Measurement system

Abstract

To achieve both reduction of frictional force between terminals and a contact surface of a sensor and reliable holding of the sensor by the terminals.SOLUTION: A measurement system comprises a sensor and a measurement device having an insertion port into which the sensor is inserted, and the measurement device measures a measurement target component contained in a liquid sample attached to the inserted sensor. The measurement device includes a plurality of terminals contacting the sensor, the plurality of terminals slides on a contact surface of the sensor, a first electrode group located on a rear end side in an insertion direction and a second electrode group located closer to a tip side are provided on the contact surface of the sensor, the plurality of terminals receives static frictional force from the contact surface by insertion of an insertion region and include a first terminal group contacting the first electrode group on a side closer to the insertion port and a second terminal group contacting the second electrode group on a side farther from the insertion port, and a sum of static frictional force that the first terminal group receives from the contact surface is smaller than a sum of static frictional force that the second terminal group receives from the contact surface in a state in which the sensor is inserted into the insertion port.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a measurement system including a sensor and a measurement device into which the sensor is inserted, and for measuring a measurement target component contained in a liquid sample attached to the sensor in a state where the sensor is inserted.

Background Art

[0002] A blood glucose measurement system using a disposable type sensor and a self-blood glucose measurement device (hereinafter referred to as a measurement device) is widely used. In such a system, the sensor is inserted into the measurement device, and both are electrically connected. As a specific example of such a connection, as in the technique described in Patent Document 1 below, the swinging side terminal of the connector of the measurement device contacts a conductive terminal portion continuously extending from the measurement electrode of the sensor, thereby achieving electrical connection.

[0003] In recent years, there has been a demand to obtain not only blood glucose but also second and third information such as hematocrit using a single sensor. For this reason, there is a need to increase the number of conductive terminal portions in the sensor. Therefore, as in the technique described in Patent Document 2 below, a measurement device provided with a first conductive portion group (connector internal swinging side metal terminal group) extending in the insertion direction of the sensor and a second conductive portion group (connector group) extending in a direction intersecting the insertion direction of the sensor has been proposed. In addition, as in the technique described in Patent Document 3 below, a measurement device provided with two rows of conductive portion groups in the longitudinal direction and a test strip corresponding thereto have been proposed.

[0004] On the other hand, as a technique for reducing the friction between the measurement device and the test strip, as described in Patent Document 4 below, a technique for devising the shape of the arm portion of the connector is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the prior art described above, when inserting a sensor into a measuring device, friction inevitably occurs between the terminals provided on the measuring device and the sensor surface from the starting position to the completion position of insertion. This friction can damage the wiring on the sensor surface or the plating on the terminal surface. On the other hand, if the holding force of the terminals is weakened in an attempt to reduce such friction, the sensor may not be held securely in the measuring device, and depending on the orientation of the measuring device, the sensor may fall out. [Means for solving the problem]

[0007] A first aspect of this disclosure is a measurement system comprising a sensor and a measuring device having an insertion port into which the sensor is inserted, wherein the measuring device measures a target component contained in a liquid sample attached to the sensor while the sensor is inserted into the insertion port, the measuring device having a plurality of terminals that contact the sensor inside the insertion port, the terminals sliding on the contact surface of the sensor that is opposite to the terminals from the start to the completion of insertion of the sensor, the contact surface of the sensor that contacts the terminals in the insertion region which is the part of the sensor that is inserted inside the insertion port is provided with a first electrode group located on the rear end side in the insertion direction and a second electrode group located on the front side of the first electrode group, the plurality of terminals receiving static friction force from the contact surface by pressing the contact surface and including a first terminal group that contacts the first electrode group on the side closer to the insertion port and a second terminal group that contacts the second electrode group on the side farther from the insertion port, the sum of static friction forces received by the first terminal group from the contact surface when the sensor is inserted into the insertion port is smaller than the sum of static friction forces received by the second terminal group from the contact surface. [Effects of the Invention]

[0008] According to the embodiment of the present invention, it is possible to achieve both a reduction in the frictional force received by the terminal from the contact surface of the sensor and secure holding of the sensor by the terminal. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing the appearance of the measuring device and measuring system of the embodiment. [Figure 2] This is a schematic plan view (A) and a cross-sectional view (B) of the upstream portion as seen from direction II, illustrating the general configuration of the sensor. [Figure 3] This is a schematic perspective view showing the general configuration of the terminal shapes inside the insertion port of the measuring device. [Figure 4] This is a schematic side view showing the general configuration of the terminal shape in Figure 3. [Figure 5] This is a schematic plan view showing the general configuration of the terminal shape in Figure 3. [Figure 6] This is a schematic perspective view showing the state in which the sensor has just begun to be inserted into the measuring device. [Figure 7] This is a schematic perspective view showing the state after the sensor has been inserted into the measuring device. [Figure 8] Figure 7 shows the state in a side view. [Figure 9] This is a schematic plan view showing the contact state between the sensor and the first group of terminals. [Figure 10] This is a schematic plan view showing the contact state between the sensor and the second group of terminals. [Figure 11] This diagram schematically illustrates the relationship between the normal force exerted on the terminal by the sensor's contact surface and the gravitational force acting on the sensor. [Figure 12] This diagram schematically illustrates the relationship between the frictional force exerted on the terminal by the sensor's contact surface and the gravitational force acting on the sensor. [Modes for carrying out the invention]

[0010] Hereinafter, an example of an embodiment of the present disclosure will be described while referring to the drawings. In each of the drawings, the same or equivalent components and parts are given the same reference numerals. Also, the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may be different from the actual ratios. Further, the functions of each electrode mentioned below are merely examples, and the configuration of the present invention is not limited thereto.

[0011] In the following description, “upstream side” and “downstream side” are defined along the direction in which the liquid sample attached to the sensor flows in the flow path.

[0012] The measurement system of the present embodiment includes a sensor and a measuring device having an insertion port into which the sensor is inserted. In a state where the sensor is inserted into the insertion port, the measuring device measures a measurement target component contained in the liquid sample attached to the sensor. Further, the measuring device has a plurality of terminals that come into contact with the sensor inside the insertion port, and during the period from the start to the completion of the insertion of the sensor, the terminals slide on the contact surface of the sensor facing the terminals.

[0013] The liquid sample is a liquid sample used for measurement by the measuring device, for example, a body fluid collected from a living body, and specifically, blood and urine are examples thereof. The measurement target component is a component contained in the liquid sample and measurable quantitatively or qualitatively by the measuring device. When the liquid sample is blood, examples of the measurement target component include blood glucose, hemoglobin, or HbA1c. When the liquid sample is urine, examples of the measurement target component include urine sugar, bilirubin, or urinary protein. Hereinafter, an example of measuring a blood glucose level as the measurement target component for blood as the liquid sample will be described.

[0014] Here, in the insertion region, which is the portion of the sensor inserted inside the insertion port, on the contact surface that contacts the terminal, a first electrode group located on the rear end side in the insertion direction and a second electrode group located on the tip side of the first electrode group are provided.

[0015] In other words, when viewed from the side in which the sensor is inserted into the measuring device, the first electrode group is located on the front side of the sensor, and the second electrode group is located on the back side of the sensor. The first and second electrode groups can be formed as electrode layers made of metal or carbon material on a substrate formed on the contact surface of the sensor. Here, the first and second electrode groups are used for different purposes and it is desirable that they be insulated from each other.

[0016] Furthermore, in the measuring device, the multiple terminals receive static friction force from the contact surface by pressing against the contact surface due to stress generated when the sensor is inserted into the insertion area, for example, by elastic deformation. In addition, the multiple terminals include a first terminal group that contacts the first electrode group on the side closer to the insertion opening, and a second terminal group that contacts the second electrode group on the side further from the insertion opening. Moreover, when the sensor is inserted into the insertion opening, the sum of the static friction forces received by the first terminal group from the sensor's contact surface is smaller than the sum of the static friction forces received by the second terminal group from the sensor's contact surface.

[0017] Each of the terminals can be formed from a metallic material such as copper, brass, phosphor bronze, iron, or stainless steel, or from a conductive material such as carbon, and may be further subjected to surface treatments such as nickel plating, tin plating, chromium plating, palladium plating, or gold plating.

[0018] Each of the multiple terminals experiences an elastic deformation-like stress equal to the thickness of the sensor when a sensor is inserted, compared to when the sensor is not inserted. Due to the restoring force of this stress, the terminals press against the contact surface of the sensor, and in reaction to this, they receive a normal force from the contact surface.

[0019] With the sensor inserted into the measuring device, the first terminal group contacts the first electrode group, and the second terminal group contacts the second electrode group. When the sensor insertion begins, the first terminal group first contacts the tip of the sensor. The sensor is then inserted further into the insertion opening as its contact surface slides against the first terminal group. Only just before the sensor is fully inserted does the second terminal group come into contact with the tip of the sensor. Therefore, the distance the first terminal group moves on the sensor's contact surface is longer than the distance the second terminal group moves on the sensor's contact surface.

[0020] Therefore, in order to reduce damage occurring between the first group of terminals, which travel a longer distance on the sensor's contact surface, and the sensor's contact surface, the sum of the normal forces that the first group of terminals receives from the sensor's contact surface is made smaller than the sum of the normal forces that the second group of terminals receives from the sensor's contact surface.

[0021] Furthermore, it is desirable to make the sum of the static frictional forces acting on the first terminal group from the contact surface less than the gravitational force generated by the sensor's mass, and to make the sum of the static frictional forces acting on the second terminal group from the contact surface greater than the gravitational force generated by the sensor's mass. With this configuration, even if the sensor mounted on the measuring device is facing downwards, the second terminal group, which has a greater static frictional force, can support the gravitational force acting on the sensor, preventing it from falling. On the other hand, the first terminal group, which has a smaller static frictional force, contributes almost nothing to preventing the sensor from falling.

[0022] The difference in static friction force experienced by the first and second terminal groups described above can be achieved, for example, by making the amount of deflection caused by the insertion of the insertion area for each terminal of the first terminal group smaller than the amount of deflection caused by the insertion of the insertion area for each terminal of the second terminal group.

[0023] Furthermore, it is desirable that each of the multiple terminals be configured to have a mounting base, an extension portion extending from the mounting base toward the insertion opening, and a contact portion that bends toward the direction of the contact surface at the tip of the extension portion and contacts the contact surface, such that the extension portion of the terminals of the second terminal group is located closer to the side where the contact surface is located than the extension portion of the terminals of the first terminal group. This configuration makes it easier to realize the above-described configuration in which the amount of deflection of the first terminal group is smaller than the amount of deflection of the second terminal group.

[0024] Furthermore, it is desirable that some of the terminals of the second terminal group be configured to be bifurcated. This configuration makes it possible to reduce the normal force generated at each contact point of the second terminal group while increasing the total normal force generated in the second terminal group.

[0025] Figure 1 is a perspective view showing the external appearance of the measurement system 3 according to this embodiment. This embodiment is an example in which the measurement system 3 is a portable blood glucose meter. In Figure 1, a portable blood glucose meter is provided as the measurement device 1, and a sensor 2 is provided which is detachably attached to the measurement device 1. The sensor 2 is an example of a test tool of this disclosure. The sensor 2 has a sample supply port 2d as an inlet for the flow path 2a, which will be described later, so that a liquid sample (for example, the patient's blood) is introduced into the flow path 2a, and an air hole 2e for discharging air from the flow path 2a after the liquid sample has been introduced, and is configured to have a function for detecting the target component (for example, blood glucose) in the liquid sample. The measurement device 1 shown in Figure 1 can be used as a measurement system 3, such as a portable blood glucose meter or a blood glucose self-monitoring meter, when the sensor 2 is attached, for example, when the liquid sample is the patient's blood.

[0026] The measuring device 1 also includes a main body 1a, which has an insertion slot 1b for inserting a strip-shaped sensor 2. The main body 1a is also equipped with a voltage injector (not shown) that supplies a predetermined voltage signal to the sensor 2 and receives a current signal indicating the measurement result from the sensor 2 for A / D conversion. The main body 1a is also equipped with a control unit (not shown), which is configured, for example, as a microprocessor and controls various parts of the measuring device 1. The control unit causes the voltage injector to supply a predetermined voltage signal to the sensor 2 and generates measurement data indicating the measured value based on the current value from the sensor 2 in response to the supply of the voltage signal. The measurement data obtained by the measurement unit is recorded in a recording unit (not shown). The measurement data obtained by the control unit is recorded in the recording unit in association with the measurement time or patient ID, etc.

[0027] Furthermore, the main unit 1a is equipped with a display screen 1c for displaying measurement data and a connector 1d for data communication with an external device. This connector 1d is configured to send and receive data such as measurement data, measurement time, and patient ID with an external device such as a smartphone or personal computer. In other words, the measuring device 1 is configured to transfer measurement data or measurement time to an external device, or to receive patient IDs etc. from an external device and associate them with the measurement data etc. via the connector 1d.

[0028] In addition to the above description, the control unit may be provided at the end of the sensor 2, and the measurement data may be generated on the sensor 2 side. Furthermore, the main body 1a of the measuring device 1 may be equipped with a user interface including input units such as buttons and a touch panel for a user such as a patient to input data. Alternatively, the display screen 1c or recording unit may not be provided on the main body 1a, but may be provided on an external device that can be connected to the main body 1a.

[0029] Figure 2 is a schematic plan view (A) and a cross-sectional view (B) of the upstream portion of the sensor 2 inserted into the measuring device 1 in the measurement system 3 of this embodiment, viewed from the direction of II. In the figure, the upper side is the upstream side and the lower side is the downstream side. In the sensor 2, for example, an electrode layer is formed on a substrate 2h made of synthetic resin (plastic), using a metallic material such as gold (Au) or a carbon material such as carbon. On the electrode layer, a spacer 2i having a rectangular cutout as a covering area, and a synthetic resin cover 2j with air holes 2e formed thereon are laminated. The lamination of the substrate 2h, spacer 2i, and cover 2j creates a space with a sample supply port 2d formed by the cutout of the spacer 2i, and this space becomes a flow path 2a. The air holes 2e are formed near the downstream end of the flow path 2a. The area near the downstream end of sensor 2 is an exposed region where the electrodes are not covered by cover 2j, and is clearly divided into an upstream first measurement region 2b and a downstream second measurement region 2c. Furthermore, the area on the downstream end of sensor 2 that is inserted into the insertion port 1b of measuring device 1 is the insertion region 2f, which includes the first measurement region 2b and the second measurement region 2c, as well as the lower end portion of cover 2j.

[0030] In this embodiment, the electrode layer is formed as a first electrode group 10 consisting of a first measuring electrode 11, a second measuring electrode 12, a third measuring electrode 13, a fourth measuring electrode 14, and a fifth measuring electrode 15, and as a second electrode group 20 consisting of a first reference electrode 21, a second reference electrode 22, and a third reference electrode 23.

[0031] The first electrode group 10 consists of electrodes used to measure the target components contained in a liquid sample. Each electrode in the first electrode group 10 is arranged parallel to the longitudinal direction in the first measurement area 2b, and from left to right in Figure 2, they are the fourth measurement electrode 14, the second measurement electrode 12, the fifth measurement electrode 15, the first measurement electrode 11, and the third measurement electrode 13. The fourth measurement electrode 14, the fifth measurement electrode 15, and the third measurement electrode 13 all reach the downstream end of the first measurement area 2b, but the second measurement electrode 12 and the first measurement electrode 11 stop just before the downstream end of the first measurement area 2b.

[0032] Each electrode of the first electrode group 10 extends under the cover 2j into the flow channel 2a on the upstream end side of the sensor 2, and is exposed in the flow channel 2a in parallel to each other in a direction perpendicular to the longitudinal direction of the flow channel 2a. That is, within the flow channel 2a, the third point attachment end 13a, the fourth point attachment end 14a, the first point attachment end 11a, the second point attachment end 12a, and the fifth point attachment end 15a are arranged in parallel from the upstream side, and these are the upstream ends of the third measuring electrode 13, the fourth measuring electrode 14, the first measuring electrode 11, the second measuring electrode 12, and the fifth measuring electrode 15, respectively. Note that adjacent electrodes are insulated from each other. For example, when the electrode layer is formed from a metallic material formed by physical vapor deposition, the electrodes are insulated from each other by drawing a predetermined electrode pattern with laser light (hereinafter referred to as "trimming"). In the case of an electrode layer formed using a carbon material, each electrode is formed with a predetermined spacing between them.

[0033] Downstream of the first measurement area 2b, a second measurement area 2c is provided, which is insulated from the first measurement area 2b by trimming. In the second measurement area 2c, a second electrode group 20 is formed using a conductive material, similar to the electrode layer. The second electrode group 20 does not directly participate in the measurement of the target component, but is used to acquire peripheral information such as lot or individual identification of the sensor 2, insertion detection of the sensor 2, or quality control.

[0034] The second electrode group 20 is divided into three regions in Figure 2 by a cutting line 25 trimmed with laser light: the first reference electrode 21 on the right, the second reference electrode 22 on the left, and the roughly rectangular third reference electrode 23 in the center. However, the first reference electrode 21 and the second reference electrode 22 are separated by the cutting line 25 downstream of the third reference electrode 23 and are not directly conductive, but they are conductive upstream. Also, the second reference electrode 22 and the third reference electrode 23 are conductive on the left side of the downstream edge of the third reference electrode 23. The first reference electrode 21 and the third reference electrode 23 are separated by the cutting line 25 and are not directly conductive.

[0035] Figure 3 is a perspective view showing the schematic configuration of the terminal shape inside the insertion opening 1b of the measuring device 1. Figure 4 is a schematic side view showing the schematic configuration of the terminal shape in Figure 3. Inside the measuring device 1, there is a sensor support base 1e that supports the sensor 2 inserted through the insertion opening 1b. Above this sensor support base 1e, there are multiple terminals that have a mounting base 50 (see Figure 4) on the rear side of the measuring device 1 and extend toward the insertion opening 1b. Of the multiple terminals, the first terminal group 30 has its tip extending closer to the insertion opening 1b. Also, of the multiple terminals, the second terminal group 40 has its tip located further away from the insertion opening 1b. In other words, the distance from the insertion opening 1b to the second terminal group 40 is longer than the distance from the insertion opening 1b to the first terminal group 30.

[0036] As shown in Figure 4, both the first terminal group 30 and the second terminal group 40 consist of a mounting base 50, a bent portion 51 that is bent at 90° from the mounting base 50 toward the sensor support base 1e, an extended portion 52 that extends from the lower end of the bent portion 51 toward the insertion opening 1b while maintaining a distance from the sensor support base 1e, and a contact portion 53 at the tip of the extended portion 52 that is bent in a roughly V-shape toward the sensor support base. In both the first terminal group 30 and the second terminal group 40, when the sensor 2 is not inserted, a gap of less than the thickness of the sensor 2 is maintained between the contact portion 53 and the sensor support base 1e. Furthermore, the extended portion 52 of the terminals of the second terminal group 40 is located closer to the sensor support base 1e than the extended portion 52 of the terminals of the first terminal group 30. Furthermore, the gap Δ1 between the contact portion 53 of the first terminal group 30 and the sensor support base 1e, and the gap Δ2 between the contact portion 53 of the second terminal group 40 and the sensor support base 1e are both shorter than the thickness T (see Figure 8) of the first measurement area 2b and the second measurement area 2c of the sensor 2, and the gap Δ1 is longer than the gap Δ2.

[0037] Figure 5 is a schematic plan view showing the general configuration of the terminal shape in Figure 3. In the figure, the upper side indicates the side of the insertion opening 1b. The first terminal group 30 consists of, from left to right in the figure, the fourth measuring terminal 34, the second measuring terminal 32, the fifth measuring terminal 35, the first measuring terminal 31, and the third measuring terminal 33, which are in contact with the fourth measuring electrode 14, the second measuring electrode 12, the fifth measuring electrode 15, the first measuring electrode 11, and the third measuring electrode 13 shown in Figure 2, respectively. The tips of the first measuring terminal 31 and the second measuring terminal 32 are located closer to the insertion opening 1b than the tips of the third measuring terminal 33, the fourth measuring terminal 34, and the fifth measuring terminal 35.

[0038] On the other hand, the second terminal group 40 consists of a second reference terminal 42, a third reference terminal 43, and a first reference terminal 41, from left to right in the figure, and is in contact with the second reference electrode 22, third reference electrode 23, and first reference electrode 21 shown in Figure 2, respectively. The tip of the third reference terminal 43 is located closer to the insertion opening 1b than the tips of the first reference terminal 41 and the second reference terminal 42. In addition, the tips of the first reference terminal 41 and the second reference terminal 42 of the second terminal group 40 are bifurcated.

[0039] At the mounting base 50 located at the bottom of the drawing in Figure 5, the terminals are arranged from left to right in the following order: the fourth measuring terminal 34, the second measuring terminal 32, and the fifth measuring terminal 35 of the first terminal group 30; the second reference terminal 42, the third reference terminal 43, and the first reference terminal 41 of the second terminal group 40; and the first measuring terminal 31 and the third measuring terminal 33 of the first terminal group 30. The fourth measuring terminal 34, the second measuring terminal 32, and the fifth measuring terminal 35 of the first terminal group 30 extend from a leftward position toward the center towards the insertion opening 1b. On the other hand, the first measuring terminal 31 and the third measuring terminal 33 of the first terminal group 30 extend from a rightward position toward the center towards the insertion opening 1b. All three terminals of the second terminal group 40 extend straight toward the insertion opening 1b.

[0040] Figure 6 is a schematic perspective view showing the state in which the sensor 2 is being inserted into the measuring device 1. When the sensor 2 is inserted into the measuring device 1, the second electrode group 20 of the electrodes on the contact surface 2g is first inserted into the insertion opening 1b. Then, the tip of the sensor 2 enters between the first terminal group 30 and the sensor support base 1e, while the first terminal group 30, located closer to the insertion opening 1b, is elastically deformed upward. As the sensor 2 is further inserted, the first electrode group 10 enters the insertion opening 1b. Then, the tip of the sensor 2 enters between the second terminal group 40 and the sensor support base 1e, while the second terminal group 40, located further away from the insertion opening 1b, is elastically deformed upward. In this state, as shown in the perspective view of Figure 7 and the side view of Figure 8, the insertion of the sensor 2 into the insertion opening 1b is completed when the first terminal group 30 comes into contact with the first electrode group 10, and at the same time, the second terminal group 40 comes into contact with the second electrode group 20.

[0041] Here, the distance D1 over which the terminal closest to the insertion opening 1b in the first terminal group 30 slides on the contact surface 2g (i.e., the first measurement terminal 31 and the second measurement terminal 32, see Figure 5) is longer than the distance D2 over which the terminal furthest from the insertion opening 1b in the second terminal group 40 slides on the contact surface 2g. Furthermore, the distance over which the sensor 2 causes the contact portion 53 of the first terminal group 30 to bend, in other words, the amount of bending of the first terminal group 30 (T-Δ1), is smaller than the amount of bending of the second terminal group 40 (T-Δ2).

[0042] Figures 7 and 8 show the state after the sensor 2 has been inserted, as shown in the plan views of Figures 9 and 10. However, the second terminal group 40 is omitted in Figure 9, and the first terminal group 30 is omitted in Figure 10. When the sensor 2 is inserted into the measuring device 1, as shown in Figure 9, the first measuring terminal 31 contacts the first measuring electrode 11, the second measuring terminal 32 contacts the second measuring electrode 12, the third measuring terminal 33 contacts the third measuring electrode 13, the fourth measuring terminal 34 contacts the fourth measuring electrode 14, and the fifth measuring terminal 35 contacts the fifth measuring electrode 15. At the same time, as shown in Figure 10, the first reference terminal 41 contacts the first reference electrode 21, the second reference terminal 42 contacts the second reference electrode 22, and the third reference terminal 43 contacts the third reference electrode 23.

[0043] The measurement system 3, formed by inserting the sensor 2 into the measuring device 1, makes it possible to measure the target component (e.g., blood glucose) contained in the blood as a liquid sample. Here, a reagent that reacts with the target component is applied to one of the upstream electrodes 10 (for example, the first contact end 11a) that is involved in the measurement of the specific target component. The potential difference generated when this reagent is dissolved by the liquid sample and reacts with the target component is detected through the first terminal group 30, thereby making it possible to measure the content of the target component. In this embodiment, when blood is applied to the sample supply port 2d of the sensor 2, it flows downstream through the flow path 2a by capillary force, while the third contact end 13a, fourth contact end 14a, first contact end 11a, second contact end 12a, and fifth contact end 15a are immersed from the upstream side. During this time, for example, blood glucose levels (i.e., glucose concentration) are measured by the first measuring electrode 11 and the second measuring electrode 12, other indicators of blood (e.g., hematocrit value) are measured by the third measuring electrode 13 and the fourth measuring electrode 14 located upstream in the flow path 2a, and the fifth measuring electrode 15 located furthest downstream in the flow path 2a is used to detect whether the amount of blood adhering to the flow path 2a is sufficient. On the other hand, the second electrode group 20 is not directly involved in the measurement of the target component, but is used to acquire peripheral information such as individual identification or quality control of the sensor 2. Alternatively, the sensor 2 with the liquid sample pre-adhered may be inserted into the measuring device 1.

[0044] Here, as shown in Figure 4, each electrode of the first terminal group 30 and the second terminal group 40 can be considered as a cantilever beam with the mounting base 50 as the fulcrum. If the length of each electrode is L, the Young's modulus is E, the second moment of area is I, and the force applied to the contact portion 53 is P, then the amount of deflection δ of the contact portion 53 is given by the following equation (1).

[0045] δ=(PL 3 ) / (3EI) ···(1)

[0046] Transforming equation (1) above for P yields equation (2) below.

[0047] P=(3EI / L 3 )·δ ···(2)

[0048] In other words, for the same electrode, the force P is proportional to the amount of deflection δ. Now, when the sensor 2 is inserted from the state shown in Figure 4 and each electrode is deflected upward by a distance δ as shown in Figure 8, the contact portion 53 of each electrode receives a normal force P from the contact surface 2g of the sensor 2, which is calculated using equation (2) above.

[0049] Here, assuming that the material and cross-sectional area of ​​each electrode are the same, the amount of deflection of the first terminal group 30 (T-Δ1) is smaller than the amount of deflection of the second terminal group 40 (from T-Δ2), and furthermore, since the first terminal group 30 is longer than the second terminal group 40, from equation (2) above, the normal force generated in the first terminal group 30 is smaller than the normal force generated in the second terminal group 40.

[0050] Figure 11 schematically shows the measuring device 1 with sensor 2 attached. As shown in this figure, the sum of normal forces N1 acting on the first terminal group 30 is smaller than the sum of normal forces N2 acting on the second terminal group 40.

[0051] Furthermore, the first terminal group 30, which has a smaller normal force than the second terminal group 40, slides a longer distance (D1) on the contact surface 2g than the second terminal group 40. Therefore, the possibility of surface damage to the contact surface 2g and contact portion 53 due to the sliding of the first terminal group 30 can be reduced. On the other hand, the second terminal group 40, which has a larger normal force, slides a shorter distance (D2) on the contact surface 2g, so the effect of surface damage due to the normal force of the second terminal group 40 is smaller. It is desirable to reduce the frictional force between the first terminal group 30 and the contact surface and reduce surface damage by coating a part of the area on the contact surface 2g where the first terminal group 30 slides (for example, the surface between the parts where the terminals contact the third measuring terminal 33, the fourth measuring terminal 34, and the fifth measuring terminal 35, and the part where the terminal contacts the third reference terminal 43) with a substance that reduces frictional force (for example, lubricating oil) or by applying a surface treatment that reduces surface roughness.

[0052] As shown in Figures 4 and 8, the first terminal group 30, which has a longer sliding distance with the contact surface 2g, is positioned in the upper row, and the second terminal group 40, which has a shorter sliding distance with the contact surface 2g, is positioned in the lower row. This makes it easier to make the spring modulus of the first terminal group 30 lower than that of the second terminal group 40. This configuration also contributes to making the normal force acting on the first terminal group 30 smaller than the normal force acting on the second terminal group 40.

[0053] Furthermore, as shown in Figure 5, the contact portions 53 of the second terminal group 40, specifically the first reference terminal 41 and the second reference terminal 42, are bifurcated at the tip. This allows the sum of the normal forces to remain constant even if the normal force generated at each tip of the contact portion 53 is set to be smaller.

[0054] In this embodiment of the disclosure, it is desirable that the sum of normal forces generated at the terminals furthest from the insertion opening 1b in the second terminal group 40 (specifically, the first reference terminal 41 and the second reference terminal 42) is greater than the sum of normal forces generated at the terminals furthest from the insertion opening 1b in the first terminal group 30 (specifically, the first measurement terminal 31 and the second measurement terminal 32), and it is even more desirable that the latter be more than twice the former.

[0055] Furthermore, due to the normal force P exerted on each terminal by the contact surface 2g, a static friction force F is generated between each terminal and the contact surface 2g, as derived by equation (3) below. Here, μ' is the coefficient of static friction.

[0056] F = μ′P ···(3)

[0057] Figure 12 schematically shows the measuring device 1 with the sensor 2 attached, with the insertion opening 1b facing downwards. At this time, gravity G, caused by the mass of the sensor 2, acts on the sensor 2. The sum of static friction forces F1 acting on the first terminal group 30 is smaller than the sum of static friction forces F2 acting on the second terminal group 40 (see (A) and (B)). Since the sum of static friction forces F1 acting on the first terminal group 30 is smaller than gravity G acting on the sensor 2 (see (A)), the first terminal group 30 alone cannot prevent the free fall of the sensor 2. On the other hand, the sum of static friction forces F2 acting on the second terminal group 40 is smaller than the gravity G acting on the sensor 2 Since it is greater than the gravitational force G acting on it (see (B)), the second terminal group 40 alone can prevent the sensor 2 from free falling. [Examples]

[0058] (1) Example 1 In the sensor of Example 1, the specifications of each terminal shown in Figure 5 were set as shown in Table 1 below. The normal force is the value measured using a force gauge (DPX-0.5T, IMADA) to deflect each terminal by the amount of deflection listed in Table 1 below (the same applies to subsequent tables).

[0059] [Table 1]

[0060] Note that the values ​​for the first and second reference terminals in Table 1 above refer to each of the bifurcated ends. From Table 1 above, the sum of the normal forces of the first terminal group is 1.0N (=0.2N × 5), and the sum of the normal forces of the second terminal group is 1.8N (=0.2N + 0.4N × 4). Therefore, the sum of the normal forces of the first terminal group is equal to the sum of the normal forces of the second terminals. group It is smaller than the sum of the normal forces.

[0061] Furthermore, since the sensor's mass is 0.1g, the gravitational force G acting on the sensor is 9.8 × 10⁻⁶. -4This becomes N. Here, if we let the coefficient of static friction of the contact surface be μ', the sum of the normal forces of the first terminal group is 1.0N as described above, so the static friction force F1 generated between the first terminal group and the contact surface is 1.0μ'(N). Similarly, the sum of the normal forces of the second terminal group is 1.8N as described above, so the static friction force F2 generated between the second terminal group and the contact surface is 1.8μ'(N). And, as explained in Figure 12 above, F1<G、かつ、F2> Since G, this static friction coefficient μ′ will be set to the numerical range of equation (3) below.

[0062] 5.4 × 10 -4 <μ′<9.8×10 -4 ...(3)

[0063] (2) Example 2 Examples 2 For this sensor, the specifications of each terminal shown in Figure 5 were set as shown in Table 2 below.

[0064] [Table 2]

[0065] In this embodiment, the sum of the normal forces of the terminals furthest from the insertion opening and with the shortest movement distance on the contact surface (i.e., the first reference terminal and the second reference terminal) (0.8N × 4 = 3.2N) is greater than the sum of the normal forces of the terminals furthest from the insertion opening and with the longest movement distance on the contact surface (i.e., the first and second measurement terminals) (0.2N × 2 = 0.4N), specifically by more than twice as much.

[0066] (3) Example 3 In its simplest form, the first terminal group can be configured with four terminals having equal travel distances on the contact surface, and the second terminal group can also be configured with four terminals having equal travel distances on the contact surface, resulting in the specifications shown in Table 3 below.

[0067] [Table 3]

[0068] In other words, in this embodiment, the sum of the normal forces of the second terminal group (0.6N × 4 = 2.4N) is twice the sum of the normal forces of the first terminal group (0.3N × 4 = 1.2N). [Industrial applicability]

[0069] The present invention can be used in measuring devices that are equipped with sensors to measure target components contained in liquid samples. [Explanation of symbols]

[0070] 1. Measuring device 1b Insertion port 2 sensors 2f Insertion area 2g contact surface 3. Measurement System 10 First electrode group 20 Second electrode group 30 First terminal group 40 Second terminal group

Claims

1. A measurement system comprising a sensor and a measuring device having an insertion port into which the sensor is inserted, wherein the measuring device measures the components to be measured contained in a liquid sample attached to the sensor while the sensor is inserted into the insertion port, The measuring device has a plurality of terminals that contact the sensor inside the insertion opening, and from the start to the completion of insertion of the sensor, the terminals slide on the contact surface that the sensor faces. In the aforementioned sensor, the contact surface that contacts the terminal in the insertion region, which is the portion inserted into the insertion opening, is provided with a first electrode group located at the rear end in the insertion direction and a second electrode group located at the front end of the first electrode group. The plurality of terminals receive static friction force from the contact surface by pressing the contact surface and include a first group of terminals that contact the first group of electrodes on the side closer to the insertion opening and a second group of terminals that contact the second group of electrodes on the side further from the insertion opening. With the sensor inserted into the insertion port, the sum of the static frictional forces received by the first group of terminals from the contact surface is less than the sum of the static frictional forces received by the second group of terminals from the contact surface. Measurement system.

2. The sum of the static frictional forces that the first group of terminals receives from the contact surface is less than the gravitational force generated by the mass of the sensor. The measurement system according to claim 1, wherein the sum of the static frictional forces that the second group of terminals receives from the contact surface is greater than the gravitational force generated by the mass of the sensor.

3. The measurement system according to claim 1 or claim 2, wherein the amount of deflection caused by the insertion of the insertion area for each terminal of the first terminal group is smaller than the amount of deflection caused by the insertion of the insertion area for each terminal of the second terminal group.

4. Each of the aforementioned multiple terminals is Mounting base and An extension portion extending from the mounting base in the direction of the insertion opening, The tip of the extended portion bends in the direction of the contact surface and contacts the contact surface, It has, The measurement system according to claim 3, wherein the extended portion of the terminal of the second terminal group is located closer to the side where the contact surface is located than the extended portion of the terminal of the first terminal group.

5. The measurement system according to claim 1 or claim 2, wherein some of the contact portions of the terminals of the second group of terminals are divided into two.

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