Optical fiber device and distal end position detecting device for medical catheter

Abstract

This optical fiber device (100) is provided with an optical fiber (140) and a connector (101) disposed at the proximal end of the optical fiber. The optical fiber is provided with a light entering part (142) on the proximal side and a light emission part (145) on the distal side. When light from a light source device (150) enters the light emission part of the optical fiber in a state where a medical catheter (900) with the optical fiber inserted therethrough has been inserted into a patient, the light emits from the light emission part and illuminates the body surface of the patient. The connector is provided with a first connection part (110) on the proximal side. The first connection part is provided with a sleeve (111) with the optical fiber inserted therethrough, and a first connection housing (115) surrounding the sleeve. The first connection housing is provided with an engagement structure (117) engageable with the light source device so that the connector is axially constrained by the light source device upon connecting the connector to the light source device.

Description

Optical fiber device and distal end position detection device for medical catheter

[0001] The present invention relates to a fiber optic device used to detect the position of the distal end (tip) of a medical catheter inserted into a patient, and to a device (detection device) for detecting the position of the distal end of a medical catheter inserted into a patient.

[0002] In the medical field, catheters with flexible hollow tubes are sometimes inserted into patients for examinations or treatments. For example, enteral nutrition is performed to administer liquids containing nutrients, liquid foods (commonly called "enteral nutrition"), or medications to patients who can no longer take food orally. In enteral nutrition, liquids are administered to patients through a catheter (enteral nutrition catheter) inserted into the stomach via the nose or mouth. Before administering liquids, it is necessary to confirm that the distal end (tip) of the catheter is positioned within the stomach.

[0003] Patent Documents 1 and 2 describe methods for using an optical fiber to confirm the position of the distal end of a catheter inserted into a patient. More specifically, a catheter with an optical fiber inserted therein is inserted into a patient. The optical fiber has a light incident portion on its proximal side and a light emitting portion on its distal side (tip side). Light from a light source is incident on the light incident portion of the optical fiber. The light is emitted from the light emitting portion of the optical fiber. The position of the distal end of the catheter can be confirmed by observing the light from the light emitting portion from outside the patient's body.

[0004] In this method, it is desirable for the light-emitting portion of the optical fiber to emit light more brightly, i.e., for a larger luminous flux to be emitted from the light-emitting portion of the optical fiber. To achieve this, it is necessary to suppress optical loss (coupling loss) when light from a light source enters the light-incident portion of a small-diameter optical fiber. During use, an optical fiber may be subjected to a tensile force. For example, during use, a tensile force may be applied to the optical fiber due to the operator's manipulation or the weight of the optical fiber. This tensile force may increase the distance from the light source to the light-incident portion of the optical fiber or cause the axial misalignment of the light-incident portion relative to the light source, resulting in coupling loss. Therefore, it is necessary to suppress coupling loss even when such a tensile force is applied to the optical fiber.

[0005] WO2015 / 133119WO2019 / 215791 JP 2015-119837 A

[0006] An object of the present invention is to reduce coupling loss between a light source and an optical fiber and to easily and accurately detect the position of the distal end of a medical catheter.

[0007] The optical fiber device of the present invention comprises an optical fiber and a connector provided at the proximal end of the optical fiber and connectable to and disconnectable from a light source device. The optical fiber is insertable into a medical catheter. The optical fiber has a light incident portion on its proximal side and a light emitting portion on its distal side. The optical fiber device is configured so that when light from the light source device is incident on the light incident portion of the optical fiber while the medical catheter with the optical fiber inserted is inserted into a patient, the light is emitted from the light emitting portion and illuminates the patient's body surface, thereby enabling detection of the position of the distal end of the medical catheter. The connector has a first connecting portion on its proximal side. The first connecting portion comprises a cylindrical sleeve into which the optical fiber is inserted and a first connecting tube arranged coaxially to and surrounding the sleeve. The first connecting tube has an engagement structure that can engage with the light source device so that the connector is axially constrained by the light source device when the connector is connected to the light source device.

[0008] The detection device of the present invention is a device for detecting the position of the distal end of a medical catheter, and includes the optical fiber device of the present invention and a light source device that can connect and disconnect the connector of the optical fiber device.

[0009] When the connector of the optical fiber device of the present invention is connected to a light source device, the light input portion of the optical fiber is positioned coaxially with the light source at the desired axial position relative to the light source, thereby reducing coupling loss. Furthermore, even if a tensile force acts on the optical fiber during subsequent use, misalignment of the light input portion relative to the light source can be reduced, thereby maintaining low coupling loss. Therefore, according to the present invention, coupling loss between the light source and the optical fiber can be reduced. By inserting the optical fiber device of the present invention into a medical catheter, attenuation of the light beam emitted from the distal end of the catheter is reduced and the light beam is stabilized. The light beam can be easily confirmed from outside the patient's body. Therefore, according to the present invention, the position of the distal end of a medical catheter can be easily and accurately detected.

[0010] FIG. 1 is a diagram showing a schematic configuration of a detection device according to a first embodiment of the present invention for detecting the position of the distal end of a nasal catheter. FIG. 2 is a diagram showing a method for detecting the position of the distal end of a nasal catheter in the first embodiment of the present invention. FIG. 3A is a perspective view of a connector provided in an optical fiber device according to the first embodiment of the present invention, seen from the first connecting portion side. FIG. 3B is a perspective view of the connector according to the first embodiment of the present invention, seen from the second connecting portion side. FIG. 3C is a cross-sectional perspective view of the connector according to the first embodiment of the present invention, seen from the second connecting portion side. FIG. 4 is a cross-sectional view showing a step in manufacturing the optical fiber device according to the first embodiment of the present invention. FIG. 5A is a perspective view of a catheter connector provided in a nasal catheter in which the optical fiber device of the present invention is used. FIG. 5B is a cross-sectional perspective view of the catheter connector. FIG. 6A is a perspective view of an olive of a nasal catheter. FIG. 6B is a cross-sectional perspective view of the olive. FIG. 7A is a cross-sectional view of a portion near the proximal end of a catheter set in which an optical fiber device according to the first embodiment of the present invention is incorporated into a nasal catheter. FIG. 7B is a cross-sectional view of a portion near the distal end of the catheter set according to the first embodiment of the present invention. FIG. 8 is a cross-sectional view of a portion near the proximal end of a catheter set and a light source device in the first embodiment of the present invention. FIG. 9A is a perspective view of a receiving member of the light source device according to the first embodiment of the present invention. FIG. 9B is a cross-sectional view of the receiving member according to the first embodiment of the present invention. FIG. 10 is a cross-sectional view showing a main portion of a state in which a catheter set is connected to a light source device according to the first embodiment of the present invention. FIG. 11A is a perspective view of a connector provided in an optical fiber device according to a second embodiment of the present invention, as seen from a first connecting portion side. FIG. 11B is a perspective view of a connector according to the second embodiment of the present invention, as seen from a second connecting portion side. FIG. 11C is a cross-sectional perspective view of a connector according to the second embodiment of the present invention, as seen from a second connecting portion side. FIG. 12 is a cross-sectional view of a portion near the proximal end of a catheter set in which an optical fiber device according to the second embodiment of the present invention is incorporated into a nasal catheter. FIG. 13 is a cross-sectional view of a portion near the proximal end of a catheter set and a main portion of a light source device according to the second embodiment of the present invention. FIG. 14A is a perspective view of a receiving member of the light source device according to the second embodiment of the present invention. FIG. 14B is a cross-sectional perspective view of the receiving member according to the second embodiment of the present invention.15A is a cross-sectional view taken along a first plane showing a main part of a catheter set connected to a light source device in accordance with the second embodiment of the present invention. FIG. 15B is a cross-sectional view taken along a second plane showing a main part of a catheter set connected to a light source device in accordance with the second embodiment of the present invention. FIG. 16A is a perspective view of a connector provided in an optical fiber device according to a third embodiment of the present invention, as viewed from a first connection portion side. FIG. 16B is a perspective view of a connector according to the third embodiment of the present invention, as viewed from a second connection portion side. FIG. 16C is a cross-sectional view of a connector according to the third embodiment of the present invention, as viewed from a second connection portion side. FIG. 17 is a cross-sectional view of a portion near the proximal end of a catheter set in which an optical fiber device according to the third embodiment of the present invention is incorporated into a nasal catheter. FIG. 18A is a cross-sectional view taken along a first plane of a portion near the proximal end of the catheter set and a main part of a light source device according to the third embodiment of the present invention. FIG. 18B is a cross-sectional view taken along a second plane of a portion near the proximal end of the catheter set and a main part of a light source device according to the third embodiment of the present invention. FIG. 19A is a perspective view of a receiving member of a light source device according to the third embodiment of the present invention. Fig. 19B is a cross-sectional perspective view of a receiving member according to embodiment 3 of the present invention. Fig. 20A is a cross-sectional view taken along a first plane showing a main part of a catheter set connected to a light source device according to embodiment 3 of the present invention. Fig. 20B is a cross-sectional view taken along a second plane showing a main part of a catheter set connected to a light source device according to embodiment 3 of the present invention.

[0011] (1) The optical fiber device of the present invention comprises an optical fiber and a connector provided at the proximal end of the optical fiber and connectable to and disconnectable from a light source device. The optical fiber is insertable into a medical catheter. The optical fiber has a light incident portion on its proximal side and a light emitting portion on its distal side. The optical fiber device is configured so that when the medical catheter with the optical fiber inserted therein is inserted into a patient and light from the light source device is incident on the light incident portion of the optical fiber, the light is emitted from the light emitting portion and illuminates the patient's body surface, thereby enabling detection of the position of the distal end of the medical catheter. The connector has a first connecting portion on its proximal side. The first connecting portion comprises a cylindrical sleeve into which the optical fiber is inserted and a first connecting tube arranged coaxially to and surrounding the sleeve. The first connecting tube has an engaging structure that can engage with the light source device so that the connector is axially constrained by the light source device when the connector is connected to the light source device.

[0012] (2) In the optical fiber device of (1), the connector may have a second connection part on its distal side, and the second connection part may be connectable to and disconnectable from a catheter connector provided at the proximal end of the medical catheter.

[0013] According to the optical fiber device of item (2), the light emitting portion of the optical fiber can be aligned with the distal end of the medical catheter simply by connecting the second connecting portion to the catheter connector.

[0014] (3) In the optical fiber device of the above item (2), the second connecting portion may have a female tapered surface that can be tapered and fitted into the male tapered surface of the catheter connector.

[0015] According to the optical fiber device of paragraph (3), the connector can be connected to the catheter connector at a predetermined axial position simply by tapering the female tapered surface into the male tapered surface. Therefore, the light emitting portion of the optical fiber is accurately aligned with the distal end of the medical catheter. This is advantageous for accurately detecting the position of the distal end of the catheter.

[0016] (4) In the optical fiber device according to any one of (1) to (3), the first connecting tube may have a hollow, generally cylindrical shape, and the engagement structure may include at least one engagement protrusion provided on the first connecting tube so as to protrude radially outward.

[0017] According to the optical fiber device of item (4), the connector can be connected to and disconnected from the light source device simply by performing the simple operation of rotating the connector relative to the light source device.

[0018] (5) In the optical fiber device of (4) above, the at least one engaging protrusion may include two or more and four or less engaging protrusions.

[0019] The optical fiber device of paragraph (5) includes two to four engaging protrusions. Having two or more engaging protrusions is advantageous, first, in preventing displacement of the light entrance portion of the optical fiber relative to the light source when axial or radial pulling force acts on the optical fiber with the connector connected to the light source device, and second, in preventing damage to the engaging protrusions. Having four or less engaging protrusions is advantageous in avoiding a complex structure for the first connecting tube.

[0020] (6) In the optical fiber device of (4) or (5) above, the distance from the distal surface of the at least one engaging protrusion to the proximal end of the first connecting tube may be 70% or more of the outer diameter of the first connecting tube.

[0021] According to the optical fiber device of paragraph (6), it is possible to increase the insertion depth of the first connecting tube into the light source device. Therefore, when a radial tensile force acts on the optical fiber while the connector is connected to the light source device, it is possible to suppress tilt of the connector relative to the light source device. This is advantageous, first, in preventing damage to the engagement protrusion and sleeve, and second, in preventing axial displacement of the light entrance portion of the optical fiber relative to the light source.

[0022] (7) A detection device according to one aspect of the present invention includes the optical fiber device according to any one of (4) to (6) above, and a light source device capable of connecting and disconnecting the connector of the optical fiber device. The light source device may include at least one engaging portion. By rotating the first connecting tube of the connector relative to the light source device, the at least one engaging protrusion of the first connecting tube may be engaged with the at least one engaging portion of the light source device, and the engagement may be released.

[0023] According to the detecting device of item (7), the connector can be connected to and disconnected from the light source device simply by performing the simple operation of rotating the connector relative to the light source device.

[0024] (8) In the detection device of (7) above, the at least one engaging portion may have a locking groove extending along the circumferential direction. The width of the locking groove may be determined by a first side surface and a second side surface facing the first side surface and disposed distally relative to the first side surface. The first side surface may extend along a plane perpendicular to a rotation axis of the first connecting tube relative to the light source device. The second side surface may extend at an angle relative to the first side surface so that the width of the locking groove decreases toward the side where the engaging projection engages with the locking groove. The at least one engaging portion may be capable of axially sandwiching and restraining the at least one engaging projection between the first side surface and the second side surface of the locking groove.

[0025] The detection device of paragraph (8) has the following advantages. First, even if too much rotational force is applied to the connector when connecting the connector to the light source device, the engagement protrusion is unlikely to be damaged. Second, the light entrance portion of the optical fiber can always be positioned at a desired axial position relative to the light source. This is advantageous in stably suppressing coupling loss between the light source and the light entrance portion of the optical fiber.

[0026] (9) In the detection device of paragraph (7) above, the at least one engaging protrusion provided on the first connecting tube may be at least one first engaging protrusion. The at least one engaging portion provided on the light source device may be at least one second engaging protrusion extending circumferentially. The first connecting portion may be provided with an annular abutment end surface perpendicular to the axis of the connector. The first connecting portion may be configured such that when the at least one first engaging protrusion engages with the at least one second engaging protrusion, the abutment end surface abuts against a flat surface of the light source device in the axial direction.

[0027] The detecting device of paragraph (9) has the following advantages. First, with a simple configuration in which the first engaging protrusion is engaged with the second engaging protrusion and the abutting end face is abutted against a flat surface, the light entrance portion of the optical fiber can be positioned at a desired axial position relative to the light source. Second, because the abutting end face extends in an annular shape, when a radial tensile force acts on the optical fiber with the connector connected to the light source device, tilt of the connector relative to the light source device can be suppressed.

[0028] (10) In the optical fiber device according to any one of (1) to (3), the first connecting tube may have a hollow, generally rectangular prism shape, and the engagement structure may include a recess provided in a wall of the first connecting tube.

[0029] According to the optical fiber device of paragraph (10), when the connector is connected to the light source device, the light input portion of the optical fiber is positioned coaxially with the light source at a desired axial position relative to the light source, thereby reducing coupling loss. Furthermore, even if a tensile force is applied to the optical fiber during subsequent use, misalignment of the light input portion relative to the light source can be reduced, thereby maintaining low coupling loss. Therefore, attenuation of the light beam emitted from the distal end of the medical catheter is reduced and the light beam is stabilized. This makes it easy to observe the light beam from outside the patient's body, which is advantageous for easily and accurately detecting the position of the distal end of the catheter.

[0030] (11) A detection device according to another aspect of the present invention includes the optical fiber device according to the above (10) and a light source device capable of connecting and disconnecting the connector of the optical fiber device. The light source device may include an elastic arm that is elastically bendable. When the connector is connected to the light source device, a protrusion provided on the elastic arm may fit into the recess.

[0031] According to the detecting device of the above item (11), the connector can be connected to and disconnected from the light source device simply by performing the simple operation of inserting and removing the connector from the light source device.

[0032] (12) In the optical fiber device according to any one of the above items (1) to (6) and (10), at least one gripping protrusion protruding radially outward may be provided on the outer surface of the connector distal to the first connecting tube.

[0033] According to the optical fiber device of item (12), it is easy to apply force to the connector when connecting and disconnecting the connector to and from the catheter connector of the medical catheter, and when connecting and disconnecting the connector to and from the light source device.

[0034] (13) In the optical fiber device according to any one of (4) to (6), at least one gripping protrusion protruding radially outward may be provided on an outer peripheral surface of the connector distal to the first connecting tube, and the at least one gripping protrusion may be disposed at the same position in the circumferential direction as the at least one engaging protrusion.

[0035] According to the optical fiber device of item (13), when the operator applies a rotational force to the gripping projection, it is possible to avoid a situation in which the operator's fingers come into contact with the engaging projection and the operator feels pain.

[0036] (14) A detection device according to another aspect of the present invention includes the optical fiber device according to (12) or (13) above, and a light source device capable of connecting and disconnecting the connector of the optical fiber device. The connector may have a second connection portion on its distal side. The second connection portion may be connectable to and disconnectable from a catheter connector provided at the proximal end of the medical catheter. When the second connection portion is connected to the catheter connector and the connector is connected to the light source device, the at least one gripping protrusion may be disposed between the catheter connector and the light source device and exposed to the outside.

[0037] According to the detection device of item (14), it is easy to apply force to the connector when connecting and disconnecting the connector to and from the catheter connector of the medical catheter, and when connecting and disconnecting the connector to and from the light source device.

[0038] (15) In the optical fiber device according to any one of (1) to (6), (10), (12), and (13), the sleeve may protrude from the tip of the first connecting tube, and the light entrance portion of the optical fiber may be located at the same position in the axial direction as the tip of the sleeve.

[0039] Such an optical fiber device as described in (15) is advantageous in reducing coupling loss between the light source and the light entrance portion of the optical fiber, and is also advantageous in easily and accurately detecting the position of the distal end of the catheter.

[0040] (16) A detection device according to another aspect of the present invention includes the optical fiber device according to any one of (1) to (6), (10), (12), (13), and (15) above, and a light source device capable of connecting and disconnecting the connector of the optical fiber device. The light source device may include a light source and a female member into which the sleeve of the connector fits when the connector is connected to the light source device. When the sleeve fits into the female member, an inner circumferential surface of the female member may position the sleeve so that the light incident portion of the optical fiber is coaxial with the light source.

[0041] According to the detection device of paragraph (16), the light input portion of the optical fiber can be positioned coaxially with the light source with a simple structure. This makes it possible to reduce coupling loss between the light source and the light input portion of the optical fiber. This is advantageous for easily and accurately detecting the position of the distal end of the catheter.

[0042] (17) In the detection device of the above item (16), the female member may have a tapered surface distal to the inner circumferential surface of the female member, the inner diameter of which increases toward the tip of the female member.

[0043] The detection device of paragraph (17) has the following advantages. First, the tapered surface guides the sleeve into the female member when connecting the connector to the light source device. This is advantageous in making it easier to connect the connector to the light source device. Second, the tapered surface allows the sleeve to tilt relative to the female member when disconnecting the connector from the light source device. This is advantageous in making it easier to disconnect the connector from the light source device.

[0044] (18) In the optical fiber device according to any one of (1) to (6), (10), (12), (13), and (15), the connector may further include an optical fiber fixing portion for fixing the optical fiber to the connector. The optical fiber fixing portion may be disposed distally of the sleeve.

[0045] According to the optical fiber device of item (18), the optical fiber can be firmly fixed to the connector using a sufficient amount of adhesive, compared to when the optical fiber fixing part is placed inside the sleeve (i.e., when the optical fiber is fixed to the sleeve using adhesive).

[0046] (19) In the optical fiber device of (18), the connector may further include a through-hole that connects the optical fiber fixing portion to the outside of the connector. The adhesive may be continuously filled from the optical fiber fixing portion to the through-hole.

[0047] According to the optical fiber device of item (19), the adhesive can be easily applied to the optical fiber fixing portion, which is advantageous in facilitating the manufacture of the optical fiber device.

[0048] (20) In the optical fiber device of (19), at least one gripping protrusion protruding radially outward may be provided on an outer peripheral surface of the connector distal to the first connecting tube, and the through hole may pass through the at least one gripping protrusion.

[0049] The optical fiber device of paragraph (20) has the following advantages. First, the length of the through hole can be ensured. Second, in order to provide a through hole of the required length, it is not necessary to provide a protrusion (second protrusion) through which the through hole passes on the outer surface of the connector, separate from the gripping protrusion. Therefore, the original function of the gripping protrusion, which is to make it easy to apply force to the connector, can be reliably performed without being hindered by the second protrusion. Furthermore, since there is no second protrusion, the external shape of the connector can be simplified.

[0050] (21) In the optical fiber device of (20), the at least one gripping protrusion may include a first gripping protrusion and a second gripping protrusion. The through-hole may pass through the first gripping protrusion. The second gripping protrusion may have a cavity that communicates with the inner cavity of the first connecting tube.

[0051] According to the optical fiber device of paragraph (21), the second gripping protrusion that is not penetrated by the through-hole is provided with a cavity, which is advantageous in preventing resin sink marks from occurring in the second gripping protrusion and in the portion of the second connecting tube near the second gripping protrusion when the connector is resin-molded.

[0052] The present invention will be described in detail below, illustrating preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. For the sake of convenience, the drawings referred to in the following description show simplified views of the main components constituting the embodiments of the present invention. Therefore, the present invention may include any components not shown in the following drawings. Furthermore, within the scope of the present invention, the components shown in the following drawings may be modified or omitted. In the drawings referred to in the description of each embodiment, components corresponding to components shown in the drawings referred to in the preceding embodiment are designated by the same reference numerals as those in the drawings of the preceding embodiment. Duplicate descriptions of such components are omitted, and the descriptions of the preceding embodiment should be taken into consideration as appropriate.

[0053] In the present invention, the "axis" of a component (e.g., a connector, a catheter connector, or a receiving component of a light source device) refers to the central axis of the component. The "axis" passes through the center of a shape (e.g., a circle or a rectangle) included in the component and / or coincides with the central axis of a column (e.g., a cylinder or a rectangular column; a column includes a hollow column) or a conical surface (e.g., a tapered conical surface) included in the component. Unless otherwise specified, the direction parallel to the axis is referred to as the "axial direction." "Planar view" means viewing along the axis. The direction along a straight line perpendicular to the axis is referred to as the "radial direction." In the radial direction, the side closer to the axis is referred to as the "inner" side, and the side farther from the axis is referred to as the "outer" side. The direction of rotation around the axis is referred to as the "circumferential direction." Since those skilled in the art can easily and unambiguously identify axes, axes are omitted from the drawings cited in the following description for simplicity.

[0054] In the present invention, the "proximal" side means the side closer to the surgeon (or user), and the "distal" side means the side farther from the surgeon (or user) (see Figure 1 described below). Here, the "surgeon (or user)" means a person (e.g., a doctor, nurse, caregiver, etc.) who uses the optical fiber device of the present invention, or the medical catheter to which the optical fiber device is applied, or the detection device of the present invention. Unless otherwise specified, the "tip" means the axial end (terminal end) of a component, and generally means the end opposite the "base end." The "tip" can be located on either the "proximal" or "distal" side of the "base end."

[0055] (Embodiment 1) Figure 1 shows a schematic configuration of a detection device (medical catheter distal end position detection device, hereinafter referred to as the "detection device") 1 according to embodiment 1 of the present invention for detecting the position of the distal end (tip) of a nasal catheter 900 as a medical catheter. The detection device 1 comprises an optical fiber device 100 and a light source device 150. The optical fiber device 100 comprises an optical fiber 140 and a connector 101 provided at the proximal end (base end) of the optical fiber 140. The connector 101 can be repeatedly connected to and disconnected from the light source device 150. The light source device 150 has a built-in light source (not visible in Figure 1). The nasal catheter 900 comprises a flexible tube 910, a catheter connector 920 provided at the proximal end (base end) of the tube 910, and an olive 970 provided at the distal end (tip) of the tube 910. The tube 910 is a hollow cylindrical object with a continuous flow path (not visible in FIG. 1; see FIGS. 5B and 6B described below) formed throughout its entire length. The optical fiber 140 of the optical fiber device 100 can be inserted into and pulled out of the nasal catheter 900 from its catheter connector 920 side. The nasal catheter 900 with the optical fiber device 100 inserted therein is called a catheter set 103. The entire combination of the detection device 1 and the nasal catheter 900 is called a "catheter system."

[0056] Figure 2 shows a method for detecting the position of the distal end (tip) of a nasal catheter 900 using the detection device 1. Figure 2 shows a catheter set 103 in which the optical fiber device 100 is incorporated into the nasal catheter 900, and a light source device 150. With an optical fiber 140 (not visible in Figure 2; see Figure 1) inserted into a tube 910, a connector 101 is connected to a catheter connector 920 (see Figure 7A described below). A light emitting portion 145 (not visible in Figure 2; see Figure 1) at the distal end (tip) of the optical fiber 140 reaches the olive 970 (see Figure 7B described below).

[0057] The catheter set 103 (nasal catheter 900) is inserted through the nasal cavity of the patient 990, and the olive 970 at its distal end reaches the stomach 991. Prior to enteral nutrition, the connector 101 is connected to the light source device 150, and the light source of the light source device 150 is turned on. Light from the light source passes through the optical fiber 140 (see FIG. 1) and is emitted from the light emitting portion 145 (see FIG. 1) of the optical fiber 140. The light passes through the olive 970 and further passes through the body of the patient 990, causing the body surface to emit light. The surgeon can detect (or confirm) the position of the olive 970, i.e., the distal end (tip) of the nasal catheter 900, from the position of the light emission on the body surface of the patient 990.

[0058] FIG. 3A is a perspective view of the connector 101 of the optical fiber device 100 according to the first embodiment, as seen from the first connecting portion 110 side. FIG. 3B is a perspective view of the connector 101, as seen from the second connecting portion 120 side. FIG. 3C is a cross-sectional perspective view of the connector 101, as seen from the second connecting portion 120 side. The cross section of FIG. 3C includes the axis (not shown) of the connector 101 and the through-hole 133. The connector 101 includes the first connecting portion 110 on its proximal side and the second connecting portion 120 on its distal side. The first connecting portion 110 and the second connecting portion 120 are coaxially arranged. The first connecting portion 110 can be connected to and disconnected from the light source device 150 (see FIG. 1). The second connecting portion 120 can be connected to and disconnected from the catheter connector 920 (see FIGS. 1, 5A, and 5B).

[0059] The first connecting portion 110 includes a sleeve 111 and a first connecting tube 115. The sleeve 111 and the first connecting tube 115 each have a hollow, generally cylindrical shape. The first connecting tube 115 is arranged coaxially with the sleeve 111, radially spaced from the sleeve 111, and surrounding the sleeve 111. The sleeve 111 and the first connecting tube 115 are connected via an annular wall 139 (see FIG. 3C ). The annular wall 139 is an elongated plate extending from the base end (distal end) of the sleeve 111 to the base end (distal end) of the first connecting tube 115. The annular wall 139 is continuous in a circumferential ring shape surrounding the base end of the sleeve 111. The first connecting tube 115 is open toward the proximal side. The sleeve 111 protrudes proximally (opposite the second connecting portion 120) beyond the first connecting tube 115 (see FIGS. 4 and 7A , described below).

[0060] The outer peripheral surface 111a of the sleeve 111 may be, but is not limited to, a cylindrical surface with a constant outer diameter in the axial direction, or a male tapered surface (conical surface) whose outer diameter decreases toward the tip of the sleeve 111 (the end opposite the second connection portion 120). The tip of the sleeve 111 is provided with a tapered surface (male tapered surface) 111b with a relatively large taper angle, in which the outer diameter decreases toward the tip. An optical fiber 140 is inserted into the sleeve 111 (see FIG. 3C ). The radial position of the optical fiber 140 is restricted by the inner peripheral surface of the sleeve 111 or by multiple protrusions (not shown; the protrusions may extend axially or circumferentially) provided on the inner peripheral surface of the sleeve 111 so as to be coaxial with the sleeve 111. The proximal light incident portion 142 of the optical fiber 140 is located at the same axial position as the tip of the sleeve 111.

[0061] The outer peripheral surface 115a of the first connecting tube 115 is a cylindrical surface with a constant outer diameter in the axial direction, although this is not limited thereto. Two engaging protrusions 117 protruding radially outward are provided on the outer peripheral surface 115a. The engaging protrusions 117 are disposed along the base end (the end on the second connecting portion 120 side) of the first connecting tube 115 or in the vicinity of the base end. The engaging protrusions 117 extend in the circumferential direction. The dimension (thickness) of the engaging protrusions 117 in the axial direction of the connector 101 is constant in the circumferential direction. The number of engaging protrusions 117 is not limited to two, and may be at least one.

[0062] The second connecting portion 120 includes a second connecting tube 121 having a hollow, generally cylindrical shape. The second connecting tube 121 extends from the annular wall 139 toward the opposite side (distal side) from the sleeve 111 and the first connecting tube 115 (see FIG. 3B ) and is arranged coaxially with the sleeve 111 and the first connecting tube 115. The outer circumferential surface 121a of the second connecting tube 121 is a cylindrical surface having a constant outer diameter in the axial direction, although this is not limited thereto. The second connecting tube 121 has a smaller outer diameter than the first connecting tube 115. However, the present invention is not limited thereto, and the outer diameter of the second connecting tube 121 may be larger than or the same as the outer diameter of the first connecting tube 115. Two protrusions 126 and two gripping protrusions 137a, 137b are provided on the outer circumferential surface 121a of the second connecting tube 121 so as to protrude radially outward. The protrusion 126 extends helically and forms a male thread. The gripping protrusions 137a, 137b are arranged closer to the first connecting portion 110 (or the first connecting tube 115) than the protrusion 126. The gripping protrusions 137a, 137b extend a predetermined length in the axial direction from the first connecting tube 115 toward the distal side. The gripping protrusions 137a, 137b are arranged at the same circumferential position as the two engaging protrusions 117 provided on the first connecting tube 115. Note that the number of protrusions 126 is not limited to two, as long as it is at least one. Similarly, the number of gripping protrusions (137a, 137b) is not limited to two, as long as it is at least one.

[0063] A through-hole 133 is provided in the gripping protrusion (first gripping protrusion) 137a (see FIG. 3C ). The through-hole 133 penetrates the gripping protrusion 137a and the second connecting tube 121 so as to communicate between the outside of the second connecting tube 121 and the inner cavity of the second connecting tube 121. The through-hole 133 is inclined so as to move away from the first connecting portion 110 in the axial direction as it moves radially outward from the axis of the connector 101 (or the second connecting tube 121).

[0064] A cavity 138 is provided within the gripping protrusion (second gripping protrusion) 137b (see FIG. 3C ). The cavity 138 is in communication with the inner cavity of the first connecting tube 115 via an opening provided in the annular wall 139. The gripping protrusion 137b is radially spaced from the second connecting tube 121 via the cavity 138. The cavity 138 allows the radial thickness of the gripping protrusion 137b to be reduced. This is advantageous in preventing resin sink marks from occurring on the gripping protrusion 137b and on the portion of the second connecting tube 121 near the gripping protrusion 137b when the connector 101 is resin-molded. Note that the cavity 138 can be omitted in the present invention.

[0065] The second connecting tube 121 communicates with the sleeve 111. However, the second connecting tube 121 has an inner diameter larger than that of the sleeve 111. A partition 131 extends axially from the annular wall 139 into the second connecting tube 121. The cross section of the partition 131 along a plane perpendicular to the axis of the connector 101 is generally U-shaped, with the two ends of the U connected to the inner circumferential surface of the second connecting tube 121. The partition 131 divides the inner cavity of the second connecting tube 121 into two sub-lumens (i.e., a first sub-lumen 132a and a second sub-lumen 132b). The first sub-lumen 132a communicates with the sleeve 111 and the through-hole 133. An optical fiber 140 passes through the first sub-lumen 132a. An adhesive 135 is continuously filled from the first sub-lumen 132a into the through-hole 133. The optical fiber 140 is fixed to the connector 101 via the adhesive 135 filled in the first sub-lumen 132a. In a cross section along a plane perpendicular to the axis of the connector 101, the adhesive 135 surrounds the entire outer periphery of the optical fiber 140. The adhesive 135 in the first sub-lumen 132a forms an optical fiber fixing portion 136 for fixing the optical fiber 140 to the connector 101. The optical fiber 140 is led out of the second connecting portion 120 through the second connecting tube 121.

[0066] It is sufficient that the partition 131 can divide the lumen of the second connecting tube 121 into two sub-lumens (first sub-lumen 132a and second sub-lumen 132b) and can connect the first sub-lumen 132a to the sleeve 111 and the through-hole 133. The cross-sectional shape of the partition 131 along a plane perpendicular to the axis of the connector 101 is not limited to the approximate "U" shape of the first embodiment, and may be, for example, an approximate arc shape, a wedge shape, a straight line, or any curve.

[0067] The adhesive 135 is filled in the first sub-lumen 132a formed by the partition wall 131, but not in the second sub-lumen 132b. This makes it possible to reduce the amount of adhesive 135 required to fix the optical fiber 140. This is advantageous for reducing the cost required for the adhesive 135 and shortening the time required for hardening the adhesive 135. However, in the present invention, the partition wall 131 may be omitted, and the adhesive 135 may be filled in the entire cross-sectional area of ​​the lumen of the second connecting tube 121.

[0068] The inner peripheral surface of the second connecting tube 121 is provided with a female tapered surface 122 whose inner diameter increases toward the tip (the end opposite the first connecting portion 110) of the second connecting tube 121. The female tapered surface 122 is located closer to the tip of the second connecting tube 121 (the end opposite the first connecting portion 110) than the partition wall 131 (or the optical fiber fixing portion 136).

[0069] An example of a method for manufacturing the optical fiber device 100 will now be described.

[0070] The connector 101 is prepared. The connector 101 is made of a hard material (rigid material) and has the mechanical strength (rigidity) to be substantially undeformed by external forces. Specifically, the connector 101 can be made of a resin material such as polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyacetal, polystyrene, polyamide, polyethylene, or rigid polyvinyl chloride. The connector 101 can be manufactured as a single component using the above resin material by injection molding or the like.

[0071] A predetermined length of optical fiber 140 is prepared. The optical fiber 140 is a thin, flexible, fibrous light-guiding member that can be bent or deformed. The optical fiber 140 has a structure in which a high-refractive-index core is covered with a low-refractive-index cladding. Light incident on one end (light incident portion 142) of the optical fiber 140 is confined in the core and propagates toward the other end (light emitting portion 145) of the optical fiber 140. The material of the optical fiber 140 is not limited, and glass, plastic, etc. may be used. The optical fiber 140 may have an optional coating layer that covers the cladding. The coating layer may be composed of a single layer or multiple layers. Note that, for simplicity of illustration, the core, cladding, and optional coating layers that constitute the optical fiber 140 are not separately shown in the cross section of the optical fiber 140 (see Figures 3C and 4, etc.).

[0072] First, as shown in Fig. 4 , the connector 101 is held with the second connecting portion 120 facing up, for example, by a jig (not shown), so that the axis of the connector 101 is parallel to the vertical direction. The optical fiber 140 is inserted into the connector 101 from the second connecting tube 121 side. The optical fiber 140 is inserted into the second connecting tube 121 and the sleeve 111. The tip of the optical fiber 140 (the lower end of the optical fiber 140 in Fig. 4 ) is made to slightly protrude from the tip of the sleeve 111 (the lower end of the sleeve 111 in Fig. 4 ). The optical fiber 140 is held with a jig or the like (not shown) so that the optical fiber 140 extends straight along the axis of the connector 101 within the second connecting tube 121.

[0073] An uncured adhesive is prepared. The adhesive is stored in a container (not shown) having a long, narrow nozzle. The container may be, for example, a syringe. The nozzle is inserted into the through-hole 133, and the adhesive is injected into the through-hole 133. As shown in FIG. 4 , the through-hole 133 and the first sub-lumen 132a are filled with uncured adhesive 134. Any adhesive capable of fixing the optical fiber 140 to the connector 101 can be used as the adhesive 134. The adhesive 134 preferably has fluidity. Specifically, an epoxy resin-based or ultraviolet-curing adhesive can be used. Next, the adhesive 134 is cured.

[0074] After the adhesive 134 has hardened, the optical fiber 140 protruding from the tip of the sleeve 111 is cut. Because the tip of the sleeve 111 protrudes axially from the first connecting tube 115, it is easy to cut the optical fiber 140 at the tip of the sleeve 111. If necessary, the cut surface of the optical fiber 140 may be smoothed (or flattened) by polishing or pressing it against a heated metal plate. The cut surface of the optical fiber 140 becomes the light incident portion 142. The light incident portion 142 is located at the same position as the tip of the sleeve 111 in the axial direction (see FIGS. 3A and 3C).

[0075] Thus, the optical fiber device 100 of the first embodiment (see FIGS. 1 and 3A to 3C) is obtained.

[0076] Unlike the above-described manufacturing method (hereinafter referred to as the "post-fixing method") in which the light incident portion 142 is formed after the optical fiber 140 is fixed to the connector 101, the light incident portion 142 may be formed in advance at the tip of the optical fiber 140, and then the optical fiber 140 may be fixed to the connector 101 (hereinafter referred to as the "pre-fixing method"). The pre-fixing method is generally performed as follows. First, the optical fiber 140 with the light incident portion 142 formed thereon is inserted into the connector 101, which is held with the second connecting portion 120 facing up, as shown in FIG. 4, from the second connecting tube 121 side. Next, uncured adhesive 134 is filled into the through-hole 133 and the first sub-lumen 132a. Next, the adhesive 134 is cured while the light incident portion 142 of the optical fiber 140 is aligned with the tip of the sleeve 111. In this manner, the optical fiber device 100 of this embodiment 1 (see FIGS. 1 and 3A to 3C) is obtained.

[0077] The fiber optic device 100 is used to detect the position of the distal end of a nasal catheter 900 (see FIG. 2) inserted into a patient 990. The nasal catheter 900 will now be described. The nasal catheter 900 includes a catheter connector 920 (see FIGS. 1, 5A, and 5B) at its proximal end and an olive 970 (see FIGS. 1, 6A, and 6B) at its distal end.

[0078] The catheter connector 920 of the nasal catheter 900 will now be described. Fig. 5A is a perspective view of the catheter connector 920, and Fig. 5B is a cross-sectional perspective view of the catheter connector 920.

[0079] The catheter connector 920 has a male connector 930 on its proximal side and a base tube 940 on its distal side. A flow channel 921 passes through the catheter connector 920 along the axis of the catheter connector 920. The inner diameter of the flow channel 921 may vary in the axial direction, but is larger at all positions than the outer diameter of the optical fiber 140 (see FIGS. 1 and 3A-3C) of the optical fiber device 100.

[0080] The male connector 930 includes a hollow, generally cylindrical male member 931, a generally cylindrical outer tube 935 that is radially spaced from the male member 931 and surrounds the male member 931, and a female thread 936 provided on the inner circumferential surface of the outer tube 935. The flow path 921 penetrates the male member 931 along its longitudinal direction. The outer circumferential surface of the male member 931 has a male tapered surface 932 whose outer diameter decreases toward the tip (proximal end, the end opposite the base tube 940) of the male member 931. The male connector 930 may be the same as a connector commonly used in enteral nutrition (see, for example, Figures 1A to 4B of Patent Document 3). The male connector 930 may be configured to be connectable to and disconnectable from a connector (female connector; see, for example, Figures 5A and 5B of Patent Document 3) provided at the downstream end of an extension tube used for enteral nutrition (sometimes called an "enteral nutrition set"). The base end of the male member 931 is connected to the base end of the outer cylinder 935 via a circumferentially continuous annular bottom plate 938 .

[0081] The base tube 940 also has a hollow, generally cylindrical shape overall. The base tube 940 extends distally from the bottom plate 938. The base tube 940 is disposed coaxially with the male member 931. The outer peripheral surface of the base tube 940 is provided with a male tapered surface 941 whose outer diameter decreases toward the tip (distal end, the end opposite the male connector 930) of the base tube 940. To facilitate gripping of the catheter connector 920, a pair of grip pieces 925 extend distally from the bottom plate 938. The grip pieces 925 are spaced apart radially from the base tube 940.

[0082] The tube 910 is connected to the base tube 940 via the connecting tube 950. The connecting tube 950 has a hollow, generally cylindrical shape overall. The inner diameter of the connecting tube 950 may vary in the axial direction, but is larger than the outer diameter of the optical fiber 140 (see FIGS. 1 and 3A-3C) of the optical fiber device 100 at all positions. The base tube 940 is inserted into the connecting tube 950 from its proximal opening. The inner circumferential surface near the proximal end of the connecting tube 950 is provided with a female tapered surface 951 whose inner diameter increases toward the proximal end of the connecting tube 950. The female tapered surface 951 is in surface contact with the male tapered surface 941 of the base tube 940, providing a liquid-tight fit (so-called tapered fit). The connecting tube 950 can be repeatedly connected and disconnected to the base tube 940. The tube 910 is inserted into the connecting tube 950 from its distal opening. The tube 910 is fixed to the inner circumferential surface of the connecting tube 950 via an adhesive (not shown). A flow path 921 of the catheter connector 920 communicates with a flow path 912 of the tube 910 via the connecting tube 950.

[0083] The catheter connector 920 and the connecting tube 950 are made of a hard material (rigid material) and have the mechanical strength (rigidity) to be substantially undeformed by external forces. Specifically, resin materials such as polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyacetal, polystyrene, polyamide, polyethylene, and rigid polyvinyl chloride can be used as the material for the catheter connector 920 and the connecting tube 950. The catheter connector 920 and the connecting tube 950 can be manufactured as a single component by injection molding or the like using the above-mentioned resin materials.

[0084] The tube 910 is a hollow cylindrical body whose inner and outer diameters are constant along the longitudinal direction of the tube 910. The inner diameter of the tube 910 (i.e., the inner diameter of the flow path 912) is larger than the outer diameter of the optical fiber 140 (see FIGS. 3A to 3C) of the optical fiber device 100. The tube 910 is flexible so that it can be easily bent and deformed. The material of the tube 910 is not limited, but examples of resins that can be used include polyvinyl chloride (PVC), polyurethane, acrylic, silicone, polyethylene, styrene-based elastomers, polybutadiene, and the like.

[0085] It should be noted that in the present invention, the connection structure of the tube 910 to the catheter connector 920 is not limited to that of the first embodiment. For example, a threaded structure may be provided between the base tube 940 and the connecting tube 950 to prevent unintentional separation of the connecting tube 950 from the base tube 940. The connecting tube 950 may be inseparably connected to the base tube 940 by means of press-fitting, adhesive bonding, welding, or the like. The connecting tube 950 may be omitted, and the tube 910 may be directly connected to the base tube 940.

[0086] The olive 970 of the nasal catheter 900 will now be described. FIG. 6A is a perspective view of the olive 970, and FIG. 6B is a cross-sectional perspective view of the olive 970. The olive 970 includes a housing 971. The housing 971 has an overall bullet shape with a dome-shaped (hemispherical) bulging tip (distal end, the end opposite the tube 910). The housing 971 is a hollow body having an internal lumen 972. An opening communicating with the internal lumen 972 is provided at the base end (proximal end) of the housing 971. The distal end of the tube 910 is inserted into this opening. The housing 971 is fixed to the tube 910 in a liquid-tight manner by adhesive or the like. A hole (side hole) 975 that penetrates the housing 971 in the radial direction is provided in the outer peripheral wall of the generally cylindrical shape of the housing 971. The flow path 912 of the tube 910 communicates with the outside of the housing 971 via the lumen 972 and holes 975 of the housing 971. In the first embodiment, four holes 975 are provided in the housing 971, but the number of holes 975 is not limited to this and may be less than four or more than four. The position of the holes 975 is also not limited to the first embodiment and may be changed as desired.

[0087] The housing 971 is preferably flexible. Furthermore, the housing 971 is preferably light-transmitting (more preferably transparent) so that light emitted from the light emitting portion 145 (see FIG. 7B , which will be described later in detail) of the optical fiber 140 can pass through the housing 971. The material of the housing 971 is not limited, but examples of resins that can be used include polyurethane, polyethylene, silicone, acrylic, and polypropylene.

[0088] The olive 970 may have a weight to facilitate insertion of the nasal catheter 900 into the digestive tract. The weight may be embedded in the housing 971 on the tip side (distal side, opposite the tube 910) of the lumen 972. The weight may be made of a metal material such as titanium, stainless steel, cobalt alloy, aluminum, or iron. The shape of the weight is not limited, and may be any shape such as a sphere or a rugby ball.

[0089] The olive 970 may have a reflective and / or refractive element. The reflective element can reflect light incident on the surface of the reflective element in a desired direction. Furthermore, the refractive element can refract light as it passes through the surface of the refractive element. The reflective and / or refractive element provided on the olive 970 can cause light emitted from the light emitting portion 145 of the optical fiber 140 (see FIG. 7B described below) to exit the olive 970 in various directions, including the radial direction (a direction perpendicular to the longitudinal direction of the optical fiber 140). Therefore, the reflective and / or refractive element makes it easy to observe the light from the light emitting portion 145 from the surface of the patient's body, regardless of the orientation of the light emitting portion 145 (or the olive 970) inside the patient's body. The reflective and / or refractive element may be formed as a separate element from the housing 971. Alternatively, the housing 971 itself may function as a reflective and / or refractive element.

[0090] An optical fiber device 100 (see FIGS. 1 and 3A-3C) is inserted into a nasal catheter 900 (see FIGS. 1 and 5A-6B) to form a catheter set 103 (see FIG. 2).

[0091] Figure 7A is a cross-sectional view of a portion near the proximal end of the catheter set 103. The cross-section of Figure 7A is the same as the cross-section of Figure 3C and includes the axis and through-hole 133 of the connector 101. The optical fiber 140 of the optical fiber device 100 is inserted into the flow path 912 of the tube 910 of the nasal catheter 900. The connector 101 of the optical fiber device 100 (particularly its second connecting portion 120 (see Figures 3B and 3C)) is connected to the catheter connector 920 of the nasal catheter 900 (particularly its male connector 930 (see Figures 5A and 5B)). More specifically, the male member 931 of the catheter connector 920 is inserted into the second connecting tube 121 of the connector 101. The second connecting tube 121 is inserted into the gap between the male member 931 and the outer tube 935. The female tapered surface 122 of the second connecting tube 121 and the male tapered surface 932 of the male member 931 have the same diameter and taper angle. Therefore, the female tapered surface 122 makes surface contact with the male tapered surface 932, providing a liquid-tight fit (so-called tapered fit). A protrusion (male thread) 126 (protrusion 126 is not visible in FIG. 7A ; see FIGS. 3A and 3B ) on the second connecting tube 121 is threadedly engaged with a female thread 936 (see FIGS. 5A and 5B ) on the outer tube 935. The threaded engagement of the protrusion 126 with the female thread 936 prevents unintended separation of the connector 101 from the catheter connector 920. The second connecting tube 121 functions as a female member to which the male member 931 can be connected.

[0092] 7B is a cross-sectional view of a portion near the distal end of the catheter set 103. The distal light-emitting portion 145 of the optical fiber 140 of the optical fiber device 100 protrudes from the tip (distal end) of the tube 910 of the nasal catheter 900. The light-emitting portion 145 of the optical fiber 140 is located within the lumen 972 of the olive 970. The lengths of the optical fiber 140 and the tube 910 are set so that the light-emitting portion 145 of the optical fiber 140 is located within the lumen 972 of the olive 970 (see FIG. 7B) when the female tapered surface 122 of the connector 101 is tapered and fitted with the male tapered surface 932 of the catheter connector 920 (see FIG. 7A). Preferably, the light-emitting portion 145 abuts against the distal-most surface (the most distal inner end surface) of the inner surfaces defining the lumen 972 of the olive 970.

[0093] The connector 101 can be separated from the catheter connector 920 by loosening the projection 126 (see FIGS. 3A and 3B) from the female thread 936 (see FIGS. 5A and 5B). Furthermore, the optical fiber 140 can be pulled out of the tube 910, thereby separating the optical fiber device 100 from the nasal catheter 900. Thereafter, if necessary, the optical fiber device 100 can be incorporated into the nasal catheter 900 as shown in FIGS. 7A and 7B.

[0094] The connector 101 (particularly the first connection portion 110) of the optical fiber device 100 can be connected to and disconnected from a light source device 150 (see FIGS. 1 and 2 ). As shown in FIG. 8 , the light source device 150 includes a housing 151. The light source device 150 further includes, within the housing 151, a connection portion 153 to which the connector 101 (first connection portion 110) can be connected, and a light source 155 disposed at a position set back from the connection portion 153. The connection portion 153 includes a receiving member 160. Note that, in FIG. 8 , for simplicity of illustration, components within the housing 151 other than the connection portion 153 (receiving member 160) and the light source 155 are omitted.

[0095] 9A is a perspective view of the receiving member 160, and FIG. 9B is a cross-sectional view of the receiving member 160. The receiving member 160 includes a female member 161 and an outer cylinder 165. The female member 161 and the outer cylinder 165 each have a hollow, approximately cylindrical shape. The outer cylinder 165 is arranged coaxially with the female member 161, spaced apart from the female member 161 in the radial direction, and surrounding the female member 161. A bottom plate 164 connects the base end (proximal end) of the female member 161 to the outer cylinder 165. The bottom plate 164 is continuous in a circumferential ring shape surrounding the base end of the female member 161. The outer cylinder 165 is open toward the distal side.

[0096] The inner peripheral surface 161a of the female member 161 may be, but is not limited to, a cylindrical surface with a constant inner diameter in the axial direction, or a female tapered surface (conical surface) with an inner diameter increasing toward the tip (distal end, the end opposite the bottom plate 164) of the female member 161. A tapered surface (female tapered surface) 161b with an inner diameter increasing toward the tip of the female member 161 is provided at the opening facing the distal side of the female member 161. The tapered surface 161b has a larger taper angle than the inner peripheral surface 161a and is located distally of the inner peripheral surface 161a.

[0097] The inner peripheral surface 165a of the outer tube 165 is a cylindrical surface with a constant inner diameter in the axial direction, although this is not a limitation. The inner peripheral surface 165a is provided with a plurality of (two in this embodiment) engagement grooves 167. When viewed from the axis of the outer tube 165 (or the receiving member 160), the engagement grooves 167 have a generally "L" shape (hook shape). More specifically, the engagement grooves 167 include a guide groove 168 extending generally parallel to the axis of the outer tube 165 from the tip (distal end, the end opposite the bottom plate 164) of the outer tube 165, and a lock groove 169 extending circumferentially from the base end (proximal end, the end on the bottom plate 164 side) of the guide groove 168. The width (axial dimension) of the lock groove 169 is determined by a first side surface 169a and a second side surface 169b. The first side surface 169a is disposed closer to the base end of the outer tube 165 (toward the proximal side, the bottom plate 164, or the light source 155) than the second side surface 169b, and faces the second side surface 169b in the axial direction. The first side surface 169a extends precisely along the circumferential direction, in other words, along a plane perpendicular to the axis of the outer tube 165 (or the receiving member 160). On the other hand, the second side surface 169b extends in an inclined manner (i.e., in a spiral shape (more specifically, in a right-handed screw shape)) so as to approach the base end of the outer tube 165 (or the bottom plate 164) as it moves away from the guide groove 168 in the circumferential direction. Therefore, the width (axial dimension) of the lock groove 169 narrows as it moves away from the guide groove 168 in the circumferential direction. More specifically, the width (axial dimension) of lock groove 169 at its starting end (the end on the guide groove 168 side) is greater than the axial dimension (thickness) of engaging protrusion 117 (see FIGS. 3A and 7A) of connector 101, and at its terminal end (the end opposite guide groove 168) is smaller than the axial dimension (thickness) of engaging protrusion 117. The multiple engaging grooves 167 are rotationally symmetrical with respect to the axis of outer tube 165 (or receiving member 160).

[0098] The receiving member 160 is made of a hard material (rigid material) and has the mechanical strength (rigidity) to be substantially undeformed by external forces. Specifically, the receiving member 160 can be made of a resin material such as polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyacetal, polystyrene, polyamide, polyethylene, or rigid polyvinyl chloride. The receiving member 160 can be manufactured as a single unit using the above-mentioned resin material by injection molding or the like.

[0099] 8 , the light source 155 is disposed proximally to the female member 161, coaxially with the receiving member 160 (connecting portion 153), and at a predetermined axial position relative to the receiving member 160. The light source 155 can emit light toward the inner cavity of the female member 161.

[0100] The light source 155 may be, but is not limited to, a light-emitting diode (LED). The light emitted by the light source 155 is preferably visible light or near-infrared light, and the wavelength of the light is, but is not limited to, preferably 360 nm or more, more preferably 630 nm or more, and 3000 nm or less, even more preferably 780 nm or less. Light with a wavelength in this range has high transmittance through the human body, is minimally invasive to the human body, and is highly safe. Visible light can be observed with the naked eye, making it easy to detect the position of the distal end of the nasal catheter 900 (i.e., the olive 970; see FIG. 2 ). Near-infrared light has better transparency than visible light and can be observed using a dedicated camera such as an infrared camera. In one example, light with a wavelength around 630 nm may be used as visible light, or light with a wavelength around 780 nm may be used as near-infrared light. In order to allow the light emitted from the light source 155 to efficiently enter the light incident portion 142 of the optical fiber 140 (see Figure 10 described below), the light source 155 may be equipped with a lens, and / or a lens may be provided between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0101] A method of using the optical fiber device 100 of the first embodiment will be described.

[0102] A catheter set 103 (see FIGS. 7A, 7B, and 8) is prepared in which the optical fiber device 100 is inserted into a nasal catheter 900. Also, a light source device 150 (see FIG. 8) is prepared.

[0103] The catheter set 103 is inserted into the nasal cavity of the patient 990 in the same manner as a typical nasal catheter (see FIG. 2).

[0104] The connector 101 (particularly the first connection portion 110) of the optical fiber device 100 is connected to the connection portion 153 (receiving member 160) of the light source device 150 (see FIG. 8). More specifically, the connection is performed as follows.

[0105] The engagement protrusion 117 of the first connecting portion 110 (see FIGS. 3A and 7A ) is circumferentially aligned with the engagement groove 167 of the receiving member 160 (particularly its guide groove 168, see FIG. 9A ), and the first connecting portion 110 is coaxially opposed to the receiving member 160. Then, the first connecting portion 110 (particularly its first connecting tube 115) is inserted into the receiving member 160 (particularly its outer tube 165, see FIGS. 9A and 9B ). The engagement protrusion 117 advances axially within the guide groove 168 of the engagement groove 167 and strikes the first side surface 169 a of the engagement groove 167. The connector 101, together with the catheter connector 920, is rotated slightly relative to the light source device 150. The engagement protrusion 117 moves from the guide groove 168 to the locking groove 169. As described above, the width (axial dimension) of the locking groove 169 narrows as it moves away from the guide groove 168 in the circumferential direction. Therefore, the engaging projection 117 is sandwiched and restrained in the axial direction by axially opposing side surfaces 169 a, 169 b of the locking groove 169. The connector 101 is positioned at a desired axial position on the connecting portion 153 (receiving member 160) via the engaging projection 117.

[0106] Concurrently, the sleeve 111 of the first connecting portion 110 is inserted into the female member 161 of the receiving member 160. The male tapered surface 111b (see FIG. 3A) at the tip of the sleeve 111 and the female tapered surface 161b (see FIGS. 9A and 9B) at the tip of the female member 161 function as guide surfaces that facilitate insertion of the sleeve 111 into the female member 161. The outer peripheral surface 111a (see FIG. 3A) of the sleeve 111 fits into the inner peripheral surface 161a (see FIGS. 9A and 9B) of the female member 161. Therefore, the sleeve 111 is disposed coaxially with the female member 161. The connector 101 is positioned coaxially with the connecting portion 153 (receiving member 160) via the sleeve 111.

[0107] Thus, as shown in FIG. 10 , the catheter set 103 is connected to the light source device 150. The connector 101 is positioned coaxially with the connecting portion 153 (receiving member 160) at a desired axial position. As a result, the light incident portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position. In this state, the light source 155 is activated to emit light. Light emitted from the light source 155 enters the light incident portion 142 of the optical fiber 140, passes through the optical fiber 140, and is emitted from the light emitting portion 145 (see FIG. 7B ) of the optical fiber 140. The light passes through the olive 970 (housing 971) and further through the patient 990 (see FIG. 2 ). The surgeon can detect the position of the olive 970, i.e., the distal end of the nasal catheter 900, from the light emission position on the body surface of the patient 990. Depending on its wavelength, the light can be detected by the naked eye or via an infrared camera.

[0108] After confirming that the distal end (olive 970) of the nasal catheter 900 has reached the stomach 991, the light source 155 stops emitting light. The catheter connector 920 of the nasal catheter 900, together with the connector 101, is rotated relative to the light source device 150 to separate the light source device 150 from the catheter set 103. Next, the connector 101 of the fiber optic device 100 is rotated relative to the catheter connector 920 to loosen the engagement of the protrusion 126 (see FIGS. 3A and 3B) with the female thread 936 (see FIGS. 5A and 5B). The connector 101 is then separated from the catheter connector 920. Next, the fiber optic device 100 is pulled out of the nasal catheter 900. The nasal catheter 900 is left indwelling in the patient 990 with its distal end (olive 970) in the stomach 991. Before separating the light source device 150 from the catheter set 103, the connector 101 may be separated from the catheter connector 920, and the optical fiber device 100 may be pulled out from the nasal catheter 900 together with the light source device 150.

[0109] A connector (female connector; see, for example, FIGS. 5A and 5B of Patent Document 3) provided at the downstream end of an extension tube used for enteral nutrition (sometimes called an "enteral nutrition set") is connected to the male connector 930 (see FIGS. 5A and 5B) of the catheter connector 920. The upstream end of the extension tube is connected to a container that stores a liquid material, including nutrients, etc. The liquid material passes through the extension tube and nasal catheter 900 (particularly tube 910) in order, and is administered into the stomach 991 of the patient 990 through the hole 975 of the olive 970 (see FIGS. 6A and 6B).

[0110] The used optical fiber device 100 is discarded after being pulled out of the nasal catheter 900. The optical fiber device 100 can be easily separated from the light source device 150 by rotating the connector 101 of the optical fiber device 100 relative to the light source device 150 in the opposite direction to that used when connecting the optical fiber device 100, and then pulling it out from the light source device 150.

[0111] As described above, the optical fiber device 100 of the first embodiment includes the optical fiber 140 and the connector 101 provided at the proximal end of the optical fiber 140. The connector 101 includes, on its proximal side, the first connection portion 110 that can be connected to and disconnected from the light source device 150. The first connection portion 110 includes a sleeve 111 into which the optical fiber 140 is inserted (see FIGS. 3A and 3C ). The sleeve 111 can position the light entrance portion 142 of the optical fiber 140 coaxially with the sleeve 111 and further with the connector 101. Therefore, when the connector 101 (first connection portion 110) is connected to the light source device 150, the light entrance portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 of the light source device 150 (see FIG. 10 ).

[0112] The first connection portion 110 further includes a first connection tube 115 that is coaxial with and surrounds the sleeve 111. The first connection tube 115 includes an engagement protrusion 117 as an engagement structure that can engage with the light source device 150 (see FIGS. 3A and 3C ). When the connector 101 is connected to the light source device 150, the engagement protrusion 117 engages with a lock groove 169 (see FIGS. 9A and 9B ) of the light source device 150, and is axially constrained to the light source device 150 (see FIG. 10 ). Therefore, when the connector 101 (first connection portion 110) is connected to the light source device 150, the light incident portion 142 of the optical fiber 140 is positioned at a desired axial position relative to the light source 155 of the light source device 150.

[0113] Therefore, when the connector 101 is connected to the light source device 150, the light entrance portion 142 of the optical fiber 140 can always be positioned coaxially with the light source 155 at the desired axial position relative to the light source 155 regardless of the surgeon (see Figure 10).

[0114] After the connector 101 (or the catheter set 103) is connected to the light source device 150 (see FIG. 10 ), a tensile force may act between the catheter set 103 (or the nasal catheter 900) and the light source device 150. For example, when a tensile force in the axial direction of the light source device 150 (hereinafter referred to as “axial tensile force”) acts on the catheter set 103 in a state where the catheter set 103 is connected to the light source device 150 (see FIG. 10 ), the engagement of the engaging protrusion 117 with the lock groove 169 prevents axial displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155. Furthermore, when the catheter set 103 is connected to the light source device 150 (see Figure 10), if a tensile force (hereinafter referred to as a "radial tensile force") acts on the catheter set 103 in a direction perpendicular to the axis of the light source device 150 (i.e., radially outward from the axis of the light source device 150) along a plane including the axis of the light source device 150 and the engaging protrusion 117, the engagement of the engaging protrusion 117 with the lock groove 169 limits the inclination of the connector 101 relative to the light source device 150, and as a result, prevents axial displacement of the light incident portion 142 of the optical fiber 140 relative to the light source 155.

[0115] In general, the optical loss (coupling loss) when light from the light source 155 enters the light entrance portion (proximal end face) 142 of the optical fiber 140 is significantly dependent on the radial position (eccentricity) and axial position of the light entrance portion 142 of the optical fiber 140 relative to the light source 155. According to the first embodiment, when the connector 101 (or the catheter set 103) is connected to the light source device 150, the light entrance portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position relative to the light source 155, thereby reducing coupling loss. Furthermore, even if a tensile force acts on the catheter set 103 during subsequent use, misalignment of the light entrance portion 142 relative to the light source 155 can be reduced, thereby maintaining low coupling loss. By applying the optical fiber device 100 of the first embodiment to the nasal catheter 900, the attenuation of the light beam emitted from the olive 970 at the distal end of the nasal catheter 900 is reduced and the light beam is stabilized, making it easy to confirm the light beam from outside the patient 990's body. Therefore, the position of the distal end (olive 970) of the nasal catheter 900 can be easily and accurately detected based on the position of the light emission on the body surface of the patient 990.

[0116] A catheter connector 920 (see FIGS. 5A and 5B ) is provided at the proximal end of the nasal catheter 900 to connect the nasal catheter 900 to an extension tube. When the optical fiber 140 of the fiber optic device 100 is inserted into the tube 910 of the nasal catheter 900, the distal portion of the connector 101 of the fiber optic device 100 faces the catheter connector 920. In the present invention, the configuration of the distal portion of the connector 101 is arbitrary. Preferably, the connector 101 has a second connecting portion 120 on its distal side (see FIGS. 3A to 3C ). The second connecting portion 120 is connectable to the catheter connector 920 provided at the proximal end of the nasal catheter 900. Therefore, simply by inserting the optical fiber 140 of the optical fiber device 100 into the tube 910 of the nasal catheter 900 and connecting the second connection portion 120 to the catheter connector 920, the light emitting portion 145 of the optical fiber 140 is aligned with the position of the distal end (i.e., the olive 970) of the nasal catheter 900 (see FIG. 7B ). Therefore, if light is emitted from the light emitting portion 145 of the optical fiber 140 while the catheter set 103 is inserted into the patient 990 (see FIG. 2 ), the distal end (olive 970) of the nasal catheter 900 can be illuminated. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0117] In the present invention, the second connecting portion 120 of the connector 101 to be connected to the catheter connector 920 may have any configuration. Preferably, the second connecting portion 120 has a female tapered surface 122 (see FIG. 3C) that can be tapered and fitted to the male tapered surface 932 (see FIG. 5A) of the catheter connector 920. Therefore, the connector 101 can be connected to a predetermined axial position relative to the catheter connector 920 simply by tapering and fitting the female tapered surface 122 to the male tapered surface 932 (see FIG. 7A). At this time, the light emitting portion 145 of the optical fiber 140 is accurately aligned with the distal end (i.e., the olive 970) of the nasal catheter 900 (see FIG. 7B). Therefore, the light emitted from the light emitting portion 145 can always illuminate the distal end (olive 970) of the nasal catheter 900. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0118] The first connecting tube 115 of the connector 101 has a hollow, generally cylindrical shape. An engagement protrusion 117 is provided on the outer circumferential surface 115a of the first connecting tube 115 so as to protrude radially outward (see FIG. 3A ). The engagement protrusion 117 functions as an engagement structure that can engage with the light source device 150. Meanwhile, the light source device 150 has an engagement groove 167 (particularly, a locking groove 169) as an engagement portion (see FIGS. 9A and 9B ). When the connector 101 (first connecting tube 115) is rotated in a first direction relative to the light source device 150, the engagement protrusion 117 of the first connecting tube 115 can be engaged with the engagement groove 167 (particularly, the locking groove 169) of the light source device 150. Furthermore, when the connector 101 (first connecting tube 115) is rotated in a second direction opposite to the first direction relative to the light source device 150, the engagement of the engagement protrusion 117 with the engagement groove 167 (particularly, the locking groove 169) can be released. In this way, the detection device 1 of this embodiment 1, which is composed of the optical fiber device 100 and the light source device 150, can repeatedly connect and disconnect the connector 101 (and further the optical fiber device 100) to the light source device 150 simply by performing the simple operation of rotating the connector 101 relative to the light source device 150.

[0119] The engagement groove 167 has a lock groove 169 extending along the circumferential direction (see FIGS. 9A and 9B ). The width of the lock groove 167 is determined by a first side surface 169 a and a second side surface 169 b, which faces the first side surface 169 a and is disposed distally relative to the first side surface 169 a. The first side surface 169 a extends along a plane perpendicular to the rotation axis of the first connecting tube 115 relative to the light source device 150 (i.e., the axis of the receiving member 160). The second side surface 169 b extends at an angle relative to the first side surface 169 a so that the width of the lock groove 169 decreases toward the side where the engagement protrusion 117 engages with the lock groove 169 (i.e., the side circumferentially away from the guide groove 168; hereinafter referred to as the “engagement side”). Therefore, when the first connecting tube 115 (i.e., the connector 101) is rotated toward the engaging side (i.e., in the first direction) relative to the light source device 150, the engaging protrusion 117 is axially sandwiched and restrained between the first side surface 169a and the second side surface 169b.

[0120] The locking groove 169 has a helical thread, and is different from a typical female thread, in which the width of the thread is constant along the length of the thread. For comparison, consider a case where the receiving member 160 has a typical female thread instead of the locking groove 169 (hereinafter referred to as a "comparative embodiment"). In this case, when the first connecting portion 110 is rotated in the threading direction relative to the receiving member 160, the first connecting portion 110 enters the receiving member 160 along the axis of the receiving member 160. When the tip of the first connecting tube 115 abuts against the bottom plate 164 in the axial direction, further entry of the first connecting portion 110 into the receiving member 160 is prevented, and the engagement between the engaging protrusion 117 and the female thread is completed. At this time, in order to counteract the distal force that the first connecting tube 110 receives from the bottom plate 164, the engaging protrusion 117 receives a proximal force (axial reaction force) from the female thread (toward the bottom plate 164). If the rotational force in the screwing direction applied to the first connecting portion 110 (i.e., the connector 101) is too large, the engaging protrusion 117 may be damaged by a large axial reaction force.

[0121] In contrast, in the first embodiment, even if the rotational force (in the first direction) applied to the first connection portion 110 (connector 101) toward the engagement side increases, the force with which the first side surface 169a and the second side surface 169b grip the engagement protrusion 117 therebetween merely increases. The axial reaction force that acts on the engagement protrusion 117 in the comparative embodiment does not act on the engagement protrusion 117 in the first embodiment. Therefore, there is little possibility that the engagement protrusion 117 will be damaged by excessive rotational force when rotating and connecting the connector 101 (first connection portion 110) to the light source device 150.

[0122] In the first embodiment, when the engaging protrusion 117 is axially sandwiched and restrained between the first side surface 169a and the second side surface 169b, the circumferential position of the engaging protrusion 117 relative to the lock groove 169 may change depending on the magnitude of the rotational force in the first direction applied to the first connection portion 110 (connector 101). Of the first side surface 169a and the second side surface 169b that restrain the engaging protrusion 117, it is the first side surface 169a on the light source 155 side that extends along a plane perpendicular to the axis of the receiving member 160, not the second side surface 169b. Therefore, even if the circumferential position of the engaging protrusion 117 relative to the lock groove 169 when restrained changes due to the applied rotational force, the axial position of the engaging protrusion 117 relative to the light source 155 does not change and remains constant. Therefore, the light incident portion 142 of the optical fiber 140 is always positioned at a desired axial position relative to the light source 155. This is advantageous in stably suppressing the coupling loss between the light source 155 and the light input portion 142 of the optical fiber 140 .

[0123] However, in the present invention, unlike the first embodiment, the lock groove 169 may be configured as a general female screw with a spiral thread groove, as in the above-described comparative embodiment. Specifically, the width of the lock groove 169 may remain constant in the longitudinal direction of the lock groove 169, and the first side surface 169 a and the second side surface 169 b may extend spirally.

[0124] In the first embodiment, two engagement protrusions 117 are provided on the first connecting tube 115 (see FIGS. 3A to 3C). In the present invention, the number of engagement protrusions 117 is not limited to two, and may be one or more. Preferably, the number of engagement protrusions 117 is two or more. The receiving member 160 of the light source device 150 is provided with engagement grooves 167, the number of which corresponds to the number of engagement protrusions 117. When two or more engagement protrusions 117 are provided on the first connecting tube 115, the two or more engagement protrusions 117 are preferably arranged on the first connecting tube 115 at equal angular intervals with respect to the axis thereof. Increasing the number of engaging protrusions 117 provided on the first connecting tube 115 is advantageous, firstly, in preventing displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155 when axial or radial tensile force acts on the catheter set 103 in a state where the catheter set 103 is connected to the light source device 150 (see FIG. 10 ), and secondly, in preventing damage to the engaging protrusions 117. However, if the number of engaging protrusions 117 is too large, the structure of the first connecting tube 115 becomes complicated, making it difficult to manufacture the connector 101. Therefore, it is preferable that the number of engaging protrusions 117 be four or less. Most preferably, two engaging protrusions 117 are provided on the first connecting tube 115.

[0125] There is no limitation on the axial position of the engaging protrusion 117 relative to the first connecting tube 115. For example, the engaging protrusion 117 may be disposed near the proximal end (tip, the end opposite the second connecting portion 120) of the first connecting tube 115. Preferably, the engaging protrusion 117 is disposed axially spaced apart from the proximal end of the first connecting tube 115. Specifically, the distance from the distal surface of the engaging protrusion 117 to the proximal end of the first connecting tube 115 is preferably 70% or more, and even 80% or more, of the outer diameter of the first connecting tube 115 (excluding the engaging protrusion 117). In this preferred configuration, when the catheter set 103 is connected to the light source device 150 (see FIG. 10 ), the first connecting tube 115 is deeply fitted into the outer tube 165 of the light source device 150. Therefore, when a radial tensile force acts on the catheter set 103 while the catheter set 103 is connected to the light source device 150 (see FIG. 10 ), it is possible to suppress tilt of the connector 101 relative to the axis of the light source device 150. This is, first, advantageous in preventing damage to the engaging protrusion 117 and the sleeve 111, and second, advantageous in preventing axial displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155.

[0126] Preferably, the engaging protrusion 117 is disposed near the distal end of the first connecting tube 115. More specifically, the engaging protrusion 117 is disposed on the first connecting tube 115 so that the axial distance from the distal end of the first connecting tube 115 to the engaging protrusion 117 is preferably equal to or less than half the axial length of the first connecting tube 115 (the axial length from the distal end to the proximal end of the first connecting tube 115), further equal to or less than 30% of the axial length, and particularly equal to or less than 10% of the axial length. This provides the following advantages. First, because the engaging protrusion 117 is disposed near the distal end of the first connecting tube 115, it is easy to visually confirm the engagement state of the engaging protrusion 117 with the engaging groove 167 of the light source device 150 when the connector 101 (or the catheter set 103) is connected to the light source device 150 (see FIG. 10 ). Second, since the engaging protrusion 117 is disposed at a distance from the proximal end of the first connecting tube 115, when the connector 101 (or the catheter set 103) is connected to the light source device 150, the first connecting tube 115 is fitted deeper into the outer tube 165 of the light source device 150. This is advantageous in suppressing tilt of the connector 101 relative to the axis of the light source device 150 when a radial tensile force acts on the catheter set 103.

[0127] The outer peripheral surface of the connector 101 is provided with gripping protrusions 137a, 137b that protrude radially outward (see FIGS. 3A to 3C). The axial positions of the gripping protrusions 137a, 137b are not limited, but are preferably located distal to the first connecting tube 115, and more preferably between the first connecting tube 115 and the protrusion 126. When the catheter set 103 is connected to the light source device 150, the gripping protrusions 137a, 137b are preferably positioned between the light source device 150 and the catheter connector 920 and exposed to the outside (see FIG. 10). The gripping protrusions 137a, 137b facilitate application of a rotational force to the connector 101 when connecting and disconnecting the connector 101 to and from the catheter connector 920 of the nasal catheter 900 and when connecting and disconnecting the connector 101 to and from the connecting portion 153 (receiving member 160) of the light source device 150.

[0128] When the catheter set 103 is connected to the light source device 150 (see FIG. 10 ), the axial distance between the light source device 150 and the catheter connector 920 is preferably 15 mm or more, and more preferably 20 mm or more. When the light source device 150 and the catheter connector 920 are spaced apart in the axial direction in this manner, it is easy to hook fingers onto the gripping protrusions 137 a and 137 b between the light source device 150 and the catheter connector 920.

[0129] The number of gripping protrusions (137a, 137b) may be one or more. Preferably, multiple gripping protrusions are arranged on the outer peripheral surface of the connector 101 at equal angular intervals relative to the axis of the connector 101. Most preferably, two gripping protrusions 137a, 137b are provided. This is because providing two gripping protrusions 137a, 137b on the connector 101 is sufficient to apply a rotational force to the connector 101. For example, the same number of gripping protrusions as the number of engaging protrusions 117 provided on the first connecting tube 115 may be provided. When the connector 101 has multiple gripping protrusions, the multiple gripping protrusions may have the same shape, dimensions, etc., or may be different.

[0130] There are no limitations on the circumferential positions of the gripping protrusions (137a, 137b). Preferably, the gripping protrusions (137a, 137b) are positioned axially opposite the engaging protrusion 117, i.e., at the same circumferential position as the engaging protrusion 117 (see FIGS. 3A to 3C). If the gripping protrusions (137a, 137b) are positioned at a different circumferential position from the engaging protrusion 117, the surgeon's fingers may come into contact with the engaging protrusion 117 when applying a rotational force to the gripping protrusions (137a, 137b), increasing the likelihood of the surgeon experiencing pain. Most preferably, the two gripping protrusions 137a, 137b and the two engaging protrusions 117 are positioned at the same circumferential positions relative to each other and at equal angular intervals with respect to the axis of the connector 101. Note that, in the present invention, the gripping protrusions (137a, 137b) may be positioned at a different circumferential position from the engaging protrusion 117. Alternatively, the connector 101 may not have gripping protrusions.

[0131] The sleeve 111 is disposed coaxially with the first connecting tube 115 (see FIGS. 3A and 3C). The tip (proximal end) of the sleeve 111 may be recessed in the axial direction from the tip (proximal end) of the first connecting tube 115, or the tip of the sleeve 111 may be located on the same plane as the tip of the first connecting tube 115. However, in the present invention, the sleeve 111 preferably protrudes in the axial direction from the tip of the first connecting tube 115 (see FIGS. 4 and 7A).

[0132] Therefore, when the optical fiber device 100 is manufactured using the above-described post-fixing method (see FIG. 4 ), in which the light input portion 142 is formed after the optical fiber 140 is fixed to the connector 101, it is easy to cut the optical fiber 140 protruding from the tip of the sleeve 111 at the same axial position as the tip of the sleeve 111 (see FIG. 4 ). This firstly makes it possible to reduce variation in the axial position of the cut surface of the optical fiber 140 (i.e., the light input portion 142) relative to the connector 101 (or the first connection portion 110), and secondly makes it possible to form a flat surface with few irregularities on the cut surface of the optical fiber 140 (i.e., the light input portion 142). These are advantageous in reducing coupling loss between the light source 155 and the light input portion 142 of the optical fiber 140.

[0133] Furthermore, when the optical fiber device 100 is manufactured using the above-described pre-fixing method in which the light incident portion 142 is formed before the optical fiber 140 is fixed to the connector 101, it is easy to align the light incident portion 142 of the optical fiber 140 with the tip of the sleeve 111. This makes it possible to reduce variations in the axial position of the light incident portion 142 of the optical fiber 140 relative to the connector 101 (or the first connection portion 110), which is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0134] In the first embodiment, when the connector 101 is connected to the light source device 150, the sleeve 111 of the connector 101 fits into the female member 161 of the light source device 150 (see FIG. 10 ). When the sleeve 111 fits into the female member 161, the inner circumferential surface 161a (see FIGS. 9A and 9B ) of the female member 161 positions the sleeve 111 in the radial direction relative to the light source device 150. In other words, with the simple structure in which the sleeve 111 fits into the female member 161, the light incident portion 142 of the optical fiber 140 can be positioned coaxially with the light source 155. This is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0135] In the first embodiment, the female member 161 is provided with a tapered surface (conical surface) 161b, whose inner diameter increases toward the tip of the female member 161, distal to the inner circumferential surface 161a (see FIGS. 9A and 9B ). The tapered surface 161b can guide the sleeve 111 into the female member 161 when connecting the connector 101 to the light source device 150. This makes it easier to connect the connector 101 to the light source device 150. Furthermore, the tapered surface 161b can allow the sleeve 111 to tilt with respect to the female member 161 when separating the connector 101 from the light source device 150. This makes it easier to separate the connector 101 from the light source device 150.

[0136] In the first embodiment, fitting of the sleeve 111 into the female member 161 is utilized to arrange the light incident portion 142 of the optical fiber 140 coaxially with the light source 155, but the present invention is not limited to this. For example, the light incident portion 142 of the optical fiber 140 may be arranged coaxially with the light source 155 by utilizing the fact that the first connection portion 110 (particularly, the first connection tube 115) of the connector 101 is fitted into the receiving member 160 (particularly, the outer tube 165). In this case, the light source device 150 (or the receiving member 160) does not need to include the female member 161.

[0137] The connector 101 is provided at the proximal end of the optical fiber 140. In the present invention, any method can be used to fix the connector 101 to the optical fiber 140. The connector 101 of this embodiment 1 includes an optical fiber fixing portion 136 for fixing the optical fiber 140 to the connector 101 (see FIG. 3C ). The optical fiber fixing portion 136 preferably includes, but is not limited to, an adhesive 135. This is advantageous, firstly, for firmly fixing the optical fiber 140 to the connector 101 with a simple configuration, and secondly, for facilitating the manufacture of the optical fiber device 100 in which the connector 101 is provided at the proximal end of the optical fiber 140.

[0138] There is no limitation on the position where the optical fiber fixing portion 136 is provided in the connector 101. For example, the optical fiber fixing portion 136 may be disposed inside the sleeve 111. In this case, the optical fiber 140 is fixed to the sleeve 111 via an adhesive. Preferably, as in the first embodiment, the optical fiber fixing portion 136 is disposed distal to the sleeve 111. This allows the optical fiber 140 to be firmly fixed to the connector 101 via a sufficient amount of adhesive. Furthermore, the optical fiber fixing portion 136 is preferably disposed proximal (closer to the first connecting portion 110) to a portion of the second connecting portion 120 (or the second connecting tube 121) to which the catheter connector 920 is connected (or inserted). This prevents the optical fiber fixing portion 136 from adversely affecting the connection of the catheter connector 920 to the connector 101.

[0139] When the optical fiber fixing portion 136 is formed of adhesive 135, any method may be used to inject the uncured adhesive into the connector 101. Preferably, a through-hole 133 that connects the optical fiber fixing portion 136 to the outside of the connector 101 is provided in the connector 101, separate from the sleeve 111 and the second connecting tube 121 (see FIG. 3C ). The through-hole 133 can be used to inject the uncured adhesive 134 into the optical fiber fixing portion 136 (or the first sub-lumen 132a) (see FIG. 4 ). In this case, the cured adhesive 135 is continuously filled from the optical fiber fixing portion 136 into the through-hole 133. In FIG. 4 , which shows a step of the manufacturing method for the optical fiber device 100, unlike the first embodiment, it is also possible to inject the uncured adhesive 134 through the second connecting tube 121 without providing the through-hole 133 in the connector 101. However, in this case, it is extremely difficult to inject the adhesive 134 deep into the second connecting tube 121 without the adhesive 134 adhering to the female tapered surface 122. In this embodiment, a dedicated through-hole 133 for injecting the adhesive 134 is provided separately from the second connecting tube 121. For example, the nozzle of a container storing the adhesive 134 can be inserted into the through-hole 133, and the adhesive 134 can be reliably injected into the optical fiber fixing portion 136 through the through-hole 133. The adhesive 134 will not adhere to the female tapered surface 122. The task of injecting the adhesive 134 into the optical fiber fixing portion 136 through the through-hole 133 does not require skill and is simple. Therefore, the optical fiber device 100 of this embodiment is easy to manufacture.

[0140] The through hole 133 extends from the optical fiber fixing portion 136 toward the outside of the connector 101, non-parallel to the axis of the connector 101 (see FIGS. 3C and 4 ). The through hole 133 may also extend radially (i.e., perpendicular to the axis of the connector 101). However, preferably, as in the first embodiment, the through hole 133 is inclined so as to move away from the first connecting portion 110 in the axial direction as it moves radially outward from the axis of the connector 101. The inclined through hole 133 in this manner prevents the uncured adhesive 134 from leaking out of the opening of the through hole 133 when the second connecting tube 121 is placed up and the uncured adhesive 134 is injected into the optical fiber fixing portion 136 through the through hole 133, as shown in FIG.

[0141] The through hole 133 can be located at any position on the connector 101 as long as it communicates with the optical fiber fixing portion 136. Preferably, the through hole 133 is located so that one (the gripping protrusion 137a) of the multiple gripping protrusions (137a, 137b) provided on the connector 101 passes through it (see FIGS. 3C and 4). This ensures the length of the through hole 133. This is advantageous for preventing the adhesive 134 from leaking out of the opening of the through hole 133 when the uncured adhesive 134 is injected into the optical fiber fixing portion 136 through the through hole 133 with the second connecting tube 121 facing up as shown in FIG. 4. Unlike the first embodiment, the through hole 133 can also be located at a position other than the gripping protrusions 137a, 137b. However, in this case, in order to ensure the necessary length for through-hole 133, it may be necessary to provide a protrusion (second protrusion) on the outer peripheral surface of connector 101, separate from gripping protrusions 137a and 137b, through which through-hole 133 passes. This second protrusion would get in the way when applying a rotational force to gripping protrusions 137a and 137b to rotate connector 101. In this first embodiment, the absence of the second protrusion on the outer peripheral surface of connector 101 allows gripping protrusions 137a and 137b to reliably perform their original function of facilitating the application of a rotational force to connector 101. Furthermore, the absence of second protrusions allows the external shape of connector 101 to be simplified.

[0142] In the present invention, the connector 101 does not necessarily have to have the through-hole 133. In this case, for example, first, uncured adhesive 134 is applied to the outer peripheral surface of the optical fiber 140, and then the optical fiber 140 is inserted into the connector 101 from the second connecting tube 121 side, thereby manufacturing the optical fiber device of the present invention in which the optical fiber 140 is fixed to the connector 101 via the adhesive.

[0143] 11A to 11C show a connector 201 and its vicinity of an optical fiber device 200 according to a second embodiment of the present invention. The optical fiber device 200 includes an optical fiber 140 and a connector 201 provided at the proximal end (base end) of the optical fiber 140. The optical fiber device 200 differs from the optical fiber device 100 of the first embodiment with respect to the connector 201. Like the optical fiber device 100 of the first embodiment, the optical fiber device 200 can be inserted into and withdrawn from a nasal catheter 900 (see FIG. 1 ) serving as a medical catheter from the catheter connector 920 side. The nasal catheter 900 with the optical fiber device 200 inserted therein is a catheter set 203 of the second embodiment.

[0144] Like the connector 101 of the first embodiment, the connector 201 can be repeatedly connected to and disconnected from the light source device 250 (see FIG. 13 described below). The optical fiber device 200 can be used to detect (or confirm) the position of the distal end (tip) of the nasal catheter 900. The optical fiber device 200 and the light source device 250 constitute a detection device (a medical catheter distal end position detection device, hereinafter referred to as the "detection device") 2 for detecting the position of the distal end (tip) of the nasal catheter 900. The entire system including the detection device 2 and the nasal catheter 900 is referred to as the "catheter system."

[0145] FIG. 11A is a perspective view of the connector 201 as viewed from the first connecting portion 210 side. FIG. 11B is a perspective view of the connector 201 as viewed from the second connecting portion 220 side. FIG. 11C is a cross-sectional perspective view of the connector 201 as viewed from the second connecting portion 220 side. The cross section of FIG. 11C includes the axis (not shown) of the connector 201 and the through-hole 133. The connector 201 has a first connecting portion 210 on its proximal side and a second connecting portion 220 on its distal side. The first connecting portion 210 and the second connecting portion 220 are arranged coaxially. The first connecting portion 210 can be connected to and disconnected from the light source device 250 (see FIG. 13 described below), and the second connecting portion 220 can be connected to and disconnected from the catheter connector 920 (see FIGS. 1, 5A, and 5B).

[0146] The first connecting portion 210 includes a sleeve 211 and a first connecting tube 215. The sleeve 211 and the first connecting tube 215 each have a hollow, generally cylindrical shape. The first connecting tube 215 is arranged coaxially with the sleeve 211, radially spaced from the sleeve 211, and surrounding the sleeve 211. The sleeve 211 and the first connecting tube 215 are connected via an annular wall 239 (see FIG. 11C ). The annular wall 239 is a plate extending from the base end (distal end) of the sleeve 211 to the base end (distal end) of the first connecting tube 215. The annular wall 239 is continuous in a circumferential ring shape surrounding the base end of the sleeve 211. The first connecting tube 215 is open toward the proximal side. The sleeve 211 protrudes proximally beyond the first connecting tube 215 (the opposite side from the second connecting portion 220) (see FIG. 12 , described later).

[0147] The outer peripheral surface 211a of the sleeve 211 may be, but is not limited to, a cylindrical surface with a constant outer diameter in the axial direction, or a male tapered surface (conical surface) whose outer diameter decreases toward the tip of the sleeve 211 (the end opposite the second connection portion 220). The tip of the sleeve 211 is provided with a tapered surface (male tapered surface) 211b with a relatively large taper angle, in which the outer diameter decreases toward the tip. An optical fiber 140 is inserted into the sleeve 211 (see FIG. 11C ). The radial position of the optical fiber 140 is restricted by the inner peripheral surface of the sleeve 211 or by multiple protrusions (not shown; the protrusions may extend axially or circumferentially) provided on the inner peripheral surface of the sleeve 211 so as to be coaxial with the sleeve 211. The light incident portion (proximal end surface) 142 of the optical fiber 140 is located at the same axial position as the tip of the sleeve 211.

[0148] An annular flange 214 extends radially outward from the proximal end of the first connecting tube 215. The proximal surface of the first connecting tube 215 and the proximal surface of the flange 214 form a common plane 210a. The plane 210a is an annular flat surface perpendicular to the axis of the connector 201 (or the first connecting portion 210) and functions as the "contact end surface" of the first connecting portion 210. A cylindrical base tube 213 extends from the outer peripheral end of the flange 214 toward the distal side (toward the second connecting portion 220). The base tube 213 is coaxial with the first connecting tube 215, radially spaced from the first connecting tube 215, and surrounds the first connecting tube 215. The outer peripheral surface 213a of the base tube 213 is provided with multiple (two in this embodiment) engagement protrusions 217 protruding radially outward. The engaging protrusions 217 extend in the circumferential direction. A surface 217a on the distal side (the second connecting portion 220 side) of the engaging protrusions 217 is composed of a combination of three inclined surfaces with different inclinations (see FIG. 11B ). The surface of the engaging protrusions 217 opposite to surface 217a forms a plane common to the abutting end surface 210a. The multiple engaging protrusions 217 are symmetrical with respect to the axis of the connector 201 (or the first connecting portion 210).

[0149] In the second embodiment, the engaging protrusion 217 is provided on the base tube 213. In other words, the engaging protrusion 217 is indirectly provided on the first connecting tube 215 via the flange 214 and the base tube 213. However, the present invention is not limited to this. For example, the flange 214 and the base tube 213 may be omitted, the first connecting tube 215 may be expanded to have the same diameter as the base tube 213, and the engaging protrusion 217 may be provided directly on the outer peripheral surface of the expanded first connecting tube 215. In this case, the surface of the first connecting tube 215 facing the proximal side becomes the abutting end surface 210a of the first connecting portion 210. In the present invention, "the engagement protrusion 217 as an engagement structure is provided on the first connecting tube 215 so as to protrude radially outward" includes both a case where the engagement protrusion 217 is indirectly provided on the first connecting tube 215 via a member separate from the first connecting tube 215 (in this embodiment 2, the flange 214 and the base tube 213), and a case where the engagement protrusion 217 is directly provided on the first connecting tube 215.

[0150] In the present invention, the number of engaging protrusions 217 is not limited to two, but may be at least one.

[0151] The second connecting portion 220 includes a second connecting tube 221 having a hollow, generally cylindrical shape. The second connecting tube 221 extends from the annular wall 239 toward the opposite side (distal side) from the sleeve 211 and the first connecting tube 215 (see FIG. 11C ) and is arranged coaxially with the sleeve 211 and the first connecting tube 215. The outer circumferential surface 221a of the second connecting tube 221 is a cylindrical surface having a constant outer diameter in the axial direction, although this is not limited thereto. The second connecting tube 221 has a smaller outer diameter than the first connecting tube 215. However, the present invention is not limited thereto, and the outer diameter of the second connecting tube 221 may be larger than or the same as the outer diameter of the first connecting tube 215. A gripping protrusion 237 is provided on the outer circumferential surface 221a of the second connecting tube 221 so as to protrude radially outward. The gripping protrusion 237 extends a predetermined length in the axial direction from the first connecting tube 215 toward the distal side. The gripping protrusion 237 is provided with a through hole 133 that is the same as the through hole 133 in the first embodiment.

[0152] Connector 201 includes only one gripping protrusion 237. However, the present invention is not limited to this, and multiple gripping protrusions 237 may be provided on the outer peripheral surface of connector 201, similar to the gripping protrusions (137a, 137b, see FIGS. 3A to 3C) of embodiment 1.

[0153] The second connecting tube 221 may have on its outer circumferential surface 221 a the plurality of protrusions 126 (see FIGS. 3A and 3B) that are provided on the connector 101 of the first embodiment.

[0154] The second connecting tube 221 communicates with the sleeve 211. However, the second connecting tube 221 has an inner diameter larger than the inner diameter of the sleeve 211. A partition 131 extends axially from the annular wall 239 into the second connecting tube 221. An adhesive 135 is continuously filled from a first sub-lumen 132a formed by the partition 131 to the through-hole 133. The optical fiber 140 is fixed to the connector 201 via the adhesive 135 filled in the first sub-lumen 132a. The adhesive 135 in the first sub-lumen 132a forms an optical fiber fixing portion 136 for fixing the optical fiber 140 to the connector 201. The optical fiber 140 passes through the second connecting tube 221 and is led out of the second connecting portion 220. The partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the second embodiment may be the same as the partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the first embodiment. The description of the partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the first embodiment can be similarly applied to the second embodiment.

[0155] The inner peripheral surface of the second connecting tube 221 is provided with a female tapered surface 222 whose inner diameter increases toward the tip (the end opposite the first connecting portion 210) of the second connecting tube 221. The female tapered surface 222 is located closer to the tip of the second connecting tube 221 (the end opposite the first connecting portion 210) than the partition wall 131 (or the optical fiber fixing portion 136).

[0156] The optical fiber device 200 can be manufactured using the same materials and substantially the same method (post-bonding or pre-bonding) as the optical fiber device 100 of the first embodiment.

[0157] The optical fiber device 200 is used to detect the position of the distal end of a nasal catheter 900 (see FIG. 2) inserted into a patient, as in the first embodiment. The nasal catheter 900 to which the optical fiber device 200 is applied is the same as the nasal catheter 900 described in the first embodiment (see FIGS. 1 and 5A to 6B).

[0158] As in the first embodiment, the optical fiber device 200 is inserted into a nasal catheter 900 to form a catheter set 203. Fig. 12 is a cross-sectional view of a portion near the proximal end of the catheter set 203. The cross-section of Fig. 12 is the same as the cross-section of Fig. 11C and includes the axis and through-hole 133 of the connector 201. The optical fiber 140 of the optical fiber device 200 is inserted into a flow path 912 of a tube 910 of the nasal catheter 900. The connector 201 (particularly, its second connecting portion 220 (see Figs. 11B and 11C)) of the optical fiber device 200 is connected to a catheter connector 920 (particularly, its male connector 930 (see Figs. 5A and 5B)) of the nasal catheter 900. More specifically, as in the first embodiment, the male member 931 of the catheter connector 920 is inserted into the second connecting tube 221 of the connector 201. The female tapered surface 222 of the second connecting tube 221 comes into surface contact with the male tapered surface 932 of the male member 931 and fits liquid-tight (so-called tapered fitting). The second connecting tube 221 functions as a female member to which the male member 931 can be connected.

[0159] The connection and disconnection of the second connecting part 220 to the male connector 930 is generally the same as the connection and disconnection of the second connecting part 120 of the first embodiment to the male connector 930 ( FIG. 7A ). However, unlike the first embodiment, the second connecting part 220 (second connecting tube 221) of the second embodiment does not have a threading structure (protrusion (male thread) 126 (see FIGS. 3A and 3B )) that can be threaded into the female thread 936 of the catheter connector 920 (see FIGS. 11A and 11B ). Therefore, the connector 201 can be easily and quickly connected to and disconnected from the catheter connector 920 simply by tapering the female tapered surface 222 of the second connecting part 220 into the male tapered surface 932 of the male connector 930 and then releasing the tapered engagement.

[0160] When the connector 201 (second connection portion 220) is connected to the catheter connector 920 (male connector 930), the light emitting portion 145 of the optical fiber 140 is located within the lumen 972 of the olive 970, as in embodiment 1 (see Figure 7B), although this is not shown.

[0161] The connector 201 (particularly the first connection portion 210) of the optical fiber device 200 can be connected to and disconnected from the light source device 250. As shown in FIG. 13 , the light source device 250 includes a connection portion 253 to which the connector 201 (first connection portion 210) can be connected, and a light source 155 disposed at a position set back from the connection portion 253. The connection portion 253 includes a receiving member 260. The connection portion 253 (receiving member 260) and the light source 155 are housed in a housing similar to the housing 151 of the light source device 150 of the first embodiment (see FIG. 8 ), but is not shown in FIG. 13 . The first connection portion 210 of the connector 201 is different from the first connection portion 110 of the first embodiment. Therefore, the receiving member 260, unlike the receiving member 160 of the first embodiment, has a configuration corresponding to the first connection portion 210.

[0162] 14A is a perspective view of the receiving member 260, and FIG. 14B is a cross-sectional perspective view of the receiving member 260. FIG.

[0163] The receiving member 260 includes a female member 261. The female member 261 has, but is not limited to, a hollow, generally cylindrical shape. The female member 261 has, at its tip (distal end), a circular opening 262 concentric with the axis of the receiving member 260. The inner circumferential surface 261a extending from the opening 262 may be, but is not limited to, a cylindrical surface having a constant inner diameter in the axial direction, or a female tapered surface (conical surface) whose inner diameter increases toward the tip of the female member 261. A tapered surface (female tapered surface) having a larger taper angle than the inner circumferential surface 261a and whose inner diameter increases toward the tip of the female member 261, similar to the tapered surface (female tapered surface) 161b (see FIGS. 9A and 9B) provided on the female member 161 of embodiment 1, may be provided adjacent to the inner circumferential surface 261a on the tip side of the female member 261 relative to the inner circumferential surface 261a.

[0164] A flat surface 263 surrounds the female member 261. The flat surface 263 extends along a plane perpendicular to the axis of the female member 261 (or the receiving member 260). A first annular groove 264a and a second annular groove 264b are provided on the flat surface 263. The first annular groove 264a and the second annular groove 264b each have a circular shape concentric with the axis of the female member 261 in a plan view. The first annular groove 264a extends along the outer circumferential surface of the female member 261. The second annular groove 264b is disposed radially outward of the first annular groove 264a. Note that, in the present invention, one or both of the first annular groove 264a and the second annular groove 264b may be omitted. For example, the annular grooves 264a and 264b may be omitted, and a circular opening 262 may be provided in the center of the flat surface 263. In this case, the inner circumferential surface of the opening 262 becomes the inner circumferential surface 261a of the female member. As can be seen from this example, the female member of the receiving member 260 does not need to have a hollow, approximately cylindrical shape like the female member 261 of this embodiment, but may have a plate shape in which an opening (through hole) 262 having an inner peripheral surface 261a is formed.

[0165] In the second embodiment, the tip of the female member 261 is located closer to the light source 155 than the flat surface 263 (see FIG. 13 ), but the present invention is not limited to this. For example, the tip of the female member 261 may be located on the same plane as the flat surface 263, or may be located further distal than the flat surface 263.

[0166] The receiving member 260 further includes a plurality of (two in this second embodiment) engagement walls 266. The engagement walls 266 are disposed radially outward from the flat surface 263 and extend distally beyond the flat surface 263. The engagement walls 266 are along a cylindrical surface coaxial with the female member 261. An engagement protrusion 267 protrudes radially inward from the tip (distal end) of the engagement wall 266. The engagement protrusion 267 extends approximately circumferentially. When viewed from the axis of the female member 261 (or the receiving member 260), one end of the engagement protrusion 267 in the length direction is open. The other end of the engagement protrusion 267 in the length direction descends to approach the flat surface 263 and forms a stop end 268. A surface 267a of the engagement protrusion 267 facing the flat surface 263 (the surface facing the proximal side) includes three inclined surfaces with different inclinations. The plurality of engagement walls 266 including the engagement protrusions 267 are symmetrical with respect to the axis of the female member 261 (or the receiving member 260).

[0167] The receiving member 260 further includes a housing 269 on the base end side of the flat surface 263. The housing 269 has a hollow cylindrical shape that is coaxial with the female member 261 (or the receiving member 260). Note that the receiving member 260 does not necessarily have to include the housing 269.

[0168] The receiving member 260 is made of a hard material (rigid material) and has the mechanical strength (rigidity) to be substantially undeformed by external forces. Specifically, the receiving member 260 can be made of a resin material such as polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyacetal, polystyrene, polyamide, polyethylene, or hard polyvinyl chloride. The receiving member 260 can be manufactured as a single component by injection molding or the like using the above-mentioned resin material.

[0169] 13 , the light source 155 is disposed proximally relative to the female member 261, coaxially with the receiving member 260 (connecting portion 253), and at a predetermined position in the axial direction relative to the receiving member 260. In the second embodiment, the light source 155 is disposed within a housing 269 of the receiving member 260. The light source 155 can emit light toward the opening 262 of the female member 261. The light source 155 may be the same as the light source 155 of the first embodiment.

[0170] A method of using the optical fiber device 200 of the second embodiment will be described.

[0171] As in the first embodiment, a catheter set 203 (see FIG. 12) is prepared in which the optical fiber device 200 is inserted into a nasal catheter 900. Also, a light source device 250 (see FIG. 13) including a light source 155 and a receiving member 260 (connecting portion 253) is prepared.

[0172] The catheter set 203 is inserted into the nasal cavity of the patient 990 in the same manner as a typical nasal catheter (see FIG. 2).

[0173] The connector 201 (particularly the first connection portion 210) of the optical fiber device 200 is connected to the connection portion 253 (receiving member 260) of the light source device 250. More specifically, the connection is performed as follows.

[0174] As shown in FIG. 13 , the first connecting portion 210 is coaxially opposed to the receiving member 260. The direction connecting the pair of engaging protrusions 217 (see FIG. 11A ) of the first connecting portion 210 and the direction connecting the pair of engaging protrusions 267 (see FIG. 14A ) of the receiving member 260 are approximately perpendicular to each other. In this state, the first connecting portion 210 is brought close to the receiving member 260. The base tube 213 (see FIG. 11A ) of the first connecting portion 210 is inserted between the pair of engaging walls 266 (see FIG. 14A ) of the receiving member 260. Concurrently, the sleeve 211 (see FIG. 11A ) of the first connecting portion 210 is inserted into the opening 262 (see FIGS. 14A and 14B ) of the female member 261 of the receiving member 260. The male tapered surface 211b at the tip of the sleeve 211 functions as a guide surface that facilitates insertion of the sleeve 211 into the female member 261. The abutment end surface 210a (see FIG. 11A) of the first connecting portion 210 abuts in the axial direction against the flat surface 263 (see FIGS. 14A and 14B) of the receiving member 260. In this state, the connector 201 is rotated relative to the receiving member 260 (i.e., the light source device 250 including the receiving member 260) until one circumferential end of the engagement protrusion 217 (see FIGS. 11A and 11B) of the first connecting portion 210 abuts against the stop end 268 (see FIGS. 14A and 14B) of the receiving member 260.

[0175] Thus, as shown in Figures 15A and 15B, the catheter set 203 is connected to the light source device 250. The cross section of Figure 15A is the same as the cross section of Figure 13 and includes the axis of the connector 201 and the through-hole 133. The cross section of Figure 15B includes the axis of the connector 201 and is perpendicular to the cross section of Figure 15A.

[0176] With the abutment end surface 210a of the first connecting portion 210 abutting against the flat surface 263 of the receiving member 260 in the axial direction, the engaging protrusion 217 of the first connecting portion 210 is axially engaged with the engaging protrusion 267 of the receiving member 260. Therefore, the connector 201 is positioned at a desired axial position relative to the connecting portion 253 (receiving member 260). Although not shown, the surface 217a of the engaging protrusion 217 (see FIG. 11B) is engaged with the surface 267a of the engaging protrusion 267 (see FIGS. 13, 14A, and 14B). This is advantageous in preventing the engagement of the engaging protrusion 217 with the engaging protrusion 267 from being unintentionally released.

[0177] The sleeve 211 of the first connecting portion 210 is inserted into an opening 262 (see FIGS. 14A and 14B) of a female member 261 of a receiving member 260. An outer peripheral surface 211a (see FIG. 11A) of the sleeve 211 is fitted into an inner peripheral surface 261a (see FIGS. 14A and 14B) of the female member 261. Therefore, the sleeve 211 is disposed coaxially with the female member 261. The connector 201 is positioned coaxially with the connecting portion 253 (receiving member 260) via the sleeve 211.

[0178] In this manner, the connector 201 is positioned coaxially with the connecting portion 253 (receiving member 260) at a desired axial position relative to the connecting portion 253 (receiving member 260). As a result, the light input portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position relative to the light source 155. In this state, the light source 155 is activated to emit light. Light emitted from the light source 155 enters the light input portion 142 of the optical fiber 140, passes through the optical fiber 140, and is emitted from the light output portion 145 (see FIG. 7B ) of the optical fiber 140. As in the first embodiment, the light passes through the olive 970 (housing 971) and further through the patient 990 (see FIG. 2 ). The surgeon can detect the position of the olive 970, i.e., the distal end of the nasal catheter 900, from the light emission position on the body surface of the patient 990. The light can be detected with the naked eye or via an infrared camera depending on its wavelength.

[0179] After confirming that the distal end (olive 970) of the nasal catheter 900 has reached the stomach 991, the light source 155 stops emitting light. The subsequent procedures are generally the same as those in the first embodiment. That is, the light source device 250 is separated from the catheter set 203. Next, the connector 201 of the optical fiber device 200 is separated from the catheter connector 920 of the nasal catheter 900, and the optical fiber device 200 is withdrawn from the nasal catheter 900. The nasal catheter 900 is left indwelling in the patient 990 with its distal end (olive 970) in the stomach 991. Note that the optical fiber device 200 and the light source device 250 may be withdrawn from the nasal catheter 900 together before the light source device 250 is separated from the catheter set 203. Next, a liquid containing a nutrient or the like is administered to the stomach 991 of the patient 990 via the nasal catheter 900. The used optical fiber device 200 is discarded after being pulled out of the nasal catheter 900. The optical fiber device 200 can be easily separated from the light source device 250 (receiving member 260) by rotating the connector 201 of the optical fiber device 200 relative to the receiving member 260 in the opposite direction to that used when the optical fiber device 200 was connected, and then pulling the optical fiber device 200 out of the receiving member 260.

[0180] As described above, the optical fiber device 200 of the second embodiment includes the optical fiber 140 and the connector 201 provided at the proximal end of the optical fiber 140. The connector 201 includes, on its proximal side, a first connection portion 210 that can be connected to and disconnected from the light source device 250. The first connection portion 210 includes a sleeve 211 into which the optical fiber 140 is inserted (see FIGS. 11A and 11C ). The sleeve 211 can position the light entrance portion 142 of the optical fiber 140 coaxially with the sleeve 211 and further with the connector 201. Therefore, when the connector 201 (first connection portion 210) is connected to the light source device 250, the light entrance portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 of the light source device 250 (see FIGS. 15A and 15B ).

[0181] The first connecting portion 210 further includes a first connecting tube 215 that is coaxial with and surrounds the sleeve 211. The first connecting tube 215 includes an engaging protrusion 217 as an engaging structure that can engage with the light source device 250 (see FIGS. 11A and 11B ). When the connector 201 is connected to the light source device 250, the engaging protrusion 217 engages with an engaging protrusion 267 of the light source device 250 and is axially constrained to the light source device 250 (see FIG. 15B ). Therefore, when the connector 201 (first connecting portion 210) is connected to the light source device 250, the light incident portion 142 of the optical fiber 140 is positioned at a desired axial position relative to the light source 155 of the light source device 250.

[0182] Therefore, when the connector 201 is connected to the light source device 250, the light entrance portion 142 of the optical fiber 140 can always be positioned coaxially with the light source 155 at the desired axial position relative to the light source 155, regardless of the surgeon (see Figures 15A and 15B).

[0183] After the connector 201 (or the catheter set 203) is connected to the light source device 250 (see FIGS. 15A and 15B ), a tensile force may act between the catheter set 203 (or the nasal catheter 900) and the light source device 250. For example, when a tensile force in the axial direction of the light source device 250 (hereinafter referred to as “axial tensile force”) acts on the catheter set 203 in a state where the catheter set 203 is connected to the light source device 250 (see FIGS. 15A and 15B ), the engagement of the engaging protrusion 217 with the engaging protrusion 267 prevents axial displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155. Furthermore, when the catheter set 203 is connected to the light source device 250 (see Figure 15B), when a tensile force (hereinafter referred to as a "radial tensile force") acts on the catheter set 203 in a direction perpendicular to the axis of the light source device 250 (i.e., radially outward from the axis of the light source device 250) along a plane including the axis of the light source device 250 and the engaging protrusion 217, the engagement of the engaging protrusion 217 with the engaging protrusion 267 limits the inclination of the connector 201 relative to the light source device 250, and as a result, prevents axial displacement of the light incident portion 142 of the optical fiber 140 relative to the light source 155.

[0184] As in the first embodiment, according to the second embodiment, when the connector 201 (or the catheter set 203) is connected to the light source device 250, the light input portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position relative to the light source 155, thereby reducing coupling loss. Furthermore, even if a tensile force acts on the catheter set 203 during subsequent use, misalignment of the light input portion 142 relative to the light source 155 can be reduced, thereby maintaining low coupling loss. By applying the optical fiber device 200 of the second embodiment to the nasal catheter 900, the attenuation of the light beam emitted from the olive 970 at the distal end of the nasal catheter 900 is reduced and the light beam is stabilized, making it easy to confirm the light beam from outside the patient's body. Therefore, the position of the distal end (olive 970) of the nasal catheter 900 can be easily and accurately detected based on the light emission position on the patient's body surface.

[0185] In the present invention, the configuration of the distal portion of the connector 201 is optional. Preferably, the connector 201 includes a second connecting portion 220 on its distal side (see FIGS. 11A to 11C ). The second connecting portion 220 is connectable to a catheter connector 920 (see FIGS. 5A and 5B ) provided at the proximal end of the nasal catheter 900. Therefore, by simply inserting the optical fiber 140 of the optical fiber device 200 into the tube 910 of the nasal catheter 900 and connecting the second connecting portion 220 to the catheter connector 920, the light emitting portion 145 of the optical fiber 140 is aligned with the distal end of the nasal catheter 900 (i.e., the olive 970) (see FIG. 7B ), as in the first embodiment. Therefore, by emitting light from the light emitting portion 145 of the optical fiber 140 while the catheter set 203 is inserted into the patient 990 (see FIG. 2 ), the distal end (olive 970) of the nasal catheter 900 can be illuminated. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0186] In the present invention, the second connecting portion 220 of the connector 201 to be connected to the catheter connector 920 may have any configuration. Preferably, the second connecting portion 220 has a female tapered surface 222 (see FIG. 11C ) that can be tapered and fitted to the male tapered surface 932 (see FIG. 5A ) of the catheter connector 920. Therefore, similar to the first embodiment, the connector 201 can be connected to a predetermined axial position relative to the catheter connector 920 simply by tapering and fitting the female tapered surface 222 to the male tapered surface 932 (see FIG. 12 ). At this time, the light emitting portion 145 of the optical fiber 140 is accurately aligned with the distal end (i.e., the olive 970) of the nasal catheter 900 (see FIG. 7B ). Therefore, the light emitted from the light emitting portion 145 can always illuminate the distal end (olive 970) of the nasal catheter 900. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0187] The first connecting tube 215 of the connector 201 has a hollow, generally cylindrical shape. An engagement protrusion (first engagement protrusion) 217 ​​is provided on the first connecting tube 215 so as to protrude radially outward (see FIG. 11A ). The engagement protrusion 217 functions as an engagement structure that can engage with the light source device 250. Meanwhile, the light source device 250 has an engagement protrusion (second engagement protrusion) 267 as an engagement portion (see FIGS. 14A and 14B ). When the connector 201 (first connecting tube 215) is rotated relative to the light source device 250 in a first direction, the engagement protrusion 217 of the first connecting tube 215 can be engaged with the engagement protrusion 267 of the light source device 250. When the connector 201 is rotated in a second direction opposite to the first direction, the engagement protrusion 217 can be released from the engagement protrusion 267. In this way, the detection device 2 of this embodiment 2, which is composed of the optical fiber device 200 and the light source device 250, can repeatedly connect and disconnect the connector 201 (and further the optical fiber device 200) to the light source device 250 simply by performing the simple operation of rotating the connector 201 relative to the light source device 250.

[0188] The first connecting tube 215 of the connector 201 is provided with an annular abutment end surface 210a perpendicular to the axis of the connector 201 (or the first connecting tube 215) (see FIG. 11A ). The first connecting portion 210 of the connector 201 is configured so that when the engaging protrusion 217 of the connector 201 engages with the engaging protrusion 267 of the light source device 250, the abutment end surface 210a of the connector 201 abuts in the axial direction against the flat surface 263 of the light source device 250 (see FIGS. 15A and 15B ). With the simple configuration of engaging the engaging protrusion 217 with the engaging protrusion 267 and abutting the abutment end surface 210a against the flat surface 263, the light incident portion 142 of the optical fiber 140 can be positioned at a desired axial position relative to the light source 155 of the light source device 250. The region where the abutment end surface 210a abuts against the flat surface 263 extends annularly along a circle concentric with the axis of the connector 201. Therefore, when a radial pulling force acts on the catheter set 203, it is possible to suppress the inclination of the connector 201 relative to the light source device 250. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0189] In the second embodiment, two engagement protrusions 217 are provided on the first connecting tube 215 (see FIG. 11A ). In the present invention, the number of engagement protrusions 217 is not limited to two, and may be one or more. Preferably, the number of engagement protrusions 217 is two or more. The receiving member 260 of the light source device 250 is provided with engagement protrusions 267, the number of which corresponds to the number of engagement protrusions 217. When two or more engagement protrusions 217 are provided on the first connecting tube 215, the two or more engagement protrusions 217 are preferably arranged on the first connecting tube 215 at equal angular intervals with respect to the axis thereof. Increasing the number of engaging protrusions 217 provided on the first connecting tube 215 is advantageous, firstly, in preventing displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155 when axial or radial pulling force acts on the catheter set 203 in a state in which the catheter set 203 is connected to the light source device 250 (see FIGS. 15A and 15B ), and secondly, in preventing damage to the engaging protrusions 217. However, if the number of engaging protrusions 217 is too large, the structure of the first connecting tube 215 becomes complicated, making it difficult to manufacture the connector 201. Therefore, it is preferable that the number of engaging protrusions 217 be four or less. Most preferably, two engaging protrusions 217 are provided on the first connecting tube 215.

[0190] There is no limitation on the axial position of the engaging protrusion 217 relative to the first connecting tube 215. For example, the engaging protrusion 217 may be disposed near the distal end (the end on the second connecting portion 220 side) of the first connecting tube 215. Preferably, the engaging protrusion 217 is disposed at a position on the proximal end (i.e., the abutting end surface 210a) side of the first connecting tube 215. More specifically, the engaging protrusion 217 is disposed so that the axial distance from the abutting end surface 210a to the engaging protrusion 217 is preferably less than half the axial length of the first connecting tube 215 (the axial length from the proximal end to the distal end of the first connecting tube 215), further less than 30% of the axial length, and particularly less than 10% of the axial length. Most preferably, as in the second embodiment, the engaging protrusion 217 is disposed along the abutting end surface 210a (see FIG. 11A ). With this arrangement, when the connector 201 is connected to the light source device 250 (see FIG. 15B ), the axial distance from the position where the abutment end surface 210 a and the flat surface 263 abut against each other to the position where the engagement protrusion 217 and the engagement protrusion 267 engage with each other is shortened. This is advantageous in limiting the inclination of the connector 201 relative to the light source device 250 when a radial pulling force acts on the catheter set 203.

[0191] The outer peripheral surface of the connector 201 is provided with a gripping protrusion 237 that protrudes radially outward (see FIGS. 11A to 11C). The axial position of the gripping protrusion 237 is not limited, but is preferably located distal to the first connecting tube 215. As in the first embodiment, if a protrusion 126 (see FIGS. 3A and 3B) is provided on the outer peripheral surface 221a of the second connecting tube 221, the gripping protrusion 237 is more preferably located between the first connecting tube 215 and the protrusion 126. When the catheter set 203 is connected to the light source device 250, the gripping protrusion 237 is preferably located between the light source device 250 and the catheter connector 920 and exposed to the outside (see FIG. 15A). The gripping protrusion 237 makes it easy to apply a rotational force to the connector 201 when connecting and disconnecting the connector 201 to the catheter connector 920 of the nasal catheter 900, and when connecting and disconnecting the connector 201 to the connection portion 253 (receiving member 260) of the light source device 250.

[0192] When the catheter set 203 is connected to the light source device 250 (see FIG. 15A ), the axial distance between the light source device 250 and the catheter connector 920 is preferably 15 mm or more, and more preferably 20 mm or more. When the light source device 250 and the catheter connector 920 are spaced apart in the axial direction in this manner, it is easy to hook a finger on the gripping protrusion 237 between the light source device 250 and the catheter connector 920.

[0193] The number of gripping protrusions 237 may be one or more. In the second embodiment, only one gripping protrusion 237 is provided on the connector 201. However, preferably, multiple gripping protrusions 237 are arranged on the outer peripheral surface of the connector 201 at equal angular intervals relative to the axis of the connector 201. Most preferably, two gripping protrusions 237 are provided. This is because providing two gripping protrusions 237 on the connector 201 is sufficient to apply a rotational force to the connector 201. When the connector 201 is provided with multiple gripping protrusions 237, the multiple gripping protrusions 237 may have the same shape, dimensions, etc., or may be different. Note that in the present invention, the connector 201 does not necessarily have to have a gripping protrusion 237.

[0194] The sleeve 211 is disposed coaxially with the first connecting tube 215 (see FIGS. 11A and 11C ). The tip (proximal end) of the sleeve 211 may be axially recessed from the tip (proximal end) of the first connecting tube 215, or the tip of the sleeve 211 may be located on the same plane as the tip of the first connecting tube 215. However, preferably, as in the first embodiment, the sleeve 211 protrudes in the axial direction from the tip (or the abutting end surface 210 a) of the first connecting tube 215 (see FIG. 12 ).

[0195] Therefore, when the optical fiber device 200 is manufactured using the above-described post-fixing method in which the light input portion 142 is formed after the optical fiber 140 is fixed to the connector 201, it is easy to cut the optical fiber 140 protruding from the tip of the sleeve 211 at the same axial position as the tip of the sleeve 211. This firstly makes it possible to reduce variation in the axial position of the cut surface of the optical fiber 140 (i.e., the light input portion 142) relative to the connector 201 (or the first connection portion 210), and secondly makes it possible to form a flat surface with few irregularities on the cut surface of the optical fiber 140 (i.e., the light input portion 142). These are advantageous in reducing coupling loss between the light source 155 and the light input portion 142 of the optical fiber 140.

[0196] Furthermore, when the optical fiber device 200 is manufactured by the above-described pre-fixing method in which the light incident portion 142 is formed before the optical fiber 140 is fixed to the connector 201, it is easy to align the light incident portion 142 of the optical fiber 140 with the tip of the sleeve 211. This makes it possible to reduce variations in the axial position of the light incident portion 142 of the optical fiber 140 relative to the connector 201 (or the first connection portion 210), which is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0197] As in the first embodiment, when the connector 201 is connected to the light source device 250, the sleeve 211 of the connector 201 fits into the female member 261 of the light source device 250 (see FIGS. 15A and 15B). When the sleeve 211 fits into the female member 261, the inner circumferential surface 261a (see FIGS. 14A and 14B) of the female member 261 radially positions the sleeve 211 with respect to the light source device 250. In other words, with the simple structure in which the sleeve 211 fits into the female member 261, the light incident portion 142 of the optical fiber 140 can be positioned coaxially with the light source 155. This is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0198] A tapered surface (conical surface) having a larger taper angle than the inner circumferential surface 261a, similar to the tapered surface 161b of the female member 161 of embodiment 1 (see FIGS. 9A and 9B ), may be provided at the opening 262 of the female member 261. Like the tapered surface 161b of embodiment 1, this tapered surface can guide the sleeve 211 into the female member 261 when connecting the connector 201 to the light source device 250, and can also allow the sleeve 211 to tilt with respect to the female member 261 when disconnecting the connector 201 from the light source device 250.

[0199] Except for the above, the second embodiment is the same as the first embodiment. The description of the first embodiment also applies to the second embodiment as appropriate.

[0200] 16A to 16C show a connector 301 and its vicinity of an optical fiber device 300 according to a third embodiment of the present invention. The optical fiber device 300 includes an optical fiber 140 and a connector 301 provided at the proximal end (base end) of the optical fiber 140. The optical fiber device 300 differs from the optical fiber device 100 of the first embodiment with respect to the connector 301. Similar to the optical fiber device 100 of the first embodiment, the optical fiber device 300 can be inserted into and removed from a nasal catheter 900 (see FIG. 1 ) serving as a medical catheter from the catheter connector 920 side. The nasal catheter 900 with the optical fiber device 300 inserted therein is a catheter set 303 according to the third embodiment.

[0201] Like the connector 101 of embodiment 1, the connector 301 can be repeatedly connected to and disconnected from the light source device 350 (see Figures 18A and 18B described below). The optical fiber device 300 can be used to detect (or confirm) the position of the distal end (tip) of the nasal catheter 900. The optical fiber device 300 and the light source device 350 constitute a detection device (medical catheter distal end position detection device, hereinafter referred to as the "detection device") 3 for detecting the position of the distal end (tip) of the nasal catheter 900. The entire system including the detection device 3 and the nasal catheter 900 is referred to as the "catheter system."

[0202] FIG. 16A is a perspective view of the connector 301 as viewed from the first connecting portion 310 side. FIG. 16B is a perspective view of the connector 301 as viewed from the second connecting portion 320 side. FIG. 16C is a cross-sectional perspective view of the connector 301 as viewed from the second connecting portion 320 side. The cross section of FIG. 16C includes the axis (not shown) of the connector 301 and the through-hole 133. The connector 301 has a first connecting portion 310 on its proximal side and a second connecting portion 320 on its distal side. The first connecting portion 310 and the second connecting portion 320 are coaxially arranged. The first connecting portion 310 can be connected to and disconnected from the light source device 350 (see FIGS. 18A and 18B described below), and the second connecting portion 320 can be connected to and disconnected from the catheter connector 920 (see FIGS. 1, 5A, and 5B). For convenience of the following description, an XYZ Cartesian coordinate system as shown in the figure is set. The Z axis is parallel to the axis of the connector 301. The through-hole 133 extends along the XZ plane.

[0203] The first connecting portion 310 includes a sleeve 311 and a first connecting tube 315. The sleeve 311 has a hollow, approximately cylindrical shape. Unlike the first connecting tubes 115 and 215 of the first and second embodiments, the first connecting tube 315 has a hollow, approximately rectangular prism shape. The first connecting tube 315 includes first to fourth walls 341a to 341d (the fourth wall 341d is not visible in FIG. 16A ). The first wall 341a and the second wall 341b are flat plates parallel to the YZ plane and face each other in the X-axis direction. The outer surfaces of the first wall 341a and the second wall 341b are flat surfaces parallel to the YZ plane. The third wall 341c and the fourth wall 341d are flat plates parallel to the XZ plane and face each other in the Y-axis direction. The outer surfaces of the third wall 341c and the fourth wall 341d are flat surfaces parallel to the XZ plane. The first connecting tube 315 has an axis (not shown) parallel to the Z axis. The axis of the first connecting tube 315 passes through the intersection of two diagonals of a rectangular cross section of the first connecting tube 315 along a plane parallel to the XY plane. The first connecting tube 315 is arranged coaxially with the sleeve 311, radially spaced from the sleeve 311, and surrounding the sleeve 311. The sleeve 311 and the first connecting tube 315 are connected via an annular wall 339 (see FIG. 16C ). The annular wall 339 is a plate extending from the base end (distal end) of the sleeve 311 to the base end (distal end) of the first connecting tube 315. The annular wall 339 is continuous in a circumferential ring shape surrounding the base end of the sleeve 311. The first connecting tube 315 is open toward the proximal side. The sleeve 311 protrudes proximally (opposite the second connecting portion 320) beyond the first connecting tube 315 (see FIG. 17 described later).

[0204] The outer peripheral surface 311a of the sleeve 311 may be, but is not limited to, a cylindrical surface with a constant outer diameter in the axial direction, or a male tapered surface (conical surface) whose outer diameter decreases toward the tip of the sleeve 311 (the end opposite the second connection portion 320). The tip of the sleeve 311 is provided with a tapered surface (male tapered surface) 311b with a relatively large taper angle, in which the outer diameter decreases toward the tip. An optical fiber 140 is inserted into the sleeve 311 (see FIG. 16C ). The radial position of the optical fiber 140 is restricted by the inner peripheral surface of the sleeve 311 or by multiple protrusions (not shown; the protrusions may extend axially or circumferentially) provided on the inner peripheral surface of the sleeve 311 so as to be coaxial with the sleeve 311. The light incident portion (proximal end surface) 142 of the optical fiber 140 is located at the same axial position as the tip of the sleeve 311.

[0205] A pair of through holes 342 are formed in the first connecting tube 315. More specifically, the through holes 342 penetrate the third wall 341c and the fourth wall 341d constituting the first connecting tube 315 in the Y-axis direction. The opening shape of the through holes 342 as viewed along the Y-axis is approximately rectangular. The open end of each through hole 342 includes a pair of side edges 343 that are approximately parallel to the Z-axis. The pair of side edges 343 face each other in the X-axis direction. Each side edge 343 is formed with a first inclined surface 344a, a raised surface 345, a second inclined surface 344b, a receding surface 346, and an abutment surface 347, in this order from the proximal side to the distal side along the Z-axis. The raised surface 345 and the receding surface 346 are flat surfaces parallel to the XZ plane. The recessed surface 346 is disposed (or recessed) more inward than the raised surface 345 (i.e., toward the axis of the first connecting portion 310 (or the sleeve 311)). The first inclined surface 344a and the second inclined surface 344b are flat surfaces parallel to the X-axis. The first inclined surface 344a is disposed adjacent to the raised surface 345 on the proximal side of the raised surface 345 and is inclined so as to approach the axis of the first connecting portion 310 (or the sleeve 311) from the raised surface 345 toward the proximal side. The second inclined surface 344b is disposed adjacent to the raised surface 345 on the distal side of the raised surface 345 and is inclined so as to approach the axis of the first connecting portion 310 (or the sleeve 311) from the raised surface 345 toward the distal side. The recessed surface 346 is disposed adjacent to the second inclined surface 344b on the distal side of the second inclined surface 344b. The abutment surface 347 is a flat surface parallel to the XY plane. The abutment surface 347 is disposed adjacent to and distal to the recessed surface 346, and extends from the recessed surface 346 in a direction away from the axis of the first connecting portion 310 (or the sleeve 311). The recessed surface 346 is recessed inward (i.e., toward the axis of the first connecting portion 310 (or the sleeve 311)) relative to the raised surface 345, the second inclined surface 344b, and the abutment surface 347, and functions as a "recess" (details will be described later).

[0206] Each side edge 343 further includes a first inclined surface 344a, a raised surface 345, a second inclined surface 344b, and a side surface 343a extending inward (i.e., toward the axis of the first connecting portion 310 or the sleeve 311) from the recessed surface 346. The side surface 343a is a flat surface parallel to the YZ plane.

[0207] The pair of through holes 342 are symmetrical with respect to a plane parallel to the YZ plane and including the axis of the first connecting tube 315. The pair of through holes 342 are also symmetrical with respect to a plane parallel to the XZ plane and including the axis of the first connecting tube 315.

[0208] In the third embodiment, the raised surfaces 345 constituting the pair of side edges 343 provided on the third wall 341c constitute part of the outer surface of the third wall 341c. Similarly, the raised surfaces 345 constituting the pair of side edges 343 provided on the fourth wall 341d constitute part of the outer surface of the fourth wall 341d. However, the present invention is not limited to this, and for example, the raised surfaces 345 may be recessed further inward than the outer surfaces of the third wall 341c and the fourth wall 341d (i.e., toward the axis (or sleeve 311) of the first connecting portion 310).

[0209] A pair of support bars 348 are provided along the opening end of the opening facing the proximal side of the first connecting tube 315. The support bars 348 extend along the X-axis to connect the first wall 341a and the second wall 341b. The support bars 348 form part of the substantially rectangular opening shape of the through-hole 342. The outer surfaces of the support bars 348 (the surfaces facing outward in the Y-axis direction) are set back more inward (toward the axis of the first connecting part 310 or the sleeve 311) than the first inclined surface 344a and the raised surface 345. In other words, the support bars 348 can be said to be thinned by scraping away the outer surfaces of the portions of the third wall 341c and the fourth wall 341d that are proximal to the through-hole 342.

[0210] The second connecting portion 320 includes a second connecting tube 321 having a hollow, approximately cylindrical shape. The second connecting tube 321 extends from an annular wall 339 toward the opposite side (distal side) from the sleeve 311 and the first connecting tube 315 (see FIG. 16C ) and is arranged coaxially with the sleeve 311 and the first connecting tube 315. The outer peripheral surface 321a of the second connecting tube 321 is a cylindrical surface with a constant outer diameter in the axial direction. The second connecting tube 321 has an outer diameter that is approximately the same as the outer dimension of the first connecting tube 315 in the X-axis direction, although this is not limited thereto. A gripping protrusion 337 is provided on the outer peripheral surface 321a of the second connecting tube 321 so as to protrude radially outward along the X-axis. The gripping protrusion 337 extends a predetermined length in the axial direction from the first connecting tube 315 (particularly, from its first wall 341a) toward the distal side. The gripping protrusion 337 has a through hole 133 that is the same as the through hole 133 in the first embodiment.

[0211] Connector 301 includes only one gripping protrusion 337. However, the present invention is not limited to this, and multiple gripping protrusions 337 may be provided on the outer peripheral surface of connector 301, similar to the gripping protrusions (137a, 137b, see FIGS. 3A to 3C) of embodiment 1.

[0212] The second connecting tube 321 may have an outer peripheral surface 321a provided with the plurality of protrusions 126 (see FIGS. 3A and 3B) that are provided on the connector 101 of the first embodiment.

[0213] The second connecting tube 321 communicates with the sleeve 311. However, the second connecting tube 321 has an inner diameter larger than the inner diameter of the sleeve 311. A partition 131 extends axially from the annular wall 339 into the second connecting tube 321. An adhesive 135 is continuously filled from a first sub-lumen 132a formed by the partition 131 to the through-hole 133. The optical fiber 140 is fixed to the connector 301 via the adhesive 135 filled in the first sub-lumen 132a. The adhesive 135 in the first sub-lumen 132a forms an optical fiber fixing portion 136 for fixing the optical fiber 140 to the connector 301. The optical fiber 140 passes through the second connecting tube 321 and is led out of the second connecting portion 320. The partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the third embodiment may be the same as the partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the first embodiment. The description of the partition 131, the sub-lumens 132a and 132b, the through-hole 133, the adhesive 135, and the optical fiber fixing portion 136 of the first embodiment can be similarly applied to the third embodiment.

[0214] The inner peripheral surface of the second connecting tube 321 is provided with a female tapered surface 322 whose inner diameter increases toward the tip (the end opposite the first connecting portion 310) of the second connecting tube 321. The female tapered surface 322 is located closer to the tip of the second connecting tube 321 (the end opposite the first connecting portion 310) than the partition wall 131 (or the optical fiber fixing portion 136).

[0215] The optical fiber device 300 can be manufactured using the same materials and substantially the same method (post-bonding method or pre-bonding method) as the optical fiber device 100 of the first embodiment.

[0216] The optical fiber device 300 is used to detect the position of the distal end of a nasal catheter 900 (see FIG. 2) inserted into a patient, as in the first embodiment. The nasal catheter 900 to which the optical fiber device 300 is applied is the same as the nasal catheter 900 described in the first embodiment (see FIGS. 5A to 6B).

[0217] As in the first embodiment, the optical fiber device 300 is inserted into a nasal catheter 900 to form a catheter set 303. Fig. 17 is a cross-sectional view of a portion near the proximal end of the catheter set 303. The cross-section of Fig. 17 is the same as the cross-section of Fig. 16C and includes the axis and through-hole 133 of the connector 301. The optical fiber 140 of the optical fiber device 300 is inserted into a flow path 912 of a tube 910 of the nasal catheter 900. The connector 301 of the optical fiber device 300 (particularly, its second connecting portion 320 (see Figs. 16B and 16C)) is connected to a catheter connector 920 of the nasal catheter 900 (particularly, its male connector 930 (see Figs. 5A and 5B)). More specifically, as in the first embodiment, the male member 931 of the catheter connector 920 is inserted into the second connecting tube 321 of the connector 301. The female tapered surface 322 of the second connecting tube 321 comes into surface contact with the male tapered surface 932 of the male member 931 and fits liquid-tight (so-called tapered fitting). The second connecting tube 321 functions as a female member to which the male member 931 can be connected.

[0218] The connection and disconnection of the second connecting part 320 to the male connector 930 is generally the same as the connection and disconnection of the second connecting part 120 of embodiment 1 to the male connector 930 ( FIG. 7A ). However, unlike embodiment 1, the second connecting part 320 (second connecting tube 321) of embodiment 3 does not have a threading structure (protrusion (male thread) 126 (see FIGS. 3A and 3B )) that can be threaded into the female thread 936 of the catheter connector 920 (see FIGS. 16A and 16B ). Therefore, the connector 301 can be easily and quickly connected to and disconnected from the catheter connector 920 simply by tapering the female tapered surface 322 of the second connecting part 320 into the male tapered surface 932 of the male connector 930 and then releasing the tapered engagement.

[0219] When the connector 301 (second connection portion 320) is connected to the catheter connector 920 (male connector 930), the light emitting portion 145 of the optical fiber 140 is located within the lumen 972 of the olive 970, as in embodiment 1 (see Figure 7B), although this is not shown.

[0220] The connector 301 (particularly the first connection portion 310) of the optical fiber device 300 can be connected to and disconnected from the light source device 350. As shown in FIGS. 18A and 18B , the light source device 350 includes a connection portion 353 to which the connector 301 (first connection portion 310) can be connected, and a light source 155 disposed at a position set back from the connection portion 353. The connection portion 353 includes a receiving member 360. The connection portion 353 (receiving member 360) and the light source 155 are housed in a housing similar to the housing 151 of the light source device 150 of the first embodiment (see FIG. 8 ), but this housing is not shown in FIGS. 18A and 18B . The first connection portion 310 of the connector 301 is different from the first connection portion 110 of the first embodiment. Therefore, the receiving member 360, unlike the receiving member 160 of the first embodiment, has a configuration corresponding to the first connection portion 310.

[0221] The cross section of Fig. 18A is the same as the cross section of Fig. 17 and includes the axis of connector 301 and through-hole 133. The cross section of Fig. 18B includes the axis of connector 301 and is perpendicular to the cross section of Fig. 18A. The XYZ Cartesian coordinate system (see Figs. 16A to 16C) set for connector 301 is also applied to connection portion 353 (receiving member 360) of the light source device and light source 155, as shown in Figs. 18A and 18B.

[0222] 19A is a perspective view of the receiving member 360, and FIG. 19B is a cross-sectional perspective view of the receiving member 360. FIG.

[0223] The receiving member 360 includes a female member 361 having a hollow, approximately cylindrical shape and an outer cylinder 365 having a hollow, approximately rectangular prism shape. The outer cylinder 365 is arranged coaxially with the female member 361, radially spaced from the female member 361, and surrounding the female member 361. The axis of the outer cylinder 365 passes through the intersection of two diagonals of a rectangular cross section of the outer cylinder 365 taken along a plane parallel to the XY plane. A bottom plate 364 connects the base end (proximal end) of the female member 361 to the outer cylinder 365. The bottom plate 364 is continuous in a circumferential ring shape surrounding the base end of the female member 361. The outer cylinder 365 is open toward the distal side.

[0224] The inner peripheral surface 361a of the female member 361 may be, but is not limited to, a cylindrical surface with a constant inner diameter in the axial direction, or a female tapered surface (conical surface) whose inner diameter increases toward the tip (distal end, the end opposite the bottom plate 364) of the female member 361. A tapered surface (female tapered surface) 361b whose inner diameter increases toward the tip of the female member 361 is provided at the opening facing the distal side of the female member 361. The tapered surface 361b has a larger taper angle than the inner peripheral surface 361a and is located distally of the inner peripheral surface 361a.

[0225] A pair of elastic arms 370 extend distally from the bottom plate 364, generally parallel to the Z axis (the axis of the receiving member 360). The pair of elastic arms 370 face each other in the Y axis direction and are disposed on either side of the female member 361, spaced apart from the female member 361. The elastic arms 370 are elongated, plate-like bodies whose width (dimension in the X axis direction) and thickness (dimension in the Y axis direction) are constant in the Z axis direction (excluding the protrusions 371 and 373). The thickness of the elastic arms 370 is smaller than their width, allowing their distal ends (distal ends, free ends) to be elastically bent and deformed so as to move toward and away from the female member 361 (in the Y axis direction). A pair of protrusions 371 and a locking protrusion 373 are provided at the distal end of each elastic arm 370. The pair of protrusions 371 protrude in opposite directions in the X axis direction. The locking projection 373 projects toward the axis of the receiving member 360 (or the female member 361).

[0226] The outer cylinder 365 includes first to fourth walls 366a to 366d. The first wall 366a and the second wall 366b are flat plates parallel to the YZ plane and face each other in the X-axis direction. The inner surfaces of the first wall 366a and the second wall 366b (the surfaces facing the female member 361) are flat surfaces parallel to the YZ plane. The third wall 366c and the fourth wall 366d are flat plates parallel to the XZ plane and face each other in the Y-axis direction. The inner surfaces of the third wall 366c and the fourth wall 366d (the surfaces facing the female member 361) are flat surfaces parallel to the XZ plane. The first to fourth walls 366a to 366d are spaced apart from the female member 361 and the elastic arm 370.

[0227] The receiving member 360 is symmetrical with respect to a plane parallel to the XZ plane and including the axis of the receiving member 360 (or the female member 361). The receiving member 360 is also symmetrical with respect to a plane parallel to the YZ plane and including the axis of the receiving member 360 (or the female member 361).

[0228] The receiving member 360 is made of a hard material. Specifically, resin materials such as polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyacetal, polystyrene, polyamide, polyethylene, and hard polyvinyl chloride can be used as the material for the receiving member 360. The receiving member 360 can be manufactured as a single unit using the above-mentioned resin materials by injection molding or the like.

[0229] 18A and 18B , the light source 155 is disposed proximally relative to the female member 361, coaxially with the receiving member 360 (connecting portion 353), and at a predetermined axial position relative to the receiving member 360. The light source 155 can emit light toward the inner cavity of the female member 361. The light source 155 may be the same as the light source 155 of the first embodiment.

[0230] A method of using the optical fiber device 300 of the third embodiment will now be described.

[0231] As in the first embodiment, a catheter set 303 (see FIG. 17) is prepared in which an optical fiber device 300 is inserted into a nasal catheter 900. Also, a light source device 350 (see FIGS. 18A and 18B) including a light source 155 and a receiving member 360 (connecting portion 353) is prepared.

[0232] Similar to a typical nasal catheter, the tube 910 of the nasal catheter 900 is inserted into the nasal cavity of a patient 990 (see FIG. 2).

[0233] The connector 301 (particularly the first connection portion 310) of the optical fiber device 300 is connected to the connection portion 353 (receiving member 360) of the light source device 350. More specifically, the connection is performed as follows.

[0234] 18A and 18B , the first connecting portion 310 is coaxially opposed to the receiving member 360. The direction in which the third wall 341c and the fourth wall 341d (see FIG. 16A ) of the first connecting portion 310 face each other (the Y-axis direction) is aligned with the direction in which the pair of elastic arms 370 (see FIGS. 19A and 19B ) of the receiving member 360 face each other (the Y-axis direction). Then, the first connecting portion 310 (particularly its first connecting tube 315) is inserted into the receiving member 360 (particularly its outer tube 365).

[0235] A protrusion 371 (see FIGS. 19A and 19B ) protruding in the X-axis direction from the elastic arm 370 of the receiving member 360 collides with the first inclined surface 344 a (see FIG. 16A ) of the first connecting portion 310. When the first connecting portion 310 is further pressed into the receiving member 360, the protrusion 371 slides sequentially over the first inclined surface 344 a, the raised surface 345, and the second inclined surface 344 b (see FIG. 16A ) and reaches the receding surface 346 (see FIG. 16A ). During this process, the elastic arm 370 elastically bends and deforms such that the tip (free end) of the elastic arm 370 moves away from the female member 361, depending on the position of the protrusion 371 in the Z-axis direction relative to the first connecting portion 310. When the protrusion 371 reaches the receding surface 346, the elastic arm 370 returns to its initial state in which it is not substantially elastically deformed. The Z-axis dimension of the protrusion 371 and the Z-axis dimension of the receding surface 346 are substantially the same. When the first connecting portion 310 is pushed further into the receiving member 360, the protrusion 371 abuts against the abutment surface 347 (see FIG. 16A ) in the Z-axis direction. When the first connecting portion 310 is pulled from the receiving member 360, the protrusion 371 abuts against the second inclined surface 344b in the Z-axis direction. Thus, with the protrusion 371 facing (engaged with) the receding surface 346 between the second inclined surface 344b and the abutment surface 347, the connector 301 is positioned in the Z-axis direction with respect to the connecting portion 353 (receiving member 360). 20A and 20B are cross-sectional views showing a state in which the protrusion 371 (not visible in FIGS. 20A and 20B; see FIGS. 19A and 19B) of the elastic arm 370 faces (engages with) the receding surface 346 (not visible in FIGS. 20A and 20B; see FIGS. 16A and 18B) of the first connecting portion 310 (first connecting tube 315) in the Y-axis direction. The cross section of FIG. 20A is the same as the cross sections of FIG. 16C, FIG. 17, and FIG. 18A. The cross section of FIG. 20B is the same as the cross sections of FIG. 18B and FIG. 19B, and is perpendicular to the cross section of FIG. 20A.

[0236] Concurrently, the sleeve 311 of the first connecting portion 310 is inserted into the female member 361 of the receiving member 360 (see FIGS. 20A and 20B). The male tapered surface 311b (see FIG. 16A) at the tip of the sleeve 311 and the female tapered surface 361b (see FIGS. 19A and 19B) at the tip of the female member 361 function as guide surfaces that facilitate insertion of the sleeve 311 into the female member 361. The outer peripheral surface 311a (see FIG. 16A) of the sleeve 311 fits into the inner peripheral surface 361a (see FIGS. 19A and 19B) of the female member 361. Therefore, the sleeve 311 is disposed coaxially with the female member 361. The connector 301 is positioned coaxially with the connecting portion 353 (receiving member 360) via the sleeve 311.

[0237] Thus, as shown in Figures 20A and 20B, the catheter set 303 is connected to the light source device 350. The connector 301 is positioned coaxially with the connecting portion 353 (receiving member 360) at a desired axial position. As a result, the light incident portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position. In this state, the light source 155 is activated to emit light. Light emitted from the light source 155 enters the light incident portion 142 of the optical fiber 140, passes through the optical fiber 140, and is emitted from the light emitting portion 145 (see Figure 7B) of the optical fiber 140. The light passes through the olive 970 (housing 971) and further through the patient 990 (see Figure 2). The surgeon can detect the position of the olive 970, i.e., the distal end of the nasal catheter 900, from the light emission position on the body surface of the patient 990. Depending on its wavelength, the light can be detected by the naked eye or via an infrared camera.

[0238] After confirming that the distal end (olive 970) of the nasal catheter 900 has reached the stomach 991, the light source 155 stops emitting light. The subsequent procedures are generally the same as those in the first embodiment. That is, the light source device 350 is separated from the catheter set 303. Next, the connector 301 of the optical fiber device 300 is separated from the catheter connector 920 of the nasal catheter 900, and the optical fiber device 300 is withdrawn from the nasal catheter 900. The nasal catheter 900 is left indwelling in the patient 990 with its distal end (olive 970) in the stomach 991. Note that the optical fiber device 300 and the light source device 350 may be withdrawn from the nasal catheter 900 together before the light source device 350 is separated from the catheter set 303. Next, a liquid containing a nutrient or the like is administered to the stomach 991 of the patient 990 via the nasal catheter 900. The used fiber optic device 300, once removed from the nasal catheter 900, is discarded. The fiber optic device 300 can be easily separated from the light source device 350 (receiving member 360) by forcefully pulling the connector 301 of the fiber optic device 300 from the receiving member 360. The protrusion 371 of the elastic arm 370 (see FIGS. 19A and 19B ) slides sequentially over the second inclined surface 344b, the raised surface 345, and the first inclined surface 344a (see FIGS. 16A and 18B ). During this process, the elastic arm 370 elastically bends and deforms such that the tip (free end) of the elastic arm 370 moves away from the female member 361 depending on the position of the protrusion 371 in the Z-axis direction relative to the first connecting portion 310. When the connector 301 is separated from the connecting portion 353 (receiving member 360), the elastic arm 370 returns to its initial, undeformed state.

[0239] As described above, the optical fiber device 300 of the third embodiment includes the optical fiber 140 and the connector 301 provided at the proximal end of the optical fiber 140. The connector 301 includes, on its proximal side, a first connection portion 310 that can be connected to and disconnected from the light source device 350. The first connection portion 310 includes a sleeve 311 into which the optical fiber 140 is inserted (see FIGS. 16A and 16C ). The sleeve 311 can position the light entrance portion 142 of the optical fiber 140 coaxially with the sleeve 311 and further with the connector 301. Therefore, when the connector 301 (first connection portion 310) is connected to the light source device 350, the light entrance portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 of the light source device 350 (see FIGS. 20A and 20B ).

[0240] The first connecting portion 310 further includes a first connecting tube 315 that is coaxial with and surrounds the sleeve 311. The first connecting tube 315 includes a recessed surface 346 as an engagement structure that can engage with the light source device 350 (see FIGS. 16A and 16B). The recessed surface 346 is a "recess" that is recessed relatively to the second inclined surface 344b and the abutment surface 347 that sandwich the recessed surface 346. When the connector 301 is connected to the light source device 350 (see FIGS. 20A and 20B), the protrusion 371 of the light source device 370 fits into the recessed surface (recessed surface) 346. That is, the recessed surface (recessed surface) 346 engages with the protrusion 371 of the light source device 350 (see FIGS. 19A and 19B) and is axially constrained to the light source device 350. Therefore, when the connector 301 (first connection portion 310 ) is connected to the light source device 350 , the light entrance portion 142 of the optical fiber 140 is positioned at a desired axial position relative to the light source 155 of the light source device 350 .

[0241] Therefore, when the connector 301 is connected to the light source device 350, the light entrance portion 142 of the optical fiber 140 can always be positioned coaxially with the light source 155 at the desired axial position relative to the light source 155, regardless of the surgeon (see Figures 20A and 20B).

[0242] After the connector 301 (or the catheter set 303) is connected to the light source device 350 (see FIGS. 20A and 20B ), a tensile force may act between the catheter set 303 (or the nasal catheter 900) and the light source device 350. For example, when a tensile force in the axial direction of the light source device 350 (hereinafter referred to as “axial tensile force”) acts on the catheter set 303 in a state where the catheter set 303 is connected to the light source device 350 (see FIGS. 20A and 20B ), the engagement of the protrusion 371 with the recess (recessed surface) 346 prevents axial displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155. Furthermore, when the catheter set 303 is connected to the light source device 350 (see Figure 20B), when a tensile force (hereinafter referred to as "radial tensile force") acts on the catheter set 303 in a direction perpendicular to the axis of the light source device 350 (i.e., radially outward from the axis of the light source device 350) along the plane (YZ plane) including the axis of the light source device 350 and the elastic arm 370, the engagement of the protrusion 371 with the recess 346 limits the inclination of the connector 301 relative to the light source device 350, and as a result, prevents axial displacement of the light incident portion 142 of the optical fiber 140 relative to the light source 155.

[0243] As in the first embodiment, according to the third embodiment, when the connector 301 (or the catheter set 303) is connected to the light source device 350, the light input portion 142 of the optical fiber 140 is positioned coaxially with the light source 155 at a desired axial position relative to the light source 155, thereby reducing coupling loss. Furthermore, even if a tensile force acts on the catheter set 303 during subsequent use, misalignment of the light input portion 142 relative to the light source 155 can be reduced, thereby maintaining low coupling loss. By applying the optical fiber device 300 of the third embodiment to a nasal catheter 900, the attenuation of the light beam emitted from the olive 970 at the distal end of the nasal catheter 900 is reduced and the light beam is stabilized, making it easy to confirm the light beam from outside the patient's body. Therefore, the position of the distal end (olive 970) of the nasal catheter 900 can be easily and accurately detected based on the light emission position on the body surface of the patient 990.

[0244] In the third embodiment, when the catheter set 303 is connected to the light source device 350 (see FIGS. 20A and 20B), each elastic arm 370 (see FIGS. 19A and 19B) of the receiving member 360 fits between a pair of side surfaces 343a (see FIGS. 16A and 16B) of the connector 301 that face each other in the X-axis direction (see FIGS. 20A and 20B). The dimension of the elastic arm 370 in the X-axis direction (excluding the protrusion 371) is substantially the same as the distance between the pair of side surfaces 343a that face each other in the X-axis direction. The fit of the elastic arm 370 between the pair of side surfaces 343a suppresses tilt of the connector 301 relative to the axis of the light source device 350 in the XZ plane. This is advantageous for, first, preventing damage to the sleeve 111 and, second, preventing axial displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155.

[0245] In the present invention, the configuration of the distal portion of the connector 301 is optional. Preferably, the connector 301 includes a second connecting portion 320 on its distal side (see FIGS. 16A to 16C ). The second connecting portion 320 is connectable to a catheter connector 920 (see FIGS. 5A and 5B ) provided at the proximal end of the nasal catheter 900. Therefore, by simply inserting the optical fiber 140 of the optical fiber device 300 into the tube 910 of the nasal catheter 900 and connecting the second connecting portion 320 to the catheter connector 920, the light emitting portion 145 of the optical fiber 140 is aligned with the distal end of the nasal catheter 900 (i.e., the olive 970) (see FIG. 7B ), as in the first embodiment. Therefore, by emitting light from the light emitting portion 145 of the optical fiber 140 while the catheter set 303 is inserted into the patient 990 (see FIG. 2 ), the distal end (olive 970) of the nasal catheter 900 can be illuminated. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0246] In the present invention, the second connecting portion 320 of the connector 301 to be connected to the catheter connector 920 may have any configuration. Preferably, the second connecting portion 320 has a female tapered surface 322 (see FIG. 16C ) that can be tapered-fitted to the male tapered surface 932 (see FIG. 5A ) of the catheter connector 920. Therefore, similar to the first embodiment, the connector 301 can be connected to a predetermined axial position relative to the catheter connector 920 simply by tapering-fitting the female tapered surface 322 to the male tapered surface 932 (see FIG. 17 ). At this time, the light emitting portion 145 of the optical fiber 140 is accurately aligned with the distal end (i.e., the olive 970) of the nasal catheter 900 (see FIG. 7B ). Therefore, the light emitted from the light emitting portion 145 can always illuminate the distal end (olive 970) of the nasal catheter 900. This is advantageous for accurately detecting the position of the distal end of the nasal catheter 900.

[0247] The first connecting tube 315 of the connector 301 has a hollow, generally rectangular prism shape. A recess (recessed surface) 346 is provided in each of two walls 341c, 341d of the first connecting tube 315 so as to be recessed from the outer surface of each wall 341c, 341d (see FIGS. 16A and 16B ). The recess 346 functions as an engagement structure that can engage with the light source device 350. Meanwhile, the light source device 350 has a pair of elastic arms 370, each of which has a protrusion 371 serving as an engagement portion (see FIGS. 19A and 19B ). When the connector 301 is inserted into the light source device 350 (see FIGS. 20A and 20B ), the protrusion 371 of the light source device 350 fits into the recess 346 of the connector 301, allowing the protrusion 371 to engage with the recess 346. Thereafter, when the connector 301 is pulled from the light source device 350 with a force greater than or equal to a predetermined strength, the protrusion 371 escapes from the recess 346, and the engagement of the protrusion 371 with the recess 346 can be released. In this way, the detection device 3 of the third embodiment, which is made up of the optical fiber device 300 and the light source device 350, can repeatedly connect and disconnect the connector 301 (and further the optical fiber device 300) to and from the light source device 350 simply by performing the simple operation of inserting and removing the connector 301 into and from the light source device 350.

[0248] A first inclined surface 344a, a raised surface 345, a second inclined surface 344b, a recessed portion (recessed surface) 346, and an abutment surface 347 are provided adjacent to each other in this order along the axial direction of the connector 301 (the direction in which the connector 301 is inserted into or removed from the light source device 350) on each of the outer surfaces of the two walls 341c, 341d of the first connecting tube 315 of the connector 301 (see FIGS. 16A and 16B). When the protrusion 371 of the elastic arm 370 (see FIGS. 19A and 19B) fits into the recessed portion 346, the elastic arm 370 is not substantially elastically deformed. When the protrusion 371 overcomes the raised surface 345, the elastic arm 370 is forced to bend. The first inclined surface 344a and the second inclined surface 344b arranged on either side of the raised surface 345 are advantageous in reducing the axial force that needs to be applied to the connector 301 when connecting and disconnecting the connector 301 to the light source device 350.

[0249] In the third embodiment, an engagement structure (recess 346) capable of engaging with the light source device 350 is provided on each of the walls 341c and 341d. However, the engagement structure of the present invention is not limited to this. For example, the engagement structure (recess 346) may be provided on only one of the walls 341c and 341d. Alternatively, the engagement structure (recess 346) may be provided on any one or more or all of the four walls 341a to 341d. The receiving member 360 of the light source device 350 is provided with a number of elastic arms 370 corresponding to the number of walls on which the engagement structure is provided. Increasing the number of walls on which the engagement structure is provided is advantageous in preventing displacement of the light entrance portion 142 of the optical fiber 140 relative to the light source 155 when axial or radial tensile force acts on the catheter set 303 in a state in which the catheter set 303 is connected to the light source device 350 (see FIGS. 20A and 20B ). However, if the number of walls provided with the engagement structure is too large, the structure of the first connecting tube 315 becomes complicated, making it difficult to manufacture the connector 301. Therefore, it is preferable that the number of walls provided with the engagement structure be two or less. Most preferably, an engagement structure is provided on each of two opposing walls.

[0250] In the third aspect of the present invention, the engagement structure (recess 346) is provided on each of a pair of side edges 343 of the through hole 342 formed in the wall (341c, 341d) of the first connecting tube 315 (see FIGS. 16A and 16B ). However, the present invention is not limited to this. For example, the engagement structure (recess 346) may be provided on the outer surface of the wall of the first connecting tube 315 without providing the through hole 342 in the wall. In one example, a groove (which does not penetrate the wall) is provided on the outer surface of the wall along the axis of the connector 301, and the bottom surface of the groove is provided with a first inclined surface 344a, a raised surface 345, a second inclined surface 344b, a recess (recessed surface) 346, and an abutment surface 347. A protrusion 371 serving as an engagement portion is provided on the elastic arm 370 so as to slide on the bottom surface of the groove. In this example, a pair of opposing side walls defining the width of the groove function as the side surface 343a.

[0251] A gripping protrusion 337 protruding radially outward is provided on the outer peripheral surface of the connector 301 (see FIGS. 16A to 16C). The axial position of the gripping protrusion 337 is not limited, but is preferably located distal to the first connecting tube 315. As in the first embodiment, when the outer peripheral surface 321a of the second connecting tube 321 is provided with a protrusion 126 (see FIGS. 3A and 3B), the gripping protrusion 337 is more preferably located between the first connecting tube 315 and the protrusion 126. When the catheter set 303 is connected to the light source device 350, the gripping protrusion 337 is preferably located between the light source device 350 and the catheter connector 920 and exposed to the outside (see FIG. 20A). The gripping protrusion 337 makes it easy to apply a rotational force to the connector 301 when connecting and disconnecting the connector 301 to the catheter connector 920 of the nasal catheter 900, and also makes it easy to grip the connector 301 when connecting and disconnecting the connector 301 to the connection portion 353 (receiving member 360) of the light source device 350.

[0252] When the catheter set 303 is connected to the light source device 350 (see FIG. 20A ), the axial distance between the light source device 350 and the catheter connector 920 is preferably 15 mm or more, and more preferably 20 mm or more. When the light source device 350 and the catheter connector 920 are spaced apart in the axial direction in this manner, it is easy to hook a finger on the gripping protrusion 337 between the light source device 350 and the catheter connector 920.

[0253] The number of gripping protrusions 337 may be one or more. In the third embodiment, only one gripping protrusion 337 is provided on the connector 301. However, preferably, multiple gripping protrusions 337 are arranged on the outer peripheral surface of the connector 301 at equal angular intervals relative to the axis of the connector 301. Most preferably, two gripping protrusions 337 are provided. This is because providing two gripping protrusions 337 on the connector 301 is sufficient for applying a rotational force to the connector 301 and for gripping the connector 301. When the connector 301 includes multiple gripping protrusions 337, the multiple gripping protrusions 337 may have the same shape, dimensions, etc., or may be different. Note that, in the present invention, the connector 301 does not necessarily have to include a gripping protrusion 337.

[0254] The sleeve 311 is disposed coaxially with the first connecting tube 315 (see FIGS. 16A and 16C ). The tip (proximal end) of the sleeve 311 may be axially recessed from the tip (proximal end) of the first connecting tube 315, or the tip of the sleeve 311 may be located on the same plane as the tip of the first connecting tube 315. However, preferably, as in the first embodiment, the sleeve 311 protrudes axially from the tip of the first connecting tube 315 (see FIG. 17 ).

[0255] Therefore, when the optical fiber device 300 is manufactured using the above-described post-fixing method in which the light input portion 142 is formed after the optical fiber 140 is fixed to the connector 301, it is easy to cut the optical fiber 140 protruding from the tip of the sleeve 311 at the same axial position as the tip of the sleeve 311. This firstly makes it possible to reduce variation in the axial position of the cut surface of the optical fiber 140 (i.e., the light input portion 142) relative to the connector 301 (or the first connection portion 310), and secondly makes it possible to form a flat surface with few irregularities on the cut surface of the optical fiber 140 (i.e., the light input portion 142). These are advantageous in reducing coupling loss between the light source 155 and the light input portion 142 of the optical fiber 140.

[0256] Furthermore, when the optical fiber device 300 is manufactured by the above-described pre-fixing method in which the light incident portion 142 is formed before the optical fiber 140 is fixed to the connector 301, it is easy to align the light incident portion 142 of the optical fiber 140 with the tip of the sleeve 311. This makes it possible to reduce variations in the axial position of the light incident portion 142 of the optical fiber 140 relative to the connector 301 (or the first connection portion 310), which is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0257] As in the first embodiment, when the connector 301 is connected to the light source device 350, the sleeve 311 of the connector 301 fits into the female member 361 of the light source device 350 (see FIGS. 20A and 20B). When the sleeve 311 fits into the female member 361, the inner circumferential surface 361a of the female member 361 (see FIGS. 19A and 19B) positions the sleeve 311 in the radial direction relative to the light source device 350. In other words, with the simple structure in which the sleeve 311 fits into the female member 361, the light incident portion 142 of the optical fiber 140 can be positioned coaxially with the light source 155. This is advantageous in reducing coupling loss between the light source 155 and the light incident portion 142 of the optical fiber 140.

[0258] As in the first embodiment, the female member 361 has a tapered surface (conical surface) 361b, whose inner diameter increases toward the tip of the female member 361, located distally of the inner circumferential surface 361a (see FIGS. 19A and 19B ). The tapered surface 361b can guide the sleeve 311 into the female member 361 when connecting the connector 301 to the light source device 350. This makes it easier to connect the connector 301 to the light source device 350. Furthermore, the tapered surface 361b can allow the sleeve 311 to tilt relative to the female member 361 when disconnecting the connector 301 from the light source device 350. This makes it easier to disconnect the connector 301 from the light source device 350.

[0259] In the third embodiment, the sleeve 311 is fitted into the female member 361 to position the light incident portion 142 of the optical fiber 140 coaxially with the light source 155, but the present invention is not limited to this. For example, the light incident portion 142 of the optical fiber 140 may be aligned in the X-axis direction with respect to the light source 155 by utilizing the elastic arms 370 (see FIGS. 19A and 19B ) of the receiving member 360 fitting between a pair of side surfaces 343 a (see FIGS. 16A and 16B ) facing each other in the X-axis direction of the connector 301. Alternatively, the light incident portion 142 of the optical fiber 140 may be aligned in the Y-axis direction with respect to the light source 155 by utilizing the pair of elastic arms 370 clamping the first connecting tube 315. In this case, the light source device 350 (or the receiving member 360) does not need to include the female member 361.

[0260] Except for the above, the third embodiment is the same as the first embodiment. The description of the first embodiment also applies to the third embodiment as appropriate.

[0261] The above-described first to third embodiments are merely examples, and the present invention is not limited to the above-described first to third embodiments, and can be modified as appropriate.

[0262] In the above-described first to third embodiments, an optical fiber 140 is used to transmit light from the light source device (150, 250, 350) to the olive 970 at the distal end of the nasal catheter 900. However, the detection devices (1, 2, 3) of the present invention are not limited to this configuration. For example, the detection devices (1, 2, 3) may be configured such that the tube 910 of the nasal catheter 900 itself transmits light from the light source device (150, 250, 350) to the olive 970. In this configuration, light emitted from the light source 155 enters the proximal end surface of the tube 910, passes through the tube 910, is emitted from the distal end surface of the tube 910, passes through the olive 970 (housing 971), and then passes through the body of the patient 990. The surgeon can detect the position of the olive 970, i.e., the distal end of the nasal catheter 900, from the position of the light emission on the body surface of the patient 990. In this configuration, after confirming that the distal end (olive 970) of the nasal catheter 900 has reached the stomach 991 using the optical fiber device (100, 200, 300), the optical fiber device (100, 200, 300) is withdrawn from the nasal catheter 900, and the nasal catheter 900 is left indwelling in the patient 990. If necessary, a light source device (150, 250, 350) can be connected to the nasal catheter 900 without using the optical fiber device (100, 200, 300) to confirm the position of the distal end (olive 970) of the nasal catheter 900. Generally, the nasal catheter 900 is left indwelling in the patient 990 for several days. During this time, the nasal catheter 900 may curl up inside the patient 990, causing the olive 970 to move from the stomach 991. Therefore, being able to check the position of the distal end (olive 970) of the nasal catheter 900 at a desired timing (for example, immediately before enteral nutrition) is advantageous in improving patient safety. Note that the configuration of the connection portion (153, 253, 353 (receiving member 160, 260, 360)) of the light source device (150, 250, 350) may be appropriately modified so that the catheter connector 920 of the nasal catheter 900 can be connected to the light source device (150, 250, 350).The catheter connector 920 may be connected to the connection portion (153, 253, 353 (receiving member 160, 260, 360)) of the light source device (150, 250, 350) via an adapter. The configuration of the catheter connector 920 may be appropriately changed so that light from the light source 155 can be incident on the proximal end surface of the tube 910 directly or indirectly via the catheter connector 920.

[0263] In the above-described first to third embodiments, the present invention is used to detect the position of the distal end of the nasal catheter 900, but the present invention can be applied to any medical catheter other than the nasal catheter 900. For example, the present invention can be applied to a catheter inserted into an artery or a vein. The liquid flowing through the medical catheter to which the present invention is applied can be any liquid, such as nutrients, medicines, contrast agents, or blood. The connector (particularly the second connecting portion) and the light source device can be modified as appropriate depending on the type of medical catheter.

[0264] The present invention can be widely used to detect the position of the distal end (tip) of a medical catheter inserted into a patient, and is particularly suitable for use with a nasal catheter used in oral and nasal tube feeding.

[0265] 1, 2, 3 Detection device (device for detecting distal end position of medical catheter) 100, 200, 300 Optical fiber device 101, 201, 301 Connector 103, 203, 303 Catheter set 110, 210, 310 First connecting portion 111, 211, 311 Sleeve 115, 215, 315 First connecting tube 117 Engagement protrusion (engagement structure) 120, 220, 320 Second connecting portion 121, 221, 321 Second connecting tube 122, 222, 322 Female tapered surface of second connecting portion 133 Through hole 135 Adhesive 136 Optical fiber fixing portion 137a Grip protrusion (first grip protrusion) 137b Grip protrusion (second grip protrusion) 138 Cavity in gripping protrusion (second gripping protrusion) 237, 337 Grip protrusion 140 Optical fiber 142 Light incident portion 145 Light emitting portion 150, 250, 350 Light source device 155 Light source 160, 260, 360 Receiving member 161, 261, 361 Female member of light source device (receiving member) 161a, 261a, 361a Inner peripheral surface of female member 161b, 361b Tapered surface of female member (female tapered surface) 167 Engagement groove (engagement portion of light source device) 169 Lock groove 169a First side surface of lock groove 169b Second side surface of lock groove 210a Contact end surface of first connection portion 217 Engagement protrusion (first engagement protrusion, engagement structure) 263 Flat surface of light source device 267 Engagement protrusion (second engagement protrusion, engagement portion of light source device) 346 Recessed portion (retraction surface, engagement structure) 370 Elastic arm of light source device 371 Protrusion (engagement portion of light source device) 900 Nasal catheter (medical catheter) 910 Tube 920 Catheter connector 932 Male tapered surface of catheter connector 970 Olive (distal end of nasal catheter) 990 Patient 991 Stomach of patient

Claims

1. An optical fiber device comprising an optical fiber and a connector provided at the proximal end of the optical fiber and capable of being connected to and disconnected from a light source device, wherein the optical fiber is insertable into a medical catheter, and the optical fiber has a light incident portion on its proximal side and a light emitting portion on its distal side, and the optical fiber device is configured so that when the medical catheter with the optical fiber inserted is inserted into a patient and light from the light source device is incident on the light incident portion of the optical fiber, the light is emitted from the light emitting portion and illuminates the surface of the patient's body, thereby making it possible to detect the position of the distal end of the medical catheter, and the connector has a first connecting portion on its proximal side, and the first connecting portion comprises a cylindrical sleeve into which the optical fiber is inserted and a first connecting tube arranged coaxially with the sleeve to surround the sleeve, and the first connecting tube has an engaging structure that can engage with the light source device so that the connector is axially constrained by the light source device when the connector is connected to the light source device.

2. The optical fiber device according to claim 1, wherein the connector has a second connection portion on its distal side, and the second connection portion can be connected to and disconnected from a catheter connector provided at the proximal end of the medical catheter.

3. An optical fiber device according to claim 2, wherein said second connecting portion has a female tapered surface that can be tapered and fitted to the male tapered surface of said catheter connector.

4. An optical fiber device according to claim 1, wherein the first connecting tube has a hollow, generally cylindrical shape, and the engagement structure includes at least one engagement protrusion provided on the first connecting tube so as to protrude radially outward.

5. The fiber optic device of claim 4, wherein said at least one engaging protrusion comprises at least two and at most four engaging protrusions.

6. The optical fiber device according to claim 4, wherein the distance from the distal surface of said at least one engaging protrusion to the proximal end of said first connecting tube is 70% or more of the outer diameter of said first connecting tube.

7. A distal end position detection device for a medical catheter, comprising the optical fiber device of claim 4 and a light source device capable of connecting and disconnecting the connector of the optical fiber device, wherein the light source device has at least one engaging portion, and by rotating the first connecting tube of the connector relative to the light source device, the at least one engaging protrusion of the first connecting tube can be engaged with the at least one engaging portion of the light source device, and the engagement can be released.

8. The distal end position detection device for a medical catheter as described in claim 7, wherein the at least one engaging portion has a locking groove extending circumferentially, the width of the locking groove is determined by a first side surface and a second side surface opposite the first side surface and disposed distally relative to the first side surface, the first side surface extends along a plane perpendicular to the rotation axis of the first connecting tube relative to the light source device, and the second side surface extends at an angle relative to the first side surface so that the width of the locking groove decreases toward the side where the engaging protrusion engages with the locking groove, and the at least one engaging portion is capable of clamping and restraining the at least one engaging protrusion axially between the first side surface and the second side surface of the locking groove.

9. A distal end position detection device for a medical catheter as described in claim 7, wherein the at least one engaging protrusion provided on the first connecting tube is at least one first engaging protrusion, the at least one engaging portion provided on the light source device is at least one second engaging protrusion extending circumferentially, the first connecting portion is provided with an annular abutment end surface perpendicular to the axis of the connector, and the first connecting portion is configured such that when the at least one first engaging protrusion engages with the at least one second engaging protrusion, the abutment end surface abuts axially against a flat surface of the light source device.

10. The optical fiber device according to claim 1, wherein the first connecting tube has a hollow, generally rectangular prism shape, and the engagement structure includes a recess provided in the wall of the first connecting tube.

11. A distal end position detection device for a medical catheter, comprising the optical fiber device according to claim 10 and a light source device capable of connecting and disconnecting the connector of the optical fiber device, wherein the light source device has an elastic arm that can be elastically bent and deformed, and when the connector is connected to the light source device, a protrusion provided on the elastic arm fits into the recess.

12. The optical fiber device according to claim 1, wherein at least one gripping projection projecting radially outward is provided on the outer peripheral surface of said connector distal to said first connecting tube.

13. An optical fiber device as described in claim 4, wherein at least one gripping protrusion protruding radially outward is provided on the outer peripheral surface of the connector distal to the first connecting tube, and said at least one gripping protrusion is arranged at the same circumferential position as said at least one engaging protrusion.

14. A distal end position detection device for a medical catheter, comprising the optical fiber device of claim 12 and a light source device capable of connecting and disconnecting the connector of the optical fiber device, wherein the connector has a second connection part on its distal side, and the second connection part is connectable to and disconnectable from a catheter connector provided at the proximal end of the medical catheter, and when the second connection part is connected to the catheter connector and the connector is connected to the light source device, the at least one gripping protrusion is positioned between the catheter connector and the light source device and is exposed to the outside world.

15. An optical fiber device according to claim 1, wherein the sleeve protrudes from the tip of the first connecting tube, and the light incident portion of the optical fiber is located at the same position in the axial direction as the tip of the sleeve.

16. A distal end position detection device for a medical catheter, comprising the optical fiber device of claim 1 and a light source device capable of connecting and disconnecting the connector of the optical fiber device, wherein the light source device comprises a light source and a female member into which the sleeve of the connector fits when the connector is connected to the light source device, and when the sleeve fits into the female member, the inner surface of the female member positions the sleeve so that the light incident portion of the optical fiber is coaxial with the light source.

17. The distal end position detection device for a medical catheter according to claim 16, wherein the female member has a tapered surface distal to the inner circumferential surface of the female member, the inner diameter of which increases toward the tip of the female member.

18. The optical fiber device according to claim 1, wherein the connector further comprises an optical fiber fixing portion for fixing the optical fiber to the connector, the optical fiber fixing portion being disposed distally of the sleeve.

19. The optical fiber device according to claim 18, wherein the connector further comprises a through-hole that connects the optical fiber fixing portion to the outside of the connector, and the adhesive is continuously filled from the optical fiber fixing portion to the through-hole.

20. An optical fiber device as described in claim 19, wherein at least one gripping protrusion protruding radially outward is provided on the outer peripheral surface of the connector distal to the first connecting tube, and the through hole passes through the at least one gripping protrusion.

21. The optical fiber device according to claim 20, wherein the at least one gripping protrusion includes a first gripping protrusion and a second gripping protrusion, the through-hole penetrates the first gripping protrusion, and the second gripping protrusion is provided with a cavity that communicates with the inner cavity of the first connecting tube.

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