Medical liquid detection sheet

Abstract

Provided is a medical liquid detection sheet having a novel structure with which it is possible to minimize false detection of a patient's perspiration, etc., that does not need to be detected, and accurately detect a liquid to be detected.　A medical liquid detection sheet 10 in which first detection wiring 22 and second detection wiring 24 are provided, set away from each other, on an electrically insulating base member 16 and that detects leakage of a liquid 6 subject to detection, such as blood, on the basis of a change in the state of electrical connection between the first detection wiring 22 and the second detection wiring 24 due to adhesion of the liquid 6 subject to detection, a main detection region 37 in which the first detection wiring 22 and the second detection wiring 24 extend substantially parallel to each other being provided on the base member 16, and the distance by which the first detection wiring 22 and the second detection wiring 24 face each other in the main detection region 37 being set to the range of 40-100 mm.

Description

Liquid detection sheet for medical use

[0001] The present invention relates to a medical liquid sensing sheet used in the medical field to detect blood leakage and the like.

[0002] In medical settings, early detection of blood or other liquid leaks is sometimes necessary. For example, during dialysis or infusion, a needle may come out of the patient's body, causing blood or liquid medicine to leak from the puncture site. It is necessary to detect and address leaks before they become a major problem. However, because it is not practical for busy medical professionals to continuously monitor dialysis, infusion, and other procedures from start to finish, the adoption of liquid detection devices that automatically detect leaks is being considered.

[0003] Conventionally, for example, Japanese Patent Application Laid-Open No. 2012-196293 (Patent Document 1) has proposed a liquid detection device that detects liquid leakage based on a change in electrical resistance caused by a short circuit between two detection wires due to blood or a chemical solution.

[0004] JP 2012-196293 A

[0005] However, with conventional liquid detection devices, when using the device, it is necessary to check that there are no breaks in either of the two detection wires that are wired in parallel, and this requires a relatively large check voltage, making the check before use cumbersome.

[0006] In addition, there are cases where the patient's sweating or the like is mistakenly detected as a liquid leak, and there is a need to effectively detect target liquids such as blood and medicinal liquids while avoiding the mistaken detection of liquids that do not need to be detected, such as sweat.

[0007] Furthermore, in Patent Document 1, the sheet that constitutes the liquid detection area has a six-layer structure, which results in a large number of parts and makes manufacturing time-consuming.

[0008] Furthermore, in conventional liquid detection devices, an external circuit is generally connected to two detection wires via a detachable connector, but there is a risk that the electrical connection will not be properly established if the connector is connected at an angle. Furthermore, external forces are often applied to the connector, which can cause the connector to become misaligned or the connector wiring to break. There is also a need for a device that allows the connector to be easily attached to the sheet that constitutes the liquid detection area.

[0009] The problem to be solved by the present invention is to provide a medical liquid detection sheet with a novel structure that can solve at least one of the problems inherent in conventional liquid detection devices as described above.

[0010] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely examples and may be appropriately combined with one another. Multiple components described in each embodiment may be recognized and employed independently to the greatest extent possible, and may also be appropriately combined with any of the components described in other embodiments. Accordingly, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0011] The first aspect is a medical liquid detection sheet in which first and second detection wirings are provided at a distance from each other on an electrically insulating base member, and which detects leakage of a liquid to be detected, such as blood, based on a change in the electrical connection state between the first and second detection wirings due to the adhesion of the liquid to be detected, wherein a main detection area is provided on the base member in which the first and second detection wirings extend approximately parallel to each other, and the distance between the first and second detection wirings in the main detection area is set to be within the range of 40 to 100 mm.

[0012] In a medical liquid detecting sheet constructed according to this aspect, the distance between the first and second detection wires in the main detection area is set to a range of 40 to 100 mm, making it difficult to detect relatively small amounts of liquid such as sweat, while effectively detecting target liquids that have accumulated to a certain amount on the base member. Therefore, the target target liquid can be detected with high accuracy, making it possible to reliably detect, for example, potentially dangerous blood leaks, and reduce the frequency of false detections caused by sweat, etc.

[0013] The second aspect is a medical liquid detection sheet in which a plurality of detection wires are arranged spaced apart from one another on an electrically insulating base member, and which detects leakage of the liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, and the upper surface of the base member on which the plurality of detection wires are printed is covered with nonwoven fabric, and the base member and the nonwoven fabric are fixed to each other by a heat-sealing sheet.

[0014] In a medical liquid detecting sheet constructed according to this embodiment, the detection wiring is printed on the base member, resulting in a three-layer structure with a small number of layers, which facilitates manufacturing and reduces costs. Furthermore, by providing a nonwoven fabric covering the upper surface of the base member on which the detection wiring is printed, the tactile feel of the medical liquid detecting sheet at the portion that comes into contact with the patient's arm or the like can be improved, and the liquid to be detected is absorbed and spread by the nonwoven fabric, thereby preventing the liquid from spilling or adhering to the patient. Furthermore, the base member and the nonwoven fabric can be bonded to each other by heating the thermal welding sheet in a state in which the base member, thermal welding sheet, and nonwoven fabric are layered together, without the need for an adhesive application process.

[0015] The third aspect is a medical liquid detection sheet in which a plurality of detection wires are arranged spaced apart from one another on an electrically insulating base member, and the sheet detects leakage of the liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, and a liquid-impermeable member is arranged below the plurality of detection wires to prevent the passage of the liquid to be detected.

[0016] With a medical liquid detection sheet constructed according to this embodiment, the detection target liquid is prevented from passing through the liquid-impermeable member and leaking downward, so that the detection target liquid that accumulates on the liquid-impermeable member can be detected with excellent reliability. Furthermore, by retaining the detection target liquid on the liquid-impermeable member, contamination of the bed due to the adhesion of the detection target liquid can be avoided, for example, when the medical liquid detection sheet is laid on a bed.

[0017] A fourth aspect is a medical liquid detection sheet according to the third aspect, in which the terminals of the plurality of detection wirings are arranged at the central part of the width direction of the base member at the outer peripheral edge of the base member.

[0018] A medical liquid detection sheet comprising a liquid-impermeable member cannot be used inside out, and if, for example, the terminals of the detection wires arranged at the outer peripheral edge of the base member are arranged unevenly in the width direction of the base member, the distance from the terminals of the detection wires to the external device will change when the sheet is placed under the patient's left arm and when it is placed under the patient's right arm, resulting in differences in the length and routing required for the external wires connected to the terminals of the detection wires.With a medical liquid detection sheet constructed according to this embodiment, the terminals of the detection wires are arranged in the center part in the width direction of the base member, so even if the sheet cannot be used inside out, differences in the routing of the external wires are reduced when the sheet is used on the patient's left side and when it is used on the patient's right side, and the external wires are less likely to get in the way in either case.

[0019] The fifth aspect is a medical liquid detection sheet in which a first detection wiring and a second detection wiring are arranged spaced apart from each other on an electrically insulating base member, and the sheet detects leakage of the liquid to be detected, such as blood, based on a change in the electrical connection state between the first detection wiring and the second detection wiring due to the adhesion of the liquid to be detected, and the second detection wiring is arranged so as to surround the first detection wiring on the base member.

[0020] In the medical liquid detecting sheet constructed according to this embodiment, by connecting a check circuit to both ends of the second detection wire, it is possible to check the electrical state (disconnection, etc.) of the second detection wire by applying a small check voltage. Furthermore, since the first detection wire has a specific wiring configuration relative to the second detection wire, it is possible to infer whether the second detection wire is in a normal state by checking the second detection wire.

[0021] That is, damage such as breakage of the first detection wiring and the second detection wiring generally occurs due to bending of the detection sheet. Here, in this embodiment, the first detection wiring and the second detection wiring, which detect liquid based on changes in their electrical connection state, are relatively close to each other, and the second detection wiring surrounds the first detection wiring. Therefore, bending of the first detection wiring is accompanied by bending of the second detection wiring, making it difficult to imagine breakage due to bending of the first detection wiring alone. Therefore, for example, if the first detection wiring breaks due to bending of the base member, the second detection wiring arranged to surround the first detection wiring will also break. Therefore, by checking the electrical state of the second detection wiring, the electrical state of the first detection wiring can also be estimated.

[0022] In this way, electrical abnormalities such as a broken wire in the first detection wiring can be confirmed based on the electrical state of the second detection wiring, making it possible to easily check the first and second detection wiring.

[0023] In a sixth aspect, in the medical liquid detection sheet described in the fifth aspect, the first detection wiring and the second detection wiring are each formed into a roughly comb-like shape with opposing wiring portions extending roughly parallel to each other and a plurality of branch-like wiring portions extending from each of the opposing wiring portions in opposing directions, and the branch-like wiring portions of the first detection wiring and the second detection wiring are arranged in the length direction of the opposing wiring portions so as to interdigitate with each other in the opposing directions of the opposing wiring portions.

[0024] The medical liquid detection sheet constructed according to this aspect can prevent the gap between the first detection wire and the second detection wire from becoming too large, thereby enabling accurate detection of the liquid to be detected. Furthermore, since the branched wiring portions interdigitate with each other in the opposing direction of the opposing wiring portions and are arranged in the length direction of the opposing wiring portions, a relatively wide effective detection area can be efficiently obtained.

[0025] In a seventh aspect, in the medical liquid detection sheet described in the fifth or sixth aspect, a first terminal is provided at one end of the first detection wiring, and a pair of second terminals are provided at both ends of the second detection wiring, the first terminal and the pair of second terminals are arranged in a linear line, and the first terminal is located between the pair of second terminals.

[0026] In a medical liquid detection sheet constructed according to this aspect, the first terminal provided at one end of the first detection wire and the pair of second terminals provided at both ends of the second detection wire are linearly arranged side by side, which facilitates connection of the detection circuit to the first terminal and the second terminal. In particular, the first terminal is arranged between the pair of second terminals, which facilitates arrangement of the second detection wire so as to surround the first detection wire.

[0027] In an eighth aspect, in the medical liquid detection sheet described in any one of the fifth to seventh aspects, the base member is a substrate sheet that is impermeable to the liquid to be detected, the first detection wiring and the second detection wiring are printed on the upper surface of the substrate sheet, and an electrically insulating liquid-permeable sheet that allows the liquid to be detected to pass through is provided on the upper surface of the substrate sheet so as to cover the first detection wiring and the second detection wiring.

[0028] In a medical liquid detecting sheet constructed according to this embodiment, the base sheet is impermeable to the liquid to be detected, so the liquid to be detected accumulates on the base sheet. As a result, the amount of liquid to be detected on the base sheet gradually increases, and the area of ​​the liquid to be detected on the base sheet increases, increasing the likelihood that the liquid to be detected will come into contact with both the first detection wire and the second detection wire. Furthermore, a base sheet that does not require liquid permeability can easily have a smooth surface, and by printing the first and second detection wires on the base sheet, disconnections of the first and second detection wires due to printing defects are less likely to occur.

[0029] A liquid-permeable sheet having liquid permeability is superimposed on the base sheet. The liquid-permeable sheet diffuses and transmits the liquid to be detected that adheres from above, facilitating electrical conduction between the first and second detection wires and improving detection reliability. Furthermore, the liquid-permeable sheet restricts the flow of the liquid to be detected on the base sheet, making it difficult for the liquid to spill off the base sheet. Instead, it accumulates on the base sheet, making it easier to detect, and preventing contamination of the surrounding area by the liquid to be detected. Furthermore, the liquid-permeable sheet covering the first and second detection wires printed on the base sheet is electrically insulating. Therefore, even if a patient's body comes into contact with the liquid-permeable sheet, electrical conduction between the first and second detection wires is not established, preventing false detection.

[0030] In a ninth aspect, the medical liquid detection sheet according to any one of the fifth to eighth aspects is provided with a status confirmation member that is connected to both ends of the second detection wiring and that checks the electrical status of the second detection wiring by applying a check voltage to the second detection wiring.

[0031] According to the medical liquid detection sheet constructed in accordance with this embodiment, the status confirmation member is connected to both ends of the second detection wiring, so that the electrical status of the second detection wiring can be confirmed with a relatively small check voltage.

[0032] The tenth aspect is a medical liquid detection sheet in which a plurality of detection wires are arranged spaced apart from one another on an electrically insulating base member, and which detects leakage of the liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, and the plurality of detection wires are connected to each other by resistors at a position outside the main detection area that detects leakage of the liquid to be detected.

[0033] According to a medical liquid detection sheet constructed in accordance with this embodiment, it is possible to check for disconnection of the detection wiring and detect liquid based on the difference in electrical resistance by applying the same voltage.

[0034] Furthermore, for example, a resistor can be provided in the internal circuit of a connector connected to the medical liquid detecting sheet, which allows greater freedom in resistor selection compared to providing a resistor in the main detection area of ​​the medical liquid detecting sheet. Furthermore, by locating the resistor at a position outside the main detection area with which the target liquid comes into contact, it is possible to prevent the target liquid from coming into contact with the resistor.

[0035] An eleventh aspect is a medical liquid detection sheet in which a first detection wiring and a second detection wiring are provided spaced apart from each other on an electrically insulating base member, and which detects leakage of a liquid to be detected, such as blood, based on a change in the electrical connection state between the first detection wiring and the second detection wiring due to the adhesion of the liquid to be detected, and one of the first detection wiring and the second detection wiring has a curved portion that extends in an approximately arc shape and is spaced outward from the other end of the first detection wiring or the second detection wiring.

[0036] According to a medical liquid detection sheet constructed in accordance with this aspect, the change in the distance between the end of either the first or second detection wiring and the other end of either the first or second detection wiring in the length direction of the detection wiring is reduced, thereby suppressing the change in the amount of liquid to be detected that can be detected in the length direction of one of the detection wirings, thereby enabling reliable liquid detection.

[0037] The twelfth aspect is a medical liquid detection sheet in which a plurality of detection wires are arranged spaced apart from one another on an electrically insulating base member, and detects leakage of a liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, in which the terminals of the plurality of detection wires are arranged side by side on the outer periphery of the base member, and positioning portions for positioning a connector, which has external wiring electrically connected to the terminals, relative to the base member are provided on both sides of the arrangement direction of the terminals on the base member and in close proximity to the terminals.

[0038] According to a medical liquid detection sheet constructed in accordance with this embodiment, the base member and the connector are positioned by the positioning portion at a position close to a pair of terminals located at both ends in the terminal arrangement direction, so that the connector is appropriately positioned relative to the pair of terminals at both ends.

[0039] Furthermore, if there is an intermediate terminal between a pair of terminals at both ends, by properly positioning the connector with respect to the pair of terminals at both ends, the connector can also be properly positioned with respect to the intermediate terminal located between the pair of terminals at both ends, and the internal circuit of the connector can be stably connected to all of the multiple terminals.

[0040] Even if an external force acts between the connector and the base member in a direction that pulls them apart, unintentional separation of the connector and the base member is prevented, and the electrical connection between the connector and the base member, and ultimately between the external wiring of the connector and the first and second detection wiring on the base member, is maintained.

[0041] In a thirteenth aspect, in the medical liquid detection sheet described in the twelfth aspect, the base member is a substrate sheet that is impermeable to the liquid to be detected, and the substrate sheet is provided with a positioning hole through which a positioning pin protruding from the connector is inserted, and the positioning portion is configured to include the positioning hole.

[0042] In a medical liquid detecting sheet constructed according to this aspect, the simple structure in which the positioning pins on the connector side are inserted into the positioning holes in the base sheet makes it easy to achieve appropriate connection between the multiple terminals provided on the base sheet and the internal circuit of the connector. In particular, when the base member is a thin base sheet, it is easy to form the positioning holes and the positioning function is also effective.

[0043] In a fourteenth aspect, in the medical liquid detection sheet described in the thirteenth aspect, a ring-shaped reinforcing portion is provided at the peripheral edge of the opening of the positioning hole in the base sheet, protruding in the thickness direction of the base sheet.

[0044] In a medical liquid detection sheet constructed according to this aspect, the reinforcing portion prevents damage such as tearing of the base sheet when the positioning pin is pressed against the inner surface of the positioning hole due to the action of an external force. Furthermore, because the length of the positioning hole provided in the thin-walled base sheet is increased by the reinforcing portion, the contact area between the positioning pin and the positioning hole is increased, making it possible to obtain a more advantageous positioning effect and also expecting improved durability due to the distribution of stress.

[0045] The fifteenth aspect is a medical liquid detection sheet in which a plurality of detection wires are arranged spaced apart from one another on an electrically insulating base member, and which detects leakage of a liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, and a connector is provided having an internal circuit electrically connected to each terminal of the plurality of detection wires, and an external wire is electrically connected to the internal circuit of the connector and extends to the outside from the connector, bent so as to fold back at the end where it extends from the internal circuit to the connection side of the connector to the terminal, and extends to the outside from the connector on the side opposite to the connection side to the terminal of the connector.

[0046] In a medical liquid detection sheet constructed in accordance with this embodiment, the external wiring is curved so that it folds back at the end where it extends from the internal circuit to the connection side to the connector terminal, so that if the external wiring is pulled, for example, by the action of an external force, deformation of the curved portion prevents damage to the external wiring itself or the connection portion between the external wiring and the internal circuit.

[0047] In a sixteenth aspect, there is provided a medical liquid detection sheet in which a plurality of detection wires are spaced apart from one another on an electrically insulating base member, and which detects leakage of a liquid to be detected, such as blood, based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the liquid to be detected, and a connector is provided which has an internal circuit electrically connected to each terminal of the plurality of detection wires, and the tip portions of the connector have an upper jaw portion and a lower jaw portion which are relatively displaceable in the direction of separation and direction of approach, and the outer periphery of the base member is sandwiched between the upper jaw portion and the lower jaw portion in the vertical direction, so that the external wiring is electrically connected to the terminal via the internal circuit of the connector, and the lower jaw portion of the connector which is arranged below the base member has an upper surface which is inclined downward toward the attachment tip side of the connector to the base member, and is thin in the vertical direction toward the attachment tip side of the connector.

[0048] In a medical liquid detection sheet constructed in accordance with this embodiment, the lower jaw of the connector is thin in the vertical direction toward the tip of the attachment to the base member, making it easy to insert the lower jaw of the connector below the base member placed on the bed, facilitating the work of connecting the connector to the base member placed on the bed.

[0049] In a seventeenth aspect, in the medical liquid detection device described in the sixteenth aspect, the connector is provided with a biasing member that biases the attachment tip portions of the upper jaw and the lower jaw to the base member in the direction of moving closer to each other.

[0050] With a medical liquid detecting sheet constructed according to this aspect, the upper and lower jaws are biased by the biasing member in directions that move them closer to each other, and the connector can be easily attached to the base member by clamping the base member between the upper and lower jaws with the biasing force of the biasing member. Furthermore, because the attached state of the connector to the base member is maintained by the biasing force applied to the upper and lower jaws by the biasing member, no special locking operation is required.

[0051] According to the present invention, for example, false detection of sweating of a patient that does not require detection can be suppressed, and the liquid to be detected can be detected with high accuracy.

[0052] FIG. 1 is a plan view showing a liquid-detection device equipped with a medical liquid-detection sheet according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 3 is a cross-sectional view of the liquid-detection device shown in FIG. 1, corresponding to the cross-section taken along line III-III of FIG. 1; FIG. 4 is a diagram illustrating the laminated structure of the liquid-detection sheet shown in FIG. 1; FIG. 5 is a diagram illustrating the use state of the liquid-detection device shown in FIG. 1, showing a state in which blood leakage has not been detected; FIG. 6 is a diagram illustrating the use state of the liquid-detection device shown in FIG. 1, showing a state in which blood leakage has been detected;

[0053] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0054] 1 to 3 show a liquid detection device 12 equipped with a medical liquid detective sheet 10 according to a first embodiment of the present invention. The liquid detection device 12 has a structure in which a connector 14 is attached to the liquid detective sheet 10. In the following description, as a general rule, the up-down direction refers to the up-down direction in FIG. 3, which is the vertical up-down direction in the state of use, the front-rear direction refers to the up-down direction in FIG. 1, and the left-right direction refers to the left-right direction in FIG. 1. In the figures, the thickness of components and the width of detection wiring are exaggerated for ease of viewing.

[0055] As shown in FIG. 4, the liquid detection sheet 10 has a laminated structure in which a substrate sheet 16 as a base member and a liquid-permeable sheet 18 superimposed on the upper surface of the substrate sheet 16 are fixed to each other by an adhesive sheet 20.

[0056] The base sheet 16 is in the form of a thin sheet or film. The base sheet 16 is a liquid-impermeable member that does not allow liquids such as blood to pass through. The base sheet 16 is made of an electrically insulating material. The base sheet 16 is made of, for example, a synthetic resin material, and specifically, can be made of polyethylene terephthalate (PET). The thickness of the base sheet 16 is preferably 0.01 mm to 0.5 mm from the viewpoint of ensuring the necessary electrical insulation while minimizing discomfort (stiffness) when a patient places their arm or the like on the liquid-detecting sheet 10; in this embodiment, the thickness is, for example, 0.05 mm.

[0057] A first detection wiring 22 and a second detection wiring 24 are provided on the base sheet 16. The first detection wiring 22 and the second detection wiring 24 are both formed from a conductive material, for example, a conductive paste made by mixing a synthetic resin material with a conductive filler made from a conductive material such as metal or carbon. The first detection wiring 22 and the second detection wiring 24 made from conductive paste are each printed in a predetermined shape (pattern) on the upper surface of the base sheet 16. Therefore, the liquid-impermeable base sheet 16 is arranged below the first detection wiring 22 and the second detection wiring 24.

[0058] 1, the first detection wiring 22 has a first central detection section 26 that is shaped like a lateral U with an open left side in the center of the base sheet 16, and a terminal connection section 28 that extends linearly from the first central detection section 26 toward the rear of the base sheet 16. A first terminal 30 is provided at the rear end of the terminal connection section 28 of the first detection wiring 22, located at the rear end portion of the base sheet 16, and is electrically connected to a connector 14, which will be described later.

[0059] The second detection wire 24 is spaced apart from the first detection wire 22 and surrounds the first detection wire 22. That is, the second detection wire 24 includes an outer periphery detection portion 32 that surrounds the first central detection portion 26 of the first detection wire 22, and a second central detection portion 34 that extends from the outer periphery detection portion 32 so as to be inserted into the left opening of the first central detection portion 26 of the first detection wire 22. The outer periphery detection portion 32 of the second detection wire 24 is located at the rear end of the base sheet 16, with both ends spaced apart on either side of the terminal connection portion 28 of the first detection wire 22. A pair of second terminals 36, 36 are provided at both ends of the outer periphery detection portion 32 of the second detection wire 24. The pair of second terminals 36, 36 are spaced apart on either side of the first terminal 30, and the first terminal 30 and the second terminals 36, 36 are linearly aligned in the left-right direction. Therefore, in this embodiment, the first terminal 30 and the second terminals 36, 36 are arranged in the left-right direction. The first terminal 30 and the second terminals 36, 36 are preferably provided in the central portion of the base sheet 16 in the left-right width direction, and more preferably, are provided approximately symmetrically with respect to the center line of the base sheet 16 in the left-right direction. As a result, when the liquid-detecting sheet 10 is used on either the left or right forearm (5) of the patient (1) in a usage state described below, the connector 14 can be positioned in the central portion of the base sheet 16 in the left-right direction with the connector 14 positioned on the opposite side (outside) of the patient's (1) to the torso. Therefore, for example, the distance from the connector 14 to a detection device (52) described below does not change significantly, making it easier to avoid excessive or insufficient wiring length.

[0060] The left end 32a of the outer periphery detection portion 32 of the second detection wiring 24 extends in the front-rear direction and is substantially parallel to the right end 26a, which extends in the front-rear direction, of the first central detection portion 26 of the first detection wiring 22, so that they face each other in the left-right direction. The right end 26a, which extends in the front-rear direction, of the first central detection portion 26 and the left end 32a, which extends in the front-rear direction, of the outer periphery detection portion 32 are each defined as opposing wiring portions in this embodiment. The first central detector 26 has front and rear end portions 26b, 26c extending leftward from the right end portion 26a, and on both the front and rear outer sides of the first central detector 26, front and rear end portions 32b, 32c of the outer peripheral detector 32 extending rightward from the left end portion 32a of the outer peripheral detector 32 are arranged, and a second central detector 34 extends rightward from the left end portion 32a of the outer peripheral detector 32 between the front and rear end portions 26b, 26c of the first central detector 26. Thus, the first detection wiring 22 and the second detection wiring 24 have branched wiring portions 26b, 26c, 32b, 32c, 34 extending linearly from the opposing wiring portions 26a, 32a in the opposing directions of the opposing wiring portions 26a, 32a. Therefore, the portions of the first detection wiring 22 and the second detection wiring 24 formed by each opposing wiring portion 26a, 32a and each branch-like wiring portion 26b, 26c, 32b, 32c, 34 are roughly comb-shaped, and the branch-like wiring portions 26b, 26c of the first detection wiring 22 and the branch-like wiring portions 32b, 32c, 34 of the second detection wiring 24 are arranged alternately at roughly regular intervals in the front-to-back direction so as to interdigitate with each other in the left-to-right direction.

[0061] Therefore, the right end 26a of the first central detection portion 26 of the first detection wiring 22 and the left end 32a of the outer periphery detection portion 32 of the second detection wiring 24 extend parallel to each other, and the front and rear end portions 26b, 26c of the first central detection portion 26 extend parallel to the front and rear end portions 32b, 32c of the outer periphery detection portion 32 of the second detection wiring 24 and the second central detection portion 34. The main detection region 37 of this embodiment is formed by the portions of the first and second detection wirings 22, 24 that extend parallel to each other and face each other. The main detection region 37 of this embodiment is set in the inner periphery of the liquid detection sheet 10 that is surrounded by the outer periphery detection portion 32 of the second detection wiring 24. In this embodiment, the right end 26a of the first central detection unit 26 and the right end 32d of the outer peripheral detection unit 32 extend approximately parallel to each other at a distance from each other, and the distance between them is approximately the same as the distance D between the front and rear ends 26b, 26c of the first central detection unit 26 and the front and rear ends 32b, 32c of the outer peripheral detection unit 32 and the second central detection unit 34, and the right end 26a of the first central detection unit 26 and the right end 32d of the outer peripheral detection unit 32 also constitute the main detection area 37.

[0062] The first detection wiring 22 and the second detection wiring 24 are spaced apart from each other on the base sheet 16, and the opposing distance D (opposing distance of the main detection region 37) between the first central detection portion 26 of the first detection wiring 22 and the outer periphery detection portion 32 and second central detection portion 34 of the second detection wiring 24 is set within a range of 40 mm to 100 mm. In this embodiment, the first central detection portion 26 of the first detection wiring 22 and the outer periphery detection portion 32 and second central detection portion 34 of the second detection wiring 24 each have a shape formed by combining a plurality of straight line portions (the right end portion 26 a, front end portion 26 b, and rear end portion 26 c of the first detection wiring 22, and the left end portion 32 a, front end portion 32 b, rear end portion 32 c, right end portion 32 d, and second central detection portion 34 of the second detection wiring 24). The opposing distance D between the first central detector 26 of the first detection wiring 22 and the outer periphery detector 32 and second central detector 34 of the second detection wiring 24 refers to the distance between each straight line portion of the first central detector 26, the outer periphery detector 32, and the second central detector 34 that extend substantially parallel to one another. In this embodiment, the distance D between each straight line portion of the first central detector 26, the outer periphery detector 32, and the second central detector 34 is substantially constant. However, the distance between each straight line portion of the first central detector 26, the outer periphery detector 32, and the second central detector 34 may vary from one straight line portion to another. In this case, the minimum distance between the straight line portions is set to 40 mm or more, and the maximum distance between the straight line portions is set to 100 mm or less.

[0063] A pair of positioning holes 38, 38 are provided at the rear end of the base sheet 16 as positioning portions. The positioning holes 38 penetrate the base sheet 16 in the thickness direction and have, for example, a circular cross section. The pair of positioning holes 38, 38 are spaced apart from each other in the left-right direction and are located on both the left and right outer sides of the pair of second terminals 36, 36. The positioning holes 38 are arranged close to the second terminals 36 in the left-right direction, and the distance between the adjacent positioning holes 38 and second terminals 36 is, for example, 30 mm or less, more preferably 15 mm or less.

[0064] An annular reinforcing portion 40 is provided around the opening periphery of each positioning hole 38. The reinforcing portion 40 is provided so as to protrude outward in the thickness direction of the base sheet 16 at the opening periphery of the positioning hole 38. The reinforcing portion 40 is formed, for example, from a synthetic resin or a metal, and increases the deformation rigidity of the base sheet 16 in the area where the reinforcing portion 40 is provided. The reinforcing portion 40 may be formed integrally with the base sheet 16, or may be formed as a separate member from the base sheet 16 and fixed to the base sheet 16 by welding or other means. In this embodiment, the reinforcing portion 40 is provided on both the upper and lower opening peripheries of the positioning hole 38, but may also be provided on only one of the upper and lower opening peripheries, for example.

[0065] The liquid-permeable sheet 18 is liquid-permeable, allowing the passage of a detection target liquid such as blood, and is electrically insulating. The liquid-permeable sheet 18 may be woven or knitted, but is, for example, made of a nonwoven fabric. As shown in FIG. 4 , the liquid-permeable sheet 18 is overlaid on the upper surface of the base sheet 16 and covers the first detection wiring 22 and the second detection wiring 24 provided on the upper surface of the base sheet 16. The liquid-permeable sheet 18 has approximately the same left-right dimension as the base sheet 16 but is shorter in the front-to-rear direction, so that the rear end of the base sheet 16 protrudes rearward from the liquid-permeable sheet 18 and is exposed. Therefore, the first terminal 30 and the second terminals 36, 36 are not covered by the liquid-permeable sheet 18 and are exposed to the outside behind the liquid-permeable sheet 18. In this embodiment, the pair of positioning holes 38, 38 arranged on the left and right outer sides of the second terminals 36, 36 are located rearward of the liquid-permeable sheet 18 and are formed only in the base sheet 16.

[0066] The base sheet 16 and the liquid-permeable sheet 18 are connected to each other by an adhesive sheet 20 serving as an adhesive layer. The adhesive sheet 20 is, for example, a synthetic resin sheet with adhesive layers on both sides. One adhesive layer is adhered to the base sheet 16, and the other adhesive layer is adhered to the liquid-permeable sheet 18, thereby holding the base sheet 16 and the liquid-permeable sheet 18 in an overlapping state. The adhesive sheet 20 is liquid-permeable, allowing the liquid to be detected to pass through. The adhesive sheet 20 may be, for example, a heat-sealed sheet. A heat-sealed sheet is formed from a thermoplastic resin such as polyimide, polyester, or polyurethane, and becomes adhesive when heated and solidifies when cooled. Therefore, the base sheet 16 and the liquid-permeable sheet 18 can be adhered to each other by overlapping the heat-sealed sheet (adhesive sheet 20) on the top surface of the base sheet 16 and interposing it between the base sheet 16 and the liquid-permeable sheet 18, and then heating and cooling the heat-sealed sheet. The adhesive sheet 20 (thermal welding sheet) may be mesh-like, for example, to allow the passage of the liquid to be detected even if it is not made of a liquid-permeable material. The base sheet 16 and the liquid-permeable sheet 18 may be connected to each other, for example, by an adhesive, without using the adhesive sheet 20. The thermal welding sheet may be made of a thermosetting resin such as an epoxy resin.

[0067] A connector 14 is attached to the liquid detective sheet 10 having such a structure. The connector 14 has an internal circuit 42 (see FIG. 3 ) that is connected to the first detection wiring 22 and the second detection wiring 24 of the liquid detective sheet 10, and has external wiring 44 that is electrically connected to the internal circuit 42 and extends to the outside. The internal circuit 42 of the connector 14 is connected to an external detection device 52 (described below) via the external wiring 44.

[0068] The connector 14 is attached to the rear end portion of the liquid-detecting sheet 10. That is, the connector 14 has a lower jaw 46 that is superimposed on the lower surface of the base sheet 16, and an upper jaw 48 that is superimposed on the upper surface of the base sheet 16, and the base sheet 16 is sandwiched between the lower jaw 46 and the upper jaw 48.

[0069] With the base sheet 16 sandwiched between the lower jaw 46 and the upper jaw 48 of the connector 14, the portion of the internal circuit 42 exposed on the underside of the upper jaw 48 is superimposed on and in contact with the first terminal 30 and the second terminals 36, 36, as shown in Figure 3. This electrically connects the internal circuit 42 of the connector 14 to the first detection wiring 22 and the second detection wiring 24.

[0070] The lower jaw 46 is provided with a pair of positioning pins 50, 50. The positioning pins 50 protrude upward from the lower jaw 46 and have a circular cross-sectional shape that corresponds to the cross-section of the positioning hole 38 in the base sheet 16. In this embodiment, the positioning hole 38 is generally cylindrical so that it can be inserted into the positioning hole 38. The pair of positioning pins 50, 50 are spaced apart from each other in the left-right direction. The left-right separation distance between the pair of positioning pins 50, 50 is greater than the left-right dimension of the portion of the upper jaw 48 that is located between the pair of positioning pins 50, 50. When the connector 14 is attached to the base sheet 16, the upper jaw 48 is located between the pair of positioning pins 50, 50.

[0071] When the base sheet 16 is sandwiched between the lower jaw 46 and the upper jaw 48, the positioning pins 50 of the connector 14 are inserted into the positioning holes 38 of the base sheet 16. Therefore, the connector 14 is positioned in the up-down direction relative to the base sheet 16 by sandwiching the base sheet 16 between the lower jaw 46 and the upper jaw 48. Furthermore, the connector 14 is positioned in the front-to-back and left-to-right directions relative to the base sheet 16 by inserting a pair of positioning pins 50 on the lower jaw 46 into the positioning holes 38 of the base sheet 16. As a result, the internal circuit 42 of the connector 14 and the first and second terminals 30, 36, 36 on the base sheet 16 are positioned in contact with each other, achieving a stable connection. The connector 14 may be provided with a locking mechanism that maintains the base sheet 16 sandwiched between the lower jaw 46 and the upper jaw 48. This prevents the lower jaw 46 and the upper jaw 48 from opening unintentionally, and prevents the positioning pins 50, 50 from coming out of the positioning holes 38, 38.

[0072] The positioning holes 38, 38 of the base sheet 16 are provided in close proximity to the second terminals 36, 36 on both the left and right outer sides, and the positioning action of the positioning holes 38, 38 and the positioning pins 50, 50 efficiently contributes to the positioning of the second terminals 36, 36 and the internal circuit 42. Furthermore, the first terminal 30 is disposed between the second terminals 36, 36, and if the second terminals 36, 36 and the internal circuit 42 are positioned, the first terminal 30 and the internal circuit 42 are also automatically positioned. Therefore, the positioning holes 38, 38 and the positioning pins 50, 50 can position all of the first and second terminals 30, 36, 36 with respect to the internal circuit 42.

[0073] Because the positioning pins 50, 50 of the connector 14 are inserted into the positioning holes 38, 38 of the base sheet 16, even if a backward force acts on the connector 14, pulling it away from the base sheet 16, the connector 14 will not easily come off the base sheet 16, and the connection between the connector 14 and the base sheet 16, and ultimately the connection between the internal circuit 42 and the first and second terminals 30, 36, 36, is maintained stably.

[0074] An annular reinforcing portion 40 is provided on the opening periphery on both the top and bottom sides of each positioning hole 38. This prevents damage to the base sheet 16 that would otherwise occur if the positioning pin 50 were pressed strongly against the inner peripheral surface of the positioning hole 38 when, for example, an external force in the front-to-back and / or left-to-right directions acts between the connector 14 and the base sheet 16. Because the reinforcing portion 40 protrudes outward in the thickness direction of the base sheet 16, the length of the positioning hole 38 is increased by the length of the reinforcing portion 40, increasing the contact area between the positioning pin 50 and the positioning hole 38. This provides a more effective positioning effect and is expected to improve durability due to stress dispersion.

[0075] 1, the external wiring 44 of the connector 14 connected to the liquid detective sheet 10 is connected to a detection device 52. The detection device 52 applies a detection voltage between the first detection wiring 22 and the second detection wiring 24 via the connector 14, and detects the target liquid on the liquid detective sheet 10 based on, for example, a change in the electrical connection state between the first detection wiring 22 and the second detection wiring 24.

[0076] That is, when a liquid to be detected adheres to the liquid detection sheet 10 from above, the liquid to be detected is first absorbed by the liquid-permeable sheet 18 and passes through the liquid-permeable sheet 18 while diffusing. The liquid to be detected that has passed through the liquid-permeable sheet 18 reaches the upper surface of the base sheet 16. Because the base sheet 16 does not allow liquid to pass through, the liquid to be detected spreads on the base sheet 16, and as the amount of the liquid to be detected increases, the area of ​​the liquid to be detected on the base sheet 16 increases. Then, when the amount of the liquid to be detected on the base sheet 16 exceeds a predetermined amount, the liquid to be detected spreads across the first detection wiring 22 and the second detection wiring 24, and the first detection wiring 22 and the second detection wiring 24 are mutually conductive via the liquid to be detected. As a result, the electrical resistance between the first and second detection wirings 22, 24 changes, and the detection device 52 detects the presence of the liquid to be detected on the base sheet 16 based on the change in the electrical connection state between the first and second detection wirings 22, 24 by applying a detection voltage between the first and second detection wirings 22, 24.

[0077] The detection device 52 also includes a state checking member 54 that checks the electrical state, such as whether the second detection wiring 24 is broken, of the second detection wiring 24. That is, since both second terminals 36, 36 at both ends of the second detection wiring 24 are connected to the detection device 52, it is possible to check the electrical state, such as whether the second detection wiring 24 is broken, by applying a relatively small check voltage between the second terminals 36, 36.

[0078] Because the first detection wiring 22 is surrounded by the second detection wiring 24, if the checking function of the detection device 52 confirms that the second detection wiring 24 is not broken, it can be assumed that the first detection wiring 22 is not broken. That is, unless there is a manufacturing defect, breaks in the first and second detection wirings 22, 24 are almost always caused by folding of the base sheet 16. However, folding of the base sheet 16 rarely bends only the first detection wiring 22 located on the inner periphery, and in most cases, it also bends the second detection wiring 24 located on the outer periphery. Therefore, it is rare for only the first detection wiring 22 to be broken without also breaking the second detection wiring 24, and there is no practical problem in assuming that the first detection wiring 22 is not broken based on the absence of a break in the second detection wiring 24.

[0079] In this embodiment, the first terminal 30 provided on the first detection wire 22 is disposed between the second terminals 36, 36 provided on both ends of the second detection wire 24, which makes it easy to arrange the second detection wire 24 so as to surround the first detection wire 22. Furthermore, the first terminal 30 and the second terminals 36, 36 are arranged side by side in the left-right direction at the rear end of the base sheet 16, which makes it easy to connect the first and second terminals 30, 36, 36 to the internal circuit 42 of the connector 14.

[0080] The first and second detection wirings 22, 24 are printed on the surface of the base sheet 16. The base sheet 16 is made of a liquid-impermeable PET film or the like, which makes it easy to make the surface smooth, so that the first and second detection wirings 22, 24 can be formed with high precision and defects such as wire breakage are unlikely to occur. Note that wire breakage due to poor formation of the first detection wiring 22 during the manufacturing stage can be checked using a known tester.

[0081] The liquid-detection device 12 having such a structure is used as shown in Fig. 5A. That is, Fig. 5A shows a case where the liquid-detection device 12 is used when a patient 1 undergoes dialysis treatment using an artificial dialysis machine 2, and external wiring 44 extending from the connector 14 of the liquid-detection device 12 is connected to a detection device 52 attached to the artificial dialysis machine 2. In Fig. 5A, the forearm 5 of the patient 1, punctured with the blood collection port 3 and blood return port 4 of the artificial dialysis circuit, is placed on the liquid-detecting sheet 10 of the liquid-detection device 12.

[0082] Although the forearm 5 of the patient 1 is conductive, an electrically insulating liquid-permeable sheet 18 is interposed between the forearm 5 and the first and second detection wires 22, 24. This reduces changes in the electrical resistance between the first and second detection wires 22, 24 due to the forearm 5, preventing erroneous detection of liquid due to the conductivity of the forearm 5. Preferably, a part of the patient 1 that is at risk of blood leakage or the like is placed on the main detection area 37 of the liquid detection sheet 10, positioned approximately at the center of the liquid detection sheet 10. In particular, in this embodiment, the forearm 5 of the patient 1 is arranged to extend in the left-right direction, which is the extension direction of the branched wiring portions 26b, 26c, 32b, 32c, 34 of the first and second detection wires 22, 24. This reduces the number of intersections between the forearm 5 and the first and second detection wires 22, 24 compared to when the forearm 5 is arranged to extend in the front-back direction, making it less likely that erroneous detection will occur due to, for example, sweating from the forearm 5.

[0083] 5B , if blood 6 leaks from the blood return port 4, for example, due to the needle being pulled out, the blood 6 will drip onto the liquid detecting sheet 10 placed under the forearm 5. The dripping blood 6 is absorbed while being diffused by the liquid-permeable sheet 18 of the liquid detecting sheet 10, passes through the liquid-permeable sheet 18, and reaches the base sheet 16. In the liquid-detecting sheet 10 of this embodiment, the blood 6 is absorbed by the liquid-permeable sheet 18 provided above the base sheet 16, and therefore, it is possible to prevent the blood 6 from dripping onto the base sheet 16 and spilling onto the bed or floor, for example.

[0084] When the amount of blood 6 that reaches the base sheet 16 exceeds a predetermined detectable blood volume, the electrical insulation state between the first detection wiring 22 and the second detection wiring 24 changes due to the conductivity of the blood 6. Specifically, for example, as the blood spreads across the first detection wiring 22 and the second detection wiring 24 on the base sheet 16, the electrical resistance between the first detection wiring 22 and the second detection wiring 24 decreases, and a current flows between the first detection wiring 22 and the second detection wiring 24 to which the detection voltage is applied. Then, based on the current flow caused by the change in electrical resistance between the first detection wiring 22 and the second detection wiring 24, the detection device 52 detects the presence of blood on the base sheet 16.

[0085] The diameter of the blood 6 that is absorbed into the liquid-permeable sheet 18 made of nonwoven fabric and spreads on the base sheet 16 is approximately 40 mm for 0.5 mL and 100 mm for 2.5 mL. Generally, the blood flow rate in an artificial dialysis circuit is about 300 mL / min, and in this embodiment, the distance between the opposing first detection wire 22 and second detection wire 24 is set within the range of 40 to 100 mm, so that blood leakage from the blood return port 4 is quickly detected within a short time of about 0.1 to 0.5 seconds after the blood 6 reaches the liquid-detecting sheet 10.

[0086] The blood 6 absorbed into the liquid-permeable sheet 18 reaches the base sheet 16 while being diffused by the liquid-permeable sheet 18, thereby more reliably coming into contact with the first and second detection wires 22, 24, and detection of the blood 6 is achieved through conduction between the first and second detection wires 22, 24. In particular, even when the forearm 5 is placed on the liquid-detecting sheet 10, the blood 6 spreads within the liquid-permeable sheet 18, making it difficult for the forearm 5 to completely block the spread of the blood 6, and stable detection based on the spread of the blood 6 can be expected. Furthermore, because the flow of the blood 6 on the base sheet 16 is restricted by the liquid-permeable sheet 18, the blood 6 can be prevented from spilling onto the bed or floor, preventing contamination due to the adhesion of the blood 6.

[0087] By setting the distance between the first detection wires 22 and the second detection wires 24 in the main detection area 37 to within a range of 40 to 100 mm, it becomes difficult to detect relatively small amounts of liquid such as sweat, and it is possible to effectively detect blood 6 that has accumulated to a predetermined amount on the base sheet 16. Therefore, it is possible to reliably detect the presence of a detection target liquid such as blood 6 that is associated with a highly dangerous event such as blood leakage during dialysis, and it is also possible to reduce the frequency of false detections caused by sweat, etc.

[0088] Since the first detection wiring 22 and the second detection wiring 24, which are arranged apart from each other, are electrically insulated without conduction via resistance or the like, a large electrical change, such as a decrease in electrical resistance, can be obtained upon contact with blood 6. Therefore, for example, false detection due to a relatively small electrical change caused by factors other than contact with blood 6 can be made less likely to occur, and the accuracy and reliability of detection can be improved.

[0089] Furthermore, first detection wiring 22 and second detection wiring 24 are arranged in a comb-like shape in main detection region 37 extending parallel to each other, with a substantially constant distance between them. This allows blood 6 to be stably detected even if the position of blood 6 pooling on base sheet 16 shifts slightly. Moreover, by arranging branch-like wiring portions 26b, 26c of first detection wiring 22 and branch-like wiring portions 32b, 32c, 34 of second detection wiring 24 at a constant interval so that they intertwine with each other in the opposing direction of opposing wiring portions 26a, 32a, a wide effective detection area can be efficiently obtained.

[0090] The detection device 52 preferably includes an alarm device that notifies the outside world of the detection of a liquid leak. The alarm device is not particularly limited in form as long as it notifies the detection of the target liquid (blood 6), but examples include sounding an alarm, turning on an alarm light, and sending a notification to a mobile device or a nurse center. By including such an alarm device, medical personnel can quickly recognize the occurrence of a liquid leak and take the necessary measures promptly. The alarm device of the detection device 52 is not essential. For example, the detection device 52 may send an emergency stop signal to the hemodialysis machine 2 upon detection of a liquid leak, automatically stopping the hemodialysis machine 2 and preventing further leakage of the blood 6.

[0091] 6 shows a medical liquid detection device 62 equipped with a medical liquid detection sheet 60 according to a second embodiment of the present invention. The liquid detection device 62 is configured to include a liquid detection sheet 60 equipped with a connector 64. In the following description, members and parts that are substantially the same as those in the first embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted.

[0092] Similar to the liquid detection sheet 10 of the first embodiment, the liquid detection sheet 60 has a three-layer structure in which a substrate sheet 16 as a base member and a liquid-permeable sheet 18 made of nonwoven fabric are superimposed and fixed to each other by an adhesive sheet 20 made of a heat-sealed sheet.

[0093] A first detection wire 66 and a second detection wire 68 are printed on the upper surface of the base sheet 16. As in the first embodiment, the first and second detection wires 66, 68 are made of conductive paste and are printed in a predetermined shape on the upper surface of the base sheet 16. As in the first embodiment, the second detection wire 68 is arranged at a distance from and surrounding the first detection wire 66. As in the first embodiment, the liquid detection sheet 60 detects the presence of a liquid to be detected on the base sheet 16 based on a change in the electrical connection state between the first and second detection wires 66, 68, as in the first embodiment. Note that in FIG. 6 , for ease of understanding, the liquid-permeable sheet 18 made of nonwoven fabric is made transparent, and the first and second detection wires 66, 68 are visible.

[0094] In this embodiment, the first and second detection wires 66, 68 have reduced variations in the separation distance at their ends and corners. That is, the portion of the first detection wire 66 that is disposed around the right end of the second central detector 34 of the second detection wire 68 forms a first curved portion 70 that curves and extends to surround the right end of the second central detector 34. In this embodiment, the first curved portion 70 is formed in a substantially semicircular arc shape, so that the distance between the first detection wire 66 and the right end of the second central detector 34 is substantially constant along the length of the first detection wire 66.

[0095] Similarly, the second detection wiring 68 has second curved portions 72a, 72a that are curved and extend so as to surround the left ends of the front and rear ends 26b, 26c of the first detection wiring 66. In the present embodiment, the second curved portions 72a, 72a are each formed in a substantially semicircular arc shape, so that the distance between the left ends of the front and rear ends 26b, 26c and the second detection wiring 68 is substantially constant along the length of the second detection wiring 68.

[0096] Furthermore, the portion of the first detection wire 66 that extends to surround the right end of the second central detection unit 34 of the second detection wire 68 has a double structure in which angular portions 74, 74 are provided on the outer periphery of the first curved portion 70. As in the first embodiment, the angular portions 74, 74 are angles formed between the right end 26a and the front and rear end portions 26b, 26c, and in this embodiment, they are approximately right angles. Note that the first curved portion 70 and the angular portions 74, 74 may be integrated by filling the gaps with conductive paste to avoid a double structure, but by providing portions without conductive paste between the first curved portion 70 and the angular portions 74, 74 as in this embodiment, the amount of conductive paste used can be reduced.

[0097] The second detection wiring 68 has a second curved portion 72b that is disposed on the outer periphery of the angular portions 74, 74 and curves to surround the angular portion 74. The second curved portion 72b is substantially arc-shaped with a central angle of 90° centered on the angular portion 74, and the distance from the angular portion 74 is substantially constant along the length.

[0098] As described above, by providing the first curved portion 70, the second curved portions 72a, 72a, 72b, 72b, and the angular portions 74, 74, in the main detection area 37, the distance between the first central detection portion 26 and the second detection wiring 68 of the first detection wiring 66 is approximately constant on both the inner and outer sides of the first central detection portion 26.

[0099] The method for manufacturing the three-layered liquid detection sheet 60 is not particularly limited, but the liquid detection sheet 60 is manufactured, for example, as follows.

[0100] First, a plurality of base sheets 16 are formed in a continuous band shape, and the first and second detection wiring 66, 68 are printed on each of the base sheets 16. Next, the adhesive sheet 20 and the liquid-permeable sheet 18, which are also formed in a continuous band shape, are overlapped on the continuous band-shaped base sheets 16, and the adhesive sheet 20 is heated and then cooled to thermally weld the base sheet 16 and the liquid-permeable sheet 18 together. The liquid-permeable sheet 18 and the adhesive sheet 20 are fixed to a position that does not reach the rear end of the base sheet 16 so that the first and second terminals 30, 36, 36 are exposed. In this embodiment, a line 76 indicating the rear end positions of the liquid-permeable sheet 18 and the adhesive sheet 20 is printed on the base sheet 16, and the relative positions of the base sheet 16, the liquid-permeable sheet 18, and the adhesive sheet 20 in the front-to-rear direction are determined by viewing the line 76 with a camera.

[0101] Next, the strip-shaped laminated sheet obtained by laminating the base sheet 16, the adhesive sheet 20, and the liquid-permeable sheet 18 is cut in the length direction (the left-right direction of the liquid-detection sheet 60 shown in FIG. 6 ), thereby completing the production of multiple liquid-detection sheets 60. In this embodiment, markers 78 for identifying the cutting position are printed on the upper surface of the rear part of the base sheet 16 that is exposed and not covered by the liquid-permeable sheet 18, and the cutting position of the strip-shaped laminated sheet can be identified by, for example, photographing the markers 78 with a camera, thereby automatically cutting the strip-shaped laminated sheet into multiple liquid-detection sheets.

[0102] As shown in FIGS. 6 to 13, the connector 64 has a structure in which an upper jaw portion 80 and a lower jaw portion 82, each of which has a hollow structure, are connected in a state in which they can tilt relative to each other.

[0103] The upper jaw 80 has a hollow structure formed by combining an upper outer member 84 and an upper inner member 86. The upper outer member 84 has a shallow, bottomed cylindrical shape that opens downward, and the end (rear portion) opposite the end where the connector 64 is connected to the liquid detection sheet 60 (base sheet 16) forms an operating portion 88 that slopes upward toward the rear. The upper inner member 86 has a generally flat plate shape, and its rear end does not reach the rear end of the operating portion 88. The upper outer member 84 and the upper inner member 86 are mechanically connected to each other, for example, by inserting and engaging a locking claw provided on the outer peripheral end of the upper inner member 86 into a hole opening in the peripheral wall portion of the upper outer member 84. The upper outer member 84 and the upper inner member 86 may also be fixed to each other by, for example, welding or adhesive.

[0104] The upper outer member 84 and the upper inner member 86 are each formed with a plurality of reinforcing ribs 90 that protrude from the opposing inner surfaces in the vertical direction, and the reinforcing ribs 90 improve the deformation rigidity while giving each outer surface of the upper outer member 84 and the upper inner member 86 a smooth shape. The number, arrangement, cross-sectional shape, size, etc. of the reinforcing ribs 90 are appropriately set based on, for example, the deformation rigidity required of the upper jaw portion 80.

[0105] A pair of downwardly protruding shaft support portions 92, 92 are integrally formed with the operating portion 88 of the upper external member 84. The shaft support portions 92 are plate-shaped and face each other in the left-right direction, and include a pair of support shaft portions 94, 94 that protrude outward in the left-right direction. The support shaft portions 94 are generally cylindrical, and the lower portion of the protruding tip portion is notched obliquely, thereby providing a first guide surface 96 that slopes upward toward the protruding tip side.

[0106] A first support rib 98 is provided between the opposing shaft support portions 92. The first support rib 98 protrudes downward from the upper outer member 84 and, in this embodiment, is a pair of plate-shaped ribs facing each other in the left-right direction. A first notch 100 is formed in the first support rib 98, penetrating the first support rib 98 in the thickness direction (left-right direction) and opening downward.

[0107] An internal substrate 102 is housed inside the upper jaw portion 80. The internal substrate 102 has a structure in which the internal circuit 42 is mounted by printed wiring or the like on an insulating substrate made of, for example, a resin. In this embodiment, the internal substrate 102 is a printed circuit board having electronic components mounted on the printed wiring board, and is provided with the internal circuit 42 as an electrical circuit. The internal substrate 102 is fixedly supported to at least one of the upper outer member 84 and the upper inner member 86 by screws, positioning ribs, or the like. The internal substrate 102 has internal terminals 104, 104, 104 that protrude downward. The internal terminals 104 are electrically connected to the internal circuit 42 on the internal substrate 102 and are exposed downward through through-holes 106 that penetrate the upper inner member 86. Then, by attaching the connector 64 to the base sheet 16, the internal terminals 104 are electrically connected to the first terminals 30 and second terminals 36 of the first and second detection wirings 66, 68, and the internal circuit 42 is electrically connected to the first and second terminals 30, 36, 36 via the internal terminals 104. The configuration of the internal circuit 42 is not particularly limited, but the internal circuit 42 may include, for example, a control circuit that applies a detection voltage to the first and second detection wirings 66, 68, a detection circuit that measures the current from the first and second detection wirings 66, 68 to detect disconnections and leakage, and a transmission circuit that transmits the detection results to the outside via external wiring 108 (described later) or wirelessly.

[0108] An end of the external wiring 108 connected to the internal circuit 42 is housed inside the upper jaw 80. As shown in Fig. 8 , the external wiring 108 extends forward from the edge of the front (lower in Fig. 8 ) side of the internal substrate 102 that includes the internal circuit 42, which is the side that is connected to the liquid detecting sheet 60, and is curved and wired inside the connector 64 so as to be folded back rearward at the end of the extension, and the end that is curved and folded back extends rearward passing the side of the internal substrate 102, and extends rearward and is exposed outside from the connector 64. As a result, even if the external wiring 108 that is exposed and extending from the connector 64 is pulled rearward, because the external wiring 108 extends in a curved manner inside the upper jaw 80, breakage of the external wiring 108 due to deformation of the curved portion or breakage due to fracture of the connection portion between the external wiring 108 and the internal circuit 42 is prevented. In addition, the external wiring 108 can be appropriately positioned inside the connector 64 by using a reinforcing rib 90, etc., to prevent the transmission of external tensile force to the connection portion with the internal circuit 42.

[0109] The lower jaw 82 has a hollow structure formed by combining a lower outer member 110 and a lower inner member 112. The lower outer member 110 and the lower inner member 112 may be mechanically fixed to each other, similar to the upper outer member 84 and the upper inner member 86 of the upper jaw 80, or may be fixed to each other by means of welding, adhesive, or the like.

[0110] A plurality of reinforcing ribs 114 are provided on the opposing inner surfaces of the lower outer member 110 and the lower inner member 112, and the reinforcing ribs 114 improve deformation rigidity while giving each outer surface of the lower outer member 110 and the lower inner member 112 a smooth shape. The rear end of the lower inner member 112 reaches the rear end of the lower outer member 110 on both left-right sides, but does not reach the rear end of the lower outer member 110 in the left-right central portion where a spring member 122 (described later) is disposed.

[0111] As shown in Figure 13, support bearings 116 are provided in a portion of the lower outer member 110 that extends rearward beyond the lower inner member 112. The support bearings 116 are in the form of a pair of opposing plates that protrude upward from the lower outer member 110, and each has a shaft insertion hole 118 that penetrates in opposing directions. The protruding tip surfaces of the pair of support bearings 116, 116 form second guide surfaces 120 that slope downward inward in the opposing direction.

[0112] A spring member 122 serving as a biasing member is disposed between the pair of opposing support bearing portions 116. The spring member 122 is a torsion coil spring having terminal portions 126 on both sides protruding outward from a spirally wound cylindrical intermediate portion 124. In a static state where no external force is applied, the terminal portions 126 extend in different directions that form an angle of approximately 90° with respect to the circumferential direction of the cylindrical intermediate portion 124. Each end of the terminal portions 126 is bent and extends in the left-right direction, which is the axial direction of the cylindrical intermediate portion 124.

[0113] One terminal portion 126 of the spring member 122 is attached to a second support rib 128. The second support rib 128 is formed integrally with the lower outer member 110 and protrudes upward from the lower outer member 110 rearward of the lower inner member 112. A second notch 130 is formed in the second support rib 128, penetrating the second support rib 128 in the thickness direction (left-right direction) and opening upward, and the end of the terminal portion 126 of the spring member 122 is fitted into the second notch 130 and rotatably supported.

[0114] A pair of positioning pieces 132, 132 that position the spring member 122 in the left-right direction are integrally formed with the lower outer member 110. The positioning pieces 132, 132 protrude upward from the lower outer member 110. The spring member 122, which is attached to the lower outer member 110 at the terminal portion 126, has a cylindrical intermediate portion 124 disposed between the opposing positioning pieces 132, 132, and the abutment between the cylindrical intermediate portion 124 and the positioning pieces 132, 132 limits the amount of relative displacement of the spring member 122 in the left-right direction with respect to the lower outer member 110. A second support rib 128 that supports the terminal portion 126 of the spring member 122 is disposed between the opposing positioning pieces 132, 132.

[0115] As shown in Figure 11, the upper surface of the front part of the lower internal member 112 forms an inclined surface 134 that slopes downward toward the front. This gives the lower jaw 82 a tapered shape in which the thickness in the up-down direction gradually decreases toward the front. The upper surface of the rear part of the lower internal member 112 widens in a direction substantially perpendicular to the up-down direction, and the inclined surface 134 is inclined relative to the upper surface of the rear part of the lower internal member 112.

[0116] As shown in Figure 12, positioning pins 136, 136 that protrude upward are provided at both left and right ends of the lower internal member 112. The positioning pins 136 are formed integrally with the lower internal member 112 and are provided rearward of the inclined surface 134 (see Figure 11). In this embodiment, the positioning pins 136 have a hollow structure with a tapered outer shape that becomes smaller in diameter toward the protruding tip. Note that pin insertion holes 138, 138 through which the positioning pins 136, 136 can be inserted are formed at both left and right ends of the upper internal member 86.

[0117] 13, the upper jaw 80 and the lower jaw 82 are connected to each other by inserting the support shafts 94, 94 into the shaft insertion holes 118, 118 of the support bearings 116, 116. The upper jaw 80 and the lower jaw 82 are assembled to be rotatable relative to each other about the support shafts 94, 94, and the front end of the upper jaw 80 and the front end of the lower jaw 82 are relatively displaceable in the up-down direction, moving toward and away from each other.

[0118] In this embodiment, the support shafts 94, 94 can be inserted into the shaft insertion holes 118, 118 by the simple operation of bringing the upper jaw 80 closer to the lower jaw 82 from above. That is, by bringing the upper jaw 80 closer to the lower jaw 82 from above, the first guide surfaces 96 of each support shaft 94 are pressed against the second guide surfaces 120 of each support bearing 116, and the support shafts 94 enter the left and right inner sides of the support bearing 116 while elastically deforming the shaft support 92 and the support bearing 116. Then, when the support shaft 94 reaches the shaft insertion hole 118, the elastic deformation of both the shaft support 92 and the support bearing 116 is released, and the support shaft 94 is inserted into the shaft insertion hole 118.

[0119] The upper jaw 80 and the lower jaw 82 are biased by a spring member 122 in a direction in which their front ends approach each other in the vertical direction. With one terminal portion 126 of the spring member 122 inserted into and pivotally supported in a second notch 130 of a second support rib 128 of the lower jaw 82, the upper jaw 80 is assembled to approach the lower jaw 82 from above, and the other terminal portion 126 is inserted into and pivotally supported in a first notch 100 of a first support rib 98 of the upper jaw 80. The underside of first support rib 98 is inclined upward and rearward, and as upper jaw 80 moves downward toward lower jaw 82, the other terminal portion 126 of spring member 122 is guided along the underside of first support rib 98 into first notch 100. Therefore, by moving upper jaw 80 toward lower jaw 82 in the vertical direction as an assembly operation, spring member 122 can be attached to jaws 80, 82. With both terminal portions 126, 126 of spring member 122 pivotally supported by first notch 100 and second notch 130, a biasing force based on the elasticity of spring member 122 acts between upper jaw 80 and lower jaw 82. The biasing force of spring member 122 acts in a direction that moves the rear portions of upper jaw 80 and lower jaw 82 away from each other in the vertical direction, and also acts in a direction that moves the front portions of upper jaw 80 and lower jaw 82, which are allowed to rotate relative to each other about support shaft 94, closer to each other, the front portions being located forward of support shaft 94. In short, when no external force is acting on connector 64, the front portions of upper jaw 80 and lower jaw 82 are held closed by the biasing force of spring member 122, and it is possible to open the front portions against the biasing force of spring member 122 by applying a downward input to operating unit 88.

[0120] As shown in Figure 6, the connector 64 is attached to the liquid-detecting sheet 60 (base sheet 16). That is, in an open state in which the front ends of the upper jaw 80 and the lower jaw 82 of the connector 64 are separated from each other by applying force to the operating unit 88, the rear end portion of the base sheet 16 is inserted between the upper jaw 80 and the lower jaw 82. When the upper jaw 80 and the lower jaw 82 are in the open state, the positioning pins 136, 136 are disengaged downward from the pin insertion holes 138, 138 of the upper jaw 80, allowing the base sheet 16 to pass between the tips of the positioning pins 136, 136 and the underside of the upper jaw 80. The base sheet 16 is inserted deeper (rearward) between the upper jaw 80 and the lower jaw 82 until the positioning holes 38, 38 reach positions corresponding to the positioning pins 136, 136.

[0121] 12, by releasing the input to the operating unit 88, the positioning pins 136, 136 are inserted into the positioning holes 38, 38 of the base sheet 16 and the pin insertion holes 138, 138 of the upper jaw 80. As a result, the base sheet 16 and the connector 64 are positioned relative to each other in the surface direction of the base sheet 16 by engagement between the positioning pins 136, 136 and the opening peripheral edges of the positioning holes 38, 38. In addition, the tip portions of the positioning pins 136, 136 that have passed through the positioning holes 38, 38 are inserted into the pin insertion holes 138, 138 of the upper jaw 80, preventing the positioning pins 136, 136 from unintentionally coming out of the positioning holes 38, 38. In particular, in this embodiment, the upper jaw portion 80 and the lower jaw portion 82 are held in a closed state by being biased by the spring member 122, so that the insertion state of the positioning pins 136, 136 into the positioning holes 38, 38 is maintained with excellent reliability.

[0122] In the base sheet 16 inserted between the upper jaw 80 and the lower jaw 82 of the connector 64, the first and second terminals 30, 36, 36 of the first and second detection wires 66, 68 are in contact with the internal terminals 104, 104, 104 of the connector 64, and the first and second detection wires 66, 68 are electrically connected to the internal circuit 42 of the connector 64. Therefore, the first and second detection wires 66, 68 are electrically connected to the external wire 108 via the internal circuit 42 of the connector 64.

[0123] In this manner, the connector 64 is positioned relative to the base sheet 16 and attached to the base sheet 16 with the internal circuit 42 of the connector 64 electrically connected to the first and second detection wirings 66, 68 of the base sheet 16.

[0124] 6, the liquid detecting sheet 60 equipped with the connector 64 is used to detect bleeding or leakage of medicinal liquid from the puncture site of the indwelling needle (blood collection port 3 and blood return port 4) placed in the forearm 5 of the patient 1. The principle of detecting the liquid to be detected (blood, etc.) is the same as in the first embodiment, and therefore will not be described here.

[0125] The lower jaw 82 of the connector 64 has an upper front surface that forms an inclined surface 134 that slopes downward toward the front, which is the end side of the attachment tip to the base sheet 16, and is thinner in the vertical direction toward the front. This makes it easier to insert the lower jaw 82 between the upper surface of the bed and the underside of the base sheet 16 when connecting the connector 64 to the base sheet 16 laid on a bed, facilitating the connection work of the connector 64.

[0126] The liquid detection sheet 60 of this embodiment cannot be used upside down because the base sheet 16 is liquid-impermeable, and the front and back sides are specified when in use. Therefore, in the liquid detection sheet 60 of this embodiment, a logo 140 is printed on the upper surface of the base sheet 16, with the front and back sides being asymmetrical, and the front and back sides of the liquid detection sheet 60 can be identified by visually recognizing the logo 140.

[0127] 6 illustrates the case where the liquid detective sheet 60 is used to monitor bleeding in the left arm of the patient 1, but the liquid detective sheet 60 can also be used to monitor bleeding in the right arm of the patient 1. The liquid detective sheet 60 has a liquid-impermeable base sheet 16 and cannot be used upside down. Therefore, when placed under the right arm, the liquid detective sheet 60 is used in an orientation rotated 180° in the circumferential direction. Therefore, the first and second terminals 30, 36, 36 of the first and second detection wirings 66, 68 are located in the center in the left-right direction, so that even when the liquid detective sheet 60 is used in an orientation rotated 180° in the circumferential direction, the first and second terminals 30, 36, 36 are located in the center in the left-right direction. As a result, even if the orientation of the liquid detection sheet 60 changes by 180°, the change in the left-right position of the first and second terminals 30, 36, 36 (connector 64) is small, and problems such as the external wiring 108 extending from the connector 64 becoming excessive and getting in the way, or the external wiring 108 being insufficient in length can be avoided.

[0128] 14 , in the internal circuit 42 of the connector 64 located outside the main detection area 37 of the liquid detection sheet 60, a first wiring portion 142 connected to the first terminal 30 of the first detection wire 66 and a second wiring portion 144a connected to one of the second terminals 36a of the second detection wire 68 are connected by a resistor 146. The electrical resistance value of the resistor 146 is set to be larger than the electrical resistance value of the short-circuited portion caused by the liquid to be detected in the liquid detection sheet 60 (the electrical resistance value of the liquid-permeable sheet 18 that has absorbed the liquid to be detected between the first and second detection wires 66, 68). Then, by applying a voltage between the first wiring portion 142 connected to the first terminal 30 and the second wiring portion 144b connected to the other second terminal 36b, the connection state between the connector 64 and the base sheet 16 and the presence or absence of a break in the second detection wire 68 are checked, and the liquid to be detected is detected.

[0129] The detection circuit can be checked by applying a voltage between the first wiring portion 142 and the second wiring portion 144b when the first and second detection wirings 66, 68 are not short-circuited by the liquid to be detected. That is, if the connector 64 and the base sheet 16 are not properly connected or if the second detection wiring 68 is broken, no current flows, and the detection current value of the detection device 52 is zero. On the other hand, if the connector 64 and the base sheet 16 are properly connected and there is no break in the second detection wiring 68, the current flows through a circuit with a high resistance, including the resistor 146, and the detection device 52 detects a small current value. Therefore, the presence and magnitude of the detection current can be used to check the connection status between the connector 64 and the base sheet 16 and whether or not the second detection wiring 68 is broken. As in the first embodiment, the first detection wiring 66 is surrounded by the second detection wiring 68, so it is unlikely that only the first detection wiring 66 will be damaged. By checking whether the second detection wiring 68 is damaged, it is also possible to check whether the first detection wiring 66 is damaged.

[0130] Furthermore, if the first and second detection wirings 66, 68 are short-circuited by the liquid to be detected, the detection device 52 detects a larger current value than when there is no short circuit, because the current flows through a circuit with a small resistance value that does not include the resistor 146. Therefore, the presence or absence of the liquid to be detected in the main detection area 37 of the liquid detecting sheet 60 can be determined based on the magnitude of the detection current.

[0131] In this way, the liquid detection device 62 of this embodiment does not need to switch the state of electrical current supplied from the connector 64 to the first and second detection wirings 66, 68 when checking the detection circuit and when monitoring the liquid to be detected. Furthermore, the liquid detection device 62 of this embodiment can simultaneously check the detection circuit and monitor the liquid to be detected.

[0132] Furthermore, the resistor 146 is provided at a position outside the main detection area 37 of the liquid detective sheet 60, and in this embodiment, is provided in the internal circuit 42 of the connector 64 connected to the base sheet 16. This allows for greater freedom in selecting the resistor 146 compared to providing a resistor in the main detection area 37 of the liquid detective sheet 60. Furthermore, by providing the resistor 146 at a position outside the main detection area 37 with which the liquid to be detected comes into contact, it is possible to prevent the liquid to be detected from adhering to the resistor 146. Furthermore, while the external wiring 44 of the first embodiment has three conductor core wires connected to the first and second terminals 30, 36, 36, the external wiring 108 of this embodiment has only two core wires connected to the first and second terminals 30, 36, and therefore the external wiring 108 can be made thinner.

[0133] In the liquid-sensing sheet 60, the distance between the first detection wires 66 and the second detection wires 68 is set within a range of 40 to 100 mm. This reduces the frequency of false detections caused by sweat, etc. Furthermore, detection target liquids that accumulate on the liquid-impermeable base sheet 16 in excess of a predetermined amount, such as blood leaks or drug solution leaks, can be effectively detected by short-circuiting the first and second detection wires 66, 68.

[0134] In the liquid detection sheet 60 of this embodiment, the distance between the first detection wires 66 and the second detection wires 68 is kept substantially constant in the main detection region 37, which is the region where the target liquid can be detected, by the first curved portion 70 and the angular portion 74 of the first detection wires 66 and the second curved portions 72a, 72b of the second detection wires 68. Therefore, regardless of the position of the target liquid in the main detection region 37 of the liquid detection sheet 60, the lower limit of the detectable liquid amount is stabilized, making it possible to more reliably detect a predetermined amount of target liquid.

[0135] The liquid detecting sheet 60 can detect the target liquid with high reliability because the base sheet 16 has a liquid-impermeable property that prevents the passage of the target liquid, and the target liquid accumulates on the base sheet 16. Furthermore, the target liquid is less likely to pass through the base sheet 16 and leak downward, and for example, when the liquid detecting sheet 60 is laid on a bed, contamination of the bed due to the adhesion of the target liquid to the bed can be avoided.

[0136] The liquid-detecting sheet 60 has a three-layer structure with a small number of layers, in which the first and second detection wires 66, 68 are printed on the base sheet 16, which facilitates manufacturing and reduces costs. Furthermore, the liquid-permeable sheet 18 covering the upper surface of the base sheet 16 on which the first and second detection wires 66, 68 are printed is made of nonwoven fabric. This improves the tactile feel of the upper surface of the liquid-detecting sheet 60 that comes into contact with the forearm 5 of the patient 1, and also prevents the liquid to be detected from spilling or adhering to the patient 1, as the nonwoven fabric absorbs and spreads the liquid to be detected. Furthermore, by heating the adhesive sheet 20 in a state in which the base sheet 16, adhesive sheet 20, and liquid-permeable sheet 18 are laminated together, the base sheet 16 and the liquid-permeable sheet 18 can be fixed to each other, for example, by utilizing the thermal welding action of a thermoplastic resin, without requiring an adhesive application process.

[0137] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific descriptions. For example, the wiring patterns of the first and second detection wirings 22, 24 are merely examples and are not particularly limited. However, considering factors such as preventing erroneous detection and ensuring an effective detection area that enables stable detection, it is desirable that the separation distance between the first and second detection wirings 22, 24 be as constant as possible. For example, as shown in the second embodiment, the corners may be rounded in an arc shape to prevent the separation distance between the first and second detection wirings 22, 24 from becoming partially larger at the corners.

[0138] In the first and second embodiments, a three-terminal wiring structure having one first terminal 30 and two second terminals 36, 36 has been described, but four or more terminals may be provided. Specifically, for example, a four-terminal wiring structure having two first terminals 30, 30 and two second terminals 36, 36 may be used, which makes it possible to check for disconnection by applying a check voltage not only to the second detection wire 24 but also to the first detection wire 22. Note that the number of detection wires may be three or more, and liquid can be detected by applying a detection voltage between each of the three or more detection wires.

[0139] In the first and second embodiments, the base sheet 16 protrudes rearward beyond the liquid-permeable sheet 18 and the adhesive sheet 20, and the positioning holes 38 are provided only in the base sheet 16 at the protruding portions. However, for example, the positioning holes 38 may be provided not only through the base sheet 16, but also through the liquid-permeable sheet 18 and the adhesive sheet 20. The base sheet 16, the liquid-permeable sheet 18, and the adhesive sheet 20 may be the same size, or, for example, the liquid-permeable sheet 18 may be larger than the base sheet 16 and protrude further outward than the base sheet 16. The connector attached to the base sheet 16 may constitute a part of the liquid-detecting sheet 10, or may be a separate component from the liquid-detecting sheet 10 to form a liquid-detecting device.

[0140] In the first and second embodiments, the reinforcing portion 40 is provided around the opening edge of the positioning hole 38, but the reinforcing portion 40 is not essential. Furthermore, the reinforcing portion 40 does not necessarily have to protrude outward in the thickness direction from the base sheet 16. For example, the reinforcing portion 40 can be provided in a recessed state around the opening edge of the positioning hole 38 in the base sheet 16 so as not to protrude outward in the thickness direction beyond the base sheet 16.

[0141] The positioning portion is not necessarily limited to a through-hole such as the positioning hole 38. For example, it is possible to form a recess that opens downward in the base sheet 16 and insert a protrusion that protrudes from the lower jaw 46 of the connector 14 into the recess to position the base sheet 16 and the connector 14, in which case the positioning portion is formed by the recess. Alternatively, a positioning pin or protrusion can be provided on the base sheet 16 side, and a positioning hole or recess can be provided on the connector 14 side, and the positioning portion can be formed by the positioning pin or protrusion.

[0142] In the first and second embodiments, a thin base sheet 16 is shown as an example of the base member, but the base member is not limited to a thin, flexible member such as a sheet or film, and may be, for example, a plate. Furthermore, the base sheet 16 may be formed of a liquid-permeable material that allows the liquid to pass through. In this case, for example, a liquid-impermeable sheet separate from the base sheet 16 may be laminated below the base sheet 16 to prevent the passage of the liquid to be detected below the detection wiring. The liquid-impermeable member is not necessarily limited to being formed by the base sheet 16.

[0143] In the first and second embodiments, an example is shown in which the forearm 5 of the patient 1 is placed on the liquid detection sheet 10 so that it extends in a direction (left-right direction) that is approximately parallel to the branch-like wiring portions 26b, 26c, 32b, 32c, and 34 of the first and second detection wirings 22, 24. However, the liquid detection device 12 can also be used in a state in which the forearm 5 is placed on the liquid detection sheet 10 so that it extends in a direction intersecting the branch-like wiring portions 26b, 26c, 32b, 32c, and 34 of the first and second detection wirings 22, 24 (for example, the front-back direction).

[0144] The detection device 52 shown in Figure 5 is separate from the artificial dialysis machine 2 and is attached to the artificial dialysis machine 2, for example, by hanging it on a hook, but the detection device 52 can also be built into the artificial dialysis machine 2.

[0145] In the first and second embodiments, an example was shown in which the liquid-detecting device 12 equipped with the medical liquid-detecting sheet 10 was used to detect blood leakage during dialysis, but the liquid-detecting sheet 10 can also be used to detect liquid leakage during, for example, infusions or medication. Furthermore, the liquid to be detected using the medical liquid-detecting sheet 10 is not limited to blood, but may be, for example, bodily fluids within the human body (bodily fluids in the broad sense including fluids secreted into the body (such as saliva) and fluids excreted outside the body (such as urine)), or medical fluids such as medicinal fluids or infusions.

[0146] In the first and second embodiments, an example was shown in which blood 6 is detected when blood 6 comes into contact with both the first detection wiring 22 (66) and the second detection wiring 24 (68), thereby establishing electrical continuity between the first detection wiring 22 (66) and the second detection wiring 24 (68). However, it is also possible to make it possible to detect a liquid to be detected, such as blood, when the liquid to be detected is separated from at least one of the first detection wiring 22 (66) and the second detection wiring 24 (68). Specifically, the presence of the liquid to be detected may be detected based on a change in the electrical connection state (e.g., a change in electrical resistance) between the first detection wiring 22 (66) and the second detection wiring 24 (68) as the liquid to be detected approaches the detection wiring while separated from it.

[0147] REFERENCE SIGNS LIST 10 Liquid detection sheet (first embodiment) 12 Liquid detection device 14 Connector 16 Base sheet (base member) 18 Liquid-permeable sheet (nonwoven fabric) 20 Adhesive sheet (thermal welding sheet) 22 First detection wiring 24 Second detection wiring 26 First central detection section 26a Right end (opposing wiring section) 26b Front end (branched wiring section) 26c Rear end (branched wiring section) 28 Terminal connection section 30 First terminal 32 Peripheral detection section 32a Left end (opposing wiring section) 32b Front end (branched wiring section) 32c Rear end (branched wiring section) 32d Right end 34 Second central detection section (branched wiring section) 36 Second terminal 36a Second terminal 36b Second terminal 37 Main detection area 38 Positioning hole (positioning section) 40 Reinforcement section 42 Internal circuit 44 External wiring 46 Lower jaw portion 48 Upper jaw portion 50 Positioning pin 52 Detection device 54 State confirmation member 60 Liquid detection sheet (second embodiment) 62 Liquid detection device 64 Connector 66 First detection wiring 68 Second detection wiring 70 First curved portion (curved portion) 72a Second curved portion (curved portion) 72b Second curved portion 74 Angular portion 76 Line 78 Marker 80 Upper jaw portion 82 Lower jaw portion 84 Upper outer member 86 Upper inner member 88 Operation portion 90 Reinforcing rib 92 Shaft support portion 94 Support shaft portion 96 First guide surface 98 First support rib 100 First notch 102 Internal substrate 104 Internal terminal 106 Through hole 108 External wiring 110 Lower outer member 112 Lower inner member 114 Reinforcing rib 116 Support bearing portion 118 Shaft insertion hole 120 Second guide surface 122 Spring member (biasing member) 124 Cylindrical intermediate portion 126 Terminal portion 128 Second support rib 130 Second notch 132 Positioning piece 134 Inclined surface 136 Positioning pin 138 Pin insertion hole 140 Logo 142 First wiring portion 144a Second wiring portion 144b Second wiring portion 146 Resistor 1 Patient 2 Dialysis device 3 Blood collection port 4 Blood return port 5 Forearm 6 Blood (liquid to be detected)

Claims

1. A medical liquid detection sheet is provided on an electrically insulating base member, with a first detection wire and a second detection wire spaced apart from each other, and detecting leakage of the target liquid, such as blood, based on a change in the electrical connection state between the first detection wire and the second detection wire due to the adhesion of the target liquid, A medical liquid detection sheet is provided on the base member, wherein a main detection region is provided on the base member, on which the first detection wiring and the second detection wiring extend substantially parallel to each other, and the distance between the first detection wiring and the second detection wiring in the main detection region is set to a range of 40 to 100 mm.

2. The medical liquid detection sheet according to Claim 1, wherein the upper surface of the base member on which the first detection wiring and the second detection wiring are printed is covered with a nonwoven fabric, and the base member and the nonwoven fabric are fixed to each other by a heat-sealable sheet.

3. A medical liquid detection sheet according to claim 1 or 2, wherein a liquid-impermeable member is provided below the first detection wiring and the second detection wiring to prevent the passage of the liquid to be detected.

4. The medical liquid detection sheet according to claim 1, wherein the second detection wiring is provided on the base member so as to surround the first detection wiring.

5. The first detection wiring and the second detection wiring are each arranged in a roughly comb-like shape, with opposing wiring sections extending substantially parallel to each other and a plurality of branch-like wiring sections extending from each opposing wiring section in each opposing direction. A medical liquid detection sheet according to claim 4, wherein each branch-shaped wiring portion in the first detection wiring and the second detection wiring is arranged in the longitudinal direction of the opposing wiring portion such that they intersect with each other in the opposing direction of the opposing wiring portion.

6. A first terminal is provided at one end of the first detection wiring, A pair of second terminals are provided at both ends of the second detection wiring. A medical liquid detection sheet according to claim 4 or 5, wherein the first terminal and the pair of second terminals are arranged in a straight line, and the first terminal is located between the pair of second terminals.

7. The base member is a substrate sheet that does not permeate the liquid to be detected. The first detection wiring and the second detection wiring are printed on the upper surface of the base sheet. A medical liquid detection sheet according to claim 4 or 5, wherein an electrically insulating, permeable sheet that allows the passage of the liquid to be detected is provided on the upper surface of the base sheet, covering the first detection wiring and the second detection wiring.

8. A medical liquid detection sheet according to claim 4 or 5, further comprising a state confirmation member connected to both ends of the second detection wiring, which confirms the electrical state of the second detection wiring by applying a check voltage to the second detection wiring.

9. A medical liquid detection sheet comprising a plurality of detection wires provided on an electrically insulating base member at a distance from each other, which detects leakage of a target liquid such as blood based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the target liquid, A medical liquid detection sheet in which the upper surface of the base member on which the plurality of detection wires are printed is covered with a nonwoven fabric, and the base member and the nonwoven fabric are fixed to each other by a heat-sealing sheet.

10. A medical liquid detection sheet comprising a plurality of detection wires provided on an electrically insulating base member at a distance from each other, which detects leakage of a target liquid such as blood based on a change in the electrical connection state between the plurality of detection wires due to the adhesion of the target liquid, A medical liquid detection sheet is provided, wherein a liquid-impermeable member is positioned below the plurality of detection wires to prevent the passage of the liquid to be detected.

11. A medical liquid detection sheet comprising an electrically insulating base member on which a first detection wire and a second detection wire are provided spaced apart from each other, and which detects leakage of a target liquid such as blood based on a change in the electrical connection state between the first detection wire and the second detection wire due to the adhesion of the target liquid, A medical liquid detection sheet in which the second detection wiring is provided on the base member so as to surround the first detection wiring.

12. A medical liquid detection sheet is provided on an electrically insulating base member, on which multiple detection wires are provided spaced apart from each other, and which detects leakage of the target liquid, such as blood, based on changes in the electrical connection state between the multiple detection wires due to the adhesion of the target liquid, A medical liquid detection sheet in which the multiple detection wires are interconnected by resistors at positions outside the main detection area for detecting leakage of the target liquid.

13. A medical liquid detection sheet is provided on an electrically insulating base member, with a first detection wire and a second detection wire spaced apart from each other, and detecting leakage of the target liquid, such as blood, based on a change in the electrical connection state between the first detection wire and the second detection wire due to the adhesion of the target liquid, A medical liquid detection sheet wherein either the first detection wiring or the second detection wiring has a curved portion that extends in a substantially arc shape, spaced outward from the end of the other end of the first detection wiring or the second detection wiring.

14. A medical liquid detection sheet is provided on an electrically insulating base member, on which multiple detection wires are provided spaced apart from each other, and which detects leakage of the target liquid, such as blood, based on changes in the electrical connection state between the multiple detection wires due to the adhesion of the target liquid, Each terminal of the plurality of detection wires is arranged in a line on the outer circumference of the base member. A medical liquid detection sheet, wherein a positioning section for positioning a connector, which has external wiring electrically connected to the terminals, relative to the base member is provided on both sides of the base member in the direction in which the terminals are aligned and in close proximity to the terminals.

15. The base member is a substrate sheet that does not permeate the liquid to be detected. The medical liquid detection sheet according to claim 14, wherein the base sheet is provided with a positioning hole through which a positioning pin protruding from the connector is inserted, and the positioning portion is configured to include the positioning hole.

16. The medical liquid detection sheet according to claim 15, wherein an annular reinforcing portion protruding in the thickness direction of the base sheet is provided on the peripheral edge of the opening of the positioning hole in the base sheet.

17. A medical liquid detection sheet is provided on an electrically insulating base member, on which multiple detection wires are provided spaced apart from each other, and which detects leakage of the target liquid, such as blood, based on changes in the electrical connection state between the multiple detection wires due to the adhesion of the target liquid, A connector is provided that has an internal circuit that is electrically connected to each terminal of the plurality of detection wires. A medical liquid detection sheet in which an external wire, electrically connected to the internal circuit of the connector and extending outward from the connector, curves back at the point where it extends from the internal circuit toward the terminal of the connector, and extends outward from the connector on the opposite side of the terminal.

18. A medical liquid detection sheet is provided on an electrically insulating base member, on which multiple detection wires are provided spaced apart from each other, and which detects leakage of the target liquid, such as blood, based on changes in the electrical connection state between the multiple detection wires due to the adhesion of the target liquid, A connector is provided that has an internal circuit that is electrically connected to each terminal of the plurality of detection wires. The connector has an upper jaw portion and a lower jaw portion whose tip portions are relatively displaceable from each other in the direction of separation and the direction of approach. The outer periphery of the base member is sandwiched vertically between the upper and lower jaw portions, thereby electrically connecting the external wiring to the terminals via the internal circuit of the connector. A medical liquid detection sheet in which the lower jaw portion of the connector, positioned below the base member, has an inclined surface on its upper surface that slopes downward toward the mounting end of the connector to the base member, and is thinner in the vertical direction toward the mounting end of the connector.

19. The medical liquid detection sheet according to claim 18, wherein the connector comprises a biasing member that biases the mounting tip portions of the upper jaw portion and the lower jaw portion toward the base member toward each other.

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