Method for manufacturing a guide wire and a sensor for living body

Abstract

Provided is a guide wire. In a structure where a diaphragm and a conductive portion are located on a plane orthogonal to the axial direction, an insulating film can be applied to the conductive portion without impairing the mobility of the diaphragm. The guide wire (10) includes: a guide wire body (30) having a housing (34) with an internal space (34S); and a pressure sensor (11) located in the internal space (34S). The pressure sensor (11) includes: a sensor body (12) having a distal end face (12a) orthogonal to the axial direction (30A) of the guide wire body (30) and facing the distal end; a diaphragm (13) located on the distal end face (12); a resistor (17) whose resistance value changes by deforming together with the diaphragm (13); a terminal (18) connected to the resistor (17); a conductive wire (15) mounted on the terminal (18) using solder (26); and an insulating film (23) electrophoretically coated on the portions of the terminal (18), the solder (26), and the conductive wire (15) that are exposed on the distal end face (12a) and not electrophoretically coated on the diaphragm (13).

Description

Technical Field

[0001] The present invention relates to a guide wire inserted into the lumen of a living body and used for measuring the pressure of a fluid in the lumen, and a method for manufacturing a sensor for a living body for the guide wire. Background Art

[0002] As a method for measuring the pressure of a fluid in the lumen of a living body, such as blood pressure in the coronary artery, a method of inserting a guide wire having a pressure sensor into a blood vessel is known. In Patent Documents 1 and 2, a pressure measuring device in which a sensor for pressure detection is disposed inside a housing provided at the tip of a guide wire is disclosed.

[0003] The above sensor includes a diaphragm and a resistor provided on the diaphragm. When the guide wire is inserted into a blood vessel, blood pressure is applied to the diaphragm of the sensor. When the diaphragm flexes due to blood pressure, the resistance value of each resistor changes. As a result, the current flowing through the resistor changes. And, when there are a plurality of resistors, a potential difference is generated between the resistors. Based on the change in current and the potential difference, blood pressure is calculated.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-540114

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-38792

[0008] During measurement, a part of the sensor comes into contact with blood. Therefore, it is preferable to apply a waterproof and insulating coating to the sensor (especially the conductive part of the sensor). The conductive part is, for example, a terminal provided at a portion where a conductive wire for connecting the sensor to an arithmetic device is connected to the sensor.

[0009] However, in the case of the pressure measuring device disclosed in Patent Document 2, the following problem occurs. In this pressure measuring device, both the diaphragm and the terminal are located on a plane orthogonal to the axial direction of the guide wire. Therefore, when coating is performed on this plane, coating is caused not only on the terminal but also on the diaphragm, making it difficult for the diaphragm to flex.

[0010] Therefore, it is considered not to apply coating to the diaphragm but only to the terminal. However, the surfaces where the diaphragm and the terminal are located are much smaller than the lumen diameter of the living body. In particular, although there are the following advantages: by positioning the diaphragm on a surface orthogonal to the axial direction of the guide wire, even if the diaphragm is close to the blood vessel wall, the pressing load on the blood vessel wall is difficult to affect the deformation of the diaphragm. On the other hand, it is difficult to apply coating by masking only a part (diaphragm part) of the above-mentioned surface. Assuming that even if masking is possible, due to the low masking accuracy, it is possible to apply a part of the coating to the diaphragm.

[0011] On the other hand, when a thin coating layer is applied to the entire surface where the diaphragm and the terminal are located, it is difficult for the diaphragm to move, and the accuracy of pressure detection deteriorates. Summary of the Invention

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide a guide wire that can apply an insulating film to a conductive part without impairing the mobility of the diaphragm in a structure where both the diaphragm and the conductive part are located on a surface intersecting the axial direction of the guide wire.

[0013] (1) The pressure measuring guide wire of the present invention includes: a guide wire body having a distal end portion with an internal space; and a sensor located in the internal space of the distal end portion. The sensor includes: a sensor body having a surface that intersects the axial direction of the guide wire body and faces the distal end; a diaphragm located on the surface; a resistor whose resistance value changes by deforming together with the diaphragm; a terminal connected to the resistor; a conductive wire electrically connected to the terminal; and an insulating film electrophoretically coated on the exposed portions of the terminal and the conductive wire on the surface and not electrophoretically coated on the diaphragm.

[0014] According to the above structure, the diaphragm is not coated with the insulating film, and the terminal and the conductive wire as the conductive part are coated with the insulating film. Therefore, it is possible to prevent the fluid from contacting the conductive part without impairing the mobility of the diaphragm.

[0015] (2) The sensor body has a through hole that opens on the surface and extends along the axial direction. The terminal is at least located in the opening or the through hole. The conductive wire is inserted through the through hole.

[0016] It is possible to coat the connection portion of the conductive wire connected to the terminal with the insulating film, and it is easy to cover the opposite side of the through hole of the conductive wire with respect to the surface with an insulating member made of resin or the like.

[0017] (3) The sensor body is cylindrical, and the diameter of the surface is less than 0.5 mm.

[0018] Since the diameter of the surface is less than 0.5 mm, it is difficult to coat only the conductive part on the surface. However, according to the above structure, since the insulating film is electrophoretically coated, even on a small surface, it is possible to coat only the conductive part, thereby preventing coating on the diaphragm.

[0019] (4) Preferably, the insulating film contains polyimide as a main component.

[0020] (5) The present invention is a method for manufacturing a living body sensor, which is located in the internal space at the distal end of a guide wire main body having an internal space at the distal end. The living body sensor insulates and coats a terminal and a conductive wire exposed on the surface of the sensor facing the distal end, and does not insulate and coat a diaphragm exposed on the surface. The method for manufacturing a living body sensor of the present invention includes: an electrophoresis step of applying a potential to the terminal through the conductive wire in a state where at least the surface of the sensor is immersed in a coating solution; a water washing step of washing off the coating components contained in the coating solution attached to at least the diaphragm in the sensor; and a baking step of heating the coating components attached to the sensor after water washing.

[0021] According to the above manufacturing method, since the insulating film is coated on the surface by electrophoretic coating, on the surface, it is possible to coat only the terminal and the conductive wire as the conductive part with the insulating film. That is, the diaphragm is not coated with the insulating film. Therefore, without impairing the mobility of the diaphragm, it is possible to prevent the fluid from coming into contact with the conductive part.

[0022] Moreover, a potential is applied to the terminal through the conductive wire in the electrophoresis step. That is, there is no need to spend time using wires other than the conductive wire when applying a potential in the electrophoresis step and installing the conductive wire after the electrophoresis step. In addition, by detecting the current in the electrophoresis step, it is possible to grasp the completion of the formation of the insulating film.

[0023] According to the present invention, in a structure where both the diaphragm and the conductive part are located on a surface intersecting the axial direction of the guide wire, without impairing the mobility of the diaphragm, it is possible to coat the conductive part with the insulating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic view of a guide wire 10 according to an embodiment of the present invention.

[0025] Figure 2 is Figure 1 an enlarged cross-sectional view taken along the II-II cutting line of

[0026] Figure 3 is Figure 1 an enlarged cross-sectional view taken along the III-III cutting line of

[0027] Figure 4 It is a perspective view of the pressure sensor 11.

[0028] Figure 5 It is Figure 4 each cross-sectional view at the V-V cutting line of

[0029] Figure 6 It is from Figure 4 the view observed from the arrow view VI of

[0030] Figure 7 It is a circuit diagram of the bridge circuit of the embodiment of the present invention.

[0031] Figure 8 It is a schematic diagram showing the electrophoresis process.

[0032] Figure 9 It is a schematic diagram showing the baking process. Detailed Embodiment

[0033] Hereinafter, preferred embodiments of the present invention will be described. In addition, this embodiment is merely one embodiment of the present invention, and of course, the embodiment can be changed within the scope of not changing the gist of the present invention.

[0034] (Guide wire 10)

[0035] As Figure 1 shown, the guide wire 10 of this embodiment includes a guide wire main body 30 and a pressure sensor 11 (an example of a sensor, a sensor for a living body) provided on the guide wire main body 30. One end of the guide wire main body 30 is electrically connected to the arithmetic control unit 40. In Figure 1 , the fixed end (the end connected to the arithmetic control unit 40) of the two ends of the guide wire main body 30 is the proximal end ( Figure 1 the right side in Figure 1 ), and the free end (the tip when inserted into the blood vessel) is the distal end (

[0036] the left side in

[0037] In Figures 1 to 3In [the figure], the axis line 30L of the guide wire body 30 is shown. In this specification, the directions related to the components constituting the guide wire body 30, that is, the axial direction 30A, the radial direction 30R, and the circumferential direction 30C are defined as follows. The axial direction 30A, the radial direction 30R, and the circumferential direction 30C are defined based on the axis line 30L in a state where the guide wire body 30 is straight without being deflected or bent, that is, the axis line 30L as a straight line. The axial direction 30A is the direction parallel to the axis line 30L and includes two directions, the direction toward the distal end and the direction toward the proximal end. The radial direction 30R is all directions orthogonal to the axis line 30L. The circumferential direction 30C is the direction around the axis line 30L.

[0038] (guide wire body 30)

[0039] As Figure 1 shown, the guide wire body 30 includes a core wire 31, a tip guide portion 32, a first helix 33, a housing 34, a second helix 35, and a catheter 38. As Figure 2 shown, the guide wire body 30 includes a tapered pin 39. As Figure 3 shown, the guide wire body 30 includes a connecting wall 36 and a tip wire 37.

[0040] As Figure 1 shown, the core wire 31 is a component that constitutes the framework of the guide wire body 30. When the guide wire body 30 is bent, a certain mechanical strength is imparted to the core wire 31 so that the guide wire body 30 can be inserted into the blood vessel without bending. The core wire 31 is a cylindrical wire rod that extends from the proximal end toward the distal side. The material of the core wire 31 is, for example, a medical stainless steel material. The axis line of the core wire 31 is parallel to the axis line 30L.

[0041] The distal side of the core wire 31 is more easily deflected than the proximal side. The core wire 31 has a small-diameter portion 31a on the distal side, a large-diameter portion 31b on the proximal side, and a tapered portion 31c that connects the small-diameter portion 31a and the large-diameter portion 31b. The small-diameter portion 31a and the large-diameter portion 31b each have a constant outer diameter, and the outer diameter of the large-diameter portion 31b is larger than the outer diameter of the small-diameter portion 31a. The outer diameter of the tapered portion 31c is equal to the outer diameter of the large-diameter portion 31b at the proximal end, gradually decreases from the proximal end toward the distal end, and is equal to the outer diameter of the small-diameter portion 31a at the distal end. By making the outer diameter of the core wire 31 gradually decrease toward the distal side, the rigidity of the core wire 31 decreases in the order of the large-diameter portion 31b, the tapered portion 31c, and the small-diameter portion 31a.

[0042] As Figure 2 shown, the tapered pin 39 is arranged on the distal side from the distal end portion of the core wire 31. The tapered pin 39 is also a component that constitutes the framework of the guide wire body 30, and a certain mechanical strength is imparted to the tapered pin 39 in the case where the guide wire body 30 is bent.

[0043] The tapered pin 39 has a shaft portion 39a on the proximal side and a tapered portion 39b extending distally from the shaft portion 39a. The outer diameter of the shaft portion 39a is constant. The shaft portion 39a is inserted into the small-diameter portion 31a of the core wire 31. The shaft portion 39a is fixed to the small-diameter portion 31a by, for example, laser welding or an adhesive. The outer diameter of the tapered portion 39b is formed to taper toward the distal tip. Therefore, the rigidity of the tapered portion 39b gradually decreases toward the distal side. Since the distal end portion of the guide wire main body 30 in which the tapered pin 39 is disposed is easily bent, the guide wire main body 30 is easily guided along the blood vessel. Further, a groove 39c that opens on the outer peripheral surface of the tapered pin 39 is formed such that the proximal end of the tapered pin 39 to the proximal side portion of the tapered portion 39b is parallel to the axial direction 30A. Four conductive wires 15 (described later) of the pressure sensor 11 pass through the core wire 31 via the groove 39c and are connected to the arithmetic control unit 40.

[0044] As Figure 1 and Figure 2 shown, the catheter 38 is located outside the small-diameter portion 31a of the core wire 31 in the radial direction 30R and covers the distal side portion of the small-diameter portion 31a. The shape of the catheter 38 is a cylindrical shape. The axis line of the core wire 38 is parallel to the axis line 30L. The catheter 38 is fixed to the outer peripheral surface of the small-diameter portion 31a of the core wire 31. The catheter 38 has flexibility. The catheter 38 is, for example, a medical synthetic resin and is, for example, heat fusion welded to the outer peripheral surface of the core wire 31.

[0045] As Figure 1 and Figure 3 shown, the tip guide portion 32 is disposed at the distal end of the guide wire main body 30. The tip guide portion 32 is a portion that guides the traveling direction of the guide wire main body 30 along the blood vessel by abutting against the blood vessel wall when the guide wire main body 30 is inserted into the blood vessel. The tip guide portion 32 has a hemispherical portion 32a on the distal side and a cylindrical portion 32b extending proximally from the hemispherical portion 32a. The hemispherical portion 32a protrudes distally in a hemispherical shape so as not to damage the blood vessel wall. The outer diameter of the hemispherical portion 32a is substantially equal to the outer diameter of the second helical member 35. The cylindrical portion 32b protrudes proximally from the hemispherical portion 32a and has a cylindrical shape with an outer diameter smaller than the outer diameter of the hemispherical portion 32a. The tip guide portion 32 is positioned relative to the second helical member 35 by inserting the cylindrical portion 32b into the second helical member 35, and the outer surfaces of the hemispherical portion 32a and the second helical member 35 are smoothly continuous without a step. The material of the tip guide portion 32 is, for example, medical stainless steel.

[0046] As Figure 1 and Figure 3As shown, a first helical member 33 and a second helical member 35 are provided on the distal side of the guide wire body 30. The bending rigidity of the first helical member 33 and the second helical member 35 is weaker than that of the tapered pin 39, that is, they are prone to bending. The first helical member 33 is formed of a wire wound in a helical shape. The material of the first helical member 33 is, for example, a medical stainless steel material. The axis line of the first helical member 33 is parallel to the axis line 30L. As Figure 2 and Figure 3 shown, the tapered portion 39b of the tapered pin 39 is inserted into the first helical member 33. The first helical member 33 has a proximal end portion 33a (refer to Figure 2 ) and a distal end portion 33b (refer to Figure 3 ). As Figure 2 shown, the proximal end portion 33a is fixed to the outer peripheral surface of the tapered portion 39b of the tapered pin 39 by, for example, laser welding or an adhesive. Thus, the bending rigidity of the first helical member 33 is strengthened by the tapered pin 39.

[0047] As Figure 1 shown, a housing 34 (an example of the distal end portion) is provided on the distal side of the guide wire body 30. As Figure 1 and Figure 3 shown, the housing 34 has a cylindrical shape and has an internal space 34S. A pressure sensor 11 is accommodated in the internal space 34S of the housing 34. The material of the housing 34 is, for example, a medical stainless steel material. The axis line of the housing 34 is parallel to the axis line 30L. The distal end portion 33b of the first helical member 33 is fixed to the proximal end portion of the housing 34 by, for example, laser welding or an adhesive.

[0048] The housing 34 has a plurality of through holes 34a. In the present embodiment, the housing 34 has two through holes 34a. The through holes 34a penetrate the cylindrical wall of the housing 34 along the radial direction 30R. The internal space 34S of the housing 34 is communicated with the outside through the through holes 34a. The two through holes 34a are arranged along the circumferential direction 30C of the guide wire body 30, with an interval of 180 degrees around the axis line 30L. In addition, the number of the through holes 34a is not limited to two. The interval between the through holes 34a is not limited to 180 degrees around the axis line 30L.

[0049] As Figure 1 and Figure 3 shown, the second helical member 35 is formed of a wire wound in a helical shape. The material of the second helical member 35 is, for example, a medical stainless steel material. The axis line of the second helical member 35 is parallel to the axis line 30L. As Figure 3As shown, the second helical member 35 has a proximal end portion 35a and a distal end portion 35b. The proximal end portion 35a of the second helical member 35 is fixed to the distal end portion of the housing 34. The second helical member 35 and the housing 34 are fixed by, for example, laser welding or an adhesive. The cylindrical portion 32b of the tip guide portion 32 is inserted into the distal end portion 35b of the second helical member 35. The distal end portion 35b is fixed to the outer peripheral surface of the cylindrical portion 32b. The second helical member 35 and the tip guide portion 32 are fixed by, for example, laser welding or an adhesive.

[0050] The connecting wall 36 is a member for connecting the tip wire 37 to the housing 34. The connecting wall 36 is fixed to the distal end portion of the housing 34. The connecting wall 36 is made of, for example, a metal solder material.

[0051] The tip wire 37 strengthens the bending rigidity of the second helical member 35. The tip wire 37 is, for example, a wire made of medical stainless steel. The axis line of the tip wire 37 is parallel to the axis line 30L. The proximal end portion of the tip wire 37 is fixed to the connecting wall 36. The distal end portion of the tip wire 37 is fixed to the cylindrical portion 32b of the tip guide portion 32 by, for example, laser welding or an adhesive.

[0052] According to the above structure, the tapered pin 39 and the tip guide portion 32 are connected via the first helical member 33, the housing 34, and the second helical member 35. Further, the housing 34 and the tip guide portion 32 are connected via the tip wire 37. The tapered pin 39 is fixed to the core wire 31. Thus, the guide wire main body 30 (except for the core wire 31) is supported by the core wire 31 and given mechanical strength.

[0053] According to the structure as described above, when the guide wire main body 30 is sent into a blood vessel at the proximal end, the guide wire main body 30 travels straight in the blood vessel without bending during this operation. Further, when the tip guide portion 32 comes into contact with the blood vessel wall, the guide wire main body 30 bends along the blood vessel wall.

[0054] (Pressure sensor 11)

[0055] As Figure 3 shown, the pressure sensor 11 is disposed in the internal space 34S of the housing 34. The proximal side portion of the internal space 34S is almost filled with the pressure sensor 11. On the other hand, the distal side portion of the internal space 34S, that is, the internal space 34S located on the distal side of the pressure sensor 11, remains in a space state. In the distal side portion of this internal space 34S, the through hole 34a of the housing 34 opens.

[0056] As Figures 3 to 6 shown, the pressure sensor 11 includes a sensor main body 12, a diaphragm 13, a bridge circuit 14, four conductive wires 15, a covering member 16, and an insulating film 23.

[0057] AsFigure 4 As shown, the shape of the sensor body 12 is cylindrical. The axis line of the sensor body 12 is parallel to the axis line 30L. The sensor body 12 has a distal end face 12a (an example of a face), a proximal end face 12b, and an outer peripheral face 12c. The distal end face 12a and the proximal end face 12b are faces orthogonal to the axial direction 30A. The distal end face 12a faces the distal end. The proximal end face 12b faces the proximal end. The outer peripheral face 12c faces the radial direction 30R. The material of the sensor body 12 is, for example, single crystal silicon.

[0058] In the present embodiment, the diameter of the sensor body 12 (the diameter of the circle of the cylindrical shape) is approximately 0.3 mm. That is, the diameters of the distal end face 12a and the proximal end face 12b are 0.3 mm or less. In addition, the diameter of the sensor body 12 (the diameters of the distal end face 12a and the proximal end face 12b) is not limited to approximately 0.3 mm. The diameter of the sensor body 12 is preferably less than 0.5 mm, but may also be 0.5 mm or more.

[0059] A diaphragm 13, a bridge circuit 14, and four conductive wires 15 are mounted on the sensor body 12.

[0060] As Figure 5 shown, the sensor body 12 has a recess 21 in the distal end face 12a. The recess 21 is a component for facilitating the deformation of the diaphragm 13 due to the pressure of the fluid in the lumen. When viewed from the distal side of the sensor body 12, the shape of the recess 21 is circular. The depth of the recess 21 in the axial direction 30A is constant. The axis line of the recess 21 coincides with the axis line of the sensor body 12.

[0061] As Figures 4 to 6 shown, the sensor body 12 has four through holes 22. The four through holes 22 are arranged such that they are spaced apart by 90 degrees along the circumferential direction 30C around the axis line of the sensor body 12. Each through hole 22 extends along the axial direction 30A and opens at both the distal end face 12a and the proximal end face 12b of the sensor body 12. When viewed from the axial direction 30A, the shape of the through hole 22 is circular.

[0062] As Figures 4 to 6 shown, the diaphragm 13 is arranged and fixed on the distal end face 12a of the sensor body 12. The material of the diaphragm 13 is, for example, single crystal silicon, and it is formed by locally etching the sensor body 12. The shape of the diaphragm 13 is circular when viewed from the axial direction 30A and rectangular when viewed from the radial direction 30R. The axis line of the diaphragm 13 coincides with the axis line of the sensor body 12. The distal end face 12a, the diaphragm 13, and the recess 21 are coaxially arranged. The outer diameter of the diaphragm 13 is larger than the diameter of the inner circumferential face of the recess 21. The diaphragm 13 covers the entire opening of the recess 21. The portion of the diaphragm 13 that covers the opening of the recess 21 can be elastically deformed by applying an external force.

[0063] As Figure 4 、 Figure 6 and Figure 7 shown, the bridge circuit 14 is arranged and fixed to the distal end face 12a of the sensor body 12. The bridge circuit 14 includes four resistors 17 (17A, 17B), four terminals 18 (18A, 18B, 18C, 18D), and four connecting members 19. The bridge circuit 14 surrounds the diaphragm 13.

[0064] The bridge circuit 14 is a full-bridge circuit in which all four resistors 17 function as measuring strain gauges. Therefore, the four resistors 17 are composed of two types of resistors having different resistance change characteristics. The two types of resistors are the first resistor 17A and the second resistor 17B. In this specification, when it is not necessary to distinguish between the first resistor 17A and the second resistor 17B, they are referred to as resistors 17.

[0065] The four resistors 17 are fixed to the distal side surface of the diaphragm 13. The material of the resistor 17 is, for example, boron. When viewed from the axial direction 30A, the four resistors 17 are fixed to the outer peripheral portion of the diaphragm 13. The four resistors 17 are arranged at intervals of 90 degrees along the circumferential direction 30C around the axis line of the sensor body 12. Here, the first resistor 17A and the second resistor 17B are alternately arranged along the circumferential direction 30C. In addition, the resistors 17 are pre-insulated.

[0066] Both the first resistor 17A and the second resistor 17B are semiconductors utilizing the piezoresistive effect. Since the resistor 17 is fixed to the diaphragm 13, it will elastically deform as the diaphragm 13 elastically deforms. When the resistor 17 elastically deforms, the resistance value of the resistor 17 changes. That is, the resistor 17 changes its resistance value by deforming together with the diaphragm 13.

[0067] The shapes of the first resistor 17A and the second resistor 17B are different from each other. The postures of the first resistor 17A and the second resistor 17B with respect to the diaphragm 13 are also different from each other. Due to the differences in shape and posture as described above, the differences in the above-mentioned resistance change characteristics are generated between the first resistor 17A and the second resistor 17B.

[0068] When viewed from the axial direction 30A, the shape of the first resistor 17A is Π-shaped. In the posture with respect to the diaphragm 13, the first resistor 17A has a circumferential component 51 and two radial components 52. The circumferential component 51 extends substantially along the circumferential direction of the diaphragm 13. The radial component 52 extends substantially along the radial direction of the diaphragm 13. The first resistor 17A is configured such that its resistance value increases as the diaphragm 13 deforms during pressurization.

[0069] When viewed from the axial direction 30A, the shape of the second resistor 17B is rectangular. In the posture with respect to the diaphragm 13, the second resistor 17B is composed of a circumferential component that extends substantially along the circumferential direction of the diaphragm 13. The second resistor 17B is configured such that its resistance value decreases as the diaphragm 13 deforms during pressurization.

[0070] As Figure 6 and Figure 7 shown, the four terminals 18 are two input terminals 18A, 18C and two output terminals 18B, 18D in the bridge circuit 14. In this specification, when it is not necessary to distinguish between the input terminals 18A, 18C and the two output terminals 18B, 18D, they are referred to as terminals 18. The material of the terminals 18 is, for example, a solder material. As Figure 5 shown, the four terminals 18 are four conductive layers provided corresponding to the four through-holes 22 of the sensor body 12. In order to solder the conductive wires 15, the four terminals 18 expose the conductive layers. The terminals 18 are stacked on at least one of the inner side surfaces of the respective through-holes 22 or the peripheries of the openings of the respective through-holes 22 on the distal end surface 12a. In the present embodiment, the terminals 18 are stacked on the peripheries of the openings of the respective through-holes 22 on the distal end surface 12a.

[0071] As Figure 4 and Figure 6 shown, the four terminals 18 are arranged outside the diaphragm 13 in the radial direction 30R. The four terminals 18 are arranged at intervals of 90 degrees around the axis line of the sensor body 12 along the circumferential direction 30C. The four terminals 18 and the four resistors 17 are alternately arranged in the circumferential direction 30C. Each terminal 18 is arranged between two adjacent resistors 17 among the four resistors 17.

[0072] As Figures 4 to 6 shown, the four connectors 19 are respectively provided corresponding to the four terminals 18. Each connector 19 is a conductive layer stacked on the periphery of the opening of each through-hole 22 on the distal end surface 12a. In the present embodiment, before the connector 19 is electrically connected to the terminal 18, its surface is subjected to insulation processing. And for the connector 19 after the insulation processing, the terminal 18 is in a state of being electrically connected to the connector 19. Each connector 19 electrically connects two adjacent resistors 17 and the terminal 18 located between the two adjacent resistors 17. In this way, the four resistors 17 and the four terminals 18 are alternately electrically connected.

[0073] As Figure 6 shown, in the bridge circuit 14, the two input terminals 18A, 18C are arranged at an interval of 180 degrees from each other, and the two output terminals 18B, 18D are arranged at an interval of 180 degrees from each other. As Figure 6 、 Figure 7As shown, the bridge circuit 14 has two paths from one input terminal 18A to the other input terminal 18C, namely one path 27 and the other path 28. One path 27 is a path via the first resistor 17A, one output terminal 18B, and the second resistor 17B. The other path 28 is a path via the second resistor 17B, the other output terminal 18D, and the first resistor 17A. Here, one input terminal 18A is the high voltage side, and the other input terminal 18C is the low voltage side.

[0074] In a state where a voltage is applied between the two input terminals 18A and 18C, in one path 27, voltage drops occur in the order of the first resistor 17A and the second resistor 17B, and in the other path 28, voltage drops occur in the order of the second resistor 17B and the first resistor 17A.

[0075] In a state where the diaphragm 13 is not pressurized, the first resistor 17A and the second resistor 17B do not deform. At this time, the resistance values of the first resistor 17A and the second resistor 17B are the same. Therefore, no potential difference is generated between the two output terminals 18B and 18D.

[0076] On the other hand, in a state where the diaphragm 13 is pressurized, the first resistor 17A and the second resistor 17B deform. As described above, when pressurized, the resistance value of the first resistor 17A increases, and the resistance value of the second resistor 17B decreases. That is, the voltage drop amount of the first resistor 17A is larger than that of the second resistor 17B. Therefore, a potential difference is generated between the two output terminals 18B and 18D.

[0077] In a state where the guide wire body 30 is inserted into a blood vessel and blood pressure is applied to the pressure sensor 11, a potential difference is generated between the two output terminals 18B and 18D according to this blood pressure. The magnitude of the blood pressure can be determined based on this potential difference.

[0078] As Figure 5 shown, the four conductive wires 15 are respectively electrically connected to the four terminals 18. The conductive wire 15 has a conductive wire body 15a made of a conductor and an insulating cover 15b made of an insulating member. For the insulating cover 15b, the portion of the conductive wire body 15a except for the two end portions of the conductive wire body 15a is covered. At the distal end portion of the conductive wire 15, the conductive wire body 15a is electrically and mechanically connected to the terminal 18 by welding. Solder 26 is filled between the conductive wire body 15a and the terminal 18, and a part of the terminal 18 may also be covered. The solder 26 blocks the openings of the distal end faces 12a of the four through holes 22 of the sensor body 12. In addition, a part of the solder 26 may also enter the four through holes 22 of the sensor body 12.

[0079] One end of the conductive wire 15 is electrically connected to the pressure sensor 11 by connecting the main body 15a of the conductive wire and the terminal 18. The conductive wire 15 extends from one end thereof and is inserted through the through-hole 22. At a position closer to the proximal side than the through-hole 22, the conductive wire 15 passes through the inside of the core wire 31 via the groove 39c and is connected to the arithmetic control unit 40. That is, one end of the conductive wire 15 is connected to the pressure sensor 11, and the other end of the conductive wire 15 is connected to the arithmetic control unit 40.

[0080] As Figures 3 to 5 shown, the covering member 16 is provided on the proximal side of the sensor main body 12. The covering member 16 is composed of an adhesive in the present embodiment. The structure of the covering member 16 is not limited to an adhesive, and may also be an insulator such as silicon, rubber, or resin. The covering member 16 is fixed to the proximal end surface 12b of the sensor main body 12 and protrudes toward the proximal side from the proximal end surface 12b. The covering member 16 closes the openings of the proximal end surface 12b of the four through-holes 22 of the sensor main body 12. That is, the openings on both sides of the through-hole 22 are closed by the solder 26 and the covering member 16, respectively. In addition, a part of the covering member 16 may also enter the four through-holes 22 of the sensor main body 12.

[0081] As Figure 4 shown, the covering member 16 is connected to and fixed to the tapered pin 39. Thereby, the sensor main body 12 is fixed relative to the tapered pin 39.

[0082] (Insulating film 23)

[0083] As Figure 5 shown, the insulating film 23 is electrophoretically coated on a part of the distal end surface 12a. Specifically, the insulating film 23 is electrophoretically coated on the parts of the terminal 18, the solder 26, and the conductive wire 15 disposed on the distal end surface 12a that are exposed on the distal end surface 12a. In the present embodiment, the parts of the terminal 18 other than the peripheral portion and the conductive wire 15 are covered by the solder 26, and the peripheral portion of the terminal 18 is not covered by the solder 26. That is, the insulating film 23 is electrophoretically coated on the peripheral portion of the terminal 18 and the solder 26 among the terminal 18, the solder 26, and the conductive wire 15 disposed on the distal end surface 12a.

[0084] On the other hand, the insulating film 23 is not electrophoretically coated on the diaphragm 13 and the connecting member 19 disposed on the distal end surface 12a.

[0085] In addition, in Figure 4 and Figure 6 , the insulating film 23 is indicated by shading. As shown in the above figure, on the distal end surface 12a, the four insulating films 23 exist independently of each other.

[0086] The insulating film 23 mainly consists of polyimide. In addition, for the insulating film 23, as long as it is an insulating component, it may also mainly consist of components other than polyimide. For example, it may mainly consist of epoxy resin or polyurethane.

[0087] (Operation control unit 40)

[0088] As Figure 1 shown, the operation control unit 40 includes a power supply unit 41 that supplies current to the pressure sensor 11, an operation unit 42 that performs arithmetic processing on the electrical information output from the pressure sensor 11, and a connector 43 connected to the four conductive wires 15.

[0089] The power supply unit 41 is configured to apply a voltage to the bridge circuit 14 of the pressure sensor 11 through the two conductive wires 15 connected to the two input terminals 18A and 18C (refer to Figure 6 and Figure 7 ).

[0090] The operation unit 42 obtains the voltage value output from the bridge circuit 14 of the pressure sensor 11 through the two conductive wires 15 connected to the two output terminals 18B and 18D (refer to Figure 6 and Figure 7 ). The operation unit 42 calculates the blood pressure acting on the pressure sensor 11 based on the change in the obtained output voltage value. The operation unit 42 includes a memory 42a. More specifically, the operation unit 42 calculates the blood pressure as described below.

[0091] The memory 42a stores the correspondence between the above output voltage value and blood pressure as one-to-one corresponding data, for example. Therefore, when the output voltage value is obtained, the operation unit 42 can determine the blood pressure corresponding to the output voltage value based on the correspondence stored in the memory 42a. In this way, the operation unit 42 can calculate the blood pressure acting on the pressure sensor 11 based on the voltage value output from the pressure sensor 11.

[0092] (Usage example of the guide wire 10)

[0093] The guide wire 10 is used, for example, to measure blood pressure in the coronary artery. The guide wire 30 inserts the distal end provided with the tip guiding portion 32 as the front in the insertion direction into the coronary artery. Based on the position of the tip guiding portion 32 shown in the X-ray fluoroscopic image of the blood vessel, the position of the guide wire main body 30 in the coronary artery is grasped.

[0094] When the pressure sensor 11 reaches the blood pressure measurement position in the coronary artery, the insertion of the guide wire main body 30 is interrupted. In the state as described above, a constant voltage is supplied from the power supply unit 41 to the pressure sensor 11 through the operation of the user.

[0095] Inside the blood vessel, blood flows into the internal space 34S of the housing 34, and blood pressure acts on the surface of the diaphragm 13 of the pressure sensor 11. As a result, the diaphragm 13 undergoes elastic deformation, and along with this, the resistance values of the four resistors 17 change.

[0096] In the bloodstream, due to the movement of the heart, there are pulsations in which blood pressure repeatedly rises and falls. The four resistors 17 undergo elastic deformation following the pulsations of the bloodstream. As a result, corresponding to the blood pressure of the pulsating bloodstream, the resistance values of the four resistors 17 change.

[0097] The arithmetic unit 42 of the arithmetic control unit 40 acquires the electrical information output from the pressure sensor 11. As described above, based on this electrical information, the arithmetic unit 42 calculates the blood pressure acting on the pressure sensor 11.

[0098] (Manufacturing method of the pressure sensor 11)

[0099] Hereinafter, with reference to Figure 8 and Figure 9 , a method of electrophoretic coating the insulating film 23 during the manufacturing process of the pressure sensor 11 will be described.

[0100] As Figure 8 shown, the conductive wire 15 of the pressure sensor 11 is wound around the reel 90. At this time, the distal end portion 91 (the portion where the sensor main body 12 is provided) and the proximal end portion 92 (the portion connected to the connector 43) of the conductive wire 15 are not wound around the reel 90. The reel 90 is fixed or supported by the plate 93 so as to be rotatable. In addition, in the present embodiment, the plate 93 is made of glass epoxy resin, but is not limited to glass epoxy resin.

[0101] The distal end portion 91 is immersed in the coating liquid 94 stored in the container 95. In the present embodiment, the coating liquid 94 contains fine particles of polyimide. In addition, the coating liquid 94 is appropriately selected according to the type of the insulating film 23 to be electrophoretically coated. And the coating liquid 94 may also contain substances other than polyimide.

[0102] The proximal end portion 92 is fixed to the plate 93 by a metal fixture 96. And a conductive wire 98 connected to the cathode of the power supply 97 is fixed to the fixture 96. As a result, the proximal end portion 92 is electrically connected to the cathode of the power supply 97 via the fixture 96 and the conductive wire 98. The electrode 100 is connected to the anode of the power supply 97 via the conductive wire 99. The electrode 100 is immersed in the coating liquid 94 stored in the container 95. In the present embodiment, the electrode 100 is made of stainless steel, but is not limited to stainless steel.

[0103] In the circuit configured as described above, the power supply 97 applies power at a specified voltage (50 V in this embodiment). As a result, a potential of 50 V is applied to the terminal 18 and the solder 26 disposed on the distal end face 12a of the sensor body 12. In this embodiment, the power application is performed for 20 seconds. Also, in this embodiment, during the power application, the coating liquid 94 is stirred using a stirrer or the like. Thereby, the fine particles of polyimide are diffused. By applying the potential, the fine particles of polyimide adhere to the distal end portion 91 immersed in the coating liquid 94. The step of applying the above potential corresponds to an electrophoresis step.

[0104] Next, the distal end portion 91 is taken out from the coating liquid 94 and cleaned. In this embodiment, it is cleaned with pure water. By the above cleaning, the polyimide fine particles attached to the distal end face 12a other than the conductive portions (the terminal 18 and the solder 26) are washed away. That is, the fine particles of polyimide attached to the diaphragm 13 and the connection member 19 other than the conductive portions are washed away. On the other hand, the fine particles of polyimide remain attached to the terminal 18 and the solder 26. In addition, the connection member 19 is covered with an insulating member, and the fine particles of polyimide do not directly adhere, so this is the portion other than the conductive portions. The step of performing this cleaning corresponds to a water washing step.

[0105] Next, the sensor body 12 of the distal end portion 91 is heated. In this embodiment, as Figure 9 shown, the distal end portion 91 is placed on the plate 93, and the heavy object 101 is placed near the distal end portion 91. In the above state, the sensor body 12 is heated. The heating of the sensor body 12 is achieved, for example, by blowing hot air toward the sensor body 12, or by placing the sensor body 12 in an oven or on a hot plate. In the case of using hot air as the heating method, by placing the heavy object 101 near the distal end portion 91, it is possible to prevent the sensor body 12 from shaking due to the blowing of the hot air. The heating is performed, for example, at about 170 to 200 °C for 30 minutes. By heating, the fine particles of polyimide attached to the terminal 18 and the solder 26 are melted, and an insulating film 23 is formed by subsequent cooling. In addition, the heating time, temperature, and heating method of the pressure sensor 11 can be appropriately selected other than the above. The step of performing the above heating corresponds to a baking step.

[0106] (Function and effect of this embodiment)

[0107] According to this embodiment, the diaphragm 13 is not coated with the insulating film 23, and the terminal 18 as the conductive portion (in the case where the conductive wire 15 and the solder 26 are exposed, the conductive wire 15 and the solder 26 in addition thereto) is coated with the insulating film 23. Therefore, it is possible to prevent the fluid from coming into contact with the conductive portion without impairing the movability of the diaphragm 13.

[0108] Further, according to the present embodiment, the connection portion of the conductive wire 15 connected to the terminal 18 can be coated with the insulating film 23, and at the same time, the opposite side of the through hole 22 of the conductive wire 15 with respect to the distal end surface 12a can be covered with the covering member 16.

[0109] Further, when the diameter of the distal end surface 12a is less than 0.5 mm (0.28 mm in the present embodiment), it is difficult to perform coating only on the conductive portion on the distal end surface 12a. However, according to the present embodiment, since the insulating film 23 is a member coated by electrophoretic coating, coating can be performed only on the conductive portion even on a small distal end surface 12a, and coating on the diaphragm 13 can be prevented.

[0110] Further, according to the present embodiment, the insulating film 23 can be set to a thickness of about 1 to 5 μm, for example. Also, in portions having an uneven shape such as the terminal 18 and the solder 26, the insulating film 23 with a uniform thickness is formed along the uneven shape. Also, the presence or absence of the insulating film 23 can be clearly grasped from the appearance.

[0111] Further, according to the manufacturing method of the pressure sensor 11 described above, since the insulating film 23 is coated on the distal end surface 12a by electrophoretic coating, on the distal end surface 12a, the insulating film 23 can be used to coat only the terminal 18, the solder 26, and the conductive wire 15 as the conductive portions. That is, the diaphragm 13 is not coated with the insulating film 23. Therefore, contact between the fluid and the conductive portion can be prevented without impairing the mobility of the diaphragm 13. Also, the thickness of the insulating film 23 can be controlled in units of 1 μm by adjusting the potential and time in the electrophoretic process. Thereby, fine particles of polyimide attached to the distal end portion 91 in the electrophoretic process can be prevented from falling into the diaphragm 13. Also, in the electrophoretic process, the insulation resistance value can be 1 MΩ or more. Thereby, it is difficult to generate pinholes in the insulating film 23, and the thickness of the insulating film 23 is likely to become uniform.

[0112] Further, according to the manufacturing method of the pressure sensor 11 described above, a potential is applied to the terminal 18 through the conductive wire 15 in the electrophoretic process. That is, there is no need to spend time using a wire other than the conductive wire 15 to apply a potential in the electrophoretic process and installing the conductive wire 15 after the electrophoretic process.

[0113] (Modification example)

[0114] As described above in detail, the embodiments of the present invention have been explained. However, the above description is merely an example of the present invention in all aspects. Of course, various improvements and modifications can be made without departing from the scope of the present invention. Regarding each component of the guide wire 10 in the above embodiments, the omission, replacement, and addition of components can be appropriately carried out according to the embodiments. Also, the shape and size of each component of the guide wire 10 can be appropriately set according to the embodiments. For example, the following changes can be made.

[0115] In the above embodiment, the shape of the sensor body 12 is cylindrical, and the distal end face 12a is perpendicular to the axial direction 30A of the guide wire body 30. The sensor body 12 only needs to have a distal end face 12a facing the distal side, and the shape of the sensor body 12 and the angle of the distal end face 12a with respect to the axial direction 30A are not limited. For example, the shape of the sensor body 12 can also be a prismatic shape, and the distal end face 12a can also be inclined with respect to the axial direction 30A.

[0116] In the above embodiment, the shape of the diaphragm 13 is a disc shape. The shape of the diaphragm 13 is not limited as long as it can elastically deform the diaphragm 13 according to the pressure change applied to the diaphragm 13. The diaphragm 13 is a plate-like member, and the shape of the above plate-like member observed from the axial direction 30A can also be any shape. Any shape is, for example, a polygonal shape, including a quadrilateral, a hexagon, an octagon, etc.

[0117] In the above embodiment, the four resistors 17 are arranged at intervals of 90 degrees around the axis line of the sensor body 12. The arrangement of the four resistors 17 is not limited to this. For example, it can also be that the four resistors 17 are arranged at uneven intervals around the axis line of the sensor body 12, for example, at intervals of 120 degrees, 60 degrees, 120 degrees, and 60 degrees, or at intervals of 60 degrees, 90 degrees, 30 degrees, and 180 degrees.

[0118] In the above embodiment, the four through holes 22 for providing the four terminals 18 are arranged at intervals of 90 degrees around the axis line of the sensor body 12. The arrangement of the four through holes 22 is not limited to this. For example, it can also be that, similar to the four resistors 17, the four through holes 22 are arranged at uneven intervals around the axis line of the sensor body 12, for example, at intervals of 120 degrees, 60 degrees, 120 degrees, and 60 degrees, or at intervals of 60 degrees, 90 degrees, 30 degrees, and 180 degrees. And, in the above embodiment, the shape of the through hole 22 observed from the axial direction 30A is circular. The shape of the through hole 22 observed from the axial direction 30A can also be a polygon, for example, without limitation.

[0119] In the above-described embodiment, four resistors 17 and four terminals 18 are provided each, but the number of resistors 17 and terminals 18 is not limited to four. The number of conductive wires 15 is determined according to the number of resistors 17 and terminals 18. When the number of resistors 17 and terminals 18 is other than four, the pressure sensor 11 has a circuit different from the bridge circuit 14 of the above-described embodiment, and has a circuit that causes all the resistors 17 to function as strain gauges. Also, the number of insulating films 23 is not limited to four.

[0120] In the above-described embodiment, before being electrically connected to the terminal 18, the surface of each connecting member 19 is subjected to insulation processing, but similar to the terminal 18, the insulating film 23 can also be applied by electrophoretic coating. Also, the electrical connection between the terminal 18 and the conductive wire 15 is not limited to solder 26. For example, instead of solder 26, the terminal 18 and the conductive wire 15 can be electrically connected using a conductive adhesive, and a member in which the terminal 18 and the conductive wire 15 are integrally formed in an electrically connected state can also be used.

[0121] Explanation of symbols

[0122] 10 Guide wire

[0123] 11 Pressure sensor (sensor, living body sensor)

[0124] 12 Sensor body

[0125] 12a Distal end face (face)

[0126] 13 Diaphragm

[0127] 15 Conductive wire

[0128] 17 Resistor

[0129] 18 Terminal

[0130] 22 Through hole

[0131] 23 Insulating film

[0132] 30 Guide wire body

[0133] 30A Axial direction

[0134] 34 Housing (distal end portion)

[0135] 34S Internal space

Claims

1. A guide wire, characterized in that, Comprising: A guide wire body having a distal end portion with an internal space; and A sensor located in the internal space of the distal end portion, The sensor comprising: A sensor body having a face that intersects the axial direction of the guide wire body and faces the distal end; A diaphragm located on the face; A resistor whose resistance value changes by deforming together with the diaphragm; A terminal connected to the resistor; A conductive wire electrically connected to the terminal; And An insulating film electrophoretically coated on the portions of the terminal and the conductive wire that are exposed on the face, and not electrophoretically coated on the diaphragm.

2. The guide wire according to claim 1, wherein The sensor body has a through hole that opens on the face and extends along the axial direction, The terminal is at least located in the opening or the through hole, The conductive wire is inserted through the through hole.

3. The guide wire according to claim 1 or 2, wherein The sensor body is cylindrical, and the diameter of the face is less than 0.5 mm.

4. The guide wire according to claim 1 or 2, wherein The insulating film has polyimide as the main component.

5. The guide wire according to claim 3, wherein The insulating film has polyimide as the main component.

6. A method for manufacturing a sensor for living body, characterized in that, The in-vivo sensor is located in the internal space of the distal end portion of a guide wire body having an internal space at the distal end portion. The in-vivo sensor insulates and coats the terminal and the conductive wire exposed on the face of the sensor facing the distal end, and does not insulate and coat the diaphragm exposed on the face. The manufacturing method of the in-vivo sensor includes: An electrophoretic coating process, in a state where at least the face of the in-vivo sensor is immersed in a coating solution, applying a potential to the terminal through the conductive wire; A water washing process, washing off the coating components contained in the coating solution that adheres to at least the diaphragm in the in-vivo sensor; and A baking process, heating the coating components adhering to the in-vivo sensor after water washing.

Images