JP5618862B2 - Endoscope - Google Patents

Description

  The present invention relates to an endoscope.

  In general, an endoscope apparatus includes an endoscope having an insertion portion that is inserted into a subject, and a light source device that supplies illumination light to the endoscope. The endoscope and the light source device are separated from each other. It is configured. As a light source of the light source device, a white light lamp such as a xenon lamp or a metal halide lamp is widely used. However, there is one that generates illumination light using a laser light source instead of the lamp. For example, in the endoscope apparatus disclosed in Patent Document 1, light from a semiconductor laser light source mounted on a light source device is transmitted to the distal end of the endoscope insertion section using an optical fiber, and fluorescent light provided at the distal end of the insertion section. It is configured to emit white light through the body.

By the way, when illuminating light is transmitted between the light source device and the distal end of the insertion portion of the endoscope using a single optical fiber or a small number of optical fibers, stress concentration occurs in a part of the optical fiber, and the fiber is disconnected. May occur. When a disconnection occurs in a part of the optical fiber, the optical transmission loss on the illumination light is large, and the illumination light quantity is greatly reduced. Thus, in order to prevent such optical transmission loss such as disconnection of the optical fiber, it is considered to protect the optical fiber as follows, for example.
(1) The optical fiber is fixed at a predetermined position in the insertion portion of the endoscope so that the optical fiber does not move in the insertion portion.
(2) A member for partitioning the insertion portion of the endoscope is provided, and the optical fiber is disposed in the partitioned space, thereby restricting the movement of the optical fiber.
(3) An optical fiber is protected by tightly winding a strand having a predetermined elasticity on the outer periphery of the optical fiber and bonding and fixing adjacent strands (see Patent Document 2).

JP 2008-73346 A JP 2007-37649 A

However, in the configuration (1) that defines the location of the optical fiber, the degree of freedom in arrangement is poor, and resistance tends to occur when the bending portion is bent. In the configuration that divides the space of (2), extra parts are disposed, which increases costs and is disadvantageous for reducing the diameter of the insertion portion. In the configuration in which the strands of (3) are densely wound in a spiral shape, the manufacturing process becomes complicated and the cost increases. Moreover, since it expands by covering with a helical strand, it becomes disadvantageous for diameter reduction of an insertion part. Furthermore, the bending rigidity is increased by the strands, the operation resistance of the bending operation of the bending portion is increased, and the operation wire for performing the bending operation is easily extended.
Therefore, the present invention is an endoscope having a structure that is not restricted by the arrangement in the endoscope insertion portion, and that can reliably prevent disconnection of the optical fiber while having an inexpensive and simple configuration, and is advantageous in reducing the diameter. The purpose is to provide.

The present invention has the following configuration.
An elongated insertion portion to be inserted into a subject, an optical fiber that is inserted through the insertion portion and transmits optical energy, and at least a portion of the insertion portion in the longitudinal direction of each of the optical fibers. An endoscope comprising a flexible protective tube covering an outer periphery,
The wall thickness of the tube tube wall of the protective tube is formed to be larger than the maximum radius of curvature at which one of the optical fibers is broken by bending .
An endoscope in which the outer diameter of the protective tube is smaller than the inner diameter of the insertion portion.

In the endoscope of the present invention, the thickness of the tube tube wall of the protective tube is formed larger than the maximum radius of curvature at which one of the optical fibers is broken by bending , and the wall thickness of the tube tube wall of the protective tube is : one optical fiber is formed larger than the maximum radius of curvature resulting in disconnection by bending, tube outer diameter of the protective tube, by Rukoto is smaller than the inner diameter of the insertion portion, an optical fiber with inexpensive and simple configuration It is possible to protect, and even if the protective tube is bent, disconnection of the optical fiber can be reliably prevented. In addition, the small diameter configuration in which a protective tube having a predetermined thickness is provided outside the optical fiber does not hinder the diameter reduction of the insertion portion. Moreover, the arrangement of the optical fiber in the insertion portion is free, and the degree of freedom in designing the endoscope can be improved.

It is a figure for describing an embodiment of the present invention, and is a lineblock diagram of an endoscope apparatus showing each apparatus to which an endoscope and an endoscope are connected. It is an external view which shows the specific structural example of an endoscope apparatus. It is a graph which shows the spectral characteristic of emitted light. It is a perspective view of an endoscope front-end | tip part. FIG. 5 is a schematic cross-sectional configuration diagram taken along the line AA in FIG. 4, and is an explanatory diagram illustrating an arrangement relationship between an endoscope insertion portion and a light guide unit. It is a block diagram of a light guide unit. FIG. 7 is a schematic cross-sectional configuration diagram of the protective tube in FIG. It is explanatory drawing which shows the state which bent the protective tube at 180 degrees. It is typical explanatory drawing which shows the case where bending generate | occur | produces in a part of light guide unit when bending operation is carried out to a bending part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining an embodiment of the present invention. FIG. 1 is a configuration diagram of an endoscope apparatus representing an endoscope and each apparatus to which the endoscope is connected. FIG. 2 is a specific example of the endoscope apparatus. It is an external view which shows a structural example.
As shown in FIG. 1, the endoscope apparatus 100 includes an endoscope 11, a control device 13, a display unit 15 such as a monitor, and an input unit 17 such as a keyboard and a mouse that input information to the control device 13. It has. The control device 13 includes a light source device 19 and a processor 21 that performs signal processing of a captured image.

  The endoscope 11 includes a main body operation unit 23 and an elongated insertion unit 25 that is connected to the main body operation unit 23 and is inserted into a subject (body cavity). A universal cord 27 is connected to the main body operation unit 23, and the tip of the universal cord 27 is connected to the light source device 19 via a light guide (LG) connector 29A, and to the processor 21 via a video connector 29B. It is connected.

  As shown in FIG. 2, the main body operation unit 23 of the endoscope 11 has various operation buttons such as buttons for performing suction, air supply, and water supply on the distal end side of the insertion unit 25, and a shutter button at the time of imaging. 31 is also provided, and a pair of angle knobs 33 are provided.

  The insertion portion 25 is composed of a flexible portion 35, a bending portion 37, and a distal end portion (endoscope distal end portion) 39 in order from the main body operation portion 23 disposed on the proximal end side. The bending portion 37 is pulled by an operation wire (not shown) by rotating the angle knob 33 of the main body operation portion 23, so that the bending portion 37 is remotely operated to turn the distal end portion 39 in a desired direction. .

  As shown in FIG. 1, an observation window 41 of an imaging optical system and illumination windows 43A and 43B of an illumination optical system are arranged at the endoscope distal end portion 39. Reflected light from the subject due to illumination light emitted from each of the illumination windows 43 </ b> A and 43 </ b> B is imaged by the image sensor 45 through the observation window 41. The captured observation image is displayed on the display unit 15 connected to the processor 21.

  Here, the imaging optical system includes optical elements such as a CCD (Charge Coupled Device) type image sensor and a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, and a lens that forms an observation image on the imaging element 45. Member 47. The observation image formed and captured on the light receiving surface of the image sensor 45 is converted into an electric signal and input to the image signal processing unit 53 of the processor 21 through the signal cable 51, and is converted into a video signal by the image signal processing unit 53. Is done.

  The processor 21 includes a control unit 63 and an imaging signal processing unit 53 that generates a video signal. The control unit 63 performs appropriate image processing on the image data of the observation image output from the imaging signal processing unit 53 and causes the display unit 15 to display the image data. In addition, a drive signal is output to the laser light source LD of the light source device 19, and illumination light having a desired light amount is emitted from each of the illumination windows 43A and 43B. The control unit 63 is connected to a network such as a LAN (not shown) and controls the entire endoscope apparatus 100 such as distributing information including image data.

  The illumination optical system includes a light source device 19, a pair of optical fibers 55A and 55B connected to the light source device 19 via a connector 29A, and wavelength conversion members 57A and 57B disposed at the light emitting ends of the optical fibers 55A and 55B, respectively. And have. The light source device 19 includes a laser light source LD, which is a semiconductor light emitting element, and an optical coupler 61 that demultiplexes light emitted from the laser light source LD and introduces the light into the optical fibers 55A and 55B.

  The laser light source LD is a blue-emitting semiconductor laser with a central wavelength of 445 nm, and for example, a broad area type InGaN laser diode can be used. The laser light source LD may be composed of a plurality of laser light sources. For example, the laser light source LD may be selectively output from each laser light source in combination with a violet-emitting semiconductor laser having a central wavelength of 405 nm.

The wavelength conversion members 57A and 57B absorb a part of the blue laser light emitted from the laser light source LD and excite and emit green to yellow light (for example, YAG phosphor or BAM (BaMgAl ₁₀ O). ₃₇ ) and the like. The wavelength conversion members 57A and 57B combine the blue laser light from the laser light source LD with the green to yellow excitation light obtained by wavelength-converting the blue laser light, as shown in FIG. As a result, white light is generated.

  That is, the control unit 63 of the processor 21 controls the light amount of the laser light source LD and outputs laser light from the laser light source LD. The output laser light is introduced into each of the optical fibers 55A and 55B and guided to the endoscope distal end portion 39. The laser light guided by the optical fibers 55A and 55B is applied to the wavelength conversion members 57A and 57B, and thereby white illumination light is emitted from the illumination windows 43A and 43B.

FIG. 4 is an external perspective view of the endoscope distal end portion 39, and FIG. 5 is a schematic cross-sectional configuration diagram taken along the line AA of FIG. 4, illustrating the arrangement relationship between the endoscope insertion portion and the light guide unit. showed that.
As shown in FIG. 4, the endoscope distal end 39 is provided with the observation window 41 for observing the subject and the illumination windows 43A and 43B for emitting illumination light, and the illumination windows 43A and 43B are Arranged on both sides of the observation window 41. In addition, a forceps port 65 through which various forceps are inserted and an air / water supply nozzle 67 for supplying air / water toward the observation window 41 are disposed at the endoscope distal end portion 39.

  As shown in the sectional configuration of FIG. 5, the endoscope distal end portion 39 is provided with a distal end hard portion 71 made of a metal material such as a stainless steel material. The light guide unit 81 is fixed by inserting and inserting a tip light projecting portion 91 that is a tip portion of the hole 71 a formed in the tip hard portion 71. In addition, an imaging unit including the imaging element 45 is fixed to the other end of the hard hole 71, but the description thereof is omitted here.

Next, the light guide unit 81 in which the illumination windows 43A and 43B of the illumination optical system, the wavelength conversion members 57A and 57B, and the optical fibers 55A and 55B are integrally formed will be described.
As shown in FIG. 6, the light guide unit 81 includes a tip light projecting unit 91, an optical fiber 55 (55A, 55B) that is a flexible body having a light emitting end connected to the tip light projecting unit 91, and an optical fiber. And a protective tube 93 covering the outer periphery of 55.

  The tip light projecting unit 91 includes a cylindrical tip sleeve 97 whose one side surface is closed by a light-transmitting plate 95 serving as the illumination window 43 (43A, 43B), and a wavelength conversion member 57 ( 57A, 57B), a connecting member 99 that connects the proximal end side of the distal end sleeve 97 and the distal end side of the protective tube 93, and a ferrule 101 that is disposed inside the connecting member 99 and supports the optical fiber 55. Composed.

  In the protective tube 93, the optical fiber 55 is inserted into an inner hole 93a formed in the central portion of the tube. The inner hole 93 a is provided along the central axis of the protective tube 93 and supports the optical fiber 55 along the central axis of the protective tube 93.

  The protective tube 93 is made of a highly flexible rubber material such as silicon rubber or fluorine rubber. These rubber-based materials are chemically stable, do not change in quality even when they are exposed to cleaning chemicals during endoscope cleaning, and have little deterioration over time. The distal end side of the protective tube 93 is inserted into the small diameter connecting portion 99a of the connecting member 99 on the distal end light projecting portion 91 side, and the proximal end side is connected to the connector 29A (see FIG. 1).

  The protective tube 93 may have a configuration in which a fluorine-based coating is applied to either or both of the inner peripheral surface and the outer peripheral surface of the rubber-based material. In that case, the slidability with the member in contact with the protective tube 93 is improved.

  The fluorine-based coating is a coating of a fluorine-based resin having good sliding property such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA).

  The protective tube 93 is made of a material having an elastic constant that is flexible and easily deformed. For this reason, even when the tube itself is bent, the pressure from the side surface loaded on the optical fiber 55 inside is deformed. Can be reduced, and disconnection of the optical fiber can be prevented. Further, since the protective tube 93 is flexible, it does not damage other built-in objects in the endoscope insertion portion 25. Furthermore, the light guide unit 81 can maintain the protective tube 93 in a straight shape by the elastic restoring force of the protective tube 93 itself, and the optical fiber 55 can be inserted into the inner hole 93a of the protective tube 93 or an endoscope. The assembling property of the endoscope can be improved by inserting the light guide unit 81 into the insertion portion 25.

  The elastic constant is a parameter representing the bending stiffness when each tube is viewed macroscopically. The larger the elastic constant, the less likely to bend, and the smaller the elastic constant, the easier to bend and flexibility. Represents.

  Since the inner hole 93a of the protective tube 93 is provided along the central axis of the protective tube, the optical fiber 55 is protected by the protective tube 93 regardless of the bending direction of the protective tube 93. That is, the optical fiber 55 is evenly protected regardless of the direction in which the protective tube 93 is bent.

  Further, the inner diameter of the inner hole 93a is formed larger than the outer diameter of the optical fiber 55, and the axial movement of the optical fiber 55 is facilitated. For this reason, even when the protective tube 93 is elastically expanded and contracted, the optical fiber 55 disposed in the inner hole 93a is movable in the axial direction, and the axial stress applied to the optical fiber 55 due to bending generated in the protective tube 93 is reduced. Can be relaxed.

FIG. 7 shows a schematic cross-sectional configuration diagram of the protective tube of FIG. The protective tube 93 of this configuration has an inner hole 93a that supports the optical fiber 55 on the central axis, and the optical fiber 55 is broken by bending the thickness t obtained as 1/2 of the difference between the outer diameter D and the inner diameter d. It is larger than the maximum curvature radius r _max to be (disconnected). Accordingly, even when the protective tube 93 is bent at 180 ° and bent with the minimum curvature radius as shown in FIG. 8, the curvature radius r of the optical fiber 55 is always larger than the curvature radius r _{max at} which breakage occurs. . For example, when the diameter of the optical fiber is 0.3 mm and the maximum radius of curvature r _{max at} which breakage occurs is 0.85 mm, if the outer diameter of the protective tube 93 is 2.8 mm and the inner diameter is 0.5 mm, the tube tube The wall thickness is 1.15 mm, which is larger than 0.85 mm, which is the maximum curvature radius r _max , and disconnection does not occur in the optical fiber.

  In the endoscope 100 having this configuration, the light guide unit 81 disposed in the endoscope insertion portion 25 covers the protective tube 93 and the optical fiber 55 in the region of the bending portion 37 as shown in FIG. Are arranged as follows. That is, in the light guide unit 81, the distal end light projecting portion 91 is fixed to the distal end hard portion 71 of the distal end portion 39 of the endoscope insertion portion 25, and the protective tube 93 includes a plurality of node rings arranged in the bending portion 37. The inside of 111 is inserted and it reaches the soft part 35. Although details will be described later, an operation wire (not shown) is pulled by the surgeon operating the angle knob 33 (see FIG. 2), and the plurality of node rings 111 are rotated around the connecting shafts 113 and 115 by pulling the operation wire. Move. As a result, the bending portion 37 is bent.

  In this way, the protective tube 93 covers the optical fiber 55 within the range of the bending portion 37, so that when the bending portion 37 is bent, the protective tube 93 is flexibly deformed and is a tube loaded on the optical fiber 55. Absorbs pressure from the side. As a result, the buckling of the optical fiber 55 covered with the protective tube 93 is prevented. Even if the protective tube 93 is bent, the occurrence of disconnection of the optical fiber 55 can be prevented as described above.

  Further, even when the protective tube 93 is bent in the bending portion 37 and abuts against another built-in object and rubs, the protection tube 93 is highly flexible and does not damage the other built-in object.

  Furthermore, since the protective tube 93 is formed of a material having a relatively small elastic constant, it is easily bent. Therefore, the resistance of the bending operation is small, the operation force for rotating the angle knob 33 shown in FIG. 2 is small, and the operability of the endoscope is improved.

  As described above, the protective tube 93 is partly covered with an extension of the optical fiber 55 in the flexible portion 35 in addition to the entire portion from the distal end side to the proximal end side of the insertion portion 25, and the bending portion 37. It is good also as a structure arrange | positioned only in the area | region. Even in this case, the optical fiber 55 is reliably protected in the region of the curved portion 37 where breakage is particularly likely to occur, and the occurrence of breakage can be prevented with the minimum arrangement of the protective tube 93.

  By the way, as shown in FIG. 5, the soft portion 35 is configured by covering a coil 117 with a tube 119. The coil 117 is fixed at the connection portion 123 between the flexible portion 35 and the bending portion 37 by the fixing member 121. Therefore, the inner diameter of the connection location 123 is relatively small because the fixing member 121 is disposed.

  Therefore, even when the protective tube 93 is partially provided in the region of the curved portion 37 of the optical fiber 55, if the protection tube 93 is extended to at least the region of the flexible portion 35 avoiding the connection portion 123, the connection portion 123 is provided. It is possible to prevent a decrease in slidability due to interference with the small diameter portion and a decrease in the bending operability of the bending portion 37. That is, the light guide unit 81 can slide smoothly without being caught by the fixing member 121 at the connection portion 123, and the flexibility is not lowered by the presence of the connection member 103 on the curved portion 37.

  Here, FIG. 9 shows a schematic explanatory diagram when bending occurs in a part of the light guide unit when the bending portion is operated to bend. In the bending portion 37 formed between the distal end portion 39 and the flexible portion 35, the plurality of node rings 111 described above are connected to each other around the connecting shafts 113 and 115, respectively. The plurality of node rings 111 can be bent in a desired direction by pulling an operation wire by operating an angle knob.

  A pivot pin 125 is disposed on each of the connecting shafts 113 (also the same as 115) for connecting adjacent node rings 111 to each other, and both node rings 111 are rotatably connected. In the pivot pin 125, a through hole 127 is formed in a head portion 125 a protruding toward the center side of the node ring 111, and an operation wire 129 is inserted through the through hole 127.

  Various built-in objects such as the light guide unit 81 are accommodated inside these node rings 111, and each built-in object is curved along the bending portion 37 as the bending portion 37 is bent. At this time, the protruding head 125a of the pivot pin 125 is pressed against the protective tube 93 of the light guide unit 81, and the protective tube 93 may be bent with a small radius of curvature. The bending generated in the protective tube 93 induces disconnection of the optical fiber 55 inserted into the tube.

However, as described above, even when the protective tube 93 of this configuration is bent at 180 ° and bent with the minimum radius of curvature, the radius of curvature of the optical fiber 55 is larger than the maximum radius of curvature r _{max at} which breakage occurs. Always grows. Therefore, according to this configuration, the optical fiber 55 is not broken by any operation of the bending portion 37.

As described above, the present invention is not limited to the above-described embodiments, and modifications and applications by those skilled in the art based on the description of the specification and well-known techniques are also within the scope of the present invention. It is included in the range to calculate. For example, the protective tube is provided so as to cover the outside of one optical fiber 55 in this configuration example, but may be arranged so as to cover a plurality of optical fibers.
Further, the protective tube may be configured by connecting a plurality of tube members, or may be a tube produced by two-color molding or insert molding of materials having different elastic constants.

As described above, the following items are disclosed in this specification.
(1) An optical fiber that is inserted into an elongated insertion portion that is inserted into a subject and transmits optical energy, and a flexible protection that covers at least a portion of the insertion portion in the longitudinal direction of the optical fiber. An endoscope comprising a tube,
An endoscope in which the protective tube has a wall thickness of a tube tube larger than a minimum radius of curvature that causes disconnection of the optical fiber and an outer diameter of the tube smaller than an inner diameter of the insertion portion.
According to this endoscope, the optical fiber inserted into the insertion portion is covered with the protective tube, so that the disconnection of the optical fiber can be prevented. In addition, since the optical fiber is simply configured to be covered with a protective tube, it can be manufactured at a low cost, and can be made into a structure advantageous for reducing the diameter of the insertion portion without being greatly enlarged by the protective tube.

(2) The endoscope according to (1),
An endoscope in which the protective tube is made of a rubber-based material containing either silicon rubber or fluorine-based rubber.
According to this endoscope, since the protective tube is made of a highly flexible rubber material, the optical fiber can be protected from pressure from the side surface. Further, by using a chemically stable rubber material, even if the cleaning chemical is touched at the time of endoscope cleaning or the like, it does not change in quality, and deterioration with time can be reduced.

(3) The endoscope according to (1),
An endoscope in which the protective tube is obtained by applying a fluorine-based coating on the surface of a rubber-based material.
According to this endoscope, when the surface of the rubber-based material is coated with a fluorine-based coating, the built-in material in the insertion portion slides outside the protective tube, or slides inside the optical fiber or protective tube. The slidability is improved. Thereby, the stress applied to the optical fiber can be relaxed, and the disconnection of the optical fiber can be made difficult to occur.

(4) The endoscope according to (3),
An endoscope in which the fluorine-based coating is a coating using a material containing either polytetrafluoroethylene (PTFE) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA).
According to this endoscope, high slidability can be obtained between the optical fiber inserted into the protective tube and other internal organs touching the outer side of the protective tube.

(5) The endoscope according to any one of (1) to (4),
An endoscope in which the protective tube supports the optical fiber along a central axis of the protective tube.
According to this endoscope, since the optical fiber is supported along the central axis of the protective tube, disconnection of the optical fiber is always prevented regardless of the bending direction of the insertion portion.

(6) The endoscope according to any one of (1) to (5),
An endoscope in which the optical fiber is supported so as to be movable in the axial direction inside the protective tube.
According to this endoscope, since the optical fiber is movable within the protective tube, stress generated in the optical fiber due to bending of the insertion portion can be reduced.

(7) The endoscope according to (6),
An endoscope in which the inner diameter of the protective tube is larger than the outer diameter of the optical fiber.
According to this endoscope, since the inner diameter of the tube is larger than the outer diameter of the optical fiber, the optical fiber is easily moved in the axial direction within the protective tube, and the stress generated in the optical fiber is well relieved.

(8) The endoscope according to any one of (1) to (7),
An endoscope operation unit provided on a proximal end side of the insertion unit and having a bending operation unit;
The insertion portion has a bending portion that is bent by an operation from the operation portion,
An endoscope in which the protective tube is disposed at least in the region of the bending portion of the insertion portion.
According to this endoscope, since the protective tube is disposed at least in the region of the bending portion, it is possible to relieve stress on the optical fiber that is caused by the bending operation of the bending portion, and to prevent disconnection of the optical fiber.

(9) The endoscope according to any one of (1) to (8),
An endoscope in which the protective tube is disposed over the entire length from the distal end side to the proximal end side of the insertion portion.
According to this endoscope, since the protective tube is disposed over the entire length of the insertion portion, the optical fiber is reliably protected and the occurrence of disconnection can be prevented.

(10) The endoscope according to any one of (1) to (9),
An endoscope in which a plurality of the optical fibers are inserted into the protective tube.
According to this endoscope, it is possible to reliably protect a plurality of optical fibers and prevent disconnection.

DESCRIPTION OF SYMBOLS 11 Endoscope 13 Control apparatus 19 Light source device 21 Processor 25 Insertion part 35 Soft part 37 Bending part 39 Tip part (Endoscope tip part)
45 Image sensor 55, 55A, 55B Optical fiber 57A, 57B Wavelength conversion part 81 Light guide unit 91 Tip light projection part 93 Protection tube 93a Inner hole 100 Endoscope device LD Laser light source

Claims (9)

An elongated insertion portion to be inserted into a subject, an optical fiber that is inserted through the insertion portion and transmits optical energy, and at least a portion of the insertion portion in the longitudinal direction of each of the optical fibers. An endoscope comprising a flexible protective tube covering an outer periphery,
The wall thickness of the tube tube wall of the protective tube is formed to be larger than the maximum radius of curvature at which one of the optical fibers is broken by bending .
An endoscope in which the outer diameter of the protective tube is smaller than the inner diameter of the insertion portion. The endoscope according to claim 1, wherein
An endoscope in which the protective tube is made of a rubber-based material containing either silicon rubber or fluorine-based rubber. The endoscope according to claim 1, wherein
An endoscope in which the protective tube is obtained by applying a fluorine-based coating on the surface of a rubber-based material. The endoscope according to claim 3, wherein
An endoscope in which the fluorine-based coating is a coating using a material containing either polytetrafluoroethylene (PTFE) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). The endoscope according to any one of claims 1 to 4,
An endoscope in which the protective tube supports the optical fiber along a central axis of the protective tube. The endoscope according to any one of claims 1 to 5,
An endoscope in which the optical fiber is supported so as to be movable in the axial direction inside the protective tube. The endoscope according to claim 6, wherein
An endoscope in which the inner diameter of the protective tube is larger than the outer diameter of the optical fiber. The endoscope according to any one of claims 1 to 7,
An endoscope operation unit provided on a proximal end side of the insertion unit and having a bending operation unit;
The insertion portion has a bending portion that is bent by an operation from the operation portion,
An endoscope in which the protective tube is disposed at least in the region of the bending portion of the insertion portion. The endoscope according to any one of claims 1 to 8,
An endoscope in which the protective tube is disposed over the entire length from the distal end side to the proximal end side of the insertion portion.

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