JP5480015B2 - Diffusing optical fiber and medical optical component using the same - Google Patents

Description

  The present invention relates to a diffusion optical fiber for irradiating a light beam such as a laser beam over a wide range, and a medical optical component using the same.

  In the medical field, various laser beams ranging from the ultraviolet region to the near-infrared region and the infrared region are used for photochemical treatment of living tissue, welding of living tissue, prevention of restenosis after cardiovascular percutaneous coronary angioplasty, and arrhythmia. It is used for various treatments such as ablation of myocardial tissue for treatment. As a method for irradiating the living tissue with such laser light, a method using an optical fiber has been studied. However, the light emitted from the optical fiber has a strong directivity and can be irradiated only to a narrow range of the living tissue. Therefore, a medical optical fiber has been proposed in which a structure for diffusing light is provided at the tip of the optical fiber so that uniform light can be irradiated over a wide range of living tissue (see Patent Documents 1 to 7). .

  Note that light diffusion plates that diffuse laser light and light from light emitting diodes have been developed in fields other than medical treatment, and are applied to displays, signs, LCD backlights, automobile lights, and the like. Examples of such light diffusing plates include those using microlens arrays and holography, ground glass with roughened surfaces, polymer plates containing spherical inorganic fine particles, those with a milky white film formed on the glass plate surface, diffusion function and Examples include a light diffusing plate composed of a diffusing lens combined with a lens function, and these have been proposed and commercialized by many companies.

Japanese Utility Model Publication No. 7-36101 JP 2000-193894 A JP 2001-204831 A JP 2009-247629 JP-A-6-273678 JP 2003-111789 A JP-A-9-51882

However, the medical optical fibers described in Patent Documents 1 to 7 have the following problems.
Patent Document 1 describes a medical optical fiber in which a hollow polyethylene diffuser is attached to the tip of an optical fiber. In the medical optical fiber of Patent Document 1, the distal end portion of the optical fiber is arranged in the hollow portion of the diffuser, and there is attenuation of the light amount due to the reflected return light from the distal end portion. Difficult to do.

  Patent Document 2 describes a medical optical fiber in which an optical member is disposed on the light emission end side (biological side) of a light guide fiber, and a light diffusion surface is formed on at least one surface of the optical member excluding the biological side surface. ing. However, even in the medical optical fiber of Patent Document 2, there is attenuation of the light amount due to the reflected return light from the living body in addition to the reflected return light from the emission end face of the optical member. Is difficult.

  The medical optical fiber described in Patent Document 3 has a groove structure with a predetermined pattern on the peripheral side surface of the core glass protruding from the tip of the fiber. However, it is extremely difficult to form a concave groove structure on the peripheral side surface of a member having a very small diameter such as core glass, and even if it can be formed, it is difficult to uniformly diffuse the amount of light toward the living body surface.

  In the medical optical fiber described in Patent Document 4, a coiled light diffuser made of a metal wire is attached to the output end of the optical fiber. Since the attenuation of light in the coiled light diffuser is large, It is difficult to irradiate the surface with a sufficient amount of light.

  Patent Document 5 describes a medical illumination optical system in which a concave lens is provided at the distal end portion of a light guide made of an optical fiber bundle, and the concave curvature of the concave lens is multiplexed to diffuse light. However, it is practically difficult to form a concave curvature of a minute concave lens in a multiple structure, and there is a problem in manufacturing at a low cost.

  Patent Document 6 describes that emitted light is diffused by processing the tip of an optical fiber into a bullet shape (ellipsoidal shape). However, the effect of diffusing light by making the tip of the optical fiber into a bullet shape is not sufficient.

  Patent Document 7 describes a visual stimulation device including a light projecting block including a plurality of optical fibers and a plurality of light projecting elements, and a plurality of diffusion elements. This visual stimulation apparatus requires diffusion elements corresponding to the number of optical fibers, and it is difficult to diffuse light over a sufficiently wide range that exceeds the number of optical fibers.

  Therefore, the problem to be solved by the present invention is to provide a diffusion optical fiber and a medical optical component that can uniformly irradiate a sufficient amount of light over a wide range.

The first invention of the present application made to solve the above problems is
An optical fiber having a core part and a cladding part covering the outer periphery of the core part and having a refractive index lower than that of the core part;
A spherical or ellipsoidal diffuser made of a light-transmitting material, provided at one end of the optical fiber, having a refractive index equal to or higher than the refractive index of the core. A diffusion fiber comprising:
A number of rectangular cylindrical recesses are formed in a honeycomb shape on the surface of the diffuser, and at one end of the optical fiber, the core portion protrudes from the clad portion into the diffuser. It is characterized by.

In 1st invention, it is good for the said optical fiber to be arrange | positioned in the protective layer whose refractive index is lower than the said core part.
In this case, a plurality of the optical fibers may be arranged in the protective layer with a predetermined interval, and in particular, the plurality of optical fibers are arranged in the protective layer with an interval of at least 1 μm. Good to be.

  The outer diameter of the diffuser is preferably 1 to 4 times the outer diameter of the optical fiber. When the optical fiber is disposed in a protective layer, the diffuser The outer diameter of the protective layer is preferably 1 to 4 times the outer diameter of the protective layer.

  The length of the part where the core part protrudes from the clad part is preferably longer than 0.5 mm and shorter than 6 mm. Moreover, it is preferable that the protruding portion is processed into a tapered shape.

  The diffuser may be made of a transparent or milky white glass material or polymer material. In addition, it is preferable that a light scattering member is mixed in the diffuser, the surface of the diffuser is roughened, or a large number of concave portions are formed in a mesh shape or a honeycomb shape. According to such a configuration, light propagating through the optical fiber can be diffused and radiated over a wider range.

A second invention of the present application is a medical optical component, comprising the above-described diffusion fiber and a light source that makes light incident on the other end of the diffusion fiber.
In this case, if a plurality of laser beams having different wavelengths are incident on the diffusing fiber from a plurality of light sources, it can be applied to detection and treatment of more lesions.

  According to the present invention, laser light incident from the other end of the optical fiber propagates in the optical fiber toward the diffuser, and exits from the protruding portion of the core into the diffuser. The laser light emitted into the diffuser is diffused and emitted from the diffuser over a wide range. At this time, since the light from the protruding portion is directly emitted into the diffuser, there is no attenuation of the light amount due to the reflected return light. Therefore, by using the diffusing fiber of the present invention, it is possible to irradiate a wide area of living tissue with a sufficient amount of laser light, and it can also be used as an illumination optical component for an endoscope. In addition, since the laser beam can be irradiated over such a wide range, the diffusion fiber of the present invention and the medical optical component using the same are used for photochemical treatment of living tissue, welding of living tissue, cardiovascular treatment. Prevention of restenosis after percutaneous coronary angioplasty, treatment related to ablation of myocardial tissue for the treatment of veins, detection of oxygenated state of living tissue, living tissue (living tissue such as tumor tissue and cancer) It can also be used as a heating device. In this case, by using a light source of one wavelength or a plurality of wavelengths as the laser light, it can be applied to detection and treatment of more lesions.

  Specifically, in the present invention, one end portion of the core portion is covered with a diffuser made of a light transmissive material having a refractive index equal to or higher than the refractive index of the core portion. Therefore, the light propagating in the core portion of the optical fiber is radiated in the diffuser, spreads into the spherical or ellipsoidal shape of the diffuser, and is uniformly diffused and emitted outside the diffuser. The That is, when laser light or light from a light emitting diode is incident and propagated in the optical fiber, the emitted light is uniformly spread in a spherical shape or an ellipsoid shape by the diffuser, and is irradiated on the living body. Therefore, a lesioned part of a living tissue can be detected or treated using the diffusing optical fiber of the first invention.

Further, in the configuration of the present invention, there is almost no attenuation of the light due to the reflected return light, and the light can be transmitted through the optical fiber and uniformly diffused at the emission end of the optical fiber to widely irradiate the living tissue. it can.
Further, as the light transmissive material constituting the diffuser, a material whose transmittance is higher than at least 50% and close to 100% can be used for the optical signal transmitted through the optical fiber.

  In the above configuration, a plurality of the optical fibers are arranged at a desired interval in a protective layer having a lower refractive index than the core part, and one end of the protective layer and one core part protruding from one end of the optical fiber are diffused. If a so-called multi-core fiber structure covered with a body is used, a living tissue can be irradiated by diffusing laser light uniformly over a larger volume. For example, in the case of a multi-core fiber having nine core parts, light can be diffused over the entire volume at least nine times that in the case of one core part. As described above, the more core portions, the more light can be diffused and irradiated in a wider area of the living tissue.

  For example, a multi-core fiber can be easily realized by making a hole in a glass protective layer having a low refractive index, for example, and inserting the optical fiber into the hole. In this case, it is desirable to arrange the optical fibers in the protective layer so that the interval between adjacent optical fibers is at least 1 μm. As the optical fiber used for the multi-core fiber, an appropriate one such as an optical fiber made of a glass material or a plastic material, a single mode fiber, or a multi mode fiber can be used.

  If the outer diameter of the diffuser is 1 to 4 times larger than the outer diameter of the cladding portion of the optical fiber or the protective layer, the laser can be applied to a very wide range of living tissue without causing any inconvenience when inserted into the living body. Light can be diffused and irradiated. However, if the outer diameter of the diffuser is too large, there will be inconvenience when inserted into the living body, so it is preferable to use an optical fiber having an outer diameter of 125 μm. In this case, the outer diameter of the diffuser is 125 μm to 0.5 mm. Since the outer diameter of the optical fiber having a multi-core fiber structure is about 250 μm, the outer diameter of the diffuser is increased to about 250 μm to 1 mm. Even when the outer periphery of the optical fiber is coated with a plastic coating material, the outer diameter of the optical fiber is about 250 μm. In this case, the outer diameter of the diffuser is about 250 μm to 1 mm. Therefore, when the outer diameter of the diffuser is about 1 mm, there is no particular problem in inserting into the living body.

  Further, when the length of the portion of the core portion protruding from the cladding portion is longer than 0.5 mm and shorter than 6 mm, the core portion protruding from the cladding portion can be reliably covered with the diffuser. When the length of the core portion protruding from the clad portion is long, the shape of the diffuser is preferably not an spherical shape but an ellipsoidal shape extending elongated in the tip direction. By doing so, the laser beam propagating through the optical fiber can be emitted into the diffuser in the form of a sphere or an ellipsoid, and after exiting the diffuser, it is diffused and spreads over a wide area of biological tissue. It becomes possible to irradiate.

  The core part protruding from the clad part is processed into a tapered shape so that laser light is emitted to the front surface at a larger angle as it propagates in the sharpened direction of the core part. In addition, the light radiated into the diffuser can be emitted uniformly, and the light radiated into the diffuser is diffused almost uniformly over a wide area after leaving the diffuser to irradiate a wide area of living tissue. Will be able to. As a method of processing the projecting portion of the core portion into a tapered shape, for example, when the optical fiber is made of a glass material, a method of etching in hydrofluoric acid or an aqueous solution of hydrofluoric acid can be mentioned.

If the diffuser is made of a transparent or milky white glass material or a polymer material, it can be easily manufactured at the tip of the optical fiber. Moreover, there is no harm even if it inserts in the living body, and it can be used for a long time. Examples of the glass material include, as water glass, an aqueous solution of potassium silicate (K ₂ SiO ₃ ), an aqueous solution of sodium silicate (Na ₂ SiO ₃ ), an aqueous solution of lithium silicate (Li ₂ SiO ₃ ), and an aqueous solution of ammonium silicate. Can be used, and polymethyl methacrylate, polymethyl acrylate, polyisobutyl methacrylate, or the like can be used as the polymer material.

  By mixing a light scattering member into the diffuser, it is possible to actively cause light scattering in the diffuser and diffuse the light to a wider range. As a result, the light diffuses into a wider area of the living tissue. Can be irradiated. As a material for the light scattering member, fine particles having different refractive indexes or metal fine particles are preferable. The size of these fine particles is preferably in the range of 1 μm to 50 μm. When the size of the fine particles is small, the quantity is increased, and when the size is large, the quantity is preferably decreased. Here, the number of the fine particles may be determined within a range in which the transmittance of the diffuser with respect to the optical signal transmitted through the optical fiber is higher than 50% and close to 100%.

  Further, if the roughened surface having a large number of irregularities on the surface portion of the diffuser, the diffusion of light from the surface portion can be expanded to a wider range. The unevenness formed on the surface of the diffuser is preferably about 0.1 to 5 μm deep.

Further, by processing the surface portion of the diffuser into a honeycomb shape composed of a large number of small rectangular recesses, the light from the surface portion can be spread and radiated to a wide range. In the small rectangular recess, the smaller the plane area, the greater the light diffusion, and the area is preferably in the range of 10 μm ² to 200 μm ² .

  Furthermore, the diffusion fiber is entirely covered with a polymer resin layer (for example, silicon resin, UV resin, nylon resin, polyethylene resin, etc.) or a metal layer (Al, Cu, etc.) as a reinforcing member. By doing so, the strength increases, and it can be prevented from being broken or destroyed when inserted into the living body.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the diffusion type fiber which concerns on Example 1 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 2 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 3 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 4 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 5 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 6 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 7 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 8 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. It is a schematic block diagram of the diffusion type fiber which concerns on Example 9 of this invention, (a) is an external view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view. The external appearance perspective view of the diffusion type fiber which concerns on Example 10 of this invention. The external appearance perspective view of the diffusion type fiber which concerns on Example 11 of this invention. The schematic block diagram of the medical optical component which concerns on Example 12 of this invention. The schematic block diagram of the medical optical component which concerns on Example 13 of this invention.

    Hereinafter, specific examples of the present invention will be described.

FIG. 1 shows a diffusing fiber according to Embodiment 1 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 1, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along the line X1-X1. The diffusion fiber 1 of Example 1 includes an optical fiber 4 including a core portion 2 having a high refractive index and a cladding portion 3 having a lower refractive index than the core portion 2 covering the outer periphery of the core portion 2, and the optical fiber 4. And a spherical diffuser 5 provided at one end of the.

As shown in FIG. 1C, at one end of the optical fiber 4, one end of the core 2 protrudes from the one end of the cladding 3 by a length L, and this protrusion (hereinafter referred to as “protrusion”). The diffuser 5 is attached to one end of the optical fiber 4 so as to cover the portion 2 </ b> A ”.
The protruding portion 2A can be formed by covering the entire outer periphery of the core portion 2 with the cladding portion 3 and then removing a portion of the cladding portion 3 to expose one end portion of the core portion 2. As a method for removing a part of the clad part 3, for example, when the clad part 3 is made of a glass material, an optical fiber is put in hydrofluoric acid or a hydrofluoric acid aqueous solution, and the clad part 3 is partially etched. is there. In this case, the cladding 3 may not be completely removed from the outer periphery of one end of the core 2 (that is, the protruding portion 2A), and a part of the cladding 3 may remain on the outer periphery of the protruding portion 2A. good.
Moreover, you may form the protrusion part 2A of the core part 2 by forming the clad part 3 only in the outer periphery of the part except one edge part of the core part 2. FIG.

  The diffuser 5 is a solid member made of a light transmissive material having a refractive index equal to or higher than the refractive index of the core portion 2, and the refraction of the solid member made of the light transmissive material. The upper limit of the rate can be selected depending on the material used for it. That is, it is possible to select a material that covers the core part and the clad part easily and attaches good importance to the adhesive. When a glass material is used for the core, the upper limit of the refractive index of a solid member made of the light transmissive material is about 1.5, and when a polymer material is used, the upper limit is about 1.6. Materials can be selected. The material of the diffuser 5 may be selected so that the transmittance is greater than 50% and close to 100% with respect to the optical signal transmitted through the optical fiber 4.

As the material of the diffuser 5, for example, water glass or a polymer material can be used. As water glass, for example, an aqueous solution of potassium silicate (K ₂ SiO ₃ ), an aqueous solution of sodium silicate (Na ₂ SiO ₃ ), an aqueous solution of lithium silicate (Li ₂ SiO ₃ ), or an aqueous solution of ammonium silicate. Can be used. As the polymer material, for example, polymethyl methacrylate, polymethyl acrylate, or polyisobutyl methacrylate can be used. The diffuser 5 preferably has an outer diameter that is about the same as the outer diameter of the clad portion 3 and about four times that of the cladding portion 3 because it is necessary to radiate and diffuse light over a wide range.
The

  When the diffusion fiber 1 according to the present embodiment is a quartz glass-based single mode fiber, the outer diameter of the cladding portion 3 is preferably 125 μm and the diameter of the core portion 2 is preferably 10 μm. Further, the length L of the protruding portion 2A is preferably about 0.5 mm at the minimum in consideration of manufacturability of the optical fiber 4 and about 6 mm at the maximum in consideration of the diffusion region in the living body. Further, the relative refractive index difference Δ between core part 2 and clad part 3 (= [(refractive index nc of core part 2−refractive index ncl of clad part 3) / refractive index nc of core part 2] × 100 (%)). The material of the core part 2 and the clad part 3 may be selected so that the ratio is 0.5%.

  In the diffusing fiber 1 having the above configuration, when the laser light La is incident from the end face of the optical fiber 4 on the side opposite to the side on which the diffuser 5 is attached, the laser light La propagates in the core portion 2 and Head toward diffuser 5. And it radiates | emits from the protrusion part 2A which protruded inside the diffuser 5 to the inside of the diffuser 5, spreads uniformly from the whole surface of the diffuser 5, and is radiated | emitted. Further, in the diffusing fiber 1 of Example 1, the protrusion 2A is disposed inside the solid diffuser 5 so that the light from the protrusion 2A is directly radiated into the diffuser 5. The attenuation of light due to the return light can be almost eliminated. Therefore, when the diffusion fiber 1 is used as a medical optical fiber, a sufficient amount of light can be irradiated over a wide range in the living body.

  In addition, when inserting and using the said diffusion type fiber 1 in a biological body, it is good to coat | cover the whole outer peripheral part of the said diffusion type fiber 1 with a reinforcement member. As the reinforcing material, a polymer resin layer (for example, silicon resin, UV resin, nylon resin, polyethylene resin, etc.) or a metal layer (Al, Cu, etc.) can be used.

FIG. 2 shows a diffusion fiber according to Embodiment 2 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 2, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along the line X2-X2. The diffusion type fiber 7 of Example 2 is different from the diffusion type fiber 1 of Example 1 in that the tip of the protruding portion 2A is processed to be round. By rounding the tip of the projecting portion 2A, the light from the projecting portion 2A can be uniformly emitted throughout the diffuser 5.

  As a method for processing the protrusion 2A to be round, a method of heating the protrusion 2A with a heating source such as a burner or irradiating the protrusion 2A with a carbon dioxide laser can be used.

FIG. 3 shows a diffusing fiber according to Embodiment 3 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 3, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X3-X3. The diffusing fiber 8 according to the third embodiment includes a plurality of optical fibers 4 (five in the example shown in FIG. 3) arranged at predetermined intervals in the protective layer 10 and one end of the protective layer 10. And a spherical diffuser 5 provided on the surface. Each optical fiber 4 has the same structure as the optical fiber 4 of the first embodiment, and includes a high refractive index core portion 2 and a low refractive index clad portion 3 that covers the outer periphery of the core portion 2. One end of the core portion 2 is a protruding portion 2A that protrudes from the cladding portion 3 by a length L. The method of forming the protruding portion 2A is as shown in the first embodiment.

  The optical fiber 4 is disposed in the protective layer 10 with one end of the core portion 2 and the clad portion 3 protruding from one end of the protective layer 10. Therefore, in the diffusion fiber 8 of Example 3, not only the protruding portion 2A of the core portion 2 but also a part of the cladding portion 3 protruding from the protective layer 10 is located in the diffuser 5. The diffuser 5 is formed of a light transmissive material having a refractive index equal to or higher than the refractive index of the core portion 2 as in the first embodiment.

The distance between the optical fibers 4 arranged in the protective layer 10 is selected so that the laser light La incident from the other end of the diffusion fiber 8 can be efficiently coupled to the optical fiber 4, and is at least about 1 μm. The maximum thickness is preferably about 10 μm.
Further, as the material of the protective layer 10, a glass material or a polymer material having a refractive index lower than that of the core portion 2 of the optical fiber 4 is used.

The refractive index of the protective layer 10 is preferably a value that is approximately the same as or lower than the refractive index of the cladding portion 3 of the optical fiber 4, but a slightly higher value is not a problem.
The optical fiber 4 may be either a single mode fiber or a multimode fiber. When the optical fiber 4 is a multimode fiber, its outer diameter is preferably 125 μm. Considering the coupling efficiency between the laser beam La and the diffusion fiber 8, it is preferable that the cladding portion 3 of the optical fiber 4 is thin.

  In the example shown in FIG. 3, the diffusion fiber 8 uses five optical fibers 4, so that five laser beams La are respectively incident on the five optical fibers 4 and radiated from the diffuser 5. become. Therefore, light can be diffused and radiated to a volume that is five times or more that of a case where a single optical fiber is used.

FIG. 4 shows a diffusing fiber according to Embodiment 4 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 4, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X4-X4. In the diffusion fiber 12 of the fourth embodiment, the protruding portion 2A of the core portion 2 is processed into a tapered shape (tapered shape). As a processing method of the tip shape of the core portion 2, when the optical fiber 4 is made of a glass material, a method of etching the tip of the optical fiber 4 in hydrofluoric acid or an aqueous solution of hydrofluoric acid can be cited. Further, when the optical fiber 4 is made of a plastic material, there is a method of processing the tip into a taper shape by mechanically scraping. In this case, the leading edge of the projecting portion 2A may not be sharp, and may be, for example, an ellipsoid or a sphere.

  By making the protrusion 2A tapered, the light from the protrusion 2A is strongly emitted forward. Therefore, it is possible to irradiate light more strongly on the object located in front of the diffuser 5. The inclination angle of the tapered shape of the projecting portion 2A may be constant, and the inclination angle may be gradually increased or decreased toward the tip.

FIG. 5 shows a diffusion fiber according to Embodiment 5 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 5, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X5-X5. The diffusion fiber 14 of the fifth embodiment is different from the fourth embodiment in that a light scattering member is mixed in the diffuser 15. The diffuser 15 is formed of a light transmissive material having a refractive index equal to or higher than the refractive index of the core portion 2, and for example, a transparent or milky white glass material or polymer material can be used.

  As the light scattering member, inorganic or organic fine particles or metal fine particles having a refractive index different from that of the diffuser 15 are preferable. The size of the fine particles serving as the light scattering member is preferably in the range of 1 μm to 50 μm. When the size of the fine particles is small, the quantity should be increased, and when the size is large, it should be decreased. The number of light diffusing members may be determined in a range where the transmittance of the diffuser 15 is greater than 50% and close to 100% with respect to the optical signal transmitted through the optical fiber 4. If the diffuser 15 is formed of a transparent or milky white glass material or polymer material, the light scattering member can be easily mixed therein.

As a method for obtaining such a diffuser 24, a solution in which SiO ₂ particles having a particle diameter in the range of several μm to several tens of μm in an aqueous solution of sodium silicate (Na ₂ SiO ₃ ) is dispersed from the cladding 3. There is a method in which one end of the protruding core 2 is coated and then heated and cured.
As another method, there is a method in which SiO ₂ particles are dispersed in a solution in which polysilane is dissolved in xylene, and the solution is coated on one end portion of the core portion 2 protruding from the cladding portion 3 and then heated and cured.

  If the diffusion fiber 14 having such a configuration is used, the laser light incident from the other end of the optical fiber 1 and propagating through the core 2 can be actively scattered in the diffuser 15. The laser beam can be diffused in a wider range. Therefore, when the diffusing fiber 14 is inserted into a living body and used, a wider area of the living tissue can be irradiated with laser light.

FIG. 6 shows a diffusing fiber according to Embodiment 6 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 6, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X6-X6. The diffusion fiber 16 of the sixth embodiment is different from the fourth embodiment in that the surface of the diffuser 17 is roughened. By roughening the surface, a large number of small irregularities are formed on the surface of the diffuser 17, so that the light emitted from the protrusion 2A into the diffuser 17 is radiated from the surface of the diffuser 17 to a wider range. can do.

  In the sixth embodiment, a glass material, a plastic material, a mixed material of glass and plastic, or the like can be used as the material of the diffuser 17. Further, the rough surface structure on the surface of the diffuser 17 is preferably composed of a large number of irregularities having a depth of about 0.1 μm to 5 μm. As a method of forming a large number of irregularities, for example, there is a method of roughing the surface of the diffuser 17 with sandpaper.

FIG. 7 shows a diffusion fiber according to Embodiment 7 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 7, Fig. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X7-X7. Example 7 shows an example of a multi-fiber structure. A diffusion fiber 18 includes an optical fiber 4 in which a plurality of core parts 2 (5 in FIG. 7) are embedded in a cladding part 3, and an optical fiber. 4 has a diffuser 5 provided at one end thereof. The core portion 2 has a higher refractive index than that of the cladding portion 3, and a protruding portion 2 </ b> A that is one end portion of the core portion 2 protrudes from the one end portion of the cladding portion 3 into the diffuser 5 by a length L. The cladding part 3 of Example 7 also serves as the protective layer 10 of Example 3.

  Considering that the diffusion fiber 18 is inserted into the living body and that the range of light emitted from the diffuser 5 is widened, the interval between the core portions 2 in the cladding portion 3 is preferably in the range of 5 to 150 μm. On the other hand, in consideration of increasing the coupling efficiency between the laser beam La incident from the other end of the diffusion fiber 18 and the fiber 18, the interval between the core portions 2 is preferably about 1 μm. If it is considered that light is diffused and emitted over a wide range, the interval between the core portions 2 should be increased to 10 μm.

FIG. 8 shows a diffusion fiber according to Example 8 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 8, FIG. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along line X8-X8. Example 8 shows an example of a multimode fiber, in which the diameter of the core part 2 of the diffusion fiber 21 is 30 μm or more and 100 μm or less, and the diameter of the cladding part 3 is about 125 μm. Also in the diffusion type fiber 21 having such a configuration, it is possible to obtain the same operation and effect as in the first embodiment.

FIG. 9 shows a diffusion fiber according to Embodiment 9 of the present invention. FIG (a) is an external view of a diffusion-type fiber of Example 9, Fig. (B) is a vertical sectional view, FIG. (C) is a transverse sectional view taken along the X9-X9 line. The diffusion fiber 23 of the ninth embodiment is different from the first embodiment in that the diffuser 24 has an ellipsoidal shape and a light scattering member is mixed in the diffuser 24. As the light scattering member, inorganic or organic fine particles or metal fine particles having a refractive index different from that of the diffuser 24 can be used as in the fifth embodiment.

Similar to Example 5, the diffuser 24 according to the present example is also made of a solution in which SiO ₂ particles having a particle size in the range of several μm to several tens of μm are dispersed in an aqueous solution of sodium silicate (Na ₂ SiO ₃ ). Then, after coating one end portion of the core portion 2 protruding from the cladding portion 3, a method of heating and curing, or by dispersing SiO ₂ particles in a solution of polysilane dissolved in xylene, the solution is removed from the cladding portion 3. It can be obtained by a method in which one end portion of the protruding core portion 2 is coated and then heated and cured.

  FIG. 10 shows an external perspective view of a diffusion fiber according to Example 10 of the present invention. The diffusing fiber 25 of the tenth embodiment is different from the first embodiment in that a large number of small rectangular recesses are formed on the surface of the diffuser 26 in a honeycomb shape.

In the honeycomb structure, a spherical diffuser is formed from a polymer solution, and then the diffuser is placed in a metal container (mold) having an inner surface structure corresponding to the honeycomb structure and heated and cured. It can be formed by removing the diffuser.
When the laser beam La is incident from the other end of the diffusion fiber 25, the laser beam La propagates through the core portion 2 and is radiated into the diffuser 26 from the protruding portion 2A. The laser light radiated into the diffuser 26 propagates to the honeycomb-like surface on the surface of the diffuser 26 and is emitted so as to travel straight in a direction perpendicular to the honeycomb-like surface, and as a result, is emitted over a wide range.

Thus, by processing the surface of the diffuser 26 into a honeycomb shape, the laser light emitted in the diffuser 26 can be diffused and emitted in a wide range with a spread in a square planar portion having a small area. The diffusion of light on the surface of the diffuser 26 increases as the area of the planar shape of the many rectangular recesses constituting the honeycomb structure decreases, and considering the surface area of the diffuser 26, the size of the irradiation region in the living body, and the like. The area of the planar shape is preferably in the range of 10 μm ² to 200 μm ² .

  FIG. 11 is an external perspective view of a diffusion fiber according to Example 11 of the present invention. The diffusing fiber 28 according to the eleventh embodiment is different from the first embodiment in that the outer periphery of the cladding portion 3 is covered with a covering material 29. The covering material 29 is made of a polymer material or a metal material. With such a configuration, it is possible to reinforce the diffusion fiber 28 and to avoid the optical fiber 4 from being broken and damaging the living body when inserted into the living body.

  FIG. 12 shows a schematic configuration diagram of a medical optical component according to Embodiment 12 of the present invention. A medical optical component 30 according to the twelfth embodiment includes, for example, a diffusion fiber 28 shown in the eleventh embodiment, a light source 31 that makes a laser beam having a wavelength λ 1 incident from an end surface opposite to the diffuser of the diffusion fiber 28, and The lens 32 is disposed between the light source 31 and the diffusion fiber 28. Laser light La from the light source 31 is collected by the lens 32 and is incident on the diffusion fiber 28. As the wavelength λ1 of the laser light, a visible wavelength, for example, 0.81 μm is used.

In the medical optical component 30, it is preferable to use a diffusion fiber 28 having a length of about 50 cm to about 100 cm.
Further, the relative refractive index difference Δ (= [(refractive index of the core portion−refractive index of the cladding portion) / refractive index of the core portion) × 100 (%)) of the diffusion fiber 28 used in the medical optical component 30 is: A range of 0.1% to 7% is preferred.

FIG. 13: shows the schematic block diagram of the medical optical component which concerns on Example 13 of this invention. The medical optical component 40 according to the thirteenth embodiment is that the laser light La1 having the wavelength λ1 and the laser light La2 having the wavelength λ2 are combined by the multiplexer 41 and incident from the end face of the diffusion fiber 28. And different.
The laser beam La1 having the wavelength λ1 emitted from the light source 31a is incident on the multiplexer 41 through the condenser lens 32a. On the other hand, the laser beam La2 having the wavelength λ2 emitted from the light source 31b is input to the multiplexer 41 through the condenser lens 32b. Here, the wavelength λ2 of the laser beam La2 is preferably a visible wavelength, for example, 0.63 μm.

In addition, this invention is not limited to an above-described Example.
For example, in Example 13, two laser beams having different wavelengths are combined and entered into the diffusion fiber, but three or more laser beams having different wavelengths are combined and incident into the diffusion fiber. You may let them. In this case, the wavelength band of the laser light includes the semiconductor laser wavelength band (0.8 μm band), He-Ne laser (wavelength 0.63 μm band), argon gas laser (0.47 μm band), Er: YAG laser (2.94 μm band), etc. Can be used.
In addition to using only one diffusion fiber, a plurality of fibers can be bundled and used.
In the diffusion fiber of Example 7 shown in FIG. 7, a core portion in which a plurality of fine cores are configured in a bundle shape can be used.
In the diffusion fiber of Example 8 shown in FIG. 8, a bundle fiber can be used instead of the core portion.

DESCRIPTION OF SYMBOLS 1,7,8,12,14,16,18,21,23,25,28 ... Diffusion type fiber 2 ... Core part 2A ... Protruding part 3 ... Cladding part 4 ... Optical fiber 5, 15, 17, 24, 26 ... Diffusion body 10 ... Protective layer 29 ... Coating materials 30, 40 ... Optical optical parts 31, 31a, 31b ... Light sources 32, 32a, 32b ... Lens 41 ... Multiplexer

Claims (12)

An optical fiber having a core part and a cladding part covering the outer periphery of the core part and having a refractive index lower than that of the core part;
A spherical or ellipsoidal diffuser made of a light-transmitting material, provided at one end of the optical fiber, having a refractive index equal to or higher than the refractive index of the core. And
A number of rectangular cylindrical recesses are formed in a honeycomb shape on the surface of the diffuser, and at one end of the optical fiber, the core portion protrudes from the clad portion into the diffuser. A diffusion-type optical fiber characterized by The diffusion fiber according to claim 1, wherein the optical fiber is disposed in a protective layer having a refractive index lower than that of the core portion. 3. The diffusion fiber according to claim 2, wherein a plurality of the optical fibers are arranged in the protective layer at a predetermined interval. The diffusing fiber according to claim 3, wherein the plurality of optical fibers are arranged in the protective layer at an interval of at least 1 µm. 5. The diffusion fiber according to claim 1, wherein an outer diameter of the diffuser is 1 to 4 times larger than an outer diameter of the optical fiber. 5. The diffusion fiber according to claim 2, wherein an outer diameter of the diffuser is 1 to 4 times larger than an outer diameter of the protective layer. The length of the protruding portion is longer than 0.5 mm and shorter than 6 mm, The diffusion fiber according to any one of claims 1 to 6. The diffusion fiber according to claim 1, wherein the protruding portion is processed into a tapered shape. The diffusion fiber according to any one of claims 1 to 8, wherein the diffuser is made of a transparent or milky white glass material or a polymer material. The diffusion fiber according to any one of claims 1 to 9, wherein a light scattering member is mixed in the diffuser. The diffusion fiber according to any one of claims 1 to 10, wherein the entire outer periphery is covered with a resin layer or a metal layer. The diffusion fiber according to any one of claims 1 to 11,
A plurality of light sources that allow light to enter the other end of the diffusion fiber, and the plurality of light sources have different wavelengths from the laser light that is visible from the other end of the diffusion fiber. A medical optical component, wherein a plurality of laser beams are incident through a multiplexer.

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