JP5736236B2 - Endoscope - Google Patents

Description

  The present invention relates to an endoscope for observing a body cavity of a patient, and more specifically, a general electronic endoscope that captures a subject image captured via an objective optical system, and a principle of a confocal microscope The present invention relates to an endoscope that is integrated with a confocal probe designed by applying.

  An endoscope in which a general electronic endoscope that captures a subject image captured through an objective optical system and a confocal probe designed by applying the principle of a confocal microscope is integrated is known. (For example, refer to Patent Document 1). In the endoscope described in Patent Document 1, the outer casing portion that holds the confocal probe protrudes closer to the object (subject) than the outer casing portion that holds the electronic endoscope. Confocal observation with this endoscope uses the confocal probe to obtain the image of the tomographic position from the surface layer to the deep layer of the subject such as the biological mucous membrane. The test is performed while applied to the living mucous membrane. Hereinafter, for convenience of explanation, the front end surface of the outer casing portion that holds the electronic endoscope is referred to as a “first surface”, and the front end surface of the outer casing portion that holds the confocal probe is referred to as a “second surface”. .

JP-A-2005-640

  Many parts such as an electronic endoscope objective lens, a light distribution lens, a forceps projecting port, and an air / water feeding port need to be arranged on the first surface of the outer casing. Moreover, severe restrictions are imposed on the external dimensions of the endoscope in order to reduce the burden on the patient at the time of insertion, and the endoscope cannot be designed to be large. Therefore, the area of the second surface of the exterior housing is small. Since the contact area between the second surface and the biological mucous membrane is limited, it is difficult to stabilize the contact position of the second surface with respect to the biological mucous membrane. For example, it is pointed out that it is difficult to acquire an accurate tomographic image because the contact position may be shifted due to the movement of a patient, pulsation in a living body, or the like.

  An endoscope according to an embodiment of the present invention that solves the above problems contains a fluid path that transmits fluid supplied from a first and second optical system and a predetermined external device and discharges the fluid from a discharge port. It has an external casing. The front end surface of the exterior housing is formed at a first surface where the optical element closest to the object side of the first optical system is disposed, and at a position protruding to the object side from the first surface. A second surface on which the optical element closest to the object is disposed, and a step surface connecting the first surface and the second surface. In order to increase the area of the second surface by reducing the area of the first surface, the discharge port is disposed on the step surface instead of the first surface that has been conventionally disposed.

  According to the endoscope of the present invention, the second surface at the front end of the exterior housing can be designed to be large so that the contact area with the subject can be increased, so that the contact position of the second surface with respect to the subject can be stabilized. it can.

  The endoscope according to the present invention may have a configuration including an insertion portion flexible tube whose distal end is connected and fixed to the proximal end of the exterior casing, and a proximal end portion connected to an external device. In this case, the fluid path is disposed over substantially the entire length of the endoscope from the base end portion to the exterior housing through the insertion portion flexible tube, and the discharge port is disposed on the step surface at the distal end of the exterior housing. Thus, the flow path is bent near the front end of the fluid path.

  In order to facilitate assembly work, the fluid path includes a nozzle member having a discharge port accommodated and held in the exterior housing, and a pipe member arranged from the base end portion to a connection position with the nozzle member through the insertion portion flexible tube. It is good also as a structure which a flow path connects when an exterior housing | casing and an insertion part flexible tube are connected and fixed.

  In the step surface at the front end of the outer casing, the discharge port is disposed closer to the first surface than the second surface at the front end of the outer casing in order to efficiently clean the first surface at the front end of the outer casing. It is good. Further, the discharge port may be arranged toward the optical element closest to the object side of the first optical system, and the optical element may be efficiently cleaned.

  The second surface at the front end of the exterior housing is configured as a flat surface or a non-planar surface, for example. As the non-planar specific shape, for example, an uneven surface shape in which a groove is formed with respect to a predetermined planar shape is assumed. For example, the groove portion may have a plurality of long groove shapes arranged so as to extend radially around a predetermined reference point on the second surface.

  The second surface at the front end of the exterior housing may be a surface of an elastic body attached to the exterior housing. In this case, when the second surface is applied to the subject, the second surface is appropriately deformed and comes into close contact with the subject, so that the contact area is increased and the contact position of the second surface with respect to the subject is stabilized.

  The end surface of the second surface at the distal end of the exterior housing is, for example, a predetermined chamfered surface or a tapered surface in order to improve the insertability of the endoscope.

  The fluid paths are, for example, a single fluid path shared by air / water supply or two fluid paths that perform air / water supply.

  The exterior housing is attached to the first surface of the exterior housing tip so that an operator who views the subject image through the first optical system can grasp the approximate positional relationship between the second surface of the exterior housing tip and the subject. On the other hand, the outer shape may be formed so that a part of the portion including the second surface protruding toward the object side falls within the angle of view of the first optical system.

  The first optical system is, for example, a general electronic endoscope optical system having an optical configuration that forms an image of a subject captured from the outside on an imaging surface of a predetermined solid-state imaging device disposed in an exterior housing. is there. In addition, the second optical system, for example, applies the principle of a confocal microscope having an optical configuration having a confocal pinhole that extracts only the reflected light from the condensing point of the irradiated light beam by a predetermined point light source. This is a confocal observation optical system designed to be suitable for mounting on a endoscope.

  ADVANTAGE OF THE INVENTION According to this invention, the endoscope suitable for stabilizing the contact position of the 2nd surface of the exterior housing | casing tip with respect to a to-be-photographed object is provided. Specifically, according to the endoscope according to the present invention, the discharge port is arranged on the step surface between the first surface and the second surface of the exterior housing, so that the second surface at the front end of the exterior housing is enlarged. Since the contact area with the subject can be increased by designing, the contact position of the second surface with respect to the subject can be stabilized.

It is a figure showing roughly the composition of the endoscope system concerning the embodiment of the present invention. It is an external appearance perspective view which shows the external appearance of the front-end | tip part which the integrated endoscope which concerns on embodiment of this invention has. It is a front view which faces the front end surface of the front-end | tip part which the integrated endoscope which concerns on embodiment of this invention has. It is a figure which shows the AA cross section in FIG.3 (b). It is a disassembled perspective view which shows the relationship between the front-end | tip part exterior housing | casing and the air / water supply nozzle unit which the integrated endoscope which concerns on embodiment of this invention has. It is the external appearance perspective view and external appearance front view which show the external appearance of the front-end | tip part which the integrated endoscope which concerns on another embodiment has.

  Hereinafter, an endoscope system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically showing a configuration of an endoscope system 1 of the present embodiment. As shown in FIG. 1, the endoscope system 1 has an integrated endoscope 100 for photographing a subject. The integrated endoscope 100 includes an insertion portion flexible tube 110 that is sheathed by a flexible sheath. At the distal end of the insertion portion flexible tube 110, the proximal end of the distal end portion 112 that is sheathed by a rigid resin casing (hereinafter, referred to as “a distal end exterior housing 112 a”) is connected. The bending portion 114 at the connection portion between the insertion portion flexible tube 110 and the distal end portion 112 is configured to be bendable by remote operation from a hand operation portion 116 connected to the proximal end of the insertion portion flexible tube 110. . This bending mechanism is a well-known mechanism incorporated in a general electronic scope, and is configured to bend the bending portion 114 by pulling the operation wire in conjunction with the rotation operation of the bending operation knob of the hand operation portion 116. ing. When the direction of the distal end portion 112 is changed according to the bending operation by the rotation operation of the knob, the imaging region by the integrated endoscope 100 moves.

  The endoscope system 1 incorporates two imaging systems. One is an imaging system similar to a general endoscope imaging system (hereinafter, referred to as “normal imaging system”) that images a subject with standard magnification and resolution. The other is an imaging system (hereinafter referred to as a “confocal imaging system”) that images a subject at a higher magnification and higher resolution than a normal imaging system.

  The endoscope system 1 includes an electronic endoscope processor 200 that constitutes a normal imaging system. As shown in FIG. 1, the electronic endoscope processor 200 includes a light source device 210, an image processing controller 220, an air pump 230, and a liquid tank 240. The light source device 210 includes an igniter, a lamp, a dimming mechanism, and the like, and is coupled to an incident end of an LCB (Light Carrying Bundle) (not shown). The LCB transmits illumination light from the light source device 210 incident on the incident end, and is emitted from the emission end arranged in the distal end exterior casing 112a. Note that the air pump 230 and the liquid tank 240 are not essential elements constituting the normal imaging system. The air pump 230 and the liquid tank 240 are not limited to the configuration mounted on the electronic endoscope processor 200, and may be mounted on a separate and independent device from the electronic endoscope processor 200.

  FIG. 2 is an external perspective view showing the external appearance of the distal end portion 112. As shown in FIG. 2, the distal end surface of the distal end exterior casing 112a has a first surface 112b and a second surface 112c formed with a step therebetween. On the first surface 112b, a pair of light distribution lenses 112d and an electronic endoscope objective lens 112e constituting a normal imaging system are arranged. Also, a forceps projecting port 112f for projecting a treatment tool such as a forceps inserted into the treatment tool insertion port 118 and passed through a forceps channel (not shown) is also arranged.

  The illumination light emitted from the exit end of the LCB illuminates the subject via the light distribution lens 112d. The reflected light from the subject forms an optical image on the light receiving surface of the solid-state imaging device 120 disposed in the distal end exterior casing 112a through the electronic endoscope objective lens 112e. The solid-state imaging device 120 is, for example, a single-plate color CCD (Charge Coupled Device) having a Bayer pixel arrangement, and is driven at a timing synchronized with a video frame rate in accordance with a clock pulse supplied from the image processing controller 220. The solid-state imaging device 120 accumulates an optical image formed by each pixel on the light receiving surface as a charge corresponding to the amount of light, and converts it into a signal corresponding to each color of R, G, and B. The converted signal is input to the image processing controller 220 via a signal cable (not shown), and is subjected to predetermined image processing to a predetermined standard such as NTSC (National Television System Committee) or PAL (Phase Alternating Line). Is converted into a video signal conforming to By sequentially inputting the converted video signals to the monitor 200M, a color image of a subject having a standard magnification and resolution is displayed on the display screen of the monitor 200M.

  The endoscope system 1 includes a confocal processor 300 that constitutes a confocal imaging system. In the confocal observation using the confocal imaging system, in order to obtain an image of the tomographic position from the surface layer of the subject such as the biological mucous membrane to the deep layer, the second surface 112c of the distal outer casing 112a is applied to the subject. Do. On the other hand, when normal observation is performed using a normal imaging system, an arrangement surface (first surface 112b) of the electronic endoscope objective lens 112e is used for, for example, an electronic endoscope in order to obtain a clear subject image without blurring. It is necessary to move away from the subject by an amount equivalent to the focal length of the objective lens 112e. Therefore, the tip outer casing 112a is formed such that the second surface 112c is positioned so as to protrude a predetermined amount with respect to the first surface 112b. Therefore, the electronic endoscope objective lens 112e is stabilized at a position where the subject is within the depth of field when the second surface 112c is applied to the subject.

  As shown in FIG. 1, the confocal processor 300 includes a confocal light source device 310 and an image processing controller 320. In addition, a confocal optical system unit 130 that constitutes a confocal imaging system is arranged in the distal end exterior casing 112a of the integrated endoscope 100. The confocal optical system unit 130 and the confocal light source device 310 have a well-known configuration that is designed to be suitable for mounting on the endoscope system 1 by applying the principle of the confocal microscope. They are optically coupled via a confocal optical fiber (not shown) disposed over substantially the entire length of the endoscope 100.

  The confocal light source device 310 emits laser light having a wavelength that acts as excitation light on the subject and makes it incident on the proximal end of the confocal optical fiber. The tip of the confocal optical fiber constitutes a confocal optical system unit 130 in the tip end exterior casing 112a, and is periodically cycled in the axial direction and on a substantially plane substantially orthogonal to the direction by a triaxial actuator (not shown). Function as a secondary point light source of a confocal imaging system that moves in a moving manner. Therefore, the excitation light emitted from the tip of the confocal optical fiber scans the subject three-dimensionally via the confocal objective lens 112g disposed on the second surface 112c of the tip outer casing 112a.

  Since the tip of the confocal optical fiber is disposed at the image-side focal position of the confocal objective lens 112g, it functions as a confocal pinhole. That is, only the fluorescence from the condensing point optically conjugate with the tip of the scattering component (fluorescence) of the subject irradiated with the excitation light is incident on the tip of the confocal optical fiber. The fluorescence incident on the tip of the confocal optical fiber is transmitted to the confocal light source device 310, separated and detected from the excitation light from the laser light source, and input to the image processing controller 320.

  The image processing controller 320 obtains a digital detection signal by sample-holding and AD converting the detection signal at a constant rate. For the image corresponding to the substantially planar direction, the point image represented by each digital detection signal is assigned to the pixel address in accordance with a predetermined remapping table in which the signal acquisition timing and the pixel position (pixel address) are associated. A two-dimensional image is generated. The position of the point light source (the tip of the confocal optical fiber) in the axial direction is constantly monitored in the confocal optical system unit 130 and transferred to the image processing controller 320. The image processing controller 320 generates a two-dimensional image for each axial position with reference to the information on the axial position of the point light source. A three-dimensional image is obtained by stacking two-dimensional images corresponding to the respective axial positions. The image processing controller 320 converts the generated 3D image signal into a video signal conforming to a predetermined standard such as NTSC or PAL, and outputs the video signal to the monitor 300M. On the display screen of the monitor 300M, a high-magnification and high-resolution three-dimensional confocal image of the subject is displayed.

  The tip outer casing 112a has an outer shape so that a part of the portion including the second surface 112c protruding toward the object side with respect to the first surface 112b falls within the angle of view of the electronic endoscope objective lens 112e. Is formed. Therefore, in addition to the image of the subject with standard magnification and resolution, a part of the portion of the front end exterior casing 112a that houses the confocal optical system unit 130 is displayed on the display screen of the monitor 200M. Thereby, the surgeon can grasp the approximate positional relationship between the subject and the second surface 112c through the display screen of the monitor 200M.

  3A to 3C are front views of the distal end surface of the distal end portion 112 of the integrated endoscope 100. FIG. For convenience of explanation, in FIG. 3 (b), only the periphery of the air / water supply nozzle unit 160 disposed in the distal end exterior casing 112a is shown in a partial cross section, and in FIG. 3 (c), a partial cross section is shown. In addition, a state in which fluid is discharged from the air / water supply nozzle unit 160 is shown. FIG. 4 is a diagram showing a cross section taken along the line AA in FIG. FIGS. 5A and 5B are exploded perspective views showing the relationship between the tip outer casing 112a and the air / water nozzle unit 160. FIG.

  As shown in FIG. 4, a nozzle unit holding body 162 having a predetermined accommodation space is attached in the tip end exterior casing 112a. The air / water supply nozzle unit 160 is fitted and held in the housing space from the rear side of the outer casing 112a (see FIG. 5A) with almost no gap (see FIGS. 4 and 5B). . An O-ring 164 is attached between the air / water supply nozzle unit 160 and the nozzle unit holder 162 in order to improve airtightness and watertightness (see FIG. 4).

  The air / water supply nozzle unit 160 includes an air supply nozzle 142 and a water supply nozzle 152 arranged side by side on the left and right. When the distal end of the insertion portion flexible tube 110 is connected and fixed to the proximal end of the distal end portion 112, the distal end of the air supply pipe 140 is inserted into the proximal end of the air supply nozzle 142, and the air supply nozzle 142 and the air supply pipe 140 are connected. However, the air supply flow path communicates. At the same time, the tip of the water supply pipe 150 is inserted into the proximal end of the water supply nozzle 152, the water supply nozzle 152 and the water supply pipe 150 are connected, and the water supply flow path is communicated. As shown in FIG. 1, both the air supply pipe 140 and the water supply pipe 150 are disposed over substantially the entire length of the integrated endoscope 100. The base ends of the air supply pipe 140 and the water supply pipe 150 are connected to the air pump 230 and the liquid tank 240, respectively.

  Each of the air supply nozzle 142 and the water supply nozzle 152 has a fluid path extending from the respective base end ports in the longitudinal direction of the integrated endoscope 100 (the axial direction of the confocal optical fiber). The tips of the air supply nozzle 142 and the water supply nozzle 152 are opened to form a substantially circular air supply port 144 and a water supply port 154 centering on an axis substantially orthogonal to the longitudinal direction of the integrated endoscope 100, respectively. Yes. That is, the fluid path extending in the longitudinal direction of the integrated endoscope 100 is bent in a substantially right angle direction on the distal end side. The air / water supply nozzle unit 160 is disposed on a step surface 112h where the air supply port 144 and the water supply port 154 connect the first surface 112b and the second surface 112c (perpendicular to the first surface 112b and the second surface 112c). As shown (in addition, the air supply port 144 and the water supply port 154 are arranged at positions exposed from the opening formed in the stepped surface 112h), the nozzle unit holder 162 (the tip outer casing 112a) Is attached.

  When a predetermined operation is performed on the hand operation unit 116, pressurized air is supplied from the air pump 230 to the air supply pipe 140. The pressurized air flows through the air supply pipe 140 toward the tip 112, reaches the air supply nozzle 142, and is discharged from the air supply port 144 to the outside. When another predetermined operation is performed on the hand operation unit 116, pressurized air is supplied from the air pump 230 to the liquid layer 240. The liquid (washing water) pressurized in the liquid layer 240 flows through the water supply pipe 150 toward the tip 112, reaches the water supply nozzle 152, and is discharged from the water supply port 154 to the outside.

  The air supply port 144 and the water supply port 154 are formed to discharge fluid toward the electronic endoscope objective lens 112e side. In other words, the air supply port 144 and the water supply port 154 open around an axis that is slightly inclined toward the electronic endoscope objective lens 112e side with respect to the axis orthogonal to the longitudinal direction of the integrated endoscope 100. It has a shape. The fluid discharged from the air supply port 144 or the water supply port 154 cleans the first surface 112b (mainly the objective lens 112e for an electronic endoscope) of the tip end exterior casing 112a.

  It is desirable that the air supply port 144 or the water supply port 154 is disposed close to the electronic endoscope objective lens 112e in order to efficiently clean the electronic endoscope objective lens 112e. Therefore, in the present embodiment, the air supply port 144 or the water supply port 154 is disposed at the base of the step (on the step surface 112h, closer to the first surface 112b than the second surface 112c).

  Although not shown in order to simplify the drawing, the water supply pipe 150 actually has a bifurcated configuration, one connected to the water supply nozzle 152 and the other connected to the sub-water supply nozzle. The liquid supplied to the auxiliary water supply nozzle is discharged to the outside from the auxiliary water supply port 170 disposed on the first surface 112b of the front end exterior casing 112a, and cannot be cleaned only with the liquid from the water supply port 154. Auxiliary cleaning of the area.

  In the present embodiment, since the air / water supply port that has been conventionally arranged on the first surface is arranged on the step surface 112h orthogonal to the first surface 112b, the first surface 112b is designed to be smaller and the second surface is designed accordingly. 112c could be designed large. Therefore, the contact area between the second surface 112c and the subject at the time of confocal observation is widened, and the contact position of the second surface 112c with respect to the subject is easily stabilized. For example, the displacement of the contact position caused by the patient's movement or pulsation in the living body is suppressed, which contributes to the acquisition of an accurate tomographic image. Further, when the second surface 112c and the subject are in contact with each other with an inclination instead of the front contact, the contact area can be ensured as compared with the conventional case.

  Moreover, in this embodiment, the restrictions on the dimension of the 2nd surface 112c become loose with the area increase of the 2nd surface 112c. Therefore, for example, the R chamfer 112R of the second surface 112c can be designed to be large so that the insertability of the tip 112 can be improved. The R chamfer 112R may be replaced with a C chamfer or a tapered surface.

  The above is the description of the embodiment of the present invention. The present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention. For example, the second surface 112c is a flat surface in the present embodiment described above, but may be a non-planar surface such as an uneven surface or a curved surface in another embodiment.

  FIGS. 6A and 6B are an external perspective view and an external front view showing the external appearance of the distal end portion 112 according to another embodiment. As shown in FIGS. 6A and 6B, the second surface 112c has a plurality of groove processing portions 112i. Each groove processing portion 112i has a long groove shape, and is formed and arranged so that the long groove shape extends radially around the central axis of the confocal objective lens 112g. The long groove shape has a smooth shape having no sharp portion, and the depth with respect to the second surface 112c is, for example, about 0.1 mm even at the deepest portion. Since the surface area of the second surface 112c is increased by forming the grooved portion 112i on the second surface 112c, the contact area when the second surface 112c is applied to the subject increases. Therefore, the contact position of the second surface 112c with respect to the subject is further stabilized, and the displacement of the contact position due to the movement of the patient, pulsation in the living body, and the like is effectively suppressed. The shape, size, number, arrangement, and the like of each groove processing portion 112i are used to increase the contact area with the large intestine, small intestine, stomach, esophagus, etc., which are the objects to be contacted. It is set after considering it.

  In the present embodiment described above, the air supply channel (the air supply pipe 140, the air supply nozzle 142, the air supply port 144) and the water supply channel (the water supply pipe 150, the water supply nozzle 152, the water supply port 154) are different. In another embodiment, the air supply channel and the water supply channel may be configured as a single channel, and the air / water supply may be performed through a common channel.

  The second surface 112c may be affixed with a thin film elastic member so as to be appropriately deformed and ensure a contact area when pressed against the subject.

DESCRIPTION OF SYMBOLS 1 Endoscope system 100 Integrated endoscope 112 The front-end | tip part 112a The front-end | tip part exterior housing | casing 112b The 1st surface 112c The 2nd surface 112d The light distribution lens 112e The objective lens 112f for electronic endoscopes The forceps protrusion 112g Confocal objective lens 112h Stepped surface 112i Grooving portion 112R R chamfer 140 Air supply pipe 142 Air supply nozzle 144 Air supply port 150 Water supply pipe 152 Water supply nozzle 154 Water supply port 160 Air supply / water supply nozzle unit 162 Nozzle unit holder 164 O-ring 170 Sub-water supply port 200 Electronic endoscope processor 300 Confocal processor

Claims (11)

The first and second optical systems, and an exterior housing that contains a fluid path that transmits fluid supplied from a predetermined external device and discharges the fluid from the discharge port,
The front end surface of the outer casing is
A first surface on which an optical element closest to the object side of the first optical system is disposed;
A second surface on which an optical element closest to the object side of the second optical system is disposed, the second surface being formed at a position protruding toward the object side from the first surface;
A step surface connecting the first surface and the second surface;
Have
The discharge port is
Arranged on the step surface,
The second surface is
It is an uneven surface shape in which grooves are formed with respect to a predetermined planar shape
The groove is
Each extending in different directions, and having a plurality of groove shapes formed shallow enough to contact when the second surface is applied to the subject ,
Endoscope. An insertion portion flexible tube whose tip is connected and fixed to the base end of the exterior housing;
A proximal end connected to the external device;
Have
The fluid path is
The endoscope is disposed over substantially the entire length of the endoscope from the base end portion to the exterior casing through the insertion portion flexible tube, and the fluid passage is arranged so that the discharge port is disposed on the step surface. The flow path is bent near the tip ,
The endoscope according to claim 1. The fluid path is
A nozzle member having the discharge port accommodated and held in the exterior housing;
A pipe member disposed from the base end portion to a connection position with the nozzle member through the insertion portion flexible tube;
Have
When the outer casing and the insertion portion flexible tube are connected and fixed, the flow path communicates .
The endoscope according to claim 2. In the step surface, the discharge port is disposed closer to the first surface than the second surface .
The endoscope according to any one of claims 1 to 3. In the step surface, the discharge port is disposed toward the optical element closest to the object side of the first optical system .
The endoscope according to any one of claims 1 to 4. The groove is
Having a plurality of elongated groove shapes arranged radially extending about a predetermined reference point of the second surface ;
The endoscope according to any one of claims 1 to 5 . The second surface is
It is a surface of an elastic body attached to the exterior casing ,
The endoscope according to any one of claims 1 to 6 . The end surface of the second surface is
A predetermined chamfered surface or a tapered surface ;
The endoscope according to any one of claims 1 to 7 . The fluid path is
One fluid path for air / water sharing or two fluid paths for air / water supply ,
The endoscope according to any one of claims 1 to 8 . The outer casing is
The outer shape is formed such that a part of the portion including the second surface protruding toward the object side with respect to the first surface falls within the angle of view of the first optical system .
The endoscope according to any one of claims 1 to 9 . The first optical system includes:
An optical configuration that forms an image of the captured subject on an imaging surface of a predetermined solid-state imaging device disposed in the exterior housing;
The second optical system includes
Having an optical arrangement having a confocal pinhole to extract only the reflected light from the focal point of the irradiation light beam with a predetermined point light source,
The endoscope according to any one of claims 1 to 10 .

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