electrical shock caused by connection of an external electronic device to USB port313during electrocardiograph measurement can reliably be eliminated. In other words, in the present embodiment, the contacts for electrocardiographic measurement (spring probes312) and USB port313are prevented from being connected simultaneously to ensure safety. Furthermore, the contacts for electrocardiographic measurement (spring probes312) and USB port313are housed inside packing141and are thus waterproofed at the same time. In other words, both waterproofing and safety can be ensured by the simple configuration.

Furthermore, as illustrated inFIGS. 5A and 5B, wide portion150is formed at a distal end of tongue piece131. Also, locking cut314is formed in the back surface of terminal300. Upon insertion of packing141of connector140to insertion opening311, wide portion150of tongue piece131engages with locking cut314, whereby terminal300is locked by tongue piece131so as not to move in the arrow Z direction (direction around the ground where terminal300is attached).

Furthermore, hook-and-loop fastener160is firmly fixed to the front surface side of upper sheet120. Hook-and-loop fastener160can be stuck to hook-and-loop fastener320provided on the back side of terminal300.

Consequently, upon insertion of packing141to insertion opening311, terminal300is held on sensor sheet100by engagement between tongue piece131and locking cut314and joining between hook-and-loop fasteners160,320. Here, hook-and-loop fasteners160,320have only a small holding force in a direction perpendicular to the surface, but have a large force in the surface direction. Therefore, tongue piece131and hook-and-loop fasteners160,320reliably prevent terminal300from dropping in the surface direction.

Here, terminal300engages with tongue piece131at an upper portion and thereby hang down with tongue piece131as an axis. Upon terminal300being lightly pushed to the sensor sheet100side (that is, the subject side) in this state, hook-and-loop fasteners160,320are joined to each other and terminal300are thereby prevented from wobbling. In fact, terminal300is held by tongue piece131so as to be at least partly floated from sensor sheet100.

The subject perceives terminal300via the skin at the part of the joining between tongue piece131and the packing141and the part of the joining between hook-and-loop fasteners160,320, and as a result, for example, a feeling of discomfort the subject have due to the presence of terminal300can be reduced compared to a case where the entire back surface of terminal300is firmly fixed to sensor sheet100. A further decrease in area of hook-and-loop fasteners160,320enables further reduction of a feeling of discomfort the subject has.

Furthermore, hook-and-loop fastener160is disposed at a position corresponding to gel134. Consequently, the gel serves as a buffer, which makes the subject be less likely to feel the presence of terminal300.

Instead of hook-and-loop fasteners160,320, for example, a snap fastener or magnets may be used. In brief, any various rejoinable joining devices can be used.

<Advantageous Effects of Embodiment>

As described above, according to the present embodiment, inside shield frame315, the inside of which is shielded from the outside when shield frame315is attached to sensor sheet100, in addition to the contacts (spring probes312) to be connected to the sensors (electrodes133) of sensor sheet100, the external contact (USB port313) to be connected to an external device is provided, enabling more reliably preventing a current from an external device from flowing into a subject via terminal300and sensor sheet100during biological information measurement, with the simple configuration.

Here, when the external contact is a general-purpose one such as a USB port, an electronic device that is not a medical device can be connected as an external device. If such electronic device that is not a medical device, which is constructed with no medical safety standards taken into consideration, is connected to the sensor sheet via the external contact, a dangerous current may flow into the subject. However, according to the configuration of the present embodiment, even if a general-purpose external contact to which an electronic device that is not a medical device is connectable is provided, no electronic device can be connected to the external contact during measurement, ensuring safety of a subject.

Also, insertion of packing141to shield frame315enables both waterproofing of the contacts and prevention of current supply to the external contact during measurement to be performed at a time.

Although the above embodiment has been described in terms of a sensor sheet according to the present invention in which all of electrodes133are held inside single sheets110,120, the present invention is applicable to a sheet in which in electrodes133are disposed on individual sheets and electrodes133are interconnected via lead wires to be not applied to a subject. However, in the above embodiment, electrodes133, wires132and tongue piece131are integrally formed, and thus, a signal with small noise can be obtained in comparison to a configuration in which electrodes133, wires132and tongue piece131are formed separately and interconnected via cables or connection sections.

Also, although the above embodiment has been described in terms of the case where electric circuit section130including, e.g., wires132and electrodes133is mounted in sensor sheet100, a sensor mounted in a sensor sheet according to the present invention is not limited to electric circuit section130. For example, an optical component for measuring SpO2may be mounted as the sensor. The sensor to be mounted in the sensor sheet may be selected according to the object to be measured.

Also, although the above embodiment has been described in terms of the case where electric circuit section130, which serves as the sensor, is disposed between lower sheet110and upper sheet120, the sensor may be disposed on upper sheet120.

Also, although the above embodiment has been described in terms of the case where the center area of sensor sheet100has a multi-layer structure including lower sheet110and upper sheet120, the center area may have a single-layer structure including upper sheet120alone with no lower sheet110provided. Even in such case, upper sheet120is made to be higher in strength than lower sheet110, enabling provision of both a force for holding the sensor in the center area and the capability of following the skin in peripheral edge portion110a.

Also, although the above embodiment has been described in terms of the case where tongue piece131is formed separately from upper sheet120, tongue piece131may be formed integrally with upper sheet120. In other words, tongue piece131may be provided so as to extend from upper sheet120.

The above embodiments are mere specific examples for carrying out the present invention and the technical scope of the present invention should not be limited by these embodiments. In other words, the present invention can be carried out in various modes without departing from the spirit or the main features of the invention.

The present application claims priority based on Japanese Patent Application No.2015-179597 filed on Sep. 11, 2015. The entire disclosures in the descriptions and the drawings in these applications are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a biological information measurement apparatus that measures including biological information using a sensor sheet applied to the skin of a subject and a terminal attached to the sensor sheet.

REFERENCE SIGNS LIST