JPH04312436A - Endoscope - Google Patents

Abstract

PURPOSE:To provide the observation depth in response to the distance to a test object by stably changing the brightness aperture of the objective optical system of an endoscope with a simple structure. CONSTITUTION:Radial notches are provided on the periphery of the aperture hole 13 of a flat plate 12 made of two-polarity SMA, and the shapes of burr sections 15 formed around the aperture hole 13 according to the notches are stored. If a test object to be observed is located afar, when an observer excites the flat plate 12, the flat plate 12 is heated, burr sections 15 are formed near the optical axis of an objective optical system, the diameter of the aperture hole 13 is expanded, and the objective optical system has the brightness aperture as if it is nearly opened. If the test object to be observed is located nearby, when the observer stops the excitation of the flat plate 12, the flat plate 12 radiates heat to the periphery and is cooled, it is returned to the state with no burr section 15, the aperture hole 13 is made the minimum aperture diameter, and the objective optical system has the brightness aperture with deep observation depth.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope having an objective optical system equipped with an aperture device for observing a subject.

0002

[Prior Art] In recent years, endoscopes that can diagnose and examine internal organs in body cavities by inserting their elongated insertion portions into body cavities have been widely used. They are used not only for medical purposes but also for industrial purposes, to observe and inspect damage, corrosion, etc. inside piping of boilers, gas turbine engines, chemical plants, etc., or inside automobile engines, bodies, etc.

In many endoscopes, the objective optical system for observing the subject is equipped with an aperture device to adjust the amount of incident light, which increases the observation depth and allows for a wide range of vision even with a fixed focus. Various techniques have been conventionally proposed regarding the aperture device.

For example, Japanese Patent Application Publication No. 56-42218 discloses a technique in which a diaphragm device provided in the middle of an objective optical system is formed from a piezoelectric film.
No. 9692 and Japanese Utility Model Application No. 1-88930 disclose an aperture mechanism that moves an aperture spring using an electromagnet and a bimorph element, respectively, as an actuator for a mechanical aperture device.

Furthermore, Japanese Patent Application Laid-Open No. 126526/1983 discloses a technique in which a diaphragm device provided in the middle of an objective optical system is formed from a bimorph element. In the aperture device according to this prior art, a plurality of approximately triangular bimorph elements are arranged radially to form an approximately circular shape to form an aperture hole in the center, and when a voltage is applied to the bimorph element, the bimorph element warps and It takes advantage of the fact that the diameter of the aperture hole changes.

Furthermore, Japanese Patent Application Laid-Open No. 2-285333 discloses that a planar rotor and stator having throttle holes formed therein,
An electrostatic motor is constructed by providing comb-shaped electrodes for each.
A technique has been disclosed in which an arbitrary aperture can be selected by sliding a rotor relative to a fixed stator.

[0007]

[Problems to be Solved by the Invention] However, in an endoscope, the aperture device needs to be made as small as possible because image capturing means, illumination means, etc. are arranged at the distal end of the insertion section. It is desirable to be able to stably change the aperture aperture and to obtain an observation depth that corresponds to the distance to the subject.

On the other hand, the aforementioned aperture device, which uses an electromagnet as an actuator in a mechanical aperture device, has a complicated structure and is large in size, making it difficult to incorporate it into the distal end of the insertion section of an endoscope. Also, in the above-mentioned aperture device that uses a bimorph element as an actuator in a mechanical aperture device, since the amount of drive displacement of the bimorph element is small, there is a transmission between the bimorph element and the aperture blades to increase the amount of displacement. A mechanism must be provided, and similarly, the diaphragm device is large and difficult to incorporate into the endoscope.

Furthermore, since the size of the aperture hole in the aperture device incorporated into the endoscope is inevitably determined by the optical system of the endoscope, if the aperture device is miniaturized and incorporated into the endoscope, the aperture hole size is determined by the optical system of the endoscope. The proportion of the aperture hole in the whole becomes large.

On the other hand, in the above-mentioned aperture device using an electrostatic motor, if the proportion of the aperture hole in the entire aperture device becomes large, the strength against repeated sliding may be insufficient and stability may be lost. Similarly, the aperture device using the piezoelectric film described above also has a problem in that the amount of displacement of the piezoelectric film is not stable over time due to insufficient mechanical strength.

Furthermore, in the above-mentioned aperture device that utilizes the warpage of the bimorph element, it is difficult to increase the amount of warpage of the bimorph element. When incorporated into an endoscope, there is a risk that the required optical performance may not be achieved.

The present invention has been made in view of the above circumstances, and provides an endoscope that has a simple configuration, can stably change the aperture aperture, and can obtain an observation depth according to the distance to the subject. The purpose is to provide

[0013]

[Means for Solving the Problems] The endoscope of the present invention is such that an objective optical system for observing a subject is provided with an aperture device that changes the aperture aperture using a bidirectional shape memory material. .

[0014]

[Operation] In the endoscope of the present invention, the incident light incident from the subject to the objective optical system is focused by the diaphragm device whose diaphragm aperture is variable using a bidirectional shape memory material.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 relate to the first embodiment of the present invention, and FIG.
is an explanatory diagram showing the configuration of the tip of the insertion section of the endoscope, FIG. 2 is an explanatory diagram showing the configuration of the aperture device, FIG. 3 is an explanatory diagram with the aperture in the open state, and FIG. 4 is an explanatory diagram with the aperture in the most narrowed state. It is a diagram.

In FIG. 1, reference numeral 1 denotes an insertion section of an optical endoscope. This insertion section 1 is formed into an elongated shape so that it can be inserted into a subject, and has a hard tip 2 with an illumination window 3 and an observation window. 4 is provided. An illumination lens 5 is provided inside the illumination window 3, and the output end surface of the light guide bundle 6 is disposed at the rear end of the illumination lens 5.

The light guide bundle 6 is bundled by a base 7 and protected by, for example, a silicon tube 8, and is connected to the insertion portion 1 and a large-diameter handle (not shown) connected to the rear end of the insertion portion 1. The inside of the body is penetrated, and
It is inserted through a universal cord (not shown) extending from the operating section, and its incident end face is connected to a light source device (not shown) via a light guide connector (not shown). Illumination light emitted from this light source device is incident on the incident end face of the light guide bundle 6, passes through the light guide bundle 6 and the illumination lens 5, and is irradiated onto the observation target.

Further, an objective optical system 9 is provided inside the observation window 4, and an aperture device 10 is provided on this objective optical system 9. Further, an entrance end surface of an image guide bundle 11 serving as an image transmission means is disposed at the imaging position of the objective optical system 9, and an exit end surface of the image guide bundle 11 is connected to the rear end of the operating section. Opposed to an optical system of an eyepiece (not shown), an observation image of the subject captured by the objective optical system 9 can be observed with the naked eye from the eyepiece.

As shown in FIGS. 2 and 3, the drawing device 10 includes a flat plate 12 made of bidirectional shape memory alloy (SMA).
A diaphragm hole 13 serving as a diaphragm opening is formed approximately in the center of this flat plate 12. The aperture hole 13 is arranged centered on the optical axis of the objective optical system 9, and constitutes an objective optical system with a deep observation depth.

A radial notch 14 as shown in FIG. 3 is provided around the aperture hole 13, and as shown in FIG. The shape of the portion 15 is bidirectional SM
A is stored in the flat plate 12 consisting of A.

An electric cable 16 is connected to the diaphragm device 10, and the plane plate 12 can be energized arbitrarily by a switch (not shown) at the viewer's hand. When it is not done,
As shown in FIG. 3, when the aperture hole 13 has the minimum aperture diameter in terms of optical design and the flat plate 12 is energized and generates heat due to the energized current, as shown in FIG. A portion 15 is formed so that the diameter of the aperture hole 13 increases.

[0022] In the endoscope configured as described above, when the object to be observed is located far away, the observer can use the aperture device 1.
0 is energized. As a result, the plane plate 12 made of bidirectional SMA generates heat, causing a burr 15 near the optical axis of the objective optical system 9.
is formed, and the diameter of the aperture hole 13 increases. As a result, the objective optical system 9 comes to have an aperture aperture close to its maximum aperture.

On the other hand, when observing the periapsis, when the observer stops energizing the aperture device 10, the flat plate 12 radiates heat to the surroundings and is cooled, returning to the state without the burr 15. do. As a result, the aperture hole 13 has a minimum aperture diameter, and the objective optical system 9 has an aperture aperture that increases the observation depth.

In this case, for example, the best focus position of the objective optical system 9 is set at a slightly far side, and when approaching the object to be observed from a distance, the diaphragm device 10 is energized to widen the aperture diameter. It can be used as an endoscope with a built-in system, making it easier to discover scratches and the like. When you want to observe in more detail, you can get closer to the object to be observed and stop energizing the aperture device 10. This narrows down the aperture diameter and deepens the observation depth, which prevents you from missing the target point such as a scratch. , it is no longer difficult to see because it is too bright when approaching, allowing for detailed observation.

That is, although the configuration of the aperture device 10 is simple, it is possible to reliably adjust the amount of light and obtain stable optical performance. As a result, it is possible to obtain an observation depth that corresponds to the distance to the subject, making reliable observation possible at all times.

The diaphragm device 10 is constructed so that the plane plate 12 is made thin so that it can fully exhibit its optical performance as a diaphragm. However, if you want to expect an even better effect from the edges of the diaphragm, please refer to the diagram below. As shown in FIG. 4, edge members 17 and 18 that are thinner than the plane plate 12 may be separately bonded to the burr portion 15 and the aperture hole 13. Thereby, the thickness of the edge portion can be set arbitrarily, and the reflected light at the diaphragm portion can be reduced to obtain desired optical performance.

FIGS. 5 and 6 relate to a second embodiment of the present invention, with FIG. 5 being an explanatory view showing the aperture device in an open state, and FIG. 6 being an explanatory view showing the aperture device in a constricted state.

In this embodiment, an objective optical system 20 of an electronic endoscope is used.
A diaphragm device 21 is installed in the
As shown in FIG. 2, the aperture device 21 is made of a hollow truncated cone-shaped bidirectional SMA, and has an aperture opening 22 on the small diameter side.
It is arranged centered on the optical axis of the objective optical system 20. Furthermore, an image pickup element 23 such as a charge coupled device (CCD) is disposed at the imaging position of the objective optical system 20.

The observed image of the object captured by the objective optical system 20 is converted into an electrical signal by the image pickup device 23, and is inputted via a signal line 24 to a video processor (not shown) at the observer's hand. This video processor converts the signal from the image pickup device 23 into a television signal, and displays an observed image of the subject on a television monitor (not shown).

The aperture device 21 is provided with a plurality of notches 25 in the shape of a truncated cone from the small diameter side to the large diameter side, and the notches 25 are shaped so that one piece of the notches 25 slips under the other piece. Memories are being made. The aperture device 21 can be energized arbitrarily via an electric cable 26 by a switch at the viewer's hand (not shown).

That is, when the diaphragm device 21 is not energized, the diaphragm opening 22 is at its maximum diameter and in the open state as shown in FIG. As shown in FIG. 2, one piece of the notch 25 goes under the other piece according to the memorized shape, so that the diaphragm opening 22 forms the minimum diaphragm diameter in terms of optical design.

In the electronic endoscope having the above configuration, when the aperture device 21 is used in an open state when observing a subject, the aperture device 21 is not energized. At this time, since the diameter of the diaphragm opening 22 is widened, the objective optical system 20 becomes bright.

On the other hand, when the aperture device 21 is used in a constricted state, an electric cable 26 is connected to the aperture device 21.
energize through. As a result, the aperture device 21 made of a bidirectional SMA generates heat, and one piece of the notch 25 slips under the other piece according to the memorized shape, so that the diameter of the aperture opening 22 becomes smaller and the aperture is narrowed. The state will be as follows. As a result, the brightness of the objective optical system 20 is reduced, and the observation depth becomes deeper.

In this way, in this embodiment as well, the simple configuration of the aperture device 21 allows the
Since the aperture aperture can be changed stably, the observation depth can be determined according to the distance to the subject, and the subject can be observed reliably.

FIGS. 7 and 8 relate to a third embodiment of the present invention; FIG. 7 is an explanatory diagram showing the diaphragm device in a released state, and FIG. 8 is an explanatory diagram showing the diaphragm device in a constricted state.

This embodiment is an example in which a diaphragm device 30 using a wire-shaped bidirectional SMA is used in place of the diaphragm device 21 in the second embodiment, and the other configuration is the same as that of the second embodiment. is the same as

In the aperture device 30 of this embodiment, as shown in FIG. 7, the small diameter side of the hollow truncated conical main body 31 made of an elastic material such as rubber is the aperture opening 32, and the aperture opening 32 is opened from the small diameter side to the large diameter side. A notch portion 33 is provided toward the front. One piece of the notch 33 is previously inserted a small amount under the other piece.

[0038] Also, the main body 3 on the side of the aperture opening 32
A guide 34 made of an elastic material such as rubber is adhered to the outer periphery of the main body 31, and a wire-shaped fastener 35 made of bidirectional SMA is attached to the outer periphery of the main body 31 on the larger diameter side with respect to the guide 34. is wrapped. An electric cable 36 is connected to this fastener 35, and has a shape memory so that the overall length becomes shorter when it is energized and generates heat.

In the aperture device 30 as described above, when the aperture is used in an open state, no current is applied through the electric cable 36. At this time, as shown in FIG. 7, the diameter of the diaphragm opening 32 is widened, forming a bright objective optical system.

On the other hand, when the aperture device 30 is used in a constricted state, electricity is supplied via the electric cable 36. Then, the fastener 35 made of bidirectional SMA generates heat and shortens its overall length according to the memorized shape, and the main body 31
One piece of the notch 33 further sinks under the other. As a result, as shown in FIG. 8, an objective optical system having an aperture diaphragm is constructed in which the diameter of the diaphragm opening 32 becomes smaller and the observation depth becomes deeper.

Therefore, as in the first embodiment described above, the observation depth can be obtained in accordance with the distance to the subject, and the subject can be observed reliably.

[0042] Even if the diameter of the aperture opening 32 changes, the guide 34 prevents the fastener 35 from coming off the main body 31.

9 to 15 relate to a fourth embodiment of the present invention, in which FIG. 9 is an explanatory diagram showing the configuration of the tip of the insertion section of the endoscope, FIG. 10 is an explanatory diagram showing the configuration of the aperture device, and FIG. is an explanatory diagram showing the aperture blades in a closed state, and FIG. 12 is an illustration of O-A in FIG. 11.
13 is a partial sectional view in the O-B line direction of FIG. 11, FIG. 14 is an explanatory diagram showing the aperture blades in a released state, and FIG. 15 is an explanatory diagram showing the expansion and contraction reaction of the SMA wire. .

[0044] In this embodiment, the electronic endoscope is equipped with a two-way SM
This device incorporates a mechanical diaphragm device whose diaphragm aperture is varied by A.

As shown in FIG. 9, the insertion section 4 of the electronic endoscope
An illumination window 42 and an observation window 43 are provided at the tip 41 of the 0, and an illumination lens 44 is provided inside the illumination window 42.
is provided, and the output end surface of the light guide bundle 45 is disposed at the rear end of the illumination lens 44.

The light guide bundle 45 is inserted through the insertion section 40 and a large-diameter operation section (not shown) connected to the rear end of the insertion section 40, and further extends through the insertion section 40 and a large-diameter operation section (not shown) extending from the operation section. The input end face is connected to a light source device (not shown) via a light guide connector (not shown). and,
Illumination light emitted from the light source device is incident on the incident end face of the light guide bundle 45, passes through the light guide bundle 45 and the illumination lens 44, and is irradiated onto the observation target.

Furthermore, an objective optical system 46 is provided inside the observation window 43, and a diaphragm device 47 is provided on this objective optical system 46. Furthermore, an image sensor 48 such as a CCD is disposed at the image forming position of the objective optical system 46, and this image sensor 48 is connected to a board on which electronic components are mounted. A signal line 49 is connected to the board, and this signal line 49 connects the insertion section 40, the operation section,
The universal cord is inserted into the light guide connector, and is further inserted into a CCU cable (not shown) extending from the light guide connector, and connected to a camera control unit (CCU) (not shown) via a CCU connector (not shown). It is connected.

As shown in FIG. 10, the aperture device 47 includes a drum portion 50 fixed to the tip portion 41, a frame portion 51 rotatably attached to the drum portion 50, and an aperture opening. A plurality of aperture blades 5 forming 52
It is composed of 3. Each aperture blade 53 is
As shown in FIG. 13, the frame portion 5 is
Further, as shown in FIG. 12, a groove 55 is provided in the aperture blade 53, and a pin 56 fixed to the drum part 50 is slidably fitted into the groove 55. are combined.

As shown in FIGS. 11 and 14, the groove 55 is formed in the shape of an arc of a long hole, and the aperture blade 53
When moving clockwise with respect to the center O in FIG.
The pin 56 is configured to move to a position as shown in FIG. 14.

Further, a spiral groove is provided on the outer periphery of the drum portion 50, and an SMA wire 57 is wound along this groove as shown in FIG. The SMA wire 57
has one end fixed to the drum section 50 and the other end fixed to a handle 58 provided on the frame section 51. Further, one end of a coil spring 59 is fixed to the handle 58, and the other end of the coil spring 59 is arranged in the opposite direction to the SMA wire 57 with the handle 58 in between.
It is fixed to the drum section 50.

Further, both ends of the SMA wire 57 are connected to an externally provided energizing device 61 via an electric cable 60, and as shown in FIG. 15, when heated, the length becomes L.
When cooled, it expands and contracts so that the length becomes L+ΔL. This stretching reaction is reversible, and this type of SMA is
It is called directional, and can generate a particularly large force when it is heated and its length contracts by ΔL.

[0052] In the above configuration, when the SMA wire 57 is not energized and heated by the energizing device 61, the diaphragm device 47 provided in the objective optical system 46 of the electronic endoscope
Since the wire 57 is in an extended state, in FIG. 10, the frame portion 51 is slightly rotated counterclockwise with respect to the drum portion 50 due to the biasing force of the coil spring 59, and as shown in FIG. The blades 53 move toward the center and the diameter of the aperture opening 52 becomes smaller.

Next, when the SMA wire 57 is energized and heated, the SMA wire 57 overcomes the biasing force of the coil spring 59 and contracts, causing the frame portion 51 to move clockwise relative to the drum portion 50 in FIG. It will be in a rotated state. At this time, the aperture blades 53 held on the frame portion 51 via pins 54 also move toward the drum portion 50.
However, since the pin 56 fixed to the drum portion 50 is fitted into the groove 55 of the aperture blade 53, the aperture blade 53 moves along this groove 55. As a result, the aperture blades 53 move to the position shown in FIG. 14, and the diameter of the aperture opening 52 increases. Said SMA wire 5
When the electrical heating to 7 is stopped, the state shown in FIG. 11 occurs again.

[0054] In this way, the same effects as in the first embodiment described above can be obtained in this embodiment as well, and the mechanical diaphragm can be replaced with S.
It can be constructed compactly by using the MA wire 57. Furthermore, in this embodiment, since the resistance value of the SMA wire 57 is large, there is an advantage that it is advantageous for electrical heating.

FIGS. 16 and 17 relate to a fifth embodiment of the present invention, with FIG. 16 being an explanatory view showing the aperture device in a constricted state, and FIG. 17 being an explanatory view showing the aperture device in an open state.

In this embodiment, the aperture device 47 of the fourth embodiment described above is replaced with an aperture device 70 that forms an aperture aperture using two aperture blades 71.

As shown in FIGS. 6 and 7, the diaphragm blades 71 are approximately "L" shaped, and a diaphragm opening 72 is formed in the center of the overlapping blades. Each aperture blade 71 is rotatably fixed at its end to the distal end 41 of the endoscope, and a pin 74 fixed to the other is slidably fitted into a groove 73 provided on one side. has been done.

Further, the pin 74 is fixed to the center of the SMA wire 75, and both ends of the SMA wire 75 are fixed to the tip portion 41. SMA wire 7 used here
Similarly to the SMA wire 57 of the fourth embodiment described above, the wire 5 is a bidirectional SMA and has a shape memorized so that its length shrinks when heated.

In this embodiment, when the SMA wire 75 is heated by electricity, the SMA wire 75 contracts and the pin 74 is attached to the tip 4.
1 to the outer diameter side. At this time, since the pin 74 moves along the groove 73, the two aperture blades 71 move so that the opening area of the aperture opening 72 becomes larger, as shown in FIG. When the electrical heating of the SMA wire 75 is stopped, the SMA wire 75 is cooled and expanded, and as a result, the opening area of the diaphragm opening 72 becomes smaller, as shown in FIG. It goes without saying that the same effects as in the fourth embodiment described above can be obtained in this embodiment as well.

18 to 21 relate to a sixth embodiment of the present invention, and FIG. 18 is a front view of the aperture device in the constricted state, and FIG.
9 is a front view of the throttle device in the open state, FIG. 20 is a sectional view of the throttle device in the throttled state, and FIG. 21 is a sectional view of the throttle device in the open state.

The aperture device 80 of this embodiment is applied to an optical endoscope or an electronic endoscope, and as shown in FIGS. 20 and 21, a hole is formed in the center between two ring-shaped frames 81. A rubber sheet 82 with a hole in it is sandwiched, and the periphery of the hole in this rubber sheet 82 is folded back to wrap around a ring 83 made of bidirectional SMA. As a result, as shown in FIGS. 18 and 19, an aperture opening 8 is formed in the center.
4 is formed.

The ring 83 can be energized arbitrarily by a switch (not shown) at the observer's hand, and when heated by electricity, it contracts and the diameter of the diaphragm opening 84 becomes smaller. has shape memory.

That is, in the aperture device 80 of this embodiment, when the ring 83 is heated by electricity, the ring 83 contracts and pulls the rubber sheet 82, so that the diameter of the aperture opening 84 becomes smaller as shown in FIG. Therefore, the objective optical system of the endoscope has a brightness aperture that increases the observation depth. Then, when the heating of the ring 83 is stopped, the ring 83 expands and at the same time, the diameter of the aperture opening 84 increases due to the tension of the rubber sheet 82 as shown in FIG. 19, and the objective optical system of the endoscope changes. It will have a brightness aperture close to wide open.

In the aperture device 80 of this embodiment, the aperture device 47 using the aperture blades 53 in the fourth embodiment described above is
On the other hand, since the rubber sheet 82 serves as both the aperture blade 53 and the coil spring 59, the structure is simple and suitable for miniaturization. Other effects are similar to those of the first embodiment described above.

The present invention is not limited to the embodiments described above, and a bidirectional shape memory resin may be used in the aperture device.

[0066] Conventionally, when inspecting a narrow part such as the blade part of a jet engine using an endoscope, the insertion part of the endoscope only enters halfway due to the narrow blade spacing, which limits the observation range. The problem was that it was limited.

The endoscope 100 shown in FIG. 22 solves this problem, and the objective optical system can be arbitrarily protruded from the distal end of the insertion section, making it possible to observe narrow areas. That is, as shown in FIG. 22, this endoscope 100
includes an elongated insertion section 102 having a hard tip 101, a large-diameter operation section 103 connected to the rear end of the insertion section 102, and a universal insert section 103 extending from the operation section 103. The operation section 103 is provided with a movable lever 114 for protruding an observation optical section 108, which will be described later, from the distal end section 101, and an eyepiece section 105 for naked eye observation is provided at the rear end. They are installed consecutively. Furthermore, a light guide connector 106 is provided at the end of the universal cord 104 to be connected to a light source device (not shown).

As shown in FIG. 23, the distal end portion 101 is provided with an illumination lens 107 and an observation optical section 108 for observing the subject, and a light guide bundle 109 is provided at the rear end of the illumination lens 107. A light emitting end face is provided.

The light guide bundle 109 is inserted through the insertion section 102, the operation section 103, and the universal cord 104, and the incident end surface is connected to a light source device (not shown) via the light guide connector 106. The illumination light emitted from this light source device is
The light enters the incident end face of the light guide bundle 109, is guided through the light guide bundle 109, and is irradiated onto the observation target from the illumination lens 107.

Further, in the observation optical section 108, the objective optical system 110 and the incident end of the image guide bundle 111 disposed at the image forming position of the objective optical system 110 are held together by a holding tube 112. It is composed of The holding tube 112 is held by a flexible but non-stretchable operating tube 113 such as a Teflon tube, which extends to the operating section 103 and is connected to the movable lever 114. has been done.

The image guide bundle 111 is connected to the objective optical system 11 by operating the movable lever 114 from the movable lever 114 to the eyepiece section 105.
0 is arranged with an appropriate amount of slack so that it does not become strained even if it protrudes from the tip 101, and the output end is fixed facing the eyepiece optical system of the eyepiece 105, and the objective optical system The observation image of the subject captured by the system 110 can be observed with the naked eye from the eyepiece section 105.

When observing a narrow part such as a blade part of a jet engine with the endoscope 100 having such a configuration, insert the insertion part 102 close to the part to be observed, aim at the narrow part, and then Movable lever 1 of the operating unit 103 at hand
14 to move the objective optical system 110 from the tip 101.
By protruding appropriately, the narrow area can be observed in more detail.

Note that the observation optical section 108 does not necessarily have to be operated by the movable lever 114, and as shown in FIG. The observation optical section 124 may have a structure in which a holding tube 122, which is integrally held with the input end and urged by a spring 121 in a direction protruding from the tip 120, is locked by a claw 123.

That is, the observation optical section 124 is protected within the distal end section 120 so that no external force is applied to the objective optical system 110 when inserted into the observation object, and the image guide bundle 111 is protected from the objective optical system 110. It is arranged with an appropriate amount of slack so that it does not become strained even if it is protruded. When observing a narrow part, the objective optical system 110 is made to protrude by releasing the claw 123 using a switch at hand (not shown). When the insertion portion of the endoscope is withdrawn after the observation is completed, it is safe because no large compressive force is applied to the objective optical system 110.

[0075]

As described above, according to the present invention, the aperture diaphragm can be stably changed with a simple configuration, and the observation depth can be obtained in accordance with the distance to the object. Therefore, excellent effects such as reliable detailed observation can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of the distal end of the insertion section of an endoscope according to the first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the configuration of an aperture device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of the first embodiment of the present invention with the aperture in an open state.

FIG. 4 is an explanatory diagram of the diaphragm in the most closed state according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing the aperture device in an open state according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the aperture device in a constricted state according to the second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a throttle device in a released state according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing the aperture device in a constricted state according to the third embodiment of the present invention.

FIG. 9 is an explanatory diagram showing the configuration of the tip of the insertion section of the endoscope according to the fourth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing the configuration of an aperture device according to a fourth embodiment of the present invention.

FIG. 11 is an explanatory diagram showing the aperture blades in a narrowed state according to the fourth embodiment of the present invention.

FIG. 12 relates to the fourth embodiment of the present invention, O- in FIG. 11;
Partial cross-sectional view in the A-line direction

FIG. 13 relates to the fourth embodiment of the present invention, O- in FIG. 11;
Partial sectional view in the B line direction

FIG. 14 is an explanatory diagram showing aperture blades in a released state according to a fourth embodiment of the present invention.

FIG. 15 is an explanatory diagram showing the stretching reaction of the SMA wire according to the fourth embodiment of the present invention.

FIG. 16 is an explanatory diagram showing the aperture device in a constricted state according to the fifth embodiment of the present invention.

FIG. 17 is an explanatory diagram showing the aperture device in a released state according to the fifth embodiment of the present invention.

FIG. 18 is a front view of the aperture device in a constricted state according to the sixth embodiment of the present invention.

FIG. 19 is a front view of a throttle device in a released state according to a sixth embodiment of the present invention.

FIG. 20 is a sectional view of a throttle device in a throttled state according to a sixth embodiment of the present invention.

FIG. 21 is a sectional view of a throttle device in a released state according to a sixth embodiment of the present invention.

[Fig. 22] A perspective view showing an endoscope with the objective optical system protruding from the tip of the insertion section.

[Fig. 23] Explanatory diagram showing the configuration of the tip part

[Fig. 24] Explanatory diagram showing the configuration of the tip part

[Explanation of symbols]

9 Objective optical system 10 Squeezing device

Claims (1)

[Claims] 1. An endoscope characterized in that an objective optical system for observing a subject is provided with a diaphragm device that changes the diaphragm aperture using a bidirectional shape memory material.