Light diffusion device and medical catheter kit provided with same

Abstract

Provided are: a light diffusion device capable of efficiently emitting light transmitted through a light transmission unit in a specific direction on the side surface; and a medical catheter kit provided with the light diffusion device. This light diffusion device (1) is provided with an optical fiber (20) including a core (21) and a cladding (22), and emits light incident from the base end of the optical fiber (20) from the tip side (T) of the optical fiber (20), and the optical fiber (20) has a light transmission section (20a) that transmits light toward the tip section (20TE), and a light emission section (20b) that is formed by removing the outer peripheral side of the cladding (22) on the tip side (T). The outer diameter (Db) of the cladding (22b) in the light emission section (20b) is reduced by more than or equal to the wavelength [lambda] of the light transmitted in the light transmission section (20a) than the outer diameter (Da) of the cladding (22a) in the light transmission section (20a) (Db < = Da-[lambda]), and an end surface (20e) inclined with respect to a plane (P) perpendicular to the axis (21A) of the core (21) is provided at the tip-side (T) end (20TE) of the optical fiber (20).

Description

TECHNICAL FIELD

[0001] The present application relates to a light diffusion device for a medical instrument and a medical catheter kit provided with the same. BACKGROUND

[0002] As a conventional light diffusion device, there is known a device provided with an optical fiber including a core located on the center side in the radial direction and a cladding located on the outer peripheral side of the core, and causing laser light incident from the base end portion of the optical fiber to be emitted from the front end portion of the optical fiber and the outer peripheral surface on the front end side (see, for example, Patent Literature 1). The optical fiber of the conventional light diffusion device has a light transmission portion that transmits laser light incident from the base end portion, and a light emission portion that causes laser light transmitted in the light transmission portion to be emitted on the front end side.

[0003] The light diffusion device is used in a photodynamic therapy, which is one of the therapies for cancer, to insert the front end side of the optical fiber into the human body and irradiate laser light to a medicament administered to the human body and reaching cancer cells. In addition, the light diffusion device is also used to be inserted into the body together with an endoscope such as a gastroscope, a catheter, or the like, and to irradiate the inside of the body and project from the body surface to the body surface.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2001-502438 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] With the conventional light diffusion device, the core is exposed by partially removing the cladding on the front end side of the optical fiber, and light is emitted from the outer peripheral surface of the light emission portion. In this case, in the conventional light diffusion device, the difference between the refractive index of the core in the light emission portion and the refractive index of the air located on the outer peripheral side of the core becomes large, and the light trapping effect of light becomes strong. Therefore, the emission intensity on the whole of the light emission portion is limited for laser light emitted from the light emission portion.

[0009] Therefore, one of the objects is to provide a light diffusion device capable of efficiently emitting light transmitted in a light transmission portion to a specific direction on the side surface and a medical catheter kit provided with the same.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] The light diffusion device according to one embodiment of the present application is a light diffusion device provided with an optical fiber and causing light incident from the base end portion of the optical fiber to be emitted from the front end side of the optical fiber, the optical fiber including a core located on the center side in the radial direction and a cladding located on the outer peripheral side of the core,

[0012] The aforementioned light diffusion device has a light transmission portion that transmits light incident from the base end portion toward the front end portion, and a light exit portion that is formed by removing a portion of the aforementioned cladding on the outer circumferential side in the front end side,

[0013] The outer diameter Db of the aforementioned cladding in the aforementioned light exit portion is reduced by more than the size of the wavelength λ of light transmitted in the aforementioned light transmission portion compared to the outer diameter Da of the aforementioned cladding in the aforementioned light transmission portion (Db≤Da-λ), and,

[0014] The end portion on the front end side of the aforementioned optical fiber has an end face that is inclined with respect to a plane perpendicular to the axis of the aforementioned core.

[0015] It can also be that, in a region of 30% or more of the total area of the aforementioned light exit portion, the thickness t of the aforementioned cladding in the aforementioned light exit portion is 1 μm or more.

[0016] It can also be that the aforementioned light exit portion extends to a region connected to the aforementioned end face on the front end side of the aforementioned optical fiber.

[0017] It can also be that the end portion on the front end side of the aforementioned optical fiber has two or more end faces that are inclined with respect to a plane perpendicular to the axis of the aforementioned core.

[0018] It can also be that the aforementioned end face is continuous in the circumferential direction of the aforementioned optical fiber, and that the shape of the end face is a conical shape.

[0019] It can also be that the angle formed by a plane perpendicular to the axis of the aforementioned core and the aforementioned end face is less than the minimum angle at which light transmitted in the aforementioned light transmission portion is totally reflected.

[0020] The aforementioned optical fiber can also be a resin optical fiber.

[0021] The numerical aperture (NA) of the aforementioned optical fiber can also be 0.5 or more.

[0022] A concave-convex can also be formed on the outer surface of the aforementioned optical fiber in the aforementioned light exit portion.

[0023] The medical catheter kit of one embodiment of the present application includes a catheter and the aforementioned light diffusion device of one embodiment of the present application.

[0024] Effects of the Invention

[0025] According to one embodiment of the present application, a light diffusion device that can efficiently cause light transmitted in a light transmission portion to exit to a specific direction in the side surface, and a medical catheter kit including the same, can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0026] [ Figure 1 ] is a schematic view of a light diffusion device according to a first embodiment of the present application.

[0027] [ Figure 2 ] is a main part cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the first embodiment and its vicinity, and is a cross-sectional view at the A-A cross section in Figure 3 and Figure 4 .

[0028] [ Figure 3 ] is a cross-sectional view of a site of the light transmission portion of the optical fiber in the light diffusing device according to the first embodiment, and is a cross-sectional view at the C-C cross section in Figure 2 .

[0029] [ Figure 4 ] is a cross-sectional view of a site of the light exit portion of the optical fiber in the light diffusing device according to the first embodiment, and is a cross-sectional view at the D-D cross section in Figure 2 .

[0030] [ Figure 5 ] is an enlarged cross-sectional view of a main part of the light exit portion of the optical fiber in the light diffusing device according to the first embodiment.

[0031] [ Figure 6 ] is an enlarged cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the first embodiment and its vicinity.

[0032] [ Figure 7 ] is an enlarged perspective view of the light exit portion of the optical fiber in the light diffusing device according to the first embodiment and its vicinity.

[0033] [ Figure 8 ] is a main part cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the second embodiment and its vicinity.

[0034] [ Figure 9 ] is an enlarged cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the second embodiment and its vicinity.

[0035] [ Figure 10 ] is a plan view of the light exit portion of the optical fiber in the light diffusing device according to the second embodiment as viewed from the front end side.

[0036] [ Figure 11 ] is a main part cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the third embodiment and its vicinity.

[0037] [ Figure 12 ] is an enlarged cross-sectional view of the light exit portion of the optical fiber in the light diffusing device according to the third embodiment and its vicinity.

[0038] [ Figure 13 ] is an enlarged perspective view of the light exit portion of the optical fiber in the light diffusing device according to the third embodiment and its vicinity.

[0039] [ Figure 14 ] is a schematic diagram showing an example of use of a medical catheter kit including the light diffusion device according to the first embodiment.

[0040] [ Figure 15 ] is a cross-sectional view showing a modified example of the light emitting portion of the optical fiber in the light diffuser according to the embodiment. DETAILED DESCRIPTION

[0041] Hereinafter, light diffusers according to three embodiments as exemplary aspects of the present invention will be described in detail with reference to the drawings.

[0042] <First embodiment>

[0043] Figure 1 is a schematic diagram of a light diffuser 1 according to a first embodiment. Figure 2 1 is a cross-sectional view of the main part of the light emitting portion of the optical fiber and its vicinity in the light diffuser 1. Figure 3 is a cross-sectional view of the light transmission portion of the optical fiber in the light diffuser 1. Figure 4 is a cross-sectional view of the light emitting portion of the optical fiber in the light diffuser 1. Figure 5 It is an enlarged cross-sectional view of a main portion of the light emitting portion of the optical fiber in the light diffuser 1. The base end side of the optical fiber is indicated by arrow B, and the tip end side is indicated by arrow T.

[0044] In detail, Figure 2 yes Figure 3 and Figure 4 The cross-sectional view at section AA in the figure, Figure 3 yes Figure 2 The cross-sectional view at the CC section in Figure 4 yes Figure 2 The cross-sectional view at the DD section in FIG. In addition, Figure 6 is an enlarged cross-sectional view of the light emitting portion of the optical fiber and its vicinity in the light diffuser 1. Figure 7 This is its perspective view.

[0045] The light diffuser 1 is a device that emits light incident from the proximal end portion 20BE of the optical fiber 20 from the distal end side T. A light source 10 for generating light is connected to the proximal end portion 20BE on the proximal end side B of the optical fiber 20 .

[0046] The light source 10 is a component that generates visible light or laser light. When generating laser light, it includes a semiconductor laser. When the semiconductor laser is energized, laser oscillation occurs and the laser light is generated. For example, the light source 10 generates red laser light having a wavelength of 670 nm to 700 nm.

[0047] The optical fiber 20 is made of a resin (plastic) member. As shown in Figures 2 to 4 The optical fiber 20 is a single-core optical fiber including a core 21 located on a radially central side and a cladding 22 located on an outer peripheral side of the core 21. In the optical fiber 20, a relative refractive index difference between the core 21 and the cladding 22 is 2% or more and 11% or less.

[0048] As the optical fiber 20, specifically, for example, the core 21 is an acrylic resin (PMMA) and the refractive index is 1.40. In addition, the cladding 22 is a fluorine resin and the refractive index can be adjusted in a range of 1.35 to 1.40 depending on the composition.

[0049] In the optical fiber 20, for example, the outer diameter is 500 μm, the outer diameter of the core 21 is 480 μm, and the thickness of the cladding 22 is 10 μm. Here, in the optical fiber 20, the outer diameter of the cladding 22 is preferably 102 μm or more and 1100 μm or less. In addition, in the optical fiber 20, the outer diameter of the core 21 is preferably 100 μm or more and 1000 μm or less. The thickness of the cladding 22 is preferably 1 μm or more and 50 μm or less.

[0050] As the numerical aperture (NA) of the used optical fiber 20, it is preferably 0.5 or more, and more preferably 0.6 or more. By using the optical fiber 20 having a numerical aperture appropriately large, light is made to be incident into the optical fiber 20 at a wide angle in advance, so that the light is easily radiated from the entire surface of the peripheral surface, and thus the effect of thinning the cladding and the effect of making the side surface light emission easier complement each other, making the side surface light emission easier.

[0051] As shown in Figure 1 and Figure 2 The optical fiber 20 has a light transmission portion 20a that transmits laser light incident from a base end portion 20BE toward a front end side T, and a light exit portion 20b that makes the laser light transmitted in the light transmission portion 20a exit from the outer peripheral surface by removing a portion of the cladding 22 located on the outer peripheral side within a prescribed range of the extension direction of the front end side T.

[0052] The light exit portion 20b is formed in a range of, for example, 10 mm or more and 30 mm or less of the front end side T of the optical fiber 20. The outer peripheral surface of the light exit portion 20b becomes a cylindrical outer peripheral surface shape (cylindrical shape). The light exit portion 20b is formed by removing only the outer peripheral side of the cladding 22 by etching processing, for example, in a manner that the inner peripheral side in the thickness direction of the cladding 22 remains.

[0053] Reference will be made to Figure 3 and Figure 4 for explanation. In the case of the light exit portion 20b, if the cladding 22 is removed so that the radial size becomes the diameter Da (see Figure 4) than the size of the laser wavelength (i.e., the thickness of the cladding 22 to be removed is more than half the size of the laser wavelength), the light intensity distribution of the cross section of the optical fiber 20 varies with the change in the structure of the wavelength level in the length direction of the optical fiber 20, so that light leaks out and the laser light is emitted from the outer peripheral surface.

[0054] However, in the case of the light emission portion 20b, it is difficult to uniformly remove the cladding 22 over the extension direction and the circumferential direction of the outer peripheral surface, and there is a deviation in part. The above-described phenomenon of causing light to be emitted with the change in the structure in the length direction of the optical fiber 20 is based on the mismatch of the mode field.

[0055] Here, as shown in Figure 4 , the outer diameter Db of the cladding 22b in the light emission portion 20b is defined as the diameter of a circle passing through the top of the concave-convex surface 22f formed along the circumferential direction of the outer peripheral surface, i.e., the smallest circumscribed circle MCC. Also, the light emission portion 20b is formed in such a manner that the diameter Db of the smallest circumscribed circle MCC is smaller than the diameter Da of the cladding 22a in the light transmission portion 20a by the size of the laser wavelength λ transmitted in the light transmission portion 20a or more (Db

[0056] That is, for example, in the case where the diameter Da of the cladding 22a in the light transmission portion 20a is 500 μm and the wavelength λ of the laser light is 680 nm (0.68 μm), the light emission portion 20b is formed in such a manner that the diameter Db of the smallest circumscribed circle MCC of the cladding 22b in the light emission portion 20b is 499.32 μm or less (Db

[0057] In addition, the maximum thickness Tb of the cladding 22b in the light emission portion 20b is max formed to be smaller (Tb max < Ta). It is preferable that the maximum thickness Tb of the cladding 22b in the light emission portion 20b be max reduced by the size of the wavelength λ of the light transmitted in the light transmission portion 20a or more (Tb max < Ta - λ) than the thickness Ta of the cladding 22a in the light transmission portion 20a.

[0058] In addition, as shown in Figure 3 and Figure 4 , it is preferable that the average thickness Tb of the cladding 22b in the light emission portion 20b (see Figure 4The thickness Tb of the cladding 22b in the light exit portion 20b is formed to be smaller than the thickness Ta of the cladding 22a in the light transmission portion 20a by an amount of at least the size of the wavelength λ of the laser light transmitted in the light transmission portion 20a (Tb≤Ta-λ). That is, for example, in the case where the thickness Ta of the cladding 22a of the light transmission portion 20a is 10 μm and the wavelength λ of the laser light is 680 nm (0.68 μm), the average thickness Tb of the cladding 22b in the light exit portion 20b is formed to be 9.32 μm or less (Tb≤10-0.68). Thus, the light intensity distribution of the cross section of the optical fiber at the cladding portion varies more with the structure change of the wavelength level in the length direction of the optical fiber, so that the laser light will be more emitted from the outer peripheral surface of the light exit portion 20b.

[0059] Further, as shown in Figure 5 , with respect to the concave-convex surface 22f formed in the circumferential direction of the cladding 22b in the light exit portion 20b, it is preferable that the difference Hb in height between the portion where the outward peripheral side protrusion becomes largest and the portion where it becomes smallest be equal to or less than the size of the wavelength λ of the laser light transmitted in the light transmission portion 20a (Hb≤λ). By making the local fine structure change in the cladding portion smaller, more uniform emission characteristics can be achieved. At the same time, the area of the interface between the outer peripheral surface of the light exit portion 20b and the air can be reduced, so that the thermal resistance of the interface can be reduced, and the heat generation can be reduced.

[0060] The thickness t of the cladding 22b in the light exit portion 20b is preferably 1 μm or more (t≥1 μm) in an area of 30% or more of the total area of the light exit portion 20b. If the cladding 22b is made too thin or is completely absent, the light in the core 21 is instead trapped, so that it is desirable to have a certain degree of thickness in advance.

[0061] The proportion of the area where the thickness t of the cladding 22b in the light exit portion 20b is 1 μm or more (t≥1 μm) in the total area of the light exit portion 20b is found by observing a plurality of cross sections obtained by cutting the optical fiber with a SEM (scanning electron microscope) or the like, finding the proportion of the total length of the area having a cladding of t≥1 μm with respect to the total circumference, and averaging the values.

[0062] If reference is made to Figure 2 , the optical fiber 20 is cut at a plurality of places (for example, 3 places) in the area of 20b, and the cross sections are observed with a SEM. Also, the proportion of the area having a cladding of t≥1 μm with respect to the total circumference is found, and the average of the obtained values is found.

[0063] As shown in Figure 2 , Figure 6 , and Figure 7As shown, the light diffusing device 1 according to the present embodiment has an end surface 20e of the front end portion 20TE of the optical fiber 20 inclined with respect to a plane P perpendicular to the axis 21A of the core 21. The end surface 20e can be provided by cutting the optical fiber 20 obliquely at the middle of the optical fiber 20. The angle Θ of the plane P with respect to the end surface 20e can be equal to or greater than the minimum angle at which total reflection of the laser light transmitted in the optical fiber 20 occurs, or can be less than the minimum angle. By being less than the minimum angle, the laser light can leak out in a direction opposite to the direction of reflection. Specifically, when the refractive index of the core of the optical fiber is ncore, and the refractive index of air is nair, then Θ = arcsin(nair / ncore), and when ncore = 1.465 and nair = 1.0, Θ = 43 degrees.

[0064] In the light diffusing device 1 according to the present embodiment, if the light source 10 is operated to cause laser light to be incident from the base end portion 20BE of the optical fiber 20, the laser light is transmitted in the light transmission portion 20a and emitted from the light emission portion 20b. In the light emission portion 20b, the front end portion 20TE of the optical fiber 20 has the end surface 20e inclined with respect to the plane P perpendicular to the axis 21A of the core 21 as described above, and the laser light is reflected at the end surface 20e. The laser light reflected at the end surface 20e is emitted to the side as indicated by the arrow L2. Figure 2 Thus, the efficiency of emission of laser light to the side can be improved (Effect 1).

[0065] In addition, as described above, in the light diffusing device 1 according to the present embodiment, the outer diameter Db of the cladding 22b in the light emission portion 20b is reduced by an amount of the wavelength λ of the light transmitted in the light transmission portion 20a or more (Db ≤ Da - λ) compared to the outer diameter Da of the cladding 22a in the light transmission portion 20a, and thus the laser light is also emitted to the side as indicated by the arrow L1 in the region of the thin film of the cladding 22b (Effect 2). Figure 2

[0066] Further, in the present embodiment, since not only the cladding 22b is thinned but also the end surface 20e of the front end portion 20TE of the optical fiber 20 is inclined by being cut obliquely, the diameter of the optical fiber 20 is narrowed, and the light is less likely to be trapped in the optical fiber 20. Thus, the light becomes more likely to leak out to the side, and as a result, the efficiency of emission of laser light to the side can be improved (Effect 3).

[0067] That is, according to the present embodiment, not only the effects of emission to the side (Effect 1) due to the oblique cutting of the front end portion 20TE of the optical fiber 20 and the effects of emission to the side (Effect 2) due to the appropriate thinning of the cladding 22b in the light emission portion 20b are simply added, but also a new combined effect of emission to the side (Effect 3) due to the organic combination of the two is exerted as a significant effect.​

[0068] The above effects are specifically verified in the examples described below. As will be clear from the examples described below, the new composite side illumination effect (effect 3) has a greater impact than the side illumination effect (effect 2) based on thinning of the cladding. In addition, as for the side illumination based on thinning of the cladding, as can be seen from the observation Figure 2 As can be understood, the irradiation area extends along the axis 21A (longitudinal direction) of the optical fiber 20. To irradiate the narrow irradiation area with high irradiation efficiency, the length of the light emitting portion 20b formed by thinning the cladding 22 along the axis 21A (longitudinal direction) is preferably short. Specifically, the light emitting portion 20b is preferably formed within a range of, for example, 40 mm or less, and more preferably 10 mm or less, from the distal end T of the optical fiber 20.

[0069] Furthermore, in order to achieve a new composite side illumination effect (effect 3), the light emitting portion 20b formed by thinning the cladding 22 preferably extends to a region connected to the end face 20e on the front end side T of the optical fiber 20.

[0070] <Second embodiment>

[0071] Figure 8 FIG2 is a cross-sectional view of a main portion of a light emitting portion of an optical fiber and its vicinity in a light diffuser 2 according to a second embodiment. Figure 9 is an enlarged cross-sectional view of the light emitting portion of the optical fiber and its vicinity in the light diffuser 2. Figure 10 This is a top view of the optical fiber in the light diffuser 2 as viewed from the front end side (from Figure 8 and Figure 9 The light diffuser 2 according to this embodiment has substantially the same configuration as the light diffuser 1 according to the first embodiment. Therefore, for an overview of the light diffuser 2, see Figure 1 .

[0072] in addition, Figure 8 The EE cross section in Figure 4 Same, FF section and Figure 3 are the same, so these sections refer to Figure 3 or Figure 4 It should be noted that the light diffuser 2 according to the second embodiment has the same configuration as the light diffuser 1 according to the first embodiment except that the shape of the front end portion 20TE of the optical fiber 20 is unique to this embodiment. Therefore, components having the same functions as those of the light diffuser 1 according to the first embodiment are marked with the same reference numerals. Figures 1 to 7 The same symbols are used and their descriptions are omitted.

[0073] like Figures 8 to 10As shown, the light diffusing device 2 according to the present embodiment is characterized in that the front end portion 20TE of the optical fiber 20 has a pair of end faces 20el and 20e2 that are inclined with respect to a plane P that is perpendicular to the axis 21A of the core 21. At this time, the angle γ that the plane P makes with the end face 20el and the angle δ that the plane P makes with the end face 20e2 can each be equal to or smaller than the minimum angle at which total reflection of the laser light that is transmitted in the optical fiber 20 occurs.

[0074] As shown, the light diffusing device 2 according to the present embodiment is characterized in that the front end portion 20TE of the optical fiber 20 has a pair of end faces 20el and 20e2 that are inclined with respect to a plane P that is perpendicular to the axis 21A of the core 21. At this time, the angle γ that the plane P makes with the end face 20el and the angle δ that the plane P makes with the end face 20e2 can each be equal to or smaller than the minimum angle at which total reflection of the laser light that is transmitted in the optical fiber 20 occurs. 21 22 Accordingly, in the present embodiment, the irradiation efficiency of the laser light to the side in the one direction and the opposite direction thereof can be improved (Effect 1).

[0075] In addition, as described above, in the light diffusing device 2 according to the present embodiment, the outer diameter Db of the cladding 22b in the light exit portion 20b is configured to be reduced by an amount that is equal to or greater than the wavelength λ of the light that is transmitted in the light transmission portion 20a as compared to the outer diameter Da of the cladding 22a in the light transmission portion 20a (Db≤Da-λ), and thus, in the region of the thin film of the cladding 22b, the laser light is also irradiated to the side in the one direction and the opposite direction thereof as shown by the arrow LI (Effect 2). Figure 8

[0076] Further, in the present embodiment, since not only the cladding 22b is thinned but also the end faces 20el and 20e2 that are obtained by obliquely cutting the front end portion 20TE of the optical fiber 20, the diameter of the optical fiber 20 is narrowed, the light is less likely to be trapped, and the light is more likely to leak out to the side, and thus the irradiation efficiency of the laser light to the side can be improved (Effect 3).

[0077] That is, according to the present embodiment, the side irradiation effects (Effects 1 to 3) that are brought about by obliquely cutting the front end portion 20TE of the optical fiber 20, appropriately thinning the cladding 22b in the light exit portion 20b, and organically combining these can be exerted as significant effects, similarly to the first embodiment.

[0078] ​​Furthermore, according to this embodiment, since a pair (two) of the obliquely cut end faces of the front end portion 20TE of the optical fiber 20 are provided, the efficiency of lateral irradiation of the laser light in two directions, one on one side and the opposite direction, can be improved. For example, when the light diffuser 2 according to this embodiment is used for irradiation inside the body or projection from the body to the surface, when the irradiation direction is adjusted by rotating the optical fiber 20 about its axis 21A, it is sufficient to align the lateral irradiation direction closer to one of the two directions, the one on one side and the opposite direction. Therefore, the light diffuser 2 according to this embodiment is particularly suitable for the aforementioned applications. It should be noted that the number of obliquely cut end faces of the front end portion 20TE of the optical fiber 20 is not limited to two as in this embodiment, but may also be three or more.

[0079] Regarding other matters, the details of the configuration, specific examples, etc. are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0080] <Third embodiment>

[0081] Figure 11 FIG. 1 is a cross-sectional view of a main portion of a light emitting portion of an optical fiber and its vicinity in a light diffuser 3 according to a third embodiment. Figure 12 is an enlarged cross-sectional view of the light emitting portion of the optical fiber in the light diffuser 3 and its vicinity. Figure 13 3 is a perspective view of the light emitting portion of the optical fiber and its vicinity in the light diffuser 3. The light diffuser 3 according to this embodiment has substantially the same configuration as the light diffuser 1 according to the first embodiment. Therefore, for an overview of the light diffuser 3, see Figure 1 .

[0082] in addition, Figure 11 The GG section in Figure 4 Same, HH section and Figure 3 are the same, so these sections refer to Figure 3 or Figure 4 It should be noted that the light diffuser 3 according to the third embodiment has the same configuration as the light diffuser 1 according to the first embodiment except that the shape of the front end portion 20TE of the optical fiber 20 is unique to this embodiment. Therefore, components having the same functions as those of the light diffuser 1 according to the first embodiment are marked with the same reference numerals. Figures 1 to 7 The same symbols are used and their descriptions are omitted.

[0083] like Figures 11 to 13 As shown, in the light diffuser 3 according to this embodiment, the front end portion 20TE of the optical fiber 20 has a conical end face 20e3 that is continuous in the circumferential direction of the optical fiber 20. In this case, the angle σ formed by the plane P and the end face 20e3 can be either greater than or less than the minimum angle at which total internal reflection of the laser light propagating through the optical fiber 20 occurs.

[0084] In the light diffuser 2 according to this embodiment, when the light source 10 is operated and laser light is incident on the base end 20BE of the optical fiber 20, the laser light is transmitted through the light transmission portion 20a and emitted from the light output portion 20b. In the light output portion 20b, as described above, the distal end 20TE of the optical fiber 20 has a conical end face 20e3 that is continuous in the circumferential direction of the optical fiber 20. Reflection occurs at this end face 20e3. The reflected laser light propagates radially in the direction of arrow L3, which intersects the axis 21A. Therefore, in this embodiment, the irradiation efficiency of the laser light that propagates radially to the side can be improved (Effect 1).

[0085] Furthermore, as described above, in the light diffuser 3 according to the present embodiment, the outer diameter Db of the cladding 22b in the light emitting portion 20b is formed to be smaller than the outer diameter Da of the cladding 22a in the light transmitting portion 20a by at least the wavelength λ of the light transmitted in the light transmitting portion 20a (Db≤Da-λ). As a result, the laser light is also transmitted in the region of the cladding 22b of the thin film. Figure 11 As shown by the arrow L1, it radiates radially to the side (effect 2).

[0086] Furthermore, in the present embodiment, since not only the cladding 22b is thinned but also the end face 20e3 is obtained by obliquely cutting the front end portion 20TE of the optical fiber 20, the diameter of the optical fiber 20 is narrowed, and light is not easily trapped but easily leaks out radially to the side, thereby improving the irradiation efficiency of the laser light traveling radially to the side (effect 3).

[0087] That is, according to this embodiment, similarly to the first embodiment, the following effects can be exerted as significant effects, namely, a lateral illumination effect (effect 1) brought about by obliquely cutting the front end portion 20TE of the optical fiber 20; a lateral illumination effect (effect 2) brought about by appropriately thinning the cladding 22b in the light emitting portion 20b; and a new composite lateral illumination effect (effect 3) brought about by organically combining these structures.

[0088] Furthermore, according to this embodiment, the provision of a conical end face 20e3 that is continuous along the circumference of the optical fiber 20 improves the efficiency of laser irradiation throughout the entire circumference. For example, similar to the second embodiment, when the light diffuser 3 of this embodiment is used for internal irradiation or projection from within the body to the surface, the irradiation is radially distributed around the entire circumference of the optical fiber 20, eliminating the need for alignment of the irradiation position in the rotational direction around the axis 21A. Therefore, the light diffuser 3 of this embodiment is particularly suitable for such applications.

[0089] As for other modifications, the materials of the components, and the like, are the same as in the first embodiment, and thus the description is omitted.

[0090] <Usage of the light diffusing device>

[0091] The light diffusing device according to the above-described embodiment can be used as a diffusing device that directly inserts into the body or inserts into the body together with an appropriate other accessory to irradiate laser light to a lesion or the like.

[0092] In addition, the light diffusing device according to the above-described embodiment can be used as so-called illumination that is inserted into the body together with an endoscope, a catheter, or the like to irradiate the inside of the body and project from the inside of the body to the surface of the body. Among the above, the use case in which the light diffusing device is used together with a catheter or the like is described below.

[0093] Figure 14 A schematic diagram of a use example of a medical catheter kit 30 in which the light diffusing device 1 according to the first embodiment is used together with a catheter is illustrated. The medical catheter kit 30 is provided with a catheter 26 and the light diffusing device 1, and as illustrated in Figure 14 , in use, the light diffusing device 1 is used in a state in which the optical fiber 20 is inserted into the catheter 26.

[0094] For example, the medical catheter kit 30 can be inserted into the body together with an endoscope from the front end side T, the light can be irradiated from the light exit portion 20b while the inside of the body is observed with the endoscope, and the front end of the catheter 26 can be guided to a target position. Alternatively, the medical catheter kit 30 can be inserted into the body without an endoscope, the light can be irradiated from the light exit portion 20b into the body and projected to the surface of the body to confirm the position of the front end of the catheter 26 from the outside of the body, and the position of the front end can be guided to a target position.

[0095] The operator can extract the optical fiber 20 of the light diffusing device 1 from the catheter 26 after guiding the front end of the catheter 26 to the target position, and the catheter 26 can be used for a target medical purpose to perform a medical action.

[0096] Note that, Figure 14 In the use example illustrated in

[0097] The above-described embodiments are merely examples of representative modes of the present application, and the present application is not limited to these embodiments. That is, those skilled in the art can implement various modifications within the scope of the gist of the present application in accordance with previously known insights. Even if the aforementioned modifications are made, as long as the optical diffusion device or the medical catheter set including the same still has the configuration, it is of course included in the scope of the present application.

[0098] For example, in the above-described embodiments, the case where the portion of the cladding 22 of the light exit portion 20b on the outer peripheral side is removed over the entire circumference is shown, but the present application is not limited thereto. As long as the optical fiber is such that laser light is emitted from the outer peripheral surface of the light exit portion 20b, it can be configured such that Figure 15 As shown in FIG. 8, only a portion of the portion of the cladding 22 of the light exit portion 20b on the outer peripheral side is removed over the circumference, and laser light is emitted only from the portion over the circumference. That is, the light exit portion can be formed on at least a portion of the circumference of the front end side of the optical fiber.

[0099] The light exit portion can be formed on a portion of 30% or more of the circumference of the front end side of the optical fiber, for example, in a range of 120 degrees to 180 degrees of the circumference of the front end side of the optical fiber. Alternatively, the light exit portion can be formed discretely on the circumference of the front end side of the optical fiber, as long as the total area is 30% or more of the total area of the outer peripheral surface of the front end portion of the optical fiber.

[0100] The area of the light exit portion in the outer peripheral surface of the front end portion of the optical fiber can be obtained by observing a plurality of cross sections obtained by cutting the optical fiber with a SEM (scanning electron microscope) or the like, obtaining the proportion of the total length of the region where the cladding is removed with respect to the total circumference, and averaging the same.

[0101] If the cross sections of the optical fiber 20 are observed with a SEM, as shown in FIG. 9, the area of the light exit portion in the outer peripheral surface of the front end portion of the optical fiber 20 can be obtained. Figure 2 Figure 15 If the cross sections of the optical fiber 20 are observed with a SEM, as shown in FIG. 9, the area of the light exit portion in the outer peripheral surface of the front end portion of the optical fiber 20 can be obtained. Figure 15 The area of the light exit portion in the outer peripheral surface of the front end portion of the optical fiber 20 is 50% in the cross section of FIG. 9. The values of the obtained plurality of cross sections are averaged, and thereby the area of the light exit portion in the outer peripheral surface of the front end portion of the optical fiber can be obtained.

[0102] ​In addition, in the above-described embodiments, an example in which the outer surface of the optical fiber 20 in the light exit portion 20b is formed with unevenness has been given, but even if the outer surface is completely free of or almost free of unevenness, the effects brought about by the present application can be expected. However, from the viewpoint of improving the radiation efficiency to the side and isotropy, it is preferable that the outer surface of the optical fiber 20 in the light exit portion 20b be formed with unevenness. Here, the "unevenness" indicates the difference between the peak of the greatest unevenness and the bottom of the deepest unevenness (see the maximum height of the profile curve: JIS B0601 reference) Rz.

[0103] Embodiment

[0104] The following embodiments and comparative examples will more specifically describe the present application.

[0105] As Embodiment 1, a light diffusing device 1 including an optical fiber 20 having the same configuration as that of the first embodiment shown in FIG. 1 was prepared. Figures 1 to 7 Figure 15 The medical catheter set 30 and the light source 10 shown in FIG. 2 were prepared. The specific specifications and conditions of Embodiment 1 are as described above. Note that the specifications and conditions not described below are as described in the description of the first embodiment above.

[0106] (Specifications and Conditions of Embodiment 1)

[0107] • Length of the optical fiber 20 in the axial direction 21A of the light exit portion 20b: 5 mm

[0108] • Area ratio of the light exit portion 20b in which the thickness t of the cladding layer 22b is 1 μm or more: 30%

[0109] • Removal method of the cladding layer 22: etching for 5 seconds

[0110] • Angle θ formed: 60°

[0111] • Length of the catheter 26 in the axial direction 21A: 2000 mm

[0112] • Material, inner diameter, and outer diameter of the catheter 26: nylon (transparent), 1 mm, 1.1 mm

[0113] • Total length of the optical fiber 20: 2000 mm

[0114] • Wavelength of the light of the light source 10: 630 nm

[0115] • Intensity of the light of the light source 10: 1.0 to 500 mW

[0116] ​Further, a device having the same specifications and conditions as those of Example 1 except that the front end portion 20TE of the optical fiber 20 is not obliquely cut and that the end surface oblique to the plane P perpendicular to the axis 21A of the core 21 is not provided, is prepared as a light diffusing device of Comparative Example 1.

[0117] Further, a device having the same specifications and conditions as those of Example 1 except that the etching is not performed and that the cladding 22 is not removed and the light exit portion 20b is not provided, is prepared as a light diffusing device of Comparative Example 2 (provided with an end surface oblique to the plane P perpendicular to the axis 21A of the core 21).

[0118] With respect to the light diffusing devices of Example 1 and Comparative Examples 1 and 2, the light source 10 is operated under the above-described specifications and conditions to cause light to be incident from the base end portion 20BE of the optical fiber 20 and to be emitted (irradiated) from the light exit portion 20b (in Comparative Example 2, a position corresponding to 20b. The same applies hereinafter). At this time, a light meter (manufactured by Thorlabs, S151C) having a light receiving diameter of 3 mm is disposed at a position 1 mm away from the side surface of the light exit portion 20b in a specific direction perpendicular to the axis 21A (side component measurement) and at a position 1 mm away from the front end portion 20TE of the optical fiber 20 in a direction perpendicular to the axis 21A (direct component measurement), and the light quantity is measured. In the case of the side component measurement, the measurement is performed at two places, and the average value thereof is taken as the measurement value. The results are shown in Table 1 below.

[0119] [Table 1]

[0120] Units Example 1 Comparative Example 1 Comparative Example 2 Laser power mW 1.83 1.79 1.89 Direct component mW 0.331 1.278 0.417 Side component 1 μW 155.6 106.6 154.1 Side component 2 μW 320 106.6 181 Side component average μW 237.8 106.6 167.55 Direct component / laser power ％ 18.1 71.4 22.1 Side component / laser power ％ 13.0 6.0 8.9 Side component / direct component ％ 71.8 8.3 40.2

[0121] As is apparent from Table 1 above, in Comparative Example 1 in which the oblique end surface is not provided, the light of the side component is not detected to a large extent, and in Comparative Example 2 in which the cladding 22 is not thinned, although the light of the side component is detected to some extent, the amount thereof is considerably smaller than that of Example 1.

[0122] On the other hand, it is found that in Example 1, the light of the side component is detected in a high proportion with respect to the direct component. Example 1 has the configurations of Comparative Examples 1 and 2, but the effect thereof is not simply the sum of the effects of Comparative Examples 1 and 2, and a particularly high side irradiation efficiency is achieved.

[0123] Explanation of Reference Numerals

[0124] 1, 2, 3 light diffusing device;

[0125] 10 light source;

[0126] 20 optical fiber;

[0127] 20a light transmitting portion;

[0128] 20b light exiting portion;

[0129] 20e, 20e1, 20e2, 20e3 end face;

[0130] 20BE base end portion;

[0131] 20TE front end portion;

[0132] 21 core;

[0133] 22, 22a, 22b cladding layer;

[0134] 22f concavo-convex surface;

[0135] 26 catheter;

[0136] 30 medical catheter kit

Claims

1. A light diffuser comprising an optical fiber and configured to emit light incident from a base end portion of the optical fiber from a distal end portion of the optical fiber, wherein the optical fiber comprises a core located at a radially central side and a cladding located on an outer peripheral side of the core, wherein: The light diffuser includes a light transmission portion that transmits light incident from the base end portion toward the tip end portion, and a light emitting portion formed by removing a portion of the cladding located on the outer peripheral side at the tip end portion. The outer diameter Db of the cladding in the light emitting portion is smaller than the outer diameter Da of the cladding in the light transmitting portion by at least the wavelength λ of the light transmitted in the light transmitting portion (Db≤Da-λ), and The optical fiber has an end face at a distal end side thereof that is inclined with respect to a plane perpendicular to the axis of the core.

2. The light diffuser according to claim 1, wherein The thickness of the cladding layer in the light emitting portion is 1 μm or more in a region that accounts for 30% or more of the total area of ​​the light emitting portion.

3. The light diffuser according to claim 1, wherein: The light emitting portion extends from the front end side of the optical fiber to a region connected to the end face.

4. The light diffuser according to claim 1, wherein: The optical fiber has two or more end faces at its distal end portion that are inclined relative to a plane perpendicular to the axis of the core.

5. The light diffuser according to claim 1, wherein The end face is continuous in the circumferential direction of the optical fiber, and has a conical shape. The light diffuser according to claim 1 , wherein: An angle formed between a plane perpendicular to the axis of the core and the end face is smaller than a minimum angle at which light transmitted in the light transmitting portion is totally reflected.

7. The light diffuser according to claim 1, wherein: The optical fiber is a resin optical fiber.

8. The light diffuser according to claim 1, wherein The numerical aperture (NA) of the optical fiber is greater than or equal to 0.

5.

9. The light diffuser according to claim 1, wherein: Concavities and convexities are formed on the outer surface of the optical fiber in the light emitting portion. 10 . A medical catheter kit comprising a catheter and the light diffuser according to claim 1 .

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