Circumferential light emitting linear light guide and its manufacturing method

Abstract

To provide a peripheral surface light emission linear light guide body and a manufacturing method therefor, capable of improving uniformity of light intensity in an axial direction as compared with the case of arranging light scattering particles in a fixed proportion along an axial direction in the outer periphery of a core exposed from a clad.SOLUTION: A peripheral surface light emission linear light guide body 3 comprises: an optical fiber 4 having one end in a longer direction at which an outer peripheral surface 41a of a core 41 is exposed from a clad 42; and a light scattering member 5 that covers the whole circumference of the outer peripheral surface 41a of the core 41 in a predetermined axial direction length range. Light emitted from the outer peripheral surface 41a of the core 41 is scattered / radiated by the light scattering member 5. The light scattering member 5 has a light-permeable base material 50, having a refractive index higher than that of the core 41, in which light scattering particles 500 are distributed and mixed. The amount of light scattering particles 500 in the outer periphery of the core 41 at the core 41's end on the tip side is greater than that at the light scattering member 5's end on the side of the clad 42.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a peripheral light-emitting linear light guide including an optical fiber and a light scattering member, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, catheter therapy has been performed in which an optical fiber catheter equipped with an optical fiber is inserted into a hollow organ such as the esophagus or intestines of the human body, or into a blood vessel or the heart, and the affected area is treated with light emitted from the core of the optical fiber (see, for example, Patent Document 1).

[0003] The light irradiation probe for irradiation treatment described in Patent Document 1 has a light guide section in which a core is disposed in a cylindrical clad, and a light scattering irradiation section that scatters the light propagated through the light guide section in all directions around the axial direction of the core. The light scattering irradiation section is formed, for example, by removing a predetermined length of the clad at the tip of an optical fiber and attaching fine powder such as metal particles to the side of the exposed core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-79136 A Summary of the Invention [Problem to be solved by the invention]

[0005] In an optical fiber catheter that scatters light on the outer periphery of the core over a certain axial length range, it is desirable for the light intensity to be highly uniform over the entire axial length range in order to improve the accuracy and safety of treatment. However, if light scattering particles such as metal particles are arranged at a constant rate along the axial direction on the outer periphery of the core exposed from the cladding, the intensity of the light emitted from near the tip of the core in the outer periphery direction will be weak.

[0006] Therefore, the present invention aims to provide a peripheral light-emitting linear light guide that can improve the uniformity of light intensity in the axial direction compared to a case in which light-scattering particles are arranged at a constant ratio along the axial direction on the outer periphery of the core exposed from the cladding, and a manufacturing method thereof. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a peripheral light-emitting linear light conductor comprising an optical fiber having an outer peripheral surface of a core exposed from a cladding at one end in a longitudinal direction, and a light scattering member covering the entire circumference of the outer peripheral surface of the core at the exposed portion over a predetermined axial length range, wherein light emitted from the outer peripheral surface of the core is scattered and radiated by the light scattering member, the diameter of the core is uniform over the predetermined axial length; The light scattering member has light scattering particles dispersed and mixed in a light-transmitting base material having a refractive index higher than that of the core, a thickness of the light scattering member in a radial direction of the core is greater at an end portion of the core on a tip side than at an end portion of the core on a cladding side; The present invention provides a peripheral light-emitting linear light guide, in which the amount of the light-scattering particles around the outer periphery of the core is greater at an end of the core on the tip side than at an end of the light-scattering member on the cladding side.

[0008] The present invention also provides a method for manufacturing the above-mentioned peripheral light-emitting linear light guide, the method comprising the steps of: an optical fiber processing step of exposing the peripheral surface of the core from the clad of the optical fiber; a preparation step of preparing a liquid body that becomes the light scattering member by hardening; and a step of forming a light scattering member protruding from an end of the clad above the liquid body. Uniform diameter The method includes a positioning step of positioning the optical fiber so that the core hangs down in a vertical direction, a moving step of relatively moving the core and the liquid in the vertical direction to move a part of the axial direction of the core below the liquid surface of the liquid, and then lifting the core out of the liquid, and a hardening step of hardening the liquid attached by lifting the core. fruit , a thickness of the light scattering member in a radial direction of the core is made thicker at an end portion of the core on a tip side than at an end portion of the core on a cladding side; A method for manufacturing a peripheral light-emitting linear light guide is provided. Effect of the Invention

[0009] The peripheral light-emitting linear light guide of the present invention and its manufacturing method make it possible to improve the uniformity of the light intensity in the axial direction compared to a case in which light-scattering particles are arranged at a constant ratio along the axial direction on the outer periphery of the core exposed from the cladding. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a treatment device having a catheter configured using a peripheral light-emitting linear light guide according to an embodiment of the present invention, together with a patient to be treated. [Diagram 2] FIG. 2 is a schematic diagram showing the tip of a catheter inserted into a patient's body. [Diagram 3] (a) is a perspective view showing one end of the peripheral light-emitting linear light-guiding body, (b) is a cross section taken along line AA in (a) along the axial direction of the peripheral light-emitting linear light-guiding body, and (c) is a cross section taken along line BB in (a) along the radial direction of the peripheral light-emitting linear light-guiding body. [Figure 4] 1(a) to 1(c) are explanatory views showing the process of processing an optical fiber. [Diagram 5] 5(a) to 5(d) are explanatory views showing a state in which first to fourth light scattering layers and a protective coating layer are formed in sequence around the outer periphery of an exposed core. [Figure 6] 1(a) and 1(b) are schematic configuration diagrams showing a light-scattering layer forming apparatus for forming the first to fourth light-scattering layers. [Figure 7] FIG. 11 is a cross-sectional view showing a peripheral light-emitting linear light-guiding body according to a comparative example. [Figure 8] 10A and 10B are explanatory diagrams showing a measurement method for measuring the light intensity distribution in the axial direction of the peripheral surface light-emitting linear light-guiding body according to the above embodiment and the peripheral surface light-emitting linear light-guiding body according to the comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment Mode] 1 is a schematic diagram showing a treatment device using a peripheral light-emitting linear light conductor according to an embodiment of the present invention as a catheter, together with a patient to be treated. The treatment device 1 has a main body 2 and a peripheral light-emitting linear light conductor 3, and the tip end of the peripheral light-emitting linear light conductor 3 is inserted into the body of a patient P. The main body 2 has a light source 21 that emits laser light, and the laser light generated by the light source 21 is incident on the base end of the peripheral light-emitting linear light conductor 3.

[0012] <Configuration of peripheral light-emitting linear light guide> Fig. 2 is a schematic diagram showing the tip of the peripheral light-emitting linear light conductor 3 inserted into the body of a patient P. In Fig. 2, a part of a blood vessel P1 of the patient P is cut out to show the tip of the peripheral light-emitting linear light conductor 3 inserted into the blood vessel P1. The laser light Lr scattered and emitted from the peripheral light-emitting linear light conductor 3 irradiates the treatment area P2, causing a reaction with a drug that has been previously contained in the treatment area P2. In this way, intravascular laser treatment is performed.

[0013] Fig. 3(a) is a perspective view showing one end of the peripheral light-emitting linear light-guiding element 3. Fig. 3(b) is a cross section taken along line AA in Fig. 3(a) along the axial direction of the peripheral light-emitting linear light-guiding element 3. Fig. 3(c) is a cross section taken along line BB in Fig. 3(a) along the radial direction of the peripheral light-emitting linear light-guiding element 3.

[0014] The peripheral light-emitting linear light guide 3 includes an optical fiber 4 that guides the laser light generated by the light source 21 to the treatment area P2, a light scattering member 5 provided at one end of the optical fiber 4, and a protective coating layer 6 that covers the light scattering member 5. The optical fiber 4 has a core 41, a clad 42, and a sheath 43. At one longitudinal end of the optical fiber 4, an outer peripheral surface 42a of the clad 42 is exposed from the sheath 43, and further, an outer peripheral surface 41a of the core 41 is exposed from the clad 42.

[0015] The light scattering member 5 covers the entire circumference of the outer circumferential surface 41a of the core 41 exposed from the clad 42 over a predetermined axial length range. The axial length of the core 41 covered with the light scattering member 5 is, for example, 1 to 5 cm. A part of the core 41 in the longitudinal direction is an uncovered portion 410 that is not covered by either the clad 42 or the light scattering member 5. The protective coating layer 6 is optically transparent, and covers the light scattering member 5, the uncovered portion 410 of the core 41, and the clad 42 exposed from the sheath 43.

[0016] In this embodiment, the core 41 is made of quartz glass, and the clad 42 is made of a polymer. The sheath 43 is a fluorine-based resin, more specifically, ETFE (ethylene tetrafluoroethylene copolymer). The diameter of the core 41 is, for example, 200 μm. The refractive index of the core 41 is higher than the refractive index of the clad 42, and light propagating through the core 41 within the clad 42 is totally reflected at the interface with the clad 42. In the portion of the core 41 exposed from the clad 42, light is emitted from the outer circumferential surface 41a of the core 41.

[0017] The light scattering member 5 scatters and radiates the light emitted from the outer peripheral surface 41a of the core 41. In the light scattering member 5, a large number of light scattering particles 500 are dispersed and mixed in a light-transmitting base material 50 having a higher refractive index than the core 41. Dispersed and mixed here means that the light scattering particles 500 are mixed so as to be evenly scattered in the base material 50 so that the light scattering particles 500 do not solidify in a part of the base material 50. In this embodiment, the base material 50 is a thermosetting resin. The light scattering particles 500 are fine particles that cannot be recognized by the naked eye, but the size of the light scattering particles 500 is exaggerated in FIG. 3(c).

[0018] The substrate 50 has a higher refractive index than the core 41, and light emitted from the outer peripheral surface 41a of the core 41 enters the light scattering member 5. In this embodiment, the substrate 50 is made of a silicone resin and has a refractive index of, for example, 1.52. The refractive index of the core 41 is, for example, 1.46. The refractive index of the protective coating layer 6 is the same as or higher than the refractive index of the light scattering member 5.

[0019] The light scattering particles 500 are metal particles that reflect light incident on the light scattering member 5. In the present embodiment, titanium oxide (TiO2) is used as the light scattering particles 500. However, the present invention is not limited to this, and the light scattering particles 500 may be aluminum oxide (alumina), or fine metal powder of silver, copper, iron, or an alloy thereof.

[0020] The light scattering member 5 has a multi-layer structure made up of a plurality of layers, and these layers overlap at least partially in the radial direction of the core 41. In this embodiment, the number of layers in the light scattering member 5 is four, and at the tip portion 41b of the core 41, four layers overlap in the radial direction. Hereinafter, these four layers are referred to as a first light scattering layer 51, a second light scattering layer 52, a third light scattering layer 53, and a fourth light scattering layer 54, in order from the inside. In each of the first to fourth light scattering layers 51 to 54, a large number of light scattering particles 500 are dispersed and mixed in a base material 50.

[0021] 3(c), the first to fourth light scattering layers 51 to 54 have the same thicknesses t1 to t4 in the radial direction of the core 41. Each of t1 to t4 is, for example, 5 to 10 μm. The thickness t5 of the protective coating layer 6 is, for example, the same as t1 to t4, but may be different from t1 to t4.

[0022] As shown in FIG. 3(b), when the axial length range E of the core 41 covered with the light scattering member 5 is divided into first to fourth regions 411 to 414 according to the number of layers (four in this embodiment), in the first region 411 closest to the tip of the core 41, the first to fourth light scattering layers 51 to 54 are formed on the outer periphery of the core 41, and in the fourth region 414 closest to the clad 42, only the fourth light scattering layer 54 is formed on the outer periphery of the core 41. In the second region 412 adjacent to the first region 411, the second to fourth light scattering layers 52 to 54 are formed on the outer periphery of the core 41, and in the third region 413 adjacent to the fourth region 414, the third and fourth light scattering layers 53, 54 are formed on the outer periphery of the core 41. The outer periphery surface 41a of the core 41 and the first to fourth light scattering layers 51 to 54 are in close contact with each other without any gaps.

[0023] Due to this multi-layer structure, the thickness of the light scattering member 5 in the radial direction of the core 41 is thicker at the outer periphery of the first region 411 (the end on the tip 41b side of the core 41) than at the outer periphery of the fourth region 414 (the end on the clad 42 side). Also, the amount of light scattering particles 500 around the outer periphery of the core 41 is greater at the outer periphery of the first region 411 (the end on the tip 41b side of the core 41) than at the outer periphery of the fourth region 414 (the end on the clad 42 side).

[0024] The first to fourth light scattering layers 51 to 54 have different mixing ratios of the light scattering particles 500 to the base material 50. In this embodiment, when the concentrations of the light scattering particles 500 in the first to fourth light scattering layers 51 to 54 are C1 to C4, respectively, the concentration C1 of the first light scattering layer 51 is, for example, 20 mg / ml, the concentration C2 of the second light scattering layer 52 is, for example, 10 mg / ml, the concentration C3 of the third light scattering layer 53 is, for example, 0 mg / ml, and the concentration C4 of the fourth light scattering layer 54 is, for example, 7 mg / ml. That is, in this embodiment, the concentrations C1 to C4 of the light scattering particles 500 in the first to fourth light scattering layers 51 to 54 have a relationship of C1>C2>C4>C3.

[0025] As described above, in this embodiment, the first light scattering layer 51, which has the highest mixing ratio of light scattering particles 500 among the first to fourth light scattering layers 51 to 54, is formed in the first region 411 closest to the tip of the core 41.

[0026] In this embodiment, the concentration C4 of the fourth light scattering layer 54 formed in contact with the outer peripheral surface 41a of the core 41 in the fourth region 414 is higher than the concentration C3 of the third light scattering layer 53 formed in contact with the outer peripheral surface 41a of the core 41 in the third region 413. This is the result of adjustments being made to improve the uniformity of the intensity of the light emitted from the light scattering member 5 and the rise of the light intensity at the end of the light scattering member 5 on the clad 42 side, since a phenomenon was observed in which the intensity of the light emitted from the light scattering member 5 peaks at a position slightly away from the end of the light scattering member 5 on the clad 42 side when the concentrations C3 and C4 are the same. In the above example, the concentration C3 of the third light scattering layer 53 is 0 mg / ml, and the third light scattering layer 53 does not contain the light scattering particles 500, but the third light scattering layer 53 may contain the light scattering particles 500. However, even in this case, it is preferable that the concentration C3 of the third light scattering layer 53 is lower than the concentration C4 of the fourth light scattering layer .

[0027] Although the case where the number of layers of the light-scattering member 5 is four has been described here, the number of layers of the light-scattering member 5 is not limited to four, and may be two, three, or five or more. When the number of layers is n (n is a natural number of two or more) and the axial length range E of the core 41 is divided into n regions according to the number of layers, among these n regions, the number of layers in the region closest to the tip of the core 41 is n, and the number of layers in the region closest to the cladding 42 is 1.

[0028] Furthermore, the light scattering member 5 is not limited to a multi-layer structure, and may be a single-layer structure in which the mixing ratio of the light scattering particles 500 in the base material 50 is uniform. In this case, by making the thickness of the light scattering member 5 in the radial direction of the core 41 thicker at the end on the tip portion 41b side of the core 41 than at the end on the clad 42 side, the amount of the light scattering particles 500 around the periphery of the core 41 can be made greater at the end on the tip portion 41b side of the core 41 than at the end on the clad 42 side.

[0029] <Method of Manufacturing Peripheral Light-Emitting Linear Light Guide 3> Next, a manufacturing method of the peripheral surface light-emitting linear light conductor 3 will be described. The manufacturing method of the peripheral surface light-emitting linear light conductor 3 includes an optical fiber processing step of exposing the outer peripheral surface 41a of the core 41 from the clad 42 of the optical fiber 4, a preparation step of preparing a liquid that becomes the light scattering member 5 by hardening, an arrangement step of arranging the optical fiber 4 so that the core 41 protruding from the end of the clad 42 hangs vertically above the liquid, a movement step of moving the core 41 and the liquid relative to each other in the vertical direction, moving a part of the axial direction of the core 41 below the liquid surface of the liquid, and then lifting the core 41 from the liquid, and a hardening step of hardening the liquid attached by lifting the core 41.

[0030] 4(a) to (c) are explanatory diagrams showing the optical fiber processing process. FIG. 4(a) shows the optical fiber 4 before processing. In this state, the outer periphery of the core 41 is covered with the cladding 42, and the outer periphery of the cladding 42 is further covered with the sheath 43. FIG. 4(b) shows the state in which the sheath 43 has been removed over a predetermined length range from the axial end, exposing the outer periphery 42a of the cladding 42. FIG. 4(c) shows the state in which the cladding 42 exposed from the sheath 43 has been removed over a predetermined length range from the axial end, exposing the outer periphery 41a of the core 41.

[0031] 5(a) to (d) are explanatory diagrams showing a state in which the first to fourth light scattering layers 51 to 54 and the protective coating layer 6 are sequentially formed on the outer periphery of the exposed core 41. As shown in Figs. 5(a) to (d), in the light scattering member 5, the first light scattering layer 51 is formed on the outer periphery of the first region 411 of the core 41, and then the second light scattering layer 52 is formed on the outer periphery of the first light scattering layer 51 and the second region 412 of the core 41. Further thereafter, the third light scattering layer 53 is formed on the outer periphery of the second light scattering layer 52 and the third region 413 of the core 41, and the fourth light scattering layer 54 is formed on the outer periphery of the third light scattering layer 53 and the fourth region 414 of the core 41.

[0032] 6(a) and (b) are schematic diagrams showing a light scattering layer forming apparatus 7 for forming the first to fourth light scattering layers 51 to 54. In Fig. 6(a) and (b), the up-down direction in the drawings corresponds to the up-down vertical direction. The light scattering layer forming apparatus 7 includes a base plate 71, a support 72 vertically connected to the base plate 71, a lift table 73 movable in the up-down direction relative to the support 72, a holder 74 for holding the optical fiber 4, and a heater 75 fixed to the support 72.

[0033] The lifting platform 73 is moved up and down relative to the support 72 by an actuator (not shown). For example, an actuator that converts the rotation of an electric motor into linear motion by a ball screw or the like can be used as this actuator. The lifting platform 73 has a support portion 731 that supports the holder 74, and the holder 74 is supported by this support portion 731.

[0034] The holder 74 holds the optical fiber 4 covered with the sheath 43 in the vertical direction over a predetermined length range. As a result, in the arrangement step, the core 41 protruding from the end of the cladding 42 is arranged to hang down vertically. The holder 74 moves up and down together with the lift table 73 while holding the optical fiber 4.

[0035] The heater 75 has an insertion hole 750 through which the optical fiber 4 is inserted vertically. A cylindrical radiating material 751 that radiates infrared rays is arranged around the insertion hole 750, and the radiating material 751 is heated by a heating wire 752, so that the infrared rays are radiated into the insertion hole 750. This makes it possible to heat the periphery of the core 41 of the optical fiber 4 evenly from all directions. The radiating material 751 and the heating wire 752 are housed in a case member 753, and the case member 753 is connected to the support 72 by a connecting arm 754.

[0036] In the preparation step, multiple types of liquids (first to fourth liquids 811-814) with different mixing ratios of light scattering particles 500 are prepared. The first liquid 811 becomes the first light scattering layer 51 when cured, and the second liquid 812 becomes the second light scattering layer 52 when cured. Furthermore, the third liquid 813 becomes the third light scattering layer 53 when cured, and the fourth liquid 814 becomes the fourth light scattering layer 54 when cured.

[0037] In the first to fourth liquid bodies 811 to 814, a large number of light scattering particles 500 are dispersed and mixed in the liquid base material 50L before hardening. The liquid base material 50L is liquid at room temperature before the heating step, and is hardened by being heated by the heater 75 to become the solid base material 50. The concentrations of the light scattering particles 500 in the first to fourth liquid bodies 811 to 814 are concentrations that satisfy the above-mentioned relationship C1>C2>C4>C3.

[0038] The first to fourth liquid materials 811 to 814 are contained in first to fourth containers 821 to 824, respectively. The first to fourth containers 821 to 824 are cup-shaped with an open top. In FIG. 6(a), the first to fourth containers 821 to 824 are shown in cross section, and the first to fourth liquid materials 811 to 814 inside them are shown. Also, FIGS. 6(a) and (b) show a state in which the second container 822 is placed on the placement surface 71a below the heater 75 of the base plate 71.

[0039] When forming the light scattering member 5, the moving step and the hardening step are repeated for each of the first to fourth liquid materials 811-814. In the present embodiment, since the light scattering member 5 has a four-layer structure, the moving step and the hardening step are each repeated four times. The first to fourth liquid materials 811-814 are sequentially placed on the placement surface 71a of the base plate 71 each time one moving step and one hardening step are completed.

[0040] In the moving step, the lift table 73 is moved downward to move a part of the core 41 in the axial direction below the liquid levels of the first to fourth liquid materials 811 to 814, and then the core 41 is lifted up from the first to fourth liquid materials 811 to 814. The liquid base material 50L has viscosity, and when the lift table 73 moves upward, the core 41 is lifted up with the base material 50L adhering to the surroundings due to its viscosity. Fig. 6(a) shows a state in which the core 41 is lifted up from the liquid level 812a of the second liquid material 812.

[0041] When the core 41 is pulled up, the lifting platform 73 is pulled up at a low speed, for example, about 0.02 mm per second, so that the base material 50L adheres to the core 41 with as uniform a thickness as possible. The speed at which the core 41 is pulled up is preferably 0.1 mm / sec or less, and more preferably 0.05 mm / sec or less. Fig. 6(a) shows a state in which the second liquid material 812 adheres to the outer periphery of the first light scattering layer 51 and the second region 412 of the core 41 with a uniform thickness.

[0042] In the curing process, as shown in FIG. 6(b), the lifting platform 73 is raised until the core 41 exposed from the cladding 42 is positioned within the insertion hole 750 of the heater 75, and the first to fourth liquid bodies 811 to 814 attached in the moving process are heated and cured by infrared rays radiated from the radiating material 751.

[0043] Then, after forming the first to fourth light scattering layers 51-54 on the outer periphery of the core 41, the protective coating layer 6 is formed to obtain the peripheral light-emitting linear light conductor 3. The protective coating layer 6 may be formed, for example, in the same manner as the first to fourth light scattering layers 51-54, but the protective coating layer 6 may also be formed in a process different from that for the first to fourth light scattering layers 51-54.

[0044] <Configuration of peripheral surface light-emitting linear light guide 3A according to comparative example> 7 is a cross-sectional view showing a peripheral surface light-emitting linear light-guiding body 3A according to a comparative example. Like the peripheral surface light-emitting linear light-guiding body 3 according to the above embodiment, this peripheral surface light-emitting linear light-guiding body 3A includes an optical fiber 4 in which an outer peripheral surface 41a of a core 41 is exposed from a cladding 42, and the entire circumference of the outer peripheral surface 41a of the core 41 is covered with a light-scattering member 5A over a predetermined axial length range, but the configuration of this light-scattering member 5A is different from that of the light-scattering member 5 according to the above embodiment.

[0045] The light-scattering member 5A of the peripheral light-emitting linear light guide 3A according to the comparative example has a single-layer structure, and the radial thickness of the core 41 is constant throughout the axial direction. As in the above embodiment, the light-scattering member 5A has a large number of light-scattering particles 500 dispersed and mixed in the base material 50. The mixing ratio of the light-scattering particles 500 to the base material 50 in the light-scattering member 5A is uniform throughout the axial direction. The outer periphery of the light-scattering member 5A is covered with a protective coating layer 6A.

[0046] <Light Intensity Distribution of the Circumferential Surface Light-Emitting Linear Light-Guide 3 According to the Embodiment and the Circumferential Surface Light-Emitting Linear Light-Guide 3A According to the Comparative Example> Fig. 8 is an explanatory diagram showing a measurement method for measuring the light intensity distribution in the axial direction of the peripheral surface light-emitting linear light-guiding element 3 according to the above embodiment and the peripheral surface light-emitting linear light-guiding element 3A according to the comparative example. Fig. 8 shows a state during measurement of the peripheral surface light-emitting linear light-guiding element 3 as an example, but the light intensity distribution is also measured in the same manner for the peripheral surface light-emitting linear light-guiding element 3A according to the comparative example.

[0047] In this measurement method, laser light Lr generated by light source 21 is incident on core 41 from base end 4a of optical fiber 4, and the intensity of light emitted from light scattering members 5, 5A in the radial direction of core 41 is measured by optical power meter 9. There are two distances D between optical power meter 9 and core 41: 2.5 mm and 5.0 mm. During measurement, optical power meter 9 is moved in the X direction parallel to core 41, and the light intensity is measured at multiple positions in the X direction. Here, length L of light scattering members 5, 5A in the axial direction of core 41 is set to 20 mm.

[0048] Next, the measurement results of the light intensity distribution of the peripheral surface light-emitting linear light conductor 3 according to the embodiment and the peripheral surface light-emitting linear light conductor 3A according to the comparative example will be described.

[0049] In the peripheral surface light-emitting linear light conductor 3 according to the embodiment, the uniformity of the light intensity in the axial direction of the core 41 was improved compared to the peripheral surface light-emitting linear light conductor 3A according to the comparative example. Specifically, when the position of the optical power meter 9 in the X direction is x, in the peripheral surface light-emitting linear light conductor 3A according to the comparative example, the light intensity peaked at about x=5 mm, and the light intensity decreased toward the tip 41b of the core 41. On the other hand, in the peripheral surface light-emitting linear light conductor 3 according to the embodiment, the light intensity was also at a maximum near the tip 41b of the core 41, and an overall flat light intensity distribution was obtained. This is due to the following reasons.

[0050] The light emitted from the core 41 and incident on the light scattering member 5, 5A passes through the substrate 50 without hitting the light scattering particles 500, and when it reaches the interface between the protective coating layer 6, 6A and the air, it is reflected at this interface and re-enters the core 41 at a large rate. This is because the light propagating through the core 41 from the light source 21 has a shallow angle with respect to the axial direction of the core 41. However, when the light incident on the light scattering member 5, 5A hits the light scattering particles 500, the light scattering particles 500 diffusely reflect the light, and the reflected light hits the interface between the protective coating layer 6, 6A and the air at a relatively large angle. As a result, the reflected light reflected by the light scattering particles 500 is easily radiated to the outside from the light scattering member 5, 5A and the protective coating layer 6, 6A.

[0051] In the peripheral light-emitting linear light conductor 3A according to the comparative example, the thickness of the light scattering member 5A and the mixing ratio of the light scattering particles 500 were uniform throughout the axial direction, so that the light intensity distribution measured by the optical power meter 9 roughly matched the intensity distribution of the light incident on the light scattering member 5A from the core 41. Since the light in the core 41 gradually becomes weaker due to external diffusion as it approaches the tip 41b, the intensity of the light emitted from the light scattering member 5A also gradually decreased as it approached the tip 41b of the core 41.

[0052] On the other hand, in the peripheral light-emitting linear light guide 3 according to the embodiment, the amount of light scattering particles 500 on the outer periphery of the core 41 is small near the reference position and is large toward the tip 41b of the core 41. Therefore, the light emitted from the fourth region 414 near the reference position of the core 41 to the light scattering member 5 is likely to be reflected at the interface between the protective coating layer 6 and the atmosphere and return to the core 41. On the other hand, the light emitted from the first region 411 near the tip 41b of the core 41 to the light scattering member 5 is likely to be reflected by the light scattering particles 500 and radiated to the outside of the protective coating layer 6. That is, in the peripheral light-emitting linear light guide 3, a flat light intensity distribution is obtained overall due to a balance between the intensity of the light in the core 41 and the ease of radiation to the outside of the light scattering member 5 and the protective coating layer 6.

[0053] (Functions and Effects of the Embodiments) According to the embodiment described above, it is possible to improve the uniformity of the intensity of light emitted from the light scattering member 5. In addition, since the light scattering member 5 has a multi-layer structure, it is possible to appropriately set the amount of light scattering particles 500 on the outer periphery of the core 41 for each region according to the number of layers.

[0054] In particular, in this embodiment, the first light scattering layer 51, which has the highest mixing ratio of light scattering particles 500, is formed on the outer periphery of the first region 411 at the tip end of the core 41. Therefore, even if the amount of light emitted from the first region 411 of the core 41 to the light scattering member 5 is small, the proportion of light emitted from the first region 411 that is radiated outside the light scattering member 5 and the protective coating layer 6 can be increased.

[0055] Furthermore, according to the method for manufacturing the peripheral surface light-emitting linear light guide 3 according to the present embodiment, the radial thickness of each of the first to fourth light scattering layers 51 to 54 can be made uniform in the axial and circumferential directions.

[0056] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0057] [1] A circumferential light-emitting linear light guide (3) comprising: an optical fiber (4) having an outer peripheral surface (41 a) of a core (41) exposed from a clad (42) at one longitudinal end; and a light-scattering member (5) covering the entire circumference of the outer peripheral surface (41 a) of the core (41) at the exposed portion over a predetermined axial length range, wherein light emitted from the outer peripheral surface (41 a) of the core (41) is scattered and radiated by the light-scattering member (5), wherein the light-scattering member (5) is a light-transmitting base material (50) having a refractive index higher than that of the core (41) in which light-scattering particles (500) are dispersed and mixed, and the amount of the light-scattering particles (500) around the outer periphery of the core (41) is greater at an end of the light-scattering member (5) on the tip side of the core (41) than at an end of the light-scattering member (5) on the clad (42) side.

[0058] [2] The peripheral surface light-emitting linear light guide (3) according to the above [1], wherein the base material (50) is a silicone resin, and the light scattering particles (500) are metal particles that reflect light.

[0059] [3] The peripheral surface light-emitting linear light guide (3) described in [1] or [2] above, wherein the thickness of the light scattering member (5) in the radial direction of the core (41) is thicker at the end on the tip side of the core (41) than at the end on the clad (42) side.

[0060] [4] The peripheral light-emitting linear light guide (3) according to any one of [1] to [3] above, wherein the light-scattering member (5) is composed of a plurality of layers (first to fourth light-scattering layers 51 to 54) having different mixing ratios of the light-scattering particles (500) in the base material (50), and the plurality of layers (51 to 54) overlap at least in part in the radial direction of the core (41).

[0061] [5] The peripheral surface light-emitting linear light guide (3) according to [4] above, wherein when the number of the plurality of layers (51-54) is n (n is a natural number equal to or greater than 2) and the specified axial length range (E) is divided into n regions (first to fourth regions 411-414) according to the number of layers, among the n regions (411-414), the number of layers in the region (first region 411) closest to the tip of the core (41) is n, and the number of layers in the region (fourth region 414) closest to the cladding is 1.

[0062] [6] The peripheral light-emitting linear light guide according to [5] above, wherein the layer (first light-scattering layer 51) having the highest mixing ratio of the light-scattering particles among the plurality of layers (51-54) is formed in the region among the n regions (411-414) closest to the tip of the core (41).

[0063] [7] A method for manufacturing the peripheral light-emitting linear light guide (3) according to any one of [1] to [6] above, comprising: an optical fiber processing step of exposing the peripheral surface (41a) of the core (41) from the clad (42) of the optical fiber (4); a preparation step of preparing liquid bodies (first to fourth liquid bodies 811 to 814) that become the light scattering member (5) by hardening; and a step of disposing the core (41) protruding from an end of the clad (42) above the liquid bodies (811 to 814) so ​​that the core (41) protruding from the end of the clad (42) hangs down in a vertical direction. a moving step of relatively moving the core (41) and the liquid material (811-814) in the vertical direction to move a part of the axial direction of the core (41) below the liquid surface of the liquid material (811-814), and then lifting the core (41) out of the liquid material (811-814); and a hardening step of hardening the liquid material (811-814) attached by lifting the core (41).

[0064] [8] A method for manufacturing a peripheral surface light-emitting linear light guide (3) according to [7] above, wherein in the preparation step, a plurality of types of the liquids (811-814) having different mixing ratios of the light scattering particles (500) are prepared, and the moving step and the hardening step are repeated for each of the plurality of types of the liquids (811-814).

[0065] [9] The method for manufacturing a peripheral surface light-emitting linear light guide (3) according to [7] or [8] above, wherein the base material (50) is a thermosetting resin, and the curing step is a step of heating and curing the liquid material (811 to 814).

[0066] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the embodiments described above. It should be noted that not all of the combinations of features described in the embodiments are essential to the means for solving the problems of the invention. [Explanation of symbols]

[0067] 3...Circumference-emitting linear light guide 4…Optical fiber 41…Core 411-414: 1st to 4th regions 41a...Outer surface 41b...Tip 42…Clad 5...Light scattering member 50...Base material 500...Light scattering particles 51 to 54: first to fourth light scattering layers 6…Protective coating layer

Claims

1. A peripheral light-emitting linear light conductor comprising: an optical fiber having an outer peripheral surface of a core exposed from a clad at one end in a longitudinal direction; and a light scattering member covering an entire circumference of the outer peripheral surface of the core at the exposed portion over a predetermined axial length range, wherein light emitted from the outer peripheral surface of the core is scattered and radiated by the light scattering member, the core has a uniform diameter over the predetermined axial length; The light scattering member has light scattering particles dispersed and mixed in a light-transmitting base material having a refractive index higher than that of the core, a thickness of the light scattering member in a radial direction of the core is greater at an end portion of the core on a tip side than at an end portion of the core on a cladding side; the amount of the light scattering particles around the periphery of the core is greater at a tip end of the core than at an end of the light scattering member on the cladding side; Circumferentially emitting linear light guide.

2. The substrate is a silicone resin. The light scattering particles are metal particles that reflect light. The peripheral light-emitting linear light conductor according to claim 1 .

3. The axial length of the core in the portion covered with the light scattering member is 1 to 5 cm.

3. The peripheral light-emitting linear light conductor according to claim 1 or 2.

4. The light scattering member is composed of a plurality of layers each having a different mixing ratio of the light scattering particles to the base material, and the plurality of layers are at least partially overlapped in the radial direction of the core. The peripheral light-emitting linear light conductor according to claim 1 .

5. When the number of the plurality of layers is n (n is a natural number of 2 or more), and the predetermined axial length range is divided into n regions according to the number of layers, Among the n regions, the number of layers in the region closest to the tip of the core is n, and the number of layers in the region closest to the cladding is 1. The peripheral light-emitting linear light conductor according to claim 4 .

6. A layer having the highest mixing ratio of the light scattering particles among the plurality of layers is formed in a region closest to the tip side of the core among the n regions. The peripheral light-emitting linear light conductor according to claim 5 .

7. A method for manufacturing the peripheral light-emitting linear light guide according to any one of claims 1 to 6, comprising the steps of: an optical fiber processing step of exposing the outer circumferential surface of the core from the cladding of the optical fiber; a preparation step of preparing a liquid material that will become the light scattering member by curing; a positioning step of positioning the optical fiber above the liquid body such that the core, which has a uniform diameter and protrudes from an end of the cladding, hangs down in a vertical direction; a moving step of relatively moving the core and the liquid in a vertical direction, moving a part of the core in an axial direction below a liquid surface of the liquid, and then lifting the core out of the liquid; a hardening step of hardening the liquid material adhered to the core by lifting the core; Including, a thickness of the light scattering member in a radial direction of the core is made thicker at an end portion of the core on a tip side than at an end portion of the core on a cladding side; A method for manufacturing a peripheral light-emitting linear light guide.

8. In the preparation step, a plurality of types of the liquid having different mixing ratios of the light scattering particles are prepared; the moving step and the hardening step are repeated for each of the plurality of types of the liquid materials. A method for producing the peripheral light-emitting linear light conductor according to claim 7.

9. the substrate is a thermosetting resin, The curing step is a step of heating the liquid material to cure it. A method for producing the peripheral light-emitting linear light conductor according to claim 7 or 8.

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