Light diffusion device

Abstract

The invention provides a light diffusion device which can be easily manufactured and can irradiate light with a flat light intensity distribution. This light diffusion device (1) is provided with: an optical transmission cable (10) that transmits laser light (L) emitted by a laser oscillator and emits the transmitted laser light (L) from an emission surface (12) of a tip section (11); and a coating layer (20) that covers the optical transmission cable (10), said coating layer (20) having at least either a function of absorbing the laser light (L) or a function of scattering light. Furthermore, the front end part (21) of the coating layer (20) protrudes in the light emitting direction by a length required for cutting the peripheral edge part of the light.

Description

Technical Field

[0001] The present invention relates to a light diffusion device. Background Art

[0002] Conventionally, in the medical field, a light diffusion device has been used to insert into the human body and irradiate light on cells. For example, Patent Document 1 describes a device including a fiber core, a cladding surrounding the fiber core, an open cavity, and a lid.

[0003] [Prior Art Documents]

[0004] (Patent Document)

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-72969 Summary of the Invention

[0006] [Problems to be Solved by the Invention]

[0007] Incidentally, a light diffusion device is used, for example, in photoimmunotherapy and photodynamic therapy, which are among the treatment methods for cancer, to insert the front end side of an optical transmission cable into the human body and irradiate a drug administered to the human body and reaching cancer cells with laser light. At this time, from the viewpoint of treatment efficiency, it is desirable to make the light intensity distribution of the laser light emitted from the optical transmission cable more uniform in a region within a specified radius from the center of the laser. In the device of Patent Document 1, although light with a flat-topped light intensity distribution can be irradiated, it is necessary to provide a sealed open cavity or the like between the lid and the cladding, and there is room for improvement in terms of workability.

[0008] An object of the present invention is to provide a light diffusion device that can be easily manufactured and can irradiate light with a flat-topped light intensity distribution.

[0009] [Means for Solving the Problems]

[0010] (1) The light diffusion device includes: an optical transmission cable that transmits light emitted from a light source and emits the transmitted light from an emission surface at the front end; and a coating layer that coats the optical transmission cable and has at least one of a function of absorbing light and a function of scattering light; and the front end portion of the coating layer protrudes in the light emission direction by a length required to cut the peripheral portion of the light.

[0011] (2) According to the light diffusion device described in Technical Solution 1, in the light diffusion device according to (1), the optical transmission cable has a core and a cladding formed on the outer periphery of the core, and the required length is equal to the length calculated by the following formula (1);

[0012] d3 = (1 / NA 2 - 1) 1 / 2×d2 ··· Formula (1)

[0013] Among them, d3 is the aforementioned required length, NA is the aperture factor of the aforementioned optical transmission cable, and d2 is the thickness of the aforementioned cladding.

[0014] (3) The light diffusion device according to (1) or (2), wherein the aforementioned optical transmission cable has a core and a cladding formed on the outer periphery of the core, the thickness of the aforementioned cladding is 1 / 10 or less of the outer diameter of the aforementioned core, and the thickness of the aforementioned coating layer is thicker than the aforementioned cladding.

[0015] (4) The light diffusion device according to any one of (1) to (3), wherein the aforementioned exit surface of the optical transmission cable is inclined with respect to the axial direction of the optical transmission cable.

[0016] (5) The light diffusion device according to any one of (1) to (4), wherein the refractive index of the aforementioned coating layer is equal to or higher than the refractive index of the coating material of the optical transmission cable.

[0017] (6) The light diffusion device according to any one of (1) to (5), wherein the refractive index of the aforementioned coating layer is 1.53 or higher.

[0018] (7) The light diffusion device according to any one of (1) to (6), further comprising: a reflection member having a refraction surface that refracts the light emitted from the aforementioned exit surface; and a resin-made tubular member into which the aforementioned optical transmission cable and the aforementioned reflection member are inserted; and the aforementioned refraction surface is disposed at a position at a predetermined distance from the aforementioned exit surface within the aforementioned tubular member and is inclined with respect to the axial direction of the optical transmission cable, and the light emitted from the aforementioned exit surface is emitted at an angle inclined by a predetermined angle or more with respect to the axial direction of the optical transmission cable.

[0019] (8) The light diffusion device according to any one of (1) to (7), wherein the aforementioned reflection member is a rod-shaped member made of quartz or silicon disposed at a space from the aforementioned optical transmission cable within the aforementioned tubular member, and the aforementioned refraction surface is formed at an end portion on the aforementioned optical transmission cable side of the rod-shaped member.

[0020] (9) The light diffusion device according to any one of (1) to (8), wherein a metal is vapor-deposited on the aforementioned refraction surface.

[0021] (10) The light diffusion device according to any one of (1) to (9), wherein the aforementioned optical transmission cable is a plastic fiber having a core with an outer diameter of 500 µm or more and a resin-made cladding formed on the outer periphery of the core, and the outer diameter of the aforementioned refraction surface observed from the axial direction of the optical transmission cable is larger than the outer diameter of the core.

[0022] (11) The light diffusion device according to any one of (1) to (10), wherein the unevenness on the light-incident surface of the refraction surface is equal to or less than the wavelength of the light generated from the light source.

[0023] (12) The light diffusion device according to any one of (1) to (11), wherein the refraction surface is formed into a curved surface that is recessed with respect to the light-emitting surface.

[0024] (Effect of the Invention)

[0025] According to the present invention, a light diffusion device can be provided, which can be easily manufactured and can irradiate light with a flat-top light intensity distribution. Description of the Drawings

[0026] Figure 1 is a side view schematically showing the appearance of the light diffusion device of the first embodiment.

[0027] Figure 2 is a longitudinal sectional view schematically showing the light diffusion device of the first embodiment.

[0028] Figure 3 is Figure 1 the cross-sectional view taken along line III-III of

[0029] Figure 4 is a longitudinal sectional view schematically showing the light diffusion device of the second embodiment.

[0030] Figure 5 is a side view schematically showing the appearance of the light diffusion device of the third embodiment.

[0031] Figure 6 is a longitudinal sectional view schematically showing the light diffusion device of the third embodiment.

[0032] Figure 7 is a view schematically showing the light diffusion device of the fourth embodiment, which is a side view of a light diffusion device that mainly irradiates laser light laterally.

[0033] Figure 8 is a view schematically showing the light diffusion device of the fourth embodiment, which is a side view of a light diffusion device that mainly irradiates laser light rearward.

[0034] Figure 9 is a side view schematically showing the light diffusion device of the fifth embodiment.

[0035] Figure 10 is a side view schematically showing the light diffusion device of the sixth embodiment.

[0036] Figure 11 is a side view schematically showing the light diffusion device of the seventh embodiment.

[0037] Figure 12 It is a side view schematically showing the light diffusing device of the eighth embodiment.

[0038] Figure 13 It is a graph showing the light intensity distribution of Example 1.

[0039] Figure 14 It is a graph showing the light intensity distribution of Example 2.

[0040] Figure 15 It is a graph showing the light intensity distribution of the comparative example. Detailed implementation manners

[0041] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the present invention is not limited to the following embodiments. In the following description, the respective drawings referred to schematically show the shape, size, and positional relationship only to the extent that the content of the present disclosure can be understood. That is, the present invention is not limited only to the shape, size, and positional relationship illustrated in each drawing.

[0042] <First embodiment>

[0043] Refer to Figures 1 to 3 , and the light diffusing device 1 of the first embodiment of the present invention will be described. Figure 1 It is a side view of the light diffusing device 1. Figure 2 It is a longitudinal sectional view of the light diffusing device 1. Figure 3 It is Figure 1 The cross-sectional view taken along the line III-III shown. In addition, in Figure 1 , the optical transmission cable 10 covered by the coating layer 20 and the core 13 inside the optical transmission cable 10 are shown by dashed lines.

[0044] The light diffusing device 1 of the present embodiment is mounted on a medical device for performing photoimmunotherapy, which is one of the methods for treating cancer. Photoimmunotherapy treats cancer by administering the following agent to the human body, that is, an agent composed of an antibody that binds to cancer cells and an object that reacts with light, and irradiating the agent bound to cancer cells with a laser beam L to destroy the cancer cells. The light diffusing device 1 is used, for example, in a state where the front end portion is exposed to the outside while being inserted into a pipeline provided in an endoscope. In addition, the present invention can also be used for photodynamic therapy and is not limited to photoimmunotherapy.

[0045] The light diffusing device 1, as shown in Figure 1 and Figure 2 , includes a laser oscillator (not shown) as a light source, an optical transmission cable 10, and a coating layer 20. The coating layer can be a resin or a metal that scatters a part of light due to slight irregularities of the wavelength order on the surface.

[0046] The laser oscillator has a semiconductor laser. By energizing the semiconductor laser, laser oscillation is induced to generate laser L. The laser oscillator generates red laser L having a wavelength of 600 nm or more and 700 nm or less.

[0047] The optical transmission cable 10 is an optical fiber cable having an optical transmission path that transmits the laser L emitted from the laser oscillator. The laser oscillator is disposed on the base end side of the optical transmission cable 10, and a coating layer 20 is provided on the front end portion 11 side. The optical transmission cable 10 transmits the laser L generated in the laser oscillator through the optical transmission path and emits it from the emission surface 12 at the front end portion 11. The emission surface 12 in the present embodiment is a surface perpendicular to the axial direction X of the optical transmission cable 10. In addition, the axial direction X of the optical transmission cable 10 in this specification refers to the axial direction of the optical transmission cable 10 at the front end portion 11.

[0048] The optical transmission cable 10 in the present embodiment is a plastic fiber and has a core 13 and a resin cladding 14 formed on the outer periphery of the core 13. Examples of the resin forming the cladding 14 include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and the like. In the present embodiment, the emission surface 12 of the optical transmission cable 10 is the surface of the core 13 at the front end portion 11. In addition, the laser L is emitted in such a manner that the optical axis is parallel to the axial direction X of the optical transmission cable 10.

[0049] The outer diameter d1 of the core 13 of the optical transmission cable 10 is preferably 250 µm or more. In the present embodiment, the outer diameter d1 of the core 13 is 500 µm. In addition, the optical transmission cable 10 in the present embodiment is a single-core optical fiber, but may also be a multi-core optical fiber. Furthermore, regarding the shape of the core 13, when observed from the axial direction X of the optical transmission cable 10, in addition to a perfect circle, it may also be an ellipse or a rectangle. In addition, the optical transmission cable 10 may be a silica optical fiber in which the core 13 and the cladding 14 are made of silica, or a polymer cladding optical fiber in which the core 13 is made of silica and the cladding 14 is made of resin. Examples of the silica-based material forming the core include silica without impurities doped in the core, silica doped with germanium, and the like. Examples of the resin forming the cladding include fluorine-based resins such as PTFE, PVDF, ethylene tetrafluoroethylene (ETFE), polyimide, silicone, or copolymers thereof.

[0050] The thickness d2 of the cladding 14 is preferably 1 / 10 or less of the outer diameter d1 of the core 13 from the viewpoint of efficiently emitting the laser L while reducing the diameter of the optical transmission cable 10. In the present embodiment, the thickness d2 of the cladding 14 is 25 µm. In addition, the laser L is transmitted within the core 13, but sometimes, a part of the laser L reflected by the cladding 14 leaks into the cladding 14 and propagates as cladding mode light. Further, the optical transmission cable 10 has a coating material (not shown) that coats the cladding 14 to protect the optical transmission cable 10 itself.

[0051] The coating layer 20 is a layer having at least one of the functions of absorbing the laser L and scattering the laser L. For example, the coating layer 20 is a layer having a refractive index higher than that of the cladding 14, and absorbs or scatters the cladding mode light leaking from the cladding 14 and the laser L emitted from the emission surface 12.

[0052] The coating layer 20 coats at least the front end portion 11 side of the optical transmission cable 10. The coating layer 20 of the present embodiment is formed of a cylindrical resin hose. The coating layer 20 coats the cladding 14 in a state where the inner peripheral surface 22 is in contact with the coating material that coats the outer peripheral surface 141 of the cladding 14. The coating layer 20 extends beyond the front end portion 11 of the optical transmission cable 10 in the direction in which the laser L is emitted. That is, the position of the front end portion 21 of the coating layer 20 on the axial X of the optical transmission cable 10 protrudes more in the direction in which the laser L is emitted than the front end portion 11. In the present embodiment, the coating layer 20 extends beyond the front end portion 11 of the optical transmission cable 10 in the direction in which the laser L is emitted. That is, the front end portion 21 of the coating layer 20 is located at a position exceeding the front end portion 11 of the optical transmission cable 10 in the direction of light emission.

[0053] Here, from the viewpoint of the treatment efficiency, the light intensity distribution of the laser L emitted from the emission surface 12 is preferably a flat top intensity distribution rather than an intensity distribution close to a Gaussian distribution, that is, the variation in the light intensity within a specified radius range from the center of the laser L is small, and when exceeding the specified radius range, the light intensity decreases rapidly. In the light diffusing device 1 of the present embodiment, the coating layer 20 covering the outer periphery of the optical transmission cable 10 absorbs or scatters the laser L and the cladding mode light emitted from the front end portion 11 in a direction inclined with respect to the axial X of the optical transmission cable 10, thereby realizing a flat top light intensity distribution.

[0054] The front end portion 21 of the coating layer 20 protrudes by a length Y required for cutting the peripheral portion of the laser L in the direction in which the laser L is emitted. The required length Y is in Figure 2The distance d3 between the front end 21 of the coating layer 20 on the axial X of the optical transmission cable 10 and the front end 11 of the optical transmission cable 10 is shown. The required length Y can also be, for example, equal to the length calculated by the following formula (1), and the following formula (1) uses the aperture factor Na of the optical transmission cable 10 and the thickness d2 of the cladding 14.

[0055] Y = (1 / NA 2 - 1) 1 / 2 × d2 ··· Formula (1)

[0056] The above formula (1) is obtained from the following formula (2). That is,

[0057] NA = sinθ = d2 / (d2 2 + Y 2 ) ··· Formula (2)

[0058] As Figure 2 shown, θ is the divergence angle of the laser L emitted from the exit surface 12. That is, by making the coating layer 20 protrude in the direction of the laser L emission, the length Y obtained by the above formula (1) can cut off the light with an angular spread wider than the divergence angle of the laser L with respect to the optical axis of the laser L. Thus, while maintaining the intensity of the laser, the light intensity distribution within a specified radius from the center of the laser L becomes more uniform, and thus a flat-top light can be irradiated. In addition, the above formula (1) can be applied to both single-core optical fibers and multi-core optical fibers.

[0059] [Table 1]

[0060] Types of optical fibers Core Cladding Aperture factor Refractive index of the cladding Projection amount of the coating layer Plastic fiber Methacrylic resin Fluorine-based resin 0.485～0.50 1.35 18 µm< Polymer-clad fiber Quartz Polymer 0.37～0.43 1.35 25 µm< Polymer-clad fiber Quartz Silicone 0.37～0.43 1.43 25 µm< Quartz optical fiber Quartz Quartz MM0.2 to 0.275 1.375～1.72 49 µm<

[0061] Table 1 shows the relationship between the type of optical fiber, that is, the type of the optical transmission cable 10, the aperture factor NA, the types of raw materials forming the core 13 and the cladding 14, etc., and the length Y obtained by the above formula (1), that is, the protrusion amount of the coating layer 20. In addition, in Table 1, the protrusion amount of the coating layer 20 when the thickness d2 of the cladding 14 is 10 µm is shown. As shown in Table 1, for example, in a plastic fiber where the core 13 is formed of a methacrylic resin and the cladding 14 is formed of a fluorine-based resin, the protrusion amount of the coating layer 20 obtained by the above formula (1) is 18 µm. By using the above formula (1), the protrusion amount of the coating layer 20 suitable for forming a flat-top can be obtained according to the type of optical fiber. Based on the obtained protrusion amount, the light on the peripheral side of the laser can be further cut off according to the use of the optical fiber. In this case, although the intensity of the emitted light as a whole decreases, a more flat-top light can be irradiated.

[0062] In addition, the thickness d4 of the coating layer 20 is preferably thicker than the thickness d2 of the cladding layer 14. From the perspective of suppressing the radial thickness of the light diffusion device 1 while making the light intensity distribution more concentrated on the center side, the thickness d4 of the coating layer 20 is preferably 1 / 10 of the outer diameter d1 of the core 13 and about twice the thickness d2 of the cladding layer 14. In the present embodiment, the thickness d4 of the coating layer 20 is 50 µm.

[0063] As the resin hose forming the coating layer 20, for example, it can be a nylon hose, a polytetrafluoroethylene (PTFE) hose, or a hose with an inner layer formed of PTFE and an outer layer formed of polyimide (hereinafter referred to as a PTFE / polyimide hose). Optionally, for the PTFE / polyimide hose, for example, the thickness of the inner layer, that is, the PTFE layer, is 25 µm, and the thickness of the outer layer, that is, the polyimide layer, is 25 µm. The so-called nylon hose includes both hoses composed only of nylon and hoses mainly composed of nylon. The so-called PTFE hose includes both hoses composed only of PTFE and hoses mainly composed of PTFE. In the present embodiment, the coating layer 20 is formed of a nylon hose.

[0064] As the resin for forming the coating layer 20, in addition to the above, for example, fluorine-based resins other than PTFE such as ETFE, silicone resin, polymethyl methacrylate resin, acrylic resin, epoxy resin, polycarbonate, etc. can be cited. In addition, as the refractive index of the resin for forming the coating layer 20, the refractive index of ETFE is 1.35, the refractive index of silicone resin is 1.43, the refractive index of polymethyl methacrylate resin is 1.49, the refractive index of acrylic resin is 1.50, the refractive index of nylon resin is 1.53, the refractive index of epoxy resin is 1.57, and the refractive index of polycarbonate is 1.59. The refractive index of the coating layer 20 is preferably equal to or greater than the refractive index of the coating material of the optical transmission cable 10. In addition, the refractive index of the coating layer 20 is preferably 1.53 or more. In addition, the above refractive index is a value obtained by a method based on Japanese Industrial Standards (JIS) K7142:2014.

[0065] <Second Embodiment>

[0066] Next, with reference to Figure 4 , the light diffusion device 1A of the second embodiment will be described. Figure 4 FIG. is a cross-sectional view schematically showing the light diffusion device 1A of the second embodiment. In addition, in the following description of the second embodiment, for the structures corresponding to the above first embodiment, the same reference signs are given with the same regularity. Sometimes the description thereof will be omitted or cited.

[0067] The light diffusion device 1A of the present embodiment includes a laser oscillator (not shown), an optical transmission cable 10A, and a coating layer 20A. The main difference between the light diffusion device 1A of the present embodiment and the light diffusion device 1 of the first embodiment lies in the structure on the front end side of the optical transmission cable and the coating layer.

[0068] The front end portion 11A of the optical transmission cable 10A is formed by cutting obliquely with respect to the axial direction X of the optical transmission cable 10A. That is, the emission surface 12A of the front end portion 11A is inclined with respect to the axial direction X of the optical transmission cable 10. Thus, as Figure 4 shown, the laser L emitted from the emission surface 12A is emitted in a direction inclined by a specified angle or more with respect to the axial direction X of the optical transmission cable 10A (in Figure 4 , it is the upper right oblique direction of the paper surface).

[0069] The coating layer 20A is formed of a cylindrical resin hose. The front end portion 21A of the coating layer 20A is formed by cutting the cylindrical hose obliquely with respect to the axial direction X of the optical transmission cable 10A. That is, the front end portion 21A is inclined with respect to the axial direction X of the optical transmission cable 10A. Specifically, the front end portion 21A of the coating layer 20A is formed such that the portion (hereinafter referred to as the emission side portion) 211A located on the emission direction side of the laser L is located on the most proximal end side of the optical transmission cable 10A, and as it moves away from the emission side portion 211A, it extends in the axial direction X of the optical transmission cable 10A in a direction away from the optical transmission cable 10A. In other words, the interval d5 between the front end portion 21A of the coating layer 20A and the front end portion 11A on the axial direction X of the optical transmission cable 10A increases as it moves away from the emission side portion 211A. That is, the front end portion 21A and the front end portion 11A of the optical transmission cable 10A are inclined in opposite directions. In addition, the coating layer 20 is formed at a position where the center of the laser L emitted from at least the emission surface 12A does not coincide.

[0070] The emission side portion 211A of the front end portion 21A of the coating layer 20A protrudes by a length Y required for cutting the peripheral portion of the laser L in the emission direction of the laser L. The required length Y represents the interval d5 between the emission side portion 211A of the front end portion 21 of the coating layer 20 and the emission side portion 211 of the front end portion 11 of the optical transmission cable 10 on the axial direction X of the optical transmission cable 10 in Figure 4 . The required length Y may also be equal to the length calculated by the above formula (1).

[0071] <Third Embodiment>

[0072] Next, with reference to Figure 5 and Figure 6 , the light diffusion device 1B of the third embodiment will be described. Figure 5 is a side view schematically showing the appearance of the light diffusion device 1B of the third embodiment.Figure 6 FIG. 1 is a cross-sectional view schematically showing the light diffusing device 1B according to the third embodiment. In addition, in the following description of the third embodiment, with respect to the structure corresponding to the first embodiment described above, the same reference numerals are given to the corresponding parts having the same regularity. Sometimes the description thereof may be omitted or cited.

[0073] The light diffusing device 1B of the present embodiment includes a laser oscillator (not shown), an optical transmission cable 10, a coating layer 20, a refracting member 30 as a reflecting member, and a holding member 40. The main difference between the light diffusing device 1B of the present embodiment and the first embodiment is that it includes a refracting member 30 and a holding member 40 as a tubular member.

[0074] The refracting member 30 is a lens that refracts the laser beam L emitted from the emission surface 12 of the optical transmission cable 10. The refracting member 30 is arranged at a distance from the front end portion 11 in the axial direction X of the optical transmission cable 10.

[0075] A refracting surface 31 is formed on the side of the refracting member 30 facing the optical transmission cable 10. The refracting surface 31 is arranged so as to face the emission surface 12 and be inclined with respect to the axial direction X of the optical transmission cable 10. As Figure 6 shown, the refracting surface 31 emits the laser beam L emitted from the emission surface 12 at the front end portion 11 of the optical transmission cable 10 to the outside of the holding member 40 at an angle inclined by a predetermined angle or more with respect to the axial direction X of the optical transmission cable 10.

[0076] The holding member 40 is a cylindrical hose. The holding member 40 is sealed at both axial ends while accommodating the optical transmission cable 10, the coating layer 20, and the refracting member 30 therein.

[0077] In addition, a window (not shown) through which the laser beam L passes may be formed on the outer periphery of the holding member 40. The window of the holding member 40 is formed at a position where the laser beam L is emitted on the outer periphery. For example, the window may be an opening having a diameter smaller than the outer diameter d1 of the core 13, or may be a plurality of small holes. Thereby, the peripheral portion of the laser beam L is cut off, so that the laser beam L having a more flat-topped light intensity distribution can be irradiated.

[0078] The optical transmission cable 10, the coating layer 20, and the refracting member 30 are fixed in the holding member 40 by, for example, making the outer diameter and width larger than the inner diameter of the holding member 40 so that the force directed radially inward generated by the holding member 40 is tightened (forming a so-called interference fit state). In addition, as the raw material of the holding member 40, a raw material having a light transmittance of 50% or more is preferably used. As the raw material of the holding member 40, for example, acrylic resin, FEP (fluororesin copolymerized from tetrafluoroethylene and hexafluoropropylene), etc. can be cited.

[0079] <Fourth Embodiment>

[0080] Next, with reference to Figure 7 and Figure 8 , the light diffusing device 1C of the fourth embodiment will be described. Figure 7 FIG. is a diagram schematically showing the light diffusing device 1C of the fourth embodiment, and is a side view of the light diffusing device 1C that mainly irradiates the laser L laterally. Figure 8 FIG. is a diagram schematically showing the light diffusing device 1C of the fourth embodiment, and is a side view of the light diffusing device 1C that mainly irradiates the laser L rearward. In Figure 7 and Figure 8 , the tubular member 40C is shown by a two-dot chain line. In addition, in the following description of the fourth embodiment, regarding the structure corresponding to the above-described first embodiment, the same reference numerals are given with the same regularity. Sometimes the description thereof may be omitted or cited.

[0081] The light diffusing device 1C of the present embodiment includes a laser oscillator (not shown), an optical transmission cable 10, a coating layer 20, a rod-shaped member 30C as a reflection member, and a tubular member 40C. The main difference between the light diffusing device 1C of the present embodiment and the first embodiment is that it includes a rod-shaped member 30C and a tubular member 40C.

[0082] The tubular member 40C is cylindrical and is a resin hose. The resin hose mentioned here includes both a hose composed only of resin and a hose mainly composed of resin. The tubular member 40C houses a part of the optical transmission cable 10, the coating layer 20, and the rod-shaped member 30C inside. The tubular member 40C is configured to be able to reduce its diameter. In the present embodiment, the optical transmission cable 10 is inserted into the tubular member 40C in such a manner that at least the front end portion 11 side is located inside the tubular member 40C. As shown in Figure 7 , the optical transmission cable 10 is housed inside the tubular member 40C in a state of extending along the axial direction of the tubular member 40C. The resin forming the tubular member 40C is preferably a resin having a light transmittance of 50% or more. Examples of the resin forming the tubular member 40C include polyimide, FEP (tetrafluoroethylene - hexafluoropropylene copolymer), acrylic resin, etc.

[0083] The rod-shaped member 30C is made of quartz and is housed inside the tubular member 40C. The rod-shaped member 30C made of quartz mentioned here includes both a rod-shaped member 30C composed only of quartz and a rod-shaped member 30C mainly composed of quartz. Specifically, the rod-shaped member 30C is housed inside the tubular member 40C in a state of extending along the axial direction of the tubular member 40C, with a space from the optical transmission cable 10. In the present embodiment, the rod-shaped member 30C is disposed substantially coaxially with the optical transmission cable 10 inside the tubular member 40C. In addition, the entire rod-shaped member 30C may be housed inside the tubular member 40C without being exposed to the outside. The optical transmission cable 10 and the rod-shaped member 30C are fixed inside the tubular member 40C, for example, by making the outer diameter larger than the inner diameter of the tubular member 40C, so that the force directed radially inward generated by the tubular member 40C fastens them (forming a so-called interference fit state). In addition, the rod-shaped member 30C may be made of silicon. The rod-shaped member 30C made of silicon mentioned here includes both a rod-shaped member 30C composed only of silicon and a rod-shaped member 30C mainly composed of silicon.

[0084] A refraction surface 31C is formed at the end of the rod-shaped member 30C on the side of the optical transmission cable 10. The refraction surface 31C is a quartz-made inclined surface formed by cutting the rod-shaped member 30C obliquely with respect to the axial direction. The quartz-made refraction surface 31C mentioned here includes both a refraction surface 31C composed only of quartz and a refraction surface 31C mainly composed of quartz. The refraction surface 31C is disposed so as to face the exit surface 12 inside the tubular member 40C and to be inclined with respect to the axial direction X of the optical transmission cable 10. In addition, the refraction surface 31C may be made of silicon. The refraction surface 31C made of silicon mentioned here includes both a refraction surface 31C composed only of silicon and a refraction surface 31C mainly composed of silicon.

[0085] As Figure 7 shown, the refraction surface 31C emits the laser beam L emitted from the exit surface 12 at the front end 11 of the optical transmission cable 10 to the outside of the tubular member 40C in a manner inclined by a specified angle or more with respect to the axial direction X of the optical transmission cable 10. At this time, due to the front end 21 of the coating layer 20 protruding in a manner of cutting off the peripheral portion of the laser beam L in the direction in which the laser beam L is emitted, the laser beam L with a flat-top light intensity distribution is irradiated. For example, as Figure 7 shown, the refraction surface 31C refracts each laser beam L emitted from multiple portions of the exit surface 12 along the axial direction X of the optical transmission cable 10 and emits it to the side of the tubular member 40C. For example, the laser beam L with a flat-top light intensity distribution refracted through the refraction surface 31C passes through the tubular member 40C and is emitted in a direction inclined with respect to the insertion direction of the optical transmission cable 10, and irradiates cancer cells or the like existing on the surface of the organ. In addition, for example, it may also be as Figure 8 shown, compared with Figure 7The refracting surface 31C shown is set to be more perpendicular to the axial direction X of the optical transmission cable 10, and the inclination of the refracting surface 31C is set accordingly. With this configuration, as Figure 7 shown, the laser beam L with a flat-top light intensity distribution can be irradiated rearward from the refracting surface 31C.

[0086] As Figure 7 shown, the entire refracting surface 31C of the present embodiment is formed in a planar shape. The unevenness of the surface of the refracting surface 31C on which the laser beam L is incident is preferably below the wavelength of the laser beam L generated from the laser oscillator. For example, by mirror-polishing the refracting surface 31C, unevenness below the wavelength of the laser beam L can be achieved. In addition, a metal 32 is vapor-deposited on the refracting surface 31C of the present embodiment. Examples of the metal 32 vapor-deposited on the refracting surface 31C include gold, silver, aluminum, etc.

[0087] In addition, as Figure 7 shown, the outer diameter d6 of the rod-shaped member 30 is larger than the outer diameter d1 of the core of the optical transmission cable 10. That is, the outer diameter of the refracting surface 31 observed from the axial direction X of the optical transmission cable 10 is larger than the outer diameter d1 of the core. With this configuration, since the refracting surface 31C that receives the laser beam L emitted from the optical transmission cable 10 is larger than the exit surface 12, a positional deviation of the refracting surface 31C with respect to the optical transmission cable 10 can be tolerated.

[0088] In addition, the refracting surface 31C is disposed at a position at a predetermined distance from the exit surface 12 within the tubular member 40C. The distance between the exit surface 12 and the refracting surface 31C is preferably in the range of 0.5 mm to 1 mm. Between the exit surface 12 and the refracting surface 31C, there is a medium whose refractive index is different from both the exit surface 12 and the refracting surface 31C. For example, in the present embodiment, only the space 41 exists as the medium with a different refractive index between the exit surface 12 and the refracting surface 31C. In addition, a lens or the like whose refractive index is different from both the exit surface 12 and the refracting surface 31C and which is in contact with both the exit surface 12 and the refracting surface 31C may be interposed between the exit surface 12 and the refracting surface 31C so as to fill the space 41.

[0089] Here, in photoimmunotherapy and photodynamic therapy, a laser with an output of about 0.5 W to 2.0 W is used. Therefore, the heat generation of the tubular member 40C through which the laser L from the optical transmission cable 10 passes is relatively small. Accordingly, the heat resistance required for the member is relatively low, and as the material of the tubular member 40C, a resin material with more excellent biocompatibility can be used instead of a metal material or a quartz material, etc. In addition, in photoimmunotherapy and photodynamic therapy, an optical transmission cable 10 is mainly used, and the optical transmission cable 10 is a multimode fiber in which the outer diameter d1 of the core 13 is relatively large and is about 500 µm. Therefore, even if heat such as resin deformation is applied to the tubular member 40C and an offset of several µm in the relative position between the emission surface 12 and the refraction surface 31C occurs, it is not easy to cause an optical influence due to this relative position offset. Therefore, in the light diffusion device 1 of the present embodiment, a resin tubular member 40C suitable for the use of photoimmunotherapy or photodynamic therapy is used.

[0090] <Fifth Embodiment>

[0091] Next, with reference to Figure 9 , the light diffusion device 1D of the fifth embodiment will be described. Figure 9 is a side view schematically showing the light diffusion device of the fifth embodiment. In Figure 9 , the tubular member 40D is shown by a two-dot chain line. In addition, in the following description of the fifth embodiment, regarding the structure corresponding to the above fourth embodiment, the same reference numerals are attached with the same regularity. Sometimes the description thereof will be omitted or cited.

[0092] The light diffusion device 1D of the present embodiment includes a laser oscillator (not shown), an optical transmission cable 10, a coating layer 20, a rod-shaped member 30C as a reflection member, and a tubular member 40D. The main difference between the light diffusion device 1D of the present embodiment and the first embodiment lies in the structure of the tubular member 40D.

[0093] In the tubular member 40D, an opening 42 is formed on its outer periphery. Specifically, the opening 42 is formed at a portion of the outer periphery of the tubular member 40D that faces the refraction surface 31C. With this structure, since the tubular member 40D does not exist on the optical path of the laser L emitted from the emission surface 12 via the refraction surface 31C, a stronger laser L can be irradiated to the outside without passing through the tubular member 40D.

[0094] <Sixth Embodiment>

[0095] Next, with reference to Figure 10 , the light diffusion device 1E of the sixth embodiment will be described. Figure 10 is a side view showing the light diffusion device 1E of the sixth embodiment. Figure 104 is a side view of the front end of the light diffuser 1E, which also shows the structure inside the tubular member 40E. Figure 10 In FIG. 4 , the tubular member 40E is shown by a double-dashed line. Figure 10 In order to facilitate the reading of the figure, some lines are omitted. In addition, in the following description of the sixth embodiment, the corresponding symbols with the same regularity are attached to the structures corresponding to the above-mentioned first embodiment. Sometimes the description thereof is omitted or quoted.

[0096] The light diffuser 1E of this embodiment includes a laser oscillator (not shown), an optical transmission cable 10, a coating layer 20, a rod-shaped member 30E as a reflective member, and a tubular member 40E. The light diffuser 1E of this embodiment is different from the light diffuser 1C of the fourth embodiment mainly in the structure of the rod-shaped member 30E.

[0097] The rod-shaped member 30E has a refractive surface 31E formed at the end portion on the optical transmission cable 10 side. The refractive surface 31E has a shape different from the refractive surface 31C of the rod-shaped member 30C of the fourth embodiment. Figure 10 As shown in FIG. 1 , the refractive surface 31E is formed into a curved surface that is concave relative to the exit surface 12 of the optical transmission cable 10. The curvature radius of the refractive surface 31E is preferably 1200 μm. By adjusting the curvature radius of the refractive surface 31E, the laser light L emitted from the exit surface 12 can be not only diffused but also converged. For example, Figure 10 As shown, by the structure of the curved refractive surface 31E recessed relative to the emission surface 12, the laser light L emitted from the emission surface 12 can be emitted uniformly as a whole.

[0098] <Seventh embodiment>

[0099] Next, refer to Figure 11 , a light diffuser 1F according to a seventh embodiment will be described. Figure 11 It is a side view schematically showing a light diffuser 1F according to the seventh embodiment. Figure 11 4 is a side view of the front end of the light diffuser 1F, which also shows the structure inside the tubular member 40F. Figure 11 In the following description of the seventh embodiment, the corresponding symbols are given to the structures corresponding to the fourth embodiment with the same regularity. The description thereof may be omitted or quoted.

[0100] The light diffuser 1F of this embodiment includes a laser oscillator (not shown), an optical transmission cable 10F, a coating layer 20, a rod-shaped member 30C, and a tubular member 40F. The light diffuser 1F of this embodiment is different from the light diffuser 1C of the fourth embodiment mainly in the structure of the front end portion 11F of the optical transmission cable 10F.

[0101] The exit surface 12F of the optical transmission cable 10F of the present embodiment is formed by obliquely cutting the front end portion 11F with respect to the axial direction X of the optical transmission cable 10F. That is, the exit surface 12F is inclined with respect to the axial direction X of the optical transmission cable 10F. Thus, as shown in Figure 11 shown, the laser beam L can be further diffused and emitted from the exit surface 12F. In addition, in the present embodiment, as shown in Figure 11 shown, the exit surface 12F is inclined with respect to the axial direction X of the optical transmission cable 10F in such a manner that it faces the refraction surface 31C substantially parallel. Thus, the optical transmission cable 10F can be brought closer to the refraction surface 31C, and the laser beam L that passes through without being refracted at the refraction surface 31C can be reduced.

[0102] <Eighth Embodiment>

[0103] Next, with reference to Figure 12 , the light diffusing device 1G of the eighth embodiment will be described. Figure 12 FIG. is a side view showing the appearance of the front end portion side of the light diffusing device 1G of the eighth embodiment. Figure 12 FIG. is a longitudinal sectional view of the front end portion side of the light diffusing device 1G further showing the structure inside the tubular member 40G. In addition, in the following description of the eighth embodiment, regarding the structure corresponding to the above-described fourth embodiment, the same reference numerals are given with the same regularity. Sometimes the description thereof will be omitted or cited.

[0104] The light diffusing device 1G of the present embodiment includes a laser oscillator (not shown), an optical transmission cable 10, a coating layer 20, a rod-shaped member 30C, a tubular member 40G, and a clamping member 50. The main difference between the light diffusing device 1G of the present embodiment and the light diffusing device 1C of the fourth embodiment lies in that it further includes the clamping member 50 and the structure of the tubular member 40G.

[0105] The tubular member 40G of the present embodiment is cylindrical and is a resin hose. The difference between the tubular member 40G and the tubular member 40C of the fourth embodiment is that the inner diameter is slightly smaller than the outer diameter of the rod-shaped member 30C and larger than the coating layer 20 that coats the optical transmission cable 10. The rod-shaped member 30C is accommodated in the tubular member 40G in such a manner that the outer peripheral surface is in close contact with the inner peripheral surface of the tubular member 40G. On the other hand, the coating layer 20 is accommodated in the tubular member 40G in a state where there is a gap between the outer peripheral surface and the inner peripheral surface of the tubular member 40G.

[0106] The sandwiching member 50 is a member made of a resin with a low refractive index. The sandwiching member 50 is disposed within the tubular member 40G along the outer circumferential surface of the coating layer 20 to fill the gap between the outer circumferential surface of the coating layer 20 and the inner circumferential surface of the tubular member 40G. Examples of the resin forming the sandwiching member 50 include acrylic resin and the like. Further, the sandwiching member 50 may be a layer that coats the outer circumferential surface of the coating layer 20 or an adhesive that bonds the outer circumferential surface of the coating layer 20 and the inner circumferential surface of the tubular member 40G.

[0107] Embodiment

[0108] Next, embodiments of the present invention will be described. The present invention is not limited to these embodiments.

[0109] <Method for Measuring Light Intensity Distribution>

[0110] In the embodiments, the light intensity distribution of the laser L emitted from the front end portion of the optical transmission cable of the light diffusion devices of Embodiments 1, 2 and the Comparative Example was confirmed. The light intensity distribution of the laser L was measured using a beam analyzer (Ophir Optronics, SP928). The light intensity distribution of the laser L was obtained by measuring the intensity of the laser L on the cross-section (hereinafter, the cross-section of the laser L) obtained by cutting the laser L with a plane orthogonal to its optical axis.

[0111] As Embodiment 1, a light diffusion device having the same structure as the light diffusion device 1 of the above-described first embodiment was used. As the optical transmission cable of Embodiment 1, a cable having a core outer diameter of 500 µm and a cladding thickness of 25 µm was used. Further, as the coating layer of Embodiment 1, a nylon hose with a thickness of 50 µm was used. The nylon hose was arranged to extend 500 µm further in the axial direction X of the optical transmission cable 10 than the front end portion of the optical transmission cable.

[0112] Embodiment 2 used a light diffusion device having the same structure as Embodiment 1 except for the type of the coating layer. In Embodiment 2, a PTFE / polyimide hose was used as the coating layer instead of the nylon hose. The PTFE / polyimide hose used had a PTFE layer thickness of 25 µm and a polyimide hose layer thickness of 25 µm. The PTFE / polyimide hose was arranged to extend 500 µm further in the axial direction X of the optical transmission cable 10 than the front end portion of the optical transmission cable.

[0113] As the Comparative Example, a light scattering device having the same structure as Embodiment 1 except for not having a coating layer was used.

[0114] <Evaluation Results of Light Intensity Distribution>

[0115] Refer toFigures 13 to 15 Explain the evaluation results. Figure 13 It is a graph showing the light intensity distribution of the laser emitted from the front end of the optical transmission cable of the light diffusion device of Example 1. Figure 14 It is a graph showing the light intensity distribution when using the laser emitted from the front end of the optical transmission cable of the light diffusion device of Example 2. Figure 15 It is a graph showing the light intensity distribution when using the laser emitted from the front end of the optical transmission cable of the light diffusion device of the comparative example. Figures 13 to 15 The vertical axis of represents the light intensity, and the horizontal axis represents the measurement position of the light intensity on the straight line passing through the center of the laser L in the cross section of the laser L, that is, the cross-sectional distance. Figures 13 to 15 The light intensity on the vertical axis of is a standard value set with the maximum value of the measured light intensity as 1, and is the moving average of the measured light intensity, that is, the average value of the light intensity measured within the measurement time. Figures 13 to 15 The cross-sectional distance on the horizontal axis of is a standard value set with one end of the measurement position on the straight line as 0 and the other end as 1. In Figures 13 to 15 The range indicated by the arrows on both sides of the solid line is the region where the core exists on the optical transmission cable side in the optical axis direction of the laser L (hereinafter referred to as the core region), and the range indicated by the arrows on both sides of the dashed line is the region where the core and the cladding exist on the optical transmission cable side in the optical axis direction of the laser L.

[0116] As Figure 15 shown, in the comparative example, the variation of the light intensity in the core region of the laser L exceeds 30%. And as it moves away from the center of the laser L, the light intensity slowly tails off and becomes lower. In contrast, as Figure 13 and Figure 14 shown, it can be confirmed that on the front end side of the optical transmission cable, in Example 1 and Example 2, the variation in the core region of the laser L is suppressed within 20%. In addition, in the region where the cladding exists on the optical transmission cable side in the optical axis direction of the laser L, as it moves away from the center of the laser L, the light intensity of the laser L decreases rapidly. It can be confirmed that at the position corresponding to the outer periphery of the cladding, the light intensity is reduced by more than 80% compared with the light intensity at the center of the laser L. That is, as Figure 13 and Figure 14 shown, it can be confirmed that the light intensity distributions of Examples 1 and 2 with cladding are more flat-topped compared with the comparative example without the cladding layer.

[0117] According to the embodiments described above, the following effects are achieved.

[0118] The light diffusing devices 1 to 1G for photoimmunotherapy or photodynamic therapy of the above-described embodiments include: optical transmission cables 10, 10A, 10F that transmit the laser beam L emitted from a laser oscillator and emit the transmitted light from the emission surfaces 12, 12A, 12F of the front ends 11, 11A, 11F; and coating layers 20, 20A that coat the optical transmission cables 10, 10A, 10F and have at least one of the functions of absorbing the laser beam L and scattering light. Moreover, the front ends 21, 21A of the coating layers 20, 20A protrude in the light emission direction by a length required to cut the peripheral portion of the light. As a result, on the front end 11, 11A, 11F side of the optical transmission cables 10, 10A, 10F, the laser beam L emitted from the peripheral side of the front ends 11, 11A, 11F is removed by the coating layers 20, 20A and reflected toward the center side of the laser beam L. Therefore, a more uniform flat-top laser beam L can be emitted from the center side of the laser beam L. As a result, the light diffusing devices 1A to 1G that irradiate the highly efficient laser beam L can be manufactured by a simple process of forming a layer that covers the optical transmission cables 10, 10A, 10F.

[0119] In addition, in the light diffusing devices 1 to 1G of the above-described embodiments, the optical transmission cables 10, 10A, 10F have a core 13 and a cladding 14 formed on the outer periphery of the core 13, and the required length Y is equal to the length calculated by the following formula (1).

[0120] Y = (1 / NA 2 −1) 1 / 2 ×d2 ··· Formula (1)

[0121] Here, Y is the required length, NA is the numerical aperture factor of the optical transmission cable, and d2 is the thickness of the cladding. As a result, the light that spreads at an angle wider than the divergence angle θ of the laser beam L with respect to the optical axis of the laser beam L can be cut, and the light with a more reliable flat-top light intensity distribution can be irradiated.

[0122] In addition, in the light diffusing device 1 of the above-described embodiment, the optical transmission cable 10 has a core 13 and a cladding 14 formed on the outer periphery of the core 13. The thickness d2 of the cladding 14 is 1 / 10 or less of the outer diameter d1 of the core 13, and the thickness d4 of the coating layer 20 is thicker than the cladding 14. As a result, the diameter of the optical transmission cable 10 can be reduced while efficiently emitting the laser beam L. In addition, even when cladding mode light leaks to the outside of the cladding 14, the cladding mode light is removed by the coating layer 20 and reflected toward the center side of the laser beam L. Therefore, a more flat-top laser beam L can be emitted.

[0123] In addition, in the light diffusion devices 1A and 1F of the above-described embodiments, the emission surfaces 12A and 12F of the optical transmission cables 10A and 10F are inclined with respect to the axial direction X of the optical transmission cables 10A and 10F. As a result, the laser beam L can be irradiated in a direction inclined with respect to the insertion direction of the optical transmission cables 10A and 10F. Therefore, the laser beam L can be efficiently irradiated onto cancer cells or the like present on the surface of a slender and narrow-space organ in the human body.

[0124] In addition, in the light diffusion device 1 of the present embodiment described above, the refractive index of the cladding layer 20 is equal to or higher than the refractive index of the cladding material of the optical transmission cable 10. As a result, the laser beam L emitted from the peripheral side of the front end portion 11 can be more reliably absorbed or scattered in the cladding layer 20 and reflected toward the center side of the laser beam L.

[0125] In addition, in the light diffusion device 1 of the present embodiment described above, the refractive index of the cladding layer 20 is 1.53 or higher. As a result, the laser beam L emitted from the peripheral side of the front end portion 11 can be more reliably absorbed or scattered in the cladding layer 20 and reflected toward the center side of the laser beam L.

[0126] In addition, the light diffusion devices 1B to 1G of the present embodiment described above further include: refraction members 30, rod-shaped members 30C and 30E, having refraction surfaces 31, 31C and 31E for refracting the light emitted from the emission surfaces 12 and 12F; and resin-made holding members 40, tubular members 40C to 40G, into which the optical transmission cables 10, 10F, and the refraction members 30, rod-shaped members 30C and 30E are inserted; the refraction surfaces 31, 31C and 31E are arranged at positions at a predetermined distance from the emission surfaces 12 and 12F within the holding members 40, tubular members 40C to 40G so as to be inclined with respect to the axial direction X of the optical transmission cables 10 and 10F, and the light emitted from the emission surfaces 12 and 12F is emitted at an angle inclined by a predetermined angle or more with respect to the axial direction X of the optical transmission cables 10 and 10F. As a result, the flat-top laser beam L emitted from the optical transmission cables 10 and 10F can be efficiently irradiated in a direction inclined with respect to the insertion direction of the optical transmission cables 10 and 10F via the refraction surfaces 31C and 31E. In addition, when performing treatment using photoimmunotherapy or photodynamic therapy, the front end portions 11 and 11F of the optical transmission cables 10 and 10F on the front end portion side of the light diffusion device 1 exposed to the outside from the endoscope and the refraction surfaces 31C and 31E are arranged within the resin-made holding members 40, tubular members 40C to 40G. As a result, contact between the relatively rigid optical transmission cables 10 and 10F and the quartz-made refraction surfaces 31C and 31E with the organs in the body can be prevented, and thus the biocompatibility is excellent. In addition to biocompatibility, the degree of freedom in material selection is excellent in terms of cost, operability, etc., which are desired by device users.

[0127] In addition, in the light diffusion devices 1B to 1G of the above-described embodiments, the refraction members 30, rod-shaped members 30C, 30E are quartz or silicon refraction members 30, rod-shaped members 30C, 30E that are arranged at a space from the optical transmission cables 10, 10F within the holding members 40, tubular members 40C to 40G, and the refraction surfaces 31, 31C, 31E are formed at the ends on the side of the optical transmission cables 10, 10F of the refraction members 30, rod-shaped members 30C, 30E. Thus, the light diffusion device 1 can be manufactured more simply.

[0128] In addition, in the light diffusion devices 1B to 1G of the above-described embodiments, a metal is vapor-deposited on the refraction surfaces 31, 31C, 31E. Thus, light can be refracted more efficiently.

[0129] In addition, in the light diffusion devices 1B to 1G of the above-described embodiments, the optical transmission cables 10, 10F are plastic fibers, having a core 13 with an outer diameter of 500 µm or more and a resin cladding 14 formed on the outer periphery of the core 13, and the outer diameters of the refraction surfaces 31, 31C, 31E observed from the axial direction X of the optical transmission cables 10, 10F are larger than the outer diameter of the core 13. Thus, since the outer diameters of the refraction surfaces 31, 31C, 31E are larger than the outer diameter d1 of the core 13, the tolerance for the deviation of the relative position of the refraction surfaces 31, 31C, 31E with respect to the optical transmission cables 10, 10F can be increased.

[0130] In addition, in the light diffusion devices 1B to 1G of the above-described embodiments, the unevenness on the light incident surface of the refraction surfaces 31, 31C, 31E is less than the wavelength of the light generated from the light source. Thus, since the unevenness on the surface of the refraction surfaces 31, 31C, 31E for the laser L to be incident is small, heat generation caused by the laser L at the refraction surfaces 31, 31C, 31E during irradiation can be suppressed.

[0131] In addition, in the light diffusion devices 1B to 1G of the above-described embodiments, the refraction surfaces 31, 31C, 31E are formed in a curved surface shape that is recessed with respect to the emission surfaces 12, 12F. Thus, since the emission surfaces 12, 12F of the optical transmission cables 10, 10F are inclined, the light emitted from the optical transmission cables 10, 10F can be further diffused.

[0132] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments and can be appropriately modified.

[0133] In the above-described embodiments, the optical transmission cables 10, 10A are configured to have a cladding 14 formed on the outer periphery of the core 13, but they may also be configured not to have the cladding 14.

[0134] Reference numerals

[0135] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G light diffusion device

[0136] 10, 10A, 10F optical transmission cable

[0137] 11, 11A, 11F front end

[0138] 13 core

[0139] 14 cladding

[0140] 20, 20A coating layer

[0141] 21, 21A front end

Claims

1. A light diffusion device, which is a light diffusion device for photoimmunotherapy or photodynamic therapy, comprising: An optical transmission cable that transmits light emitted from a light source and emits the transmitted light from an emission surface at the front end; and, A coating layer that at least has either a function of absorbing light or a function of scattering light, and coats the aforementioned optical transmission cable; and, The front end of the aforementioned coating layer protrudes in the light emission direction by a length required to cut the peripheral portion of the light.

2. The light diffusion device according to claim 1, wherein, The aforementioned optical transmission cable has a core and a cladding formed on the outer periphery of the core, The aforementioned required length is equal to the length calculated by the following formula (1); Y = (1 / NA 2 - 1) 1 / 2 ×d2 ··· Equation (1) wherein, Y is the aforementioned required length, NA is the numerical aperture factor of the aforementioned optical transmission cable, and d2 is the thickness of the aforementioned cladding.

3. The light diffusion device according to claim 1, wherein, The aforementioned optical transmission cable has a core and a cladding formed on the outer periphery of the core, The thickness of the aforementioned cladding is 1 / 10 or less of the outer diameter of the core, The thickness of the aforementioned coating layer is thicker than the aforementioned cladding.

4. The light diffusion device according to claim 1, wherein, The aforementioned emission surface of the optical transmission cable is inclined with respect to the axis of the optical transmission cable.

5. The light diffusion device according to claim 1, wherein, The refractive index of the aforementioned coating layer is equal to or higher than the refractive index of the coating material of the optical transmission cable.

6. The light diffusion device according to claim 1, wherein, The refractive index of the aforementioned coating layer is 1.53 or higher.

7. The light diffusion device according to claim 1, wherein, The light diffusion device further comprises: A reflection member having a refraction surface that refracts the light emitted from the aforementioned emission surface; and, A resin tubular member into which the aforementioned optical transmission cable and the aforementioned reflection member are inserted; and, The aforementioned refraction surface is disposed at a position within the aforementioned tubular member at a predetermined distance from the aforementioned emission surface, and is inclined with respect to the axis of the optical transmission cable, and emits the light emitted from the aforementioned emission surface at an angle inclined by a predetermined angle or more with respect to the axis of the optical transmission cable.

8. The light diffusion device according to claim 7, wherein, The aforementioned reflection member is a quartz or silicon rod-shaped member disposed at a space from the aforementioned optical transmission cable within the aforementioned tubular member, The aforementioned refraction surface is formed at the end of the aforementioned rod-shaped member on the side of the optical transmission cable.

9. The light diffusion device according to claim 7, wherein, A metal is vapor-deposited on the aforementioned refraction surface.

10. The light diffusion device according to claim 7, wherein, The aforementioned optical transmission cable is a plastic fiber, having a core with an outer diameter of 500 µm or more and a resin cladding formed on the outer periphery of the core, The outer diameter of the aforementioned refraction surface observed from the axis of the optical transmission cable is larger than the outer diameter of the core.

11. The light diffusion device according to claim 7, wherein, The unevenness of the surface of the aforementioned refraction surface for light incidence is below the wavelength of the light generated from the aforementioned light source.

12. The light diffusion device according to claim 7, wherein, The aforementioned refraction surface is formed into a curved surface shape that is recessed with respect to the aforementioned emission surface.

Images