JP6006355B2 - Scanning observation apparatus using wide-angle light detection member - Google Patents

Description

  The present invention relates to a scanning observation apparatus using a wide-angle light detection member suitable for a fiber scanning observation apparatus that can be made thinner than a conventional electronic endoscope.

For example, scanning probes described in the following Non-Patent Documents 1 and 2 have been proposed as observation apparatuses that can be made smaller in diameter than conventional electronic endoscopes.
FIG. 9 is an explanatory diagram showing a configuration example of the scanning probe described in Non-Patent Document 2. For example, as shown in FIG. 9, this type of scanning probe oscillates an illumination optical fiber 51 guided with illumination light through an actuator 52 to emit light in a predetermined pattern onto an object. Scanning is performed, and the return light from the object is received by the detection optical fiber 53 and imaged. In the figure, reference numeral 54 denotes an illumination lens.
As this type of scanning probe, one having an outer diameter of about 1 mm has been proposed. A multimode fiber is used as the detection optical fiber, and its diameter is as small as several hundreds of micrometers or less.

By the way, in such a scanning observation apparatus, the field angle is restricted to a smaller one of an irradiation angle and a detected light receiving angle (capture angle).
FIG. 10 is an explanatory diagram showing the relationship between the irradiation angle and the capture angle of the scanning observation apparatus.
The irradiation angle is determined by the vibration amplitude and deflection angle of the tip of the illumination optical fiber and the focal length of the illumination lens, and can be about 100 degrees. On the other hand, the capture angle is determined by the NA of the detection optical fiber, but at present, the NA of the detection optical fiber is about 70 degrees as the NA 0.6.
For this reason, even if it can be illuminated, the angle of view is limited by the taking-in angle of the optical fiber for detection, and an area that cannot be detected is particularly prominent around the image and is more than 90 degrees necessary for use as an endoscope. It is difficult to obtain the angle of view.
For this reason, in order to use the scanning observation apparatus as described above as an endoscope, it is necessary to widen the capture angle beyond an angle determined by the NA of the detection optical fiber.

As a conventional technique regarding widening using an optical fiber, for example, the following Patent Document 1 describes a technique for widening an irradiation angle with respect to an optical fiber for illumination.
FIG. 11 is an explanatory view showing the configuration of the wide-angle illumination device described in Patent Document 1, wherein (a) is a cross-sectional view of one configuration example thereof, (b) is a plan view of (a) as viewed from the front, c) is a cross-sectional view of another configuration example, (d) is a cross-sectional view of still another configuration example, (e) is a cross-sectional view of still another configuration example, and (f) is a cross-sectional view of still another configuration example. is there.
In the technique described in Patent Document 1, a second light guide 63 (peripheral illumination) is provided around a first light guide 62 (front-facing illumination optical fiber) arranged in a ring around the image transmission system 61. Optical fiber), and the tip of the second light guide 63 is inclined outward (see FIG. 11A), cut obliquely (see FIG. 11C), or the tip of the second light guide 63 Further, by providing the reflecting member 64 (see FIG. 11D) and the prism 65 (see FIG. 11E), the irradiation angle is expanded. Patent Document 1 also discloses a technique for expanding the irradiation angle by providing a wide-angle lens 66 (see FIG. 11 (f)) at the tip of the illumination optical fiber 62 as a conventional technique.

Japanese Patent No. 2941621

In Press, Optical fibers and Sensors for Medical Diagnosis and Treatment Applications, Ed. I. Gannot, Proc.SPIE vol. 6083 Gastrointest Endoscopy Clin N Am 18 (2008) 467-478

However, in the technique described in Patent Document 1, no consideration is given to the adhesion of the liquid to the optical member that expands the irradiation angle. For this reason, when the technique described in Patent Document 1 is used for an optical fiber for detection of an endoscope, the uptake angle is greatly changed when a component that enlarges the irradiation angle at the tip is wetted with body fluid or water. The corner changes greatly.
Further, the technique described in Patent Document 1 is thicker because the second light guide 63 (peripheral illumination optical fiber) is provided around the first light guide 62 (front illumination optical fiber). It becomes diameter.
In addition, if a lens or the like is provided at the tip of the light guide, it is difficult to form the lens smaller than the end face of the optical fiber, and as a result, the diameter of the lens increases with the diameter of the lens.
Further, the optical fiber having the end face obliquely cut as shown in FIG. 11 (c) needs to adjust the inclination direction of the end face of the optical fiber at the time of assembly so as not to cause anisotropy in the angle of view. Becomes complicated.

Here, the point that the diameter increases when a scattering member or a lens / prism is used at the tip of the optical fiber will be described.
FIG. 12 is an explanatory diagram showing the relationship between a configuration in which a scattering member or a lens is provided at the tip of an optical fiber and a diameter increase, and FIG. 12 (a) shows a thick diameter in a configuration in which a scattering member is provided at the tip of an optical fiber. FIG. 4B is a diagram illustrating the diameter increase, and FIG. 5B is a diagram illustrating the diameter increase in the configuration in which a lens is provided at the tip of the optical fiber. In FIG. 12, 71 is a detection optical fiber, 72 is a fiber core part, 73 is a fiber clad part, 74 is a scattering member in which a light scatterer such as beads is mixed and solidified, and 75 is a concave lens.
As shown in FIG. 12A, when the scattering member 74 is provided at the tip of the detection optical fiber 71, an effect of increasing the capture angle can be obtained. However, in order to obtain a sufficient expansion effect, it is necessary to increase the thickness of the scattering member 74. However, when the thickness of the scattering member 74 is increased, the diameter must be increased in order to receive light at a wide angle.

  12B, when the concave lens 75 is provided at the tip of the detection optical fiber 71, the diameter of the concave lens 75 is set to the diameter of the detection optical fiber 71 in order to suppress an increase in diameter. Must be equal or less. However, the diameter of the detection optical fiber 71 is several hundred μm or less, and it is very difficult to process the concave lens 75 into a diameter equal to or smaller than that of the detection optical fiber 71. For this reason, when the concave lens 75 is provided at the tip of the detection optical fiber 71, it is difficult to keep the entire diameter equal to that of the detection optical fiber 71. In addition, when a lens is used, the difficulty of assembly such as adjustment of the eccentricity between the optical fiber for detection and the lens becomes very high. Here, a concave lens is described as an example, but the same applies to a convex lens.

  The present invention has been made in view of the above-described conventional problems, and it is possible to widen the taking-in angle while maintaining a small diameter, and the taking-in angle is not reduced by liquid adhesion at the tip. It is an object of the present invention to provide a scanning observation apparatus using a wide-angle light detection member that can be simplified.

To achieve the above object, a scanning observation apparatus according to the present invention includes a scanning illumination optical system that vibrates an illumination optical fiber and scans illumination light on an object, and at least a side of the scanning illumination optical system. A wide-angle light detection member, the wide-angle light detection member; a detection optical fiber that receives light; and a capture angle expansion surface that is formed at a tip of the detection optical fiber and that expands the capture angle. The optical element has a refractive index different from the refractive index of the optical element located in the vicinity of the rear of the taking-in angle expanding surface, and has sealing means for sealing the taking-in angle expanding surface.

  Further, in the scanning observation apparatus of the present invention, the capture angle expansion surface is a rough surface formed on the distal end surface of the detection optical fiber, and the sealing means is a core portion of the detection optical fiber. Preferably, it is made of a sealing material having a refractive index different from the refractive index.

  Further, in the scanning observation apparatus of the present invention, the capture angle expansion surface is a spherical surface formed on the distal end surface of the detection optical fiber, and the sealing means is a core portion of the detection optical fiber. It is preferably made of a sealing material having a refractive index higher than the refractive index.

  In the scanning observation apparatus of the present invention, it is preferable that the sealing means is a mixture of light scatterers.

  Further, in the scanning observation apparatus according to the present invention, the capture angle expansion surface is formed on a surface opposite to the detection optical fiber in the thin optical member disposed in proximity to the distal end surface of the detection optical fiber. Preferably, the sealing means is made of a sealing material having a refractive index different from that of the thin optical member.

  According to the present invention, the scanning angle observation using the wide-angle light detection member that can widen the capturing angle while maintaining a small diameter, does not decrease the capturing angle due to liquid adhesion at the tip, and can be easily assembled. A device is obtained.

It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 1st Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 2nd Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 3rd Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 4th Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 5th Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the wide-angle light detection member used for the scanning observation apparatus concerning 6th Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the scanning observation apparatus using the wide angle light detection member concerning 7th Embodiment of this invention, (a) is sectional drawing, (b) is the top view seen from the front. It is the top view which looked at the structure of the scanning observation apparatus using the wide-angle light detection member concerning the modification of FIG. 7 from the front. It is explanatory drawing which shows one structural example of the scanning probe described in the nonpatent literature 2. It is explanatory drawing which shows the relationship between the irradiation angle of a scanning observation apparatus, and a taking-in angle. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of the wide angle illuminating device described in patent document 1, (a) is sectional drawing of the example of 1 structure, (b) is the top view which looked at (a) from the front, (c) is FIG. 6 is a cross-sectional view of another configuration example, FIG. 4D is a cross-sectional view of still another configuration example, FIG. 5E is a cross-sectional view of still another configuration example, and FIG. FIG. 12 is an explanatory diagram showing the relationship between a configuration in which a scattering member or a lens is provided at the tip of an optical fiber and a diameter increase, and FIG. 12 (a) shows a thick diameter in a configuration in which a scattering member is provided at the tip of an optical fiber. FIG. 4B is a diagram illustrating the diameter increase, and FIG. 5B is a diagram illustrating the diameter increase in the configuration in which a lens is provided at the tip of the optical fiber.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is an explanatory view showing the configuration of the main part of a wide-angle light detection member used in a scanning observation apparatus according to a first embodiment of the present invention.
The wide-angle light detection member used in the scanning observation apparatus of the present embodiment includes a detection optical fiber 1 that receives light, and a capture angle expansion surface 4 that is formed at the tip of the detection optical fiber 1 and expands the capture angle. And a sealing means 5 having a refractive index different from the refractive index of the optical element located in the vicinity of the rear of the taking-in angle expanding surface 4 and sealing the taking-in angle expanding surface. In FIG. 1, 2 is a core portion of the detection optical fiber 1, and 3 is a cladding portion of the detection optical fiber 1.
The capture angle expansion surface 4 is formed of a rough surface formed on the distal end surface of the detection optical fiber 1.
In the first embodiment, the optical element located in the vicinity of the rear of the taking-in angle expanding surface 4 is the core portion 2 of the detection optical fiber.
The sealing means 5 is made of a sealing material such as a resin having a refractive index different from the refractive index of the core portion 2 of the detection optical fiber 1.

According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the capture angle is expanded by the rough surface formed on the distal end surface of the detection optical fiber 1. For this reason, compared with the structure which uses a scattering member and a lens for the front end surface of the optical fiber for a detection as shown in FIG. 12, the expansion of the diameter for enlarging a taking-in angle can be suppressed.
Moreover, since the rough surface as the capture angle expansion surface 4 is sealed with a sealing material having a refractive index different from the refractive index of the fiber core portion 2, even if liquid adheres to the tip of the wide-angle light detection member, the rough surface As a result, the effect of widening the capture angle is not reduced.
Furthermore, since no optical member such as a lens is provided at the tip of the detection optical fiber 1, the number of parts is reduced, and assembly is facilitated.

Second Embodiment FIG. 2 is an explanatory view showing the configuration of the main part of a wide-angle light detection member used in a scanning observation apparatus according to a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member with the same structure as 1st Embodiment.
In the wide-angle light detection member used in the scanning observation apparatus according to the present embodiment, the capture angle expansion surface 4 ′ is configured by a spherical surface formed on the distal end surface of the detection optical fiber 1.
Further, the sealing means 5 ′ is made of a sealing material such as a resin having a higher refractive index than the refractive index of the core portion 2 of the detection optical fiber 1.

According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the tip surface of the detection optical fiber 1 is processed into a spherical surface, and the spherical surface is sealed with a refractive index higher than the refractive index of the fiber core portion 2. By sealing with a stop material, the seal material can function as a concave lens having negative power, and the take-in angle can be expanded beyond the NA of the optical fiber for detection.
In addition, the sealing material such as resin can be thinned. For this reason, compared with the structure which has optical members, such as a lens, in the front-end | tip of a detection optical fiber as shown in FIG. 12, the expansion of the diameter for expanding a taking-in angle can be suppressed.
Other functions and effects are substantially the same as those of the wide-angle light detection member used in the scanning observation apparatus of the first embodiment.

Third Embodiment FIG. 3 is an explanatory view showing the main configuration of a wide-angle light detection member used in a scanning observation apparatus according to a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member with the same structure as 1st Embodiment.
In the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the sealing means 5 ″ is composed of a sealing material in which light scatterers such as beads and gas are mixed, for example. This is substantially the same as the first embodiment.
According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the effect of enlarging the capture angle by the rough surface formed on the front end surface of the detection optical fiber 1 and the front end of the wide-angle light detection member by the sealing material In addition to the effect of maintaining the effect of enlarging the capture angle when the liquid adheres, the light scattering material mixed in the sealant provides the effect of enlarging the capture angle of the sealant itself, and the capture angle of the entire wide-angle light detection member The enlargement effect increases.
Other functions and effects are substantially the same as those of the wide-angle light detection member used in the scanning observation apparatus of the first embodiment.

Fourth Embodiment FIG. 4 is an explanatory view showing the main configuration of a wide-angle light detection member used in a scanning observation apparatus according to a fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member with the same structure as 1st Embodiment.
In the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the sealing means 5 ″ ′ is made of a sealing material in which a light scatterer such as beads or gas is mixed. Is substantially the same as in the second embodiment.
According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the effect of enlarging the capture angle by the spherical surface formed on the tip surface of the detection optical fiber 1 and the tip of the wide-angle light detection member by the sealing material In addition to maintaining the effect of enlarging the capture angle when liquid is attached, the effect of enlarging the capture angle of the encapsulant itself is obtained by the light scatterer mixed in the encapsulant, and the capture angle of the entire wide-angle light detection member is expanded. The effect is increased.
Other functions and effects are substantially the same as those of the wide-angle light detection member used in the scanning observation apparatus of the second embodiment.

Fifth Embodiment FIG. 5 is an explanatory view showing the main configuration of a wide-angle light detection member used in a scanning observation apparatus according to a fifth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member with the same structure as 1st Embodiment.
The wide-angle light detection member used in the scanning observation apparatus of this embodiment includes a thin optical member 6 at the tip of the detection optical fiber 1.
The capture angle widening surface 4 ″ is constituted by a rough surface formed on the surface of the thin optical member 6 opposite to the detection optical fiber 1.
The sealing means 5 ″ ″ is composed of a sealing material having a refractive index different from the refractive index of the thin optical member 6.

  According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the capture angle is increased by the rough surface formed on the distal end surface of the thin optical member 6 as in the first embodiment. For this reason, compared with the structure provided with the scattering member and lens of the optical fiber for a detection as shown in FIG. 12, the expansion of the diameter for expanding a taking-in angle can be suppressed. Moreover, since the rough surface as the taking-in angle expansion surface 4 ″ is sealed with a sealing material having a refractive index different from that of the thin optical member 6, even if liquid adheres to the tip of the wide-angle light detection member. The effect as a rough surface is not lost, and the effect of widening the capture angle is not reduced.

Also, according to the wide-angle light detection member used in the scanning observation apparatus of this embodiment, unlike the first embodiment, a rough surface is formed on the thin optical member 6 without forming a rough surface on the detection optical fiber. In addition, since the rough surface of the thin optical member 6 is sealed with a sealing material, the take-in angle can be changed by inserting and removing the thin optical member 6 sealed with the sealing material. Applications are expanded.
For example, when it is desired to detect light from a specific detection target located in front using a scanning observation apparatus, the detection intensity becomes weak when the capture angle is wide. On the other hand, when it is desired to detect light from a wide range of detection targets located in the vicinity, an area that cannot be detected occurs if the capture angle is narrow. However, it is expensive to replace the scanning observation device for front detection and the scanning observation device provided with the wide-angle light detection member shown in the first to fourth embodiments according to these observation applications. In addition, the replacement work of the apparatus becomes complicated.
However, according to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, any of the above can be obtained by inserting and removing the thin optical member 6 having a rough surface used in the common scanning observation apparatus. Therefore, the cost can be reduced and the work load can be reduced.

Sixth Embodiment FIG. 6 is an explanatory view showing the configuration of the main part of a wide-angle light detection member used in a scanning observation apparatus according to a sixth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member with the same structure as 1st Embodiment.
The wide-angle light detection member used in the scanning observation apparatus of this embodiment includes a thin optical member 6 at the tip of the detection optical fiber 1.
The capture angle expansion surface 4 ″ ′ is a rough surface formed on the surface of the thin optical member 6 on the detection optical fiber 1 side.
The sealing means 5 ″ ″ ′ is made of a glass material of the thin optical member 6 having a refractive index different from the refractive index of the core portion of the detection optical fiber 1.

According to the wide-angle light detection member used in the scanning observation apparatus of the present embodiment, the capture angle is expanded by the rough surface of the thin optical member 6 located near the tip of the detection optical fiber 1. For this reason, compared with the structure which has a scattering member and a lens in the front end surface of a detection optical fiber as shown in FIG. 12, the expansion of the diameter for enlarging a taking-in angle can be suppressed.
Moreover, since the rough surface as the capturing angle widening surface 4 ″ ′ is sealed with the glass material of the thin optical member 6 having a refractive index different from the refractive index of the fiber core portion 2, the liquid is applied to the tip of the wide-angle light detection member. Even if it adheres, the effect as a rough surface is not lost, the effect of expanding the take-in angle is not reduced, and a sealing material is not required.
Also, according to the wide-angle light detection member used in the scanning observation apparatus of this embodiment, unlike the first embodiment, a rough surface is formed on the thin optical member 6 without forming a rough surface on the detection optical fiber. In addition, since the rough surface is sealed with the glass material of the thin optical member 6, the taking-in angle can be changed by inserting and removing the thin optical member 6, and the observation application is expanded.

Seventh Embodiment FIG. 7 is an explanatory view showing the main configuration of a scanning observation apparatus using a wide-angle light detection member according to a seventh embodiment of the present invention, and (a) is a cross-sectional view showing the main configuration. b) is a plan view seen from the front. Members having the same configurations as those of the first embodiment are denoted by the same reference numerals.
The scanning observation apparatus according to the seventh embodiment includes a scanning illumination optical system 10 and a plurality of wide-angle light detection members 11 arranged in a ring shape on the side of the scanning illumination optical system 10.
The scanning illumination optical system 10 is configured to scan the illumination light on the object by vibrating the illumination optical fiber 10a. In FIG. 7, reference numeral 10b denotes an illumination lens.
Each wide-angle light detection member 11 is configured in substantially the same manner as the wide-angle light detection member of the first embodiment (or the second embodiment) in FIG.
In the scanning observation apparatus according to the present embodiment, the rough surface (or spherical surface) as the capture angle expansion surface 4 (or the capture angle expansion surface 4 ′) formed on the distal end surfaces of all the detection optical fibers 1 is: As shown in FIG. 7 (b), the sealing means 5 (or the sealing means 5 ′) is collectively sealed with a sealing material.

According to the scanning observation apparatus using the wide-angle light detection member of the present embodiment, the capture angle can be expanded while maintaining a small diameter, and even when liquid adheres to the tip, the capture angle can be maintained in an expanded state. .
In addition, since all the wide-angle light detection members can be configured by sealing the front end surfaces of all of the detection optical fibers 1 that have been processed into a rough surface or a spherical surface with a sealing material such as a resin, assembly performance is improved. improves.

  In the scanning observation apparatus of FIG. 7, all of the detection optical fibers 1 arranged in a ring shape on the side of the scanning illumination optical system 10 have a roughened or spherically processed tip surface. However, the detection optical fiber disposed in a ring shape on the side of the scanning illumination optical system 10 may include at least one detection optical fiber having a polished end surface. In that case, the sealing material may cover at least the roughened or spherically processed tip surface of the tip surfaces of all the detection optical fibers, and does not need to cover the tip surface that has been flat-polished. Good.

When observing a tubular object such as an intestine, the object in the front (center of angle of view) is located at a relatively long distance from the tip of the detection optical fiber, and the object near the periphery is the tip of the detection optical fiber. It tends to be in a state existing at a short distance.
However, in the scanning observation apparatus of the present embodiment, the detection optical fiber 1 whose tip surface is formed in a rough surface (or spherical surface) is used as a detection optical fiber that is annularly arranged on the side of the scanning illumination optical system 10. At the same time, if it is configured to include a detection optical fiber whose front end surface is polished, it is possible to receive more light of the object from the front which tends to be dark.

Further, as shown in FIG. 8, a wide-angle light detection member 11 made of a detection optical fiber having a roughened or spherically processed tip surface and a detection optical fiber 11 ′ having a polished tip surface are alternately arranged. May be.
In this way, light from the object can be received at a wide angle in a uniform state without the light of the object from the front becoming dark in a uniform state.

Further, in the scanning observation apparatus of the present embodiment, the wide-angle light detection members 11 arranged in a ring shape on the side of the scanning illumination optical system 10 are substantially the same as the wide-angle light detection members of the third to sixth embodiments. You may use what was comprised in.
7 and 8, the wide-angle light detection member 11 is annularly arranged on the side of the scanning illumination optical system 10, but is not limited to the annular arrangement. For example, a forceps and an illumination optical system You may arrange | position so that all the gaps according to the structure of an endoscope, such as a clearance gap, may be filled.

  The scanning observation apparatus using the wide-angle light detection member of the present invention is applicable to all fields in which it is required to observe a small-diameter object that is difficult to observe with a conventional electronic endoscope, such as a pancreatic duct or bile duct. Useful for.

DESCRIPTION OF SYMBOLS 1 Optical fiber for detection 2 Fiber core part 3 Fiber clad part 4, 4 ', 4 ", 4"' Capture angle expansion surface 5, 5 ', 5 ", 5"', 5 "", 5 ""'Sealing Means 6 Thin optical member 10 Scanning illumination optical system 10a Illumination optical fiber 10b Illumination lens 11 Wide-angle detection member 11 ′ Detection optical fiber 51 whose tip surface has been polished flat Illumination optical fiber 52 Actuator 53 Detection optical fiber 54 Illumination Lens 61 Image transmission optical system 62 First light guide 63 Second light guide 64 Reflective member 65 Prism 66 Wide angle lens 71 Optical fiber for detection 72 Fiber core portion 73 Fiber clad portion 74 Scattering member 75 Concave lens

Claims (5)

A scanning illumination optical system that scans illumination light on an object by vibrating an optical fiber for illumination; and
Having at least one wide-angle light detection member on a side of the scanning illumination optical system;
The wide-angle light detection member is
A detection optical fiber that receives light;
A capture angle widening surface formed at the tip of the optical fiber for detection, which widens the capture angle;
A scanning observation apparatus, comprising: a sealing unit that has a refractive index different from a refractive index of an optical element located in the vicinity of the rear of the capturing angle expanding surface and seals the capturing angle expanding surface. The capture angle expansion surface is a rough surface formed on the distal end surface of the detection optical fiber,
The scanning observation apparatus according to claim 1, wherein the sealing unit is made of a sealing material having a refractive index different from that of the core of the detection optical fiber. The capture angle expansion surface is a spherical surface formed on the tip surface of the detection optical fiber,
The scanning observation apparatus according to claim 1, wherein the sealing unit is made of a sealing material having a refractive index higher than the refractive index of the core portion of the detection optical fiber.   The scanning observation apparatus according to claim 1, wherein the sealing unit is a mixture of light scatterers. The capture angle expansion surface is a rough surface formed on the surface opposite to the detection optical fiber in the thin optical member disposed close to the tip surface of the detection optical fiber,
The scanning observation apparatus according to claim 1, wherein the sealing unit is made of a sealing material having a refractive index different from that of the thin optical member.

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