JPH11313795A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope without vignetting, hardly damaging a hood, made small in the outer diameter of the tip end part, easy to observe a subject in an easily movable part and preventing the hood from entering the visual field range by improving the shape of the hood provided on the tip end part of the endoscope corresponding to visual field angle. SOLUTION: The hood 22 integrated with the tip end part 12 is provided on the peripheral part of the tip part 12 where an object optical system unit 20 is arranged. In this case, the hood 22 is projected by a prescribed amount not to enter the observation field of the object optical system unit 20 from the end face 19 of the tip part at the peripheral part of the tip part 12 and formed by changing at least a hood thickness of a hood projection height corresponding to the size of the area of the observation field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope provided with a hood at a distal end of an insertion portion.

[0002]

2. Description of the Related Art As shown in Japanese Utility Model Publication No. 59-15605, a conventional hood detachably provided at the distal end of an insertion portion of an endoscope is formed in a substantially cylindrical shape, and has a front end. The movable part such as a mucous membrane is observed by contacting the part with a subject and keeping a constant distance between the subject and an end surface of a distal end portion where the first lens surface of the objective optical system is located.

[0003]

[Problems to be Solved by the Invention]
In endoscopy, when inserting the insertion portion of the endoscope into the body cavity of a patient and observing mucous membranes and the like in the body cavity, the mucous membrane observation site, which is the subject, is likely to move due to the heartbeat and the like, and It was difficult to maintain a constant distance between the two. For this reason, it is difficult to maintain a good observation state, and the visual field adjustment work has become a heavy burden on the operator.
Naturally, the examination time was longer and the pain given to the patient was greater. Furthermore, in the case of observation with an endoscope having a variable focus type objective optical system unit that enables observation of the mucous membrane at a high magnification of about 80 to 100 times at the time of close observation, even if the distance to the mucous membrane is 1 mm, it changes. If this happens, the magnification will drop significantly and the observation image will be unfocused,
It becomes a bigger problem.

Therefore, as described above, in the conventional device, a detachable hood is attached to the distal end of the insertion portion, the front end of the hood is applied to the subject, and observation is performed while maintaining a predetermined distance from the subject. Was like that. However, depending on the position where the objective optical system unit is disposed on the distal end surface of the distal end, the viewing angle of the objective optical system unit, and the thickness or height of the hood protruding from the end surface of the distal end, the hood may not be included in the observation visual field. There is a situation that a part of the light enters and a phenomenon called so-called vignetting occurs, which hinders observation and diagnosis.

[0005] Further, when the viewing field range to be observed is formed by different viewing angles, for example, when the viewing field shape is substantially square, substantially octagonal, and substantially elliptical, a wide viewing angle direction and a narrow viewing angle direction are formed. However, because the hood has a uniform thickness and a uniform projection height over the entire circumference, the hood part enters the observation field of view particularly in the direction in which the viewing angle is wide,
The observation field of view was vignetted, which hindered observation and diagnosis. Even in the objective optical system unit in which the observation field range is formed with substantially the same viewing angle, if the objective optical system unit is arranged at a position different from the center of the tip, a uniform hood thickness or hood protrusion height is formed. Even in the hood, a part of the hood entered the observation field of view, and the observation field of view was vignetted, which hindered observation and diagnosis.

Further, in the case where the viewing angle changes due to the function of the objective optical system unit, if the viewing angle is widened, a portion of the hood that has not been seen before enters the observation field of view, and the observation field of view becomes vignetting. , Observation and diagnosis were hindered. For example, in the case of an endoscope having a variable focus type objective optical system unit, a hood is attached to the distal end of the insertion section to make the observation angle narrow, and to facilitate fine observation at the maximum magnification. However, if the viewing angle is widened for normal observation, the hood enters the observation visual field, and the observation visual field is vignetted, which hinders observation and diagnosis. At this time, to avoid entering the viewing angle,
If you use a detachable hood with a different size or shape of the protrusion of the hood, position the detachable hood at the tip so that it does not enter the viewing angle of the objective optical system unit, and move the tip so that it does not rotate. Since it is necessary to attach to the part, the structure is complicated and the diameter is easily increased. When the diameter of the distal end portion is increased, the insertability is hindered, and the pain of the patient increases. On the other hand, if the tip is made thinner to reduce pain to the patient,
As the thickness of the hood becomes thinner, and the hood becomes thinner, the hood is more likely to be damaged, which is also a problem.

The object of the present invention is to improve the shape of the hood provided at the distal end of the endoscope according to the viewing angle, so that the hood is not easily damaged, the outer diameter of the distal end is small, and the endoscope is easy to move. An object of the present invention is to provide an endoscope in which a subject at a site can be easily observed, a hood does not enter a visual field range, and there is no vignetting.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an endoscope having a hood integrated with a distal end portion around a distal end portion where an objective optical system unit is disposed.
At the peripheral portion of the distal end portion, project from the distal end surface by a predetermined amount that does not enter the observation visual field of the objective optical system unit, and change at least the hood thickness or the hood projection height according to the size of the observation visual field region. It is formed. According to this configuration, the hood forming the optimum distance at the time of close observation so as not to enter the viewing angle is formed at least in a part of the peripheral portion of the distal end portion where the objective optical system unit is arranged,
By bringing the front end of the hood into contact with the mucous membrane that is the subject,
In particular, it is easy to maintain a constant distance to the subject at the time of closest observation in a part that is easy to move, making it easier to observe,
Since the hood does not need to be provided over the entire circumference of the distal end, the distal end can be narrowed. When the objective optical system unit has a viewing range formed by different viewing angles depending on the observation direction, at least the hood meat in a direction in which the viewing angle is narrower than in a direction in which the viewing angle is wider so that the hood does not enter the changing viewing angle. The hood can be made thinner by forming a thicker or larger hood protrusion height and forming the protrusion height in a part of the direction where the viewing angle is narrow so that the protrusion height is the optimum distance for close observation. Increases the strength and makes it harder to break.
Also, by forming a hood that is integral with the tip, it does not require positioning of the tip and the hood, unlike a rotating detachable hood, and ensures that the periphery of the tip does not enter the viewing angle. A projecting portion of the hood at the site can be formed. In general, since the objective optical system unit of the endoscope is provided at a position eccentric from the center of the distal end, the hood thickness is large in a narrow viewing angle direction which is arranged in substantially the same direction as the eccentric direction, and the hood thickness is large. The protruding height can form the optimum distance for close observation. In addition, by forming the hood thickness or the protruding height smaller than that in the direction of the wide viewing angle, the endoscope can be made as thin as possible and the hood strength is high and the endoscope is hard to break.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. (Configuration) First, a schematic configuration of an endoscope system will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an electronic endoscope, 2 denotes a light source device, and 3 denotes a video processor having a built-in video signal processing circuit and a driving circuit. Peripheral devices such as a monitor 4, a VTR deck 5, a video printer 6, and a video disk 7 are connected to the video processor 3.

The endoscope 1 has an insertion portion 8 for insertion into a body cavity, and an operation portion 9 connected to a proximal end of the insertion portion 8.
And The insertion portion 8 has an elongated and flexible flexible tube 10 and a rigid distal end 1 connected to a distal end of the flexible tube 10 via a bending portion 11 formed of a plurality of bending pieces.
2 are provided. The operation unit 9 is provided with a knob for up / down / left / right bending operation (not shown). Then, by bending the bending portion 11 using the knob for up / down / left / right bending operation, the direction of the distal end portion 12 is operated, and the observation of the observation target site becomes possible.

A universal cord 13 extends from a part of the operation unit 9. A connector device 14 for connecting to the light source device 2 is provided at the extending end of the universal cord 13. The illumination light generated by the light source lamp of the light source device 2 is
The illumination light can be guided to the distal end portion 12 of the endoscope 1 via a light guide fiber disposed therein. Further, the connector device 14 is connected to a connection cord 13a leading to the video processor 3. The operation unit 9 is provided with a forceps insertion port 15, an air / water switch 16 and a suction switch 17 arranged side by side.

As shown in FIG. 2, the distal end portion 12 of the insertion portion 8 is provided with a substantially cylindrical distal end member 18 made of, for example, stainless steel made of metal. The distal end portion of the distal end member 18 has a distal end portion. A hood 22 having a predetermined thickness and a protruding height protruding from the end face 19 and not entering a viewing angle 21 of an objective optical system unit 20 described later is integrally formed, for example, a plastic tip cover 23 formed by integral molding.
Are fixed and fixed to the distal end component 18 by an adhesive. The amount of protrusion of the hood 22 from the tip end face 19, that is, the hood protrusion height L is set to an optimum distance for close-up observation.

In this embodiment, FIGS. 3A and 3
As shown in (b), the hood 22 is formed from the vicinity of the objective optical system unit 20 to the vicinity of the vicinity of the two illumination system units 24, and the visual field range observed by the objective optical system unit 20. Has a viewing range 25 at the above-described optimum distance L from the cover glass 32 formed by different viewing angles, for example, a substantially octagonal shape (similarly a square shape or a substantially elliptical shape), the portion of the hood 22 is observed. The hood thickness or the hood protrusion height changes according to the viewing angle so as not to enter the area of the viewing range 25. That is, FIG. 4A shows a cross section of the hood 22 in the direction A shown in FIG. 3, and FIG. 4B shows a cross section of the hood 22 in the direction B shown in FIG. In the narrow direction A, a hood portion 22-A having a thickness t1 and at least partly formed with the optimum distance L1 in the close observation as a protruding height is provided, and in the direction B having a wide viewing angle, the direction A is provided. Has a smaller thickness t2 and a smaller protrusion height L2 than the hood portion 22-A (t1> t2, L1> L).
2) A hood 22-B is formed. Further, the ridge line portion of the hood 22 (the transition portion from the A direction to each hood portion arranged in the B direction) in which the hood thickness t or the projection height L changes according to the viewing angle is smooth, and the hood is smooth. 2
It is formed in a shape that smoothly transitions to the tip end surface 19 where no 2 is formed.

The distal end member 18 has a through hole 26 for forceps.
Are formed. A forceps pipe 27 is inserted and fixed into the inner end of the forceps through hole 26, and the forceps formed in the operation unit 9 through the forceps channel tube 28 provided in the insertion portion 8 is inserted. A forceps channel communicating with the mouth 15 is formed. The forceps inserted from the insertion opening 15 is the forceps channel tube 28 and the forceps pipe 2.
7 and projecting from the opening of the distal end portion 12 through the through hole 26 for forceps.

Further, a stepped through hole 29 is provided in the distal end component member 18, and a variable focus type objective optical system unit 20 having a focus adjusting lens 30 described later is incorporated in the through hole 29. . The objective optical system unit 20 may be of a fixed focus type.

Next, the objective optical system unit 20 will be described. A first lens frame 31 is provided. The first lens frame 31 has a cover glass 32 located at the forefront end and a laser cut A filter 33 and an infrared cut filter 34 located behind the filter 33 are mounted. A front group lens frame 35 is inserted into the rear end of the first lens frame 31, and a front group lens 36 is mounted on the front group lens frame 35. The rear end portion of the front group lens frame 35 extends rearward from the front end component member 18, and the rear group lens frame 37 is inserted inside the extended cylindrical portion. The first lens frame 31, the front group lens frame 3
5, and the rear lens group frame 37 are coaxially installed.
A rear group lens 38 is mounted on the rear group lens frame 37. The front end outer periphery of the rear lens group frame 37 is formed to have a small diameter, and a gap 39 is formed between the front end lens frame 35 and the inner peripheral surface. A notch 40 that is elongated and opens in a slit shape along the optical axis direction is provided in a peripheral wall portion of the front group lens frame 35 corresponding to the gap portion 39.

A movable lens frame 41 which is movable in the optical axis direction across the gap 39 is provided between the inner surface of the front lens frame 35 and the outer periphery of the rear lens frame 37. I have. The rear end of the movable lens frame 41 is interposed in the gap 39 between the front lens frame 35 and the rear lens frame 37, and slides in the front-rear direction. The focusing lens 30 is attached to the front end of the movable lens frame 41. Further, the first lens frame 31 and the movable lens frame 4
A plurality of flare stops 42 for preventing flare and ghost are provided inside the first and rear lens frames 37, and a brightness stop 43 is provided inside the front lens frame 35.

The front group lens frame 35 and the rear group lens frame 37 thus configured are provided with protrusions 44 and 45 located on the same side facing each other. The protruding portion 44 provided on the front lens frame 35 is located at the front end of the notch 40, and is provided in the concave space 18a provided in the front end component 18.
It is installed in. The protruding portion 45 provided on the rear lens frame 37 is located at the rear end of the notch 40.
Therefore, the protrusions 44 and 45 are provided at the front end and the rear end of the notch 40, respectively. A projection 46 is provided between the projections 44 and 45 so as to project integrally from the peripheral wall of the movable lens frame 41. The projection 46 penetrates through the cutout portion 40 and protrudes outside the front lens group frame 35 and the rear lens group frame 37. One end (tip) of the operation wire 51 is connected to the projection 46 by a connector 47. The other end of the operation wire 51 penetrates the projection 45 of the rear lens frame 37 and is connected to an operation mechanism provided in the hand operation unit 9 of the endoscope 1. And
The operation wire is moved forward and backward by operating the operation mechanism by an operation knob provided to be exposed to the outside of the operation section 9. The projecting portion 45 is provided with a through hole 48, and a base end of a fixed pipe 49 in which a stopper 50 is screwed and fixed at a distal end portion is fixedly attached to the through hole 48. The stopper 50 moves in the optical axis direction by adjusting the amount of screwing into the fixed pipe 49, and its position can be selected.

As shown in FIG. 5B, which shows a cross section taken along the line XX of FIG. 2, between the projection 44 of the front lens frame 35 and the projection 45 of the rear lens frame 37. Is provided with a dustproof cover 52 as a blocking member so as to fit the projection 46 together with the notch 40. The dust cover 52 is formed by bending a metal plate so that its cross-sectional shape becomes a U-shape, and is mounted so as to cover the protrusions 44 and 45. Accordingly, the objective lens side internal space of the objective optical system unit 20 and the other endoscope internal side space are separated by the pair of protrusions 44 and 45 and the dustproof cover 52.
Is blocked by

The objective optical system unit 20 is integrally formed as described above.
Is attached by being inserted into the through hole 29 from the rear of the tip component member 18. That is, the outer peripheral surface of the first lens frame 31 is provided with a fixing groove 53 having a V-shaped cross section, and the tip component 18 opposing the fixing groove 53.
The fixing screw 65 is screwed toward the radial direction,
The first lens frame 31 is fixed by pressing the tip of the fixing screw 65 against the fixing groove 53. The distal component 18 and the objective optical system unit 20 are integrally connected.

Reference numeral 54 in FIG. 2 designates a circuit board of the solid-state image pickup device 55, and the solid-state image pickup device 55 and the protection lens 56
After adjusting the positional relationship between the element frame 57 for adhesively fixing the element frame 57 and the rear lens group frame 37 fitted on the outer peripheral surface of the element frame 57, focusing is performed, and both are fixed using an adhesive. ing.

A distal end of a shield frame 59 which is formed in a tubular shape and whose outer periphery is covered with an insulating cover 58 is fixed to the outer periphery of the rear end lens frame 37 on the base end side. The base end side of the shield frame 59 is further extended rearward, and a ceramic circuit board 54 is held in the extended portion substantially in parallel with the optical axis of the objective optical system unit 20. . The circuit board 54 and the solid-state imaging device 55
Are electrically connected to the external leads 60 by soldering or the like. External lead lands for electrical connection to the external leads 60 of the solid-state imaging device 55 are formed on the distal end of the circuit board 54, and a signal composed of a plurality of coaxial lines 61 and a simple line 62 is formed on the proximal end. A signal line grounding land to which the cable 63 is connected is formed. The signal cable 63 is connected and fixed directly to the external lead 60 of the solid-state imaging device 55 by soldering or the like, and a drive signal to the solid-state imaging device 55 is transmitted, for example. Also, a part of the coaxial cable 61 and the simple cable 62 of the signal cable 63 is connected to a signal line grounding land provided on the circuit board 54.

On the circuit board 54, an IC 64 sealed with a sealing resin is electrically connected and wired. The circuit board 54 is electrically connected to the solid-state imaging device 5.
5, a signal processing circuit is formed between the circuit board 54 and the signal cable 63. Then, the solid-state imaging device driving signal, the solid-state imaging device output signal, the solid-state imaging device driving power, and the like, which are input / output signals of the solid-state imaging device 55, all pass through the circuit board 54.

On the other hand, the inside of the shield frame 59 is filled with, for example, a non-conductive filler 66, and the solid-state imaging device 55, the circuit board 54, the electronic components 67, the signal cable 6
3 is sealed. Similarly, the front end of the insulating cover 58 is also filled with a non-conductive adhesive 68 so as to cover the base end of the fixed pipe 49. Thereby, the gap between the fixed pipe 49 and the operation wire 51 can be blocked, and it is possible to prevent minute dust such as dust inside the endoscope from entering the objective optical system unit 20. At the rear end of the insulating cover 58 formed so as to protrude from the shield frame 59 to the base end side, a cable protection member 69 covering the outer sheath of the signal cable 63 is held and fixed. The cable protection member 69 is provided to reduce damage to other built-in components provided in the endoscope 1 or damage to other built-in components.

As shown in FIGS. 5A and 6, a nozzle 70 for air / water supply provided in a direction directed to the cover glass 32 is attached to the distal end portion 12 of the insertion portion 8. The nozzle is provided by operating the air supply / water supply switch 16 that is provided in the operation unit 9 and that connects and disconnects between the air supply flow path and the air supply flow path and between the water supply flow path and the water supply flow path. Air and water are supplied to the cover glass 32 through 70 to remove dirt, fogging, and the like on the surface of the cover glass 32. By operating the suction switch 17 provided in parallel with the air / water switch 16, the mucus in the body cavity can be sucked through the forceps channel tube 28.

As shown in FIG. 6, the nozzle 70 is mounted in a nozzle through hole 71 provided in the distal end cover 23 and the distal end member 18, and a metal retaining screw 73 provided in a screw through hole 72. It is fixed by. After this fixing, the screw through-hole 72 is filled with an adhesive, and a plastic pin 74 formed so as to be smoothly connected to the outer peripheral surface of the distal end cover 23 is fixed by the adhesive. An air / water supply hole 75 communicates obliquely from the rear with a portion cut forward from the rear end surface of the distal end component 18 to the nozzle through hole 71, and the air / water supply hole 75 extends rearward. An air supply pipe 76 bent and formed so as to be parallel to the axial direction of the insertion portion is mounted. The air supply pipe 76 is provided with an opening 79 connected to the water supply pipe 78 by brazing 77 or the like.

The water supply pipe 78 is connected to the distal end component 18 with an adhesive 80 so as to cover a connection portion of the air supply pipe 76. Thereby, the connection strength of the connection portion is increased and the watertightness of the connection portion can be sufficiently ensured, so that damage such as water leakage inside the insertion portion 8 can be prevented. At this time, the epoxy-based adhesive 8 which does not need to heat and cure the air supply pipe 76 from outside.
Because it is fixed at 0, the part of the brazing 77 is deformed,
No damage. An air supply tube 81 extending from the operation unit 9 is provided in the air supply pipe 76 and the water supply pipe 78.
The water supply tube 82 is connected to the front of the base end of the first bending piece 83 of the bending portion 11. Accordingly, stress on the connecting portion when the bending portion 11 is bent can be reduced, and the bending piece 83 that rotates can be prevented from contacting the connecting portion, thereby preventing damage to the connecting portion. it can. In addition, since the tube-retaining thread-binding portions 84 formed after the air-supplying tubes 81 and 82 are adhered and fixed to the air-supplying pipes 76 and 78 are provided at different positions in the axial direction, respectively. The distance between the pipe and the tube can be reduced, and the diameter of the distal end portion 12 can be reduced. This structure is not limited to the electronic endoscope 1, but may be used for other types, for example, an optical endoscope.

(Operation / Effect) By determining the shape of the hood 22 provided at the distal end portion 12 of the endoscope 1 according to the viewing angle corresponding to the portion, the hood 22 is hardly damaged, and The diameter can be reduced, and the vignetting of the visual field range by the hood 22 is reduced. In addition, even if the subject is in a part that is easy to move, it can be easily observed by applying the hood 22.

A hood 22 formed according to the optimum distance for close-up observation is formed at least partially around the distal end portion 12 where the objective optical system unit 20 is arranged, and the front end of the hood 22 is brought into contact with a mucous membrane as a subject. By doing so, it is easy to maintain a constant distance from the subject during close observation in a particularly mobile part, and it becomes easy to perform observation,
Since it is not necessary to provide 2 over the entire circumference of the distal end portion 12, the diameter of the distal end portion 12 can be reduced. Even in the case where the objective optical system unit 20 has a view range formed by changing viewing angles, the hood in the direction in which the viewing angle is narrower than the direction in which the viewing angle is wider so that the hood 22 does not enter the changing viewing angle. By forming the wall thickness and the projection height to be large, and by forming the projection height to be the optimum distance for close-up observation in the part where the viewing angle is narrow,
The diameter of the tip 12 can be reduced as much as possible, and the strength of the hood 22 increases, making it difficult to break. At this time, the hood 22
Is formed integrally with the distal end portion 12, even if the projection of the hood 22 changes with respect to the viewing angle of the objective optical system unit 20, for example, rotation or displacement such as a detachable hood causes Never enter. Therefore, it is possible to set so as to surely prevent the vignetting of the hood 22 in the visual field range, and it is possible to set the effective visual field range as large as possible.

Further, since the objective optical system unit 20 of the endoscope 1 is generally provided at a position eccentric from the center of the distal end portion, the hood is disposed in the direction in which the viewing angle is narrow in the same direction as the eccentric direction. It is possible to form the hood 22 having a large wall thickness and a hood protrusion height with an optimum distance for close observation. In the direction in which the viewing angle is wide, the hood thickness or the hood protrusion height is formed smaller than that, so that the distal end portion 12 is as thin as possible and the hood strength is high, so that it is difficult to break.

Further, since the ridge line of the hood 22 is smooth and smoothly transitions to the end surface of the distal end portion 12, when the distal end portion 12 is inserted into a body cavity, mucous membranes and the like are formed at the hood 22 portion. It will not hurt.

The nozzle 70 provided on the distal end surface 19 of the distal end portion 12 is fixed to the distal end component member 18 with a metal retaining screw 73, and a hood 22 is provided around the nozzle 70. Therefore, since the nozzle 22 does not directly contact the mucous membrane, it is possible to prevent a mucous membrane burn when performing a high-frequency treatment, and it is not necessary to use a member for insulating the nozzle 22 from the tip component 18. The tip 12 can be reduced in diameter.

In addition, since the nozzle 70 has a gap between the nozzle 70 and the hood 22, when cleaning and disinfecting the distal end portion 12, it is easy for the cleaning brush to pass therethrough, and the disinfecting liquid and the like are easy to rotate. Easy to disinfect.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIGS. (Construction) When the objective optical system unit 20 has a viewing range 90 at a predetermined distance X from the cover glass 32 having substantially the same viewing angle, the distance L between the center of the optical axis of the objective optical system unit 20 and the outer periphery of the distal end portion 12 is determined. The larger the value is, the larger the hood thickness or hood protrusion height can be made in a range that does not fall within the viewing angle. Here, the distances L1 and L2 between the center of the optical axis of the objective optical system unit 20 and the outer periphery of the distal end portion 12 are L1 <L2. A hood 91 having a large height is formed on the front end cover 23. Specifically, the hood thickness of the portion 91B with the distance L2 is made larger than the hood thickness or the hood projection height of the portion 91A with the distance L1, or the hood thickness and the hood projection height are increased by 91C. Like bigger. Other configurations are the same as those of the first embodiment.

(Function / Effect) The greater the distance L between the center of the optical axis of the objective optical system unit 20 and the outer periphery of the distal end portion 12, the greater the
By increasing the hood thickness or the hood protrusion height of the portion, the endoscope is provided, in which the hood 91 is configured to be hardly damaged by increasing the hood thickness or the hood protrusion height within a range that does not enter the viewing angle. be able to.

Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. 9A and 9B and FIG. (Construction) In the peripheral portion of the distal end cover 23, at least a peripheral portion of the distal end cover 23 around the objective optical system unit 20 and a peripheral portion of the through hole 26 for the forceps channel have a distal end portion 1
A hood 92 which is substantially symmetrical with respect to the center position of No. 2 and has a protruding height which is an optimum distance for close-up observation;
93 are provided. Other configurations are the same as those of the first embodiment. (Function / Effect) As shown in FIG. 10, the tip 12 can be positioned substantially perpendicular to the subject, so that the subject can be easily observed.

<Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIGS. (Configuration) Two stepped illumination through holes 94 are formed in the distal end component member 18 of the distal end portion 12 of the endoscope 1, and the illumination lens frame 95 inserted into and fixed to the illumination through holes 94. A plurality of illumination lenses 96 for irradiating the observation target with illumination light from the light source device 2 are fixed. The distal end of the light guide fiber 97 is in contact with the illumination lens 96. The hood 98 formed on the front cover 23 is located around the illumination system unit 24 or is not formed so as not to block the illumination light.

(Operation / Effect) By forming or not forming the hood 98 around the illumination optical system unit 24 so as not to block the illumination light, the illumination light does not vignet, and there is no unevenness in brightness. It is possible to obtain a proper observation image.

The present invention is not limited to the embodiment described above. According to the description of each of the above embodiments, at least the items listed below and items obtained by arbitrarily combining them can be obtained.

[Supplementary Notes] In an endoscope having a hood integrated with the distal end portion at a peripheral portion of the distal end portion where the objective optical system unit is disposed, the hood is located at a peripheral portion of the distal end portion and within an observation field of view of the objective optical system unit from an end surface of the distal end portion. An endoscope which is formed by projecting by a predetermined amount which does not fit in the hood and by changing at least a hood thickness or a hood projection height in accordance with the size of an observation field of view. 2. In an endoscope having a hood integrated with the distal end portion around a distal end portion in which an objective optical system unit in which a visual field range to be observed is formed by different viewing angles is arranged, the hood is different from the distal end surface. An endoscope formed by projecting by a predetermined amount that does not fall within a viewing range formed by a viewing angle, and changing at least a hood thickness or a hood projection height in accordance with the size of the viewing angle.

3. 2. The endoscope according to claim 2, wherein at least a hood thickness or a hood protrusion height arranged in a direction in which the viewing angle is narrow is larger than a hood arranged in a direction in which the viewing angle is wide. 4. 2. In the second and third terms, the direction in which the viewing angle is narrow, in which the objective optical system unit is disposed in substantially the same direction as the direction decentered from the center of the distal end, is at least the hood thickness or hood protrusion height with respect to the direction in which the viewing angle is wide. An endoscope characterized by having a large size.

5. In an endoscope having a hood integrated with the distal end portion around a distal end portion where an objective optical system unit in which a visual field range to be observed is formed by substantially the same viewing angle is disposed, the hood is connected to the objective optical unit. An endoscope characterized in that, as the distance between the center of the optical axis and the outer periphery of the distal end portion increases, at least the hood thickness or the hood protrusion height increases. 6. 6. The endoscope according to any one of items 1 to 5, wherein at least a part of a height of the hood protruding around the objective optical system unit is an optimum distance for close-up observation. 7. In the first to fifth aspects, the objective optical system unit is a variable focus type which has a focus adjustment moving lens provided movably back and forth on the optical axis and can change the viewing angle, and at least the objective optical system unit. An endoscope wherein a part of a height of a hood protruding around a unit is an optimum distance for close-up observation at a narrow angle.

8. 7. The endoscope according to any one of items 1 to 6, wherein the objective optical system unit is of a fixed focus type and has a fixed viewing angle. 9. In items 1 to 8, around the objective optical system unit,
An endoscope wherein a hood protrusion is formed at least at a part of a position substantially symmetrical with respect to a center position of a distal end portion. 10. In an endoscope having an objective optics unit, a nozzle, and a hood integrated with a tip portion protruding from the tip end surface by a predetermined amount that does not enter the viewing angle from the tip end surface, at least around the objective optics unit and the nozzle periphery An endoscope having a hood protrusion.

11. 11. The endoscope according to claim 10, wherein a gap is provided between the hood and the nozzle. 12. In an endoscope having an objective optics unit, an illumination system unit and a hood integrated with a distal end protruding by a predetermined amount that does not enter the viewing angle from the distal end surface around the distal end portion,
An endoscope, wherein a hood is formed around an illumination system unit so as not to block illumination light. 13. In the first to the twelfth items, the ridge line of the hood in which the hood thickness or the hood protrusion height changes is smooth,
An endoscope wherein the endoscope smoothly transitions to the end face.

[0045]

As described above, according to the present invention, the shape of the hood provided at the distal end of the endoscope is improved according to the viewing angle, so that the hood is not easily damaged and the outer diameter of the distal end is reduced. It is an object of the present invention to provide an endoscope which is thin and makes it easy to observe a subject in a portion which is easy to move, does not have a hood in a visual field range, and has no vignetting.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory diagram of an endoscope system according to a first embodiment.

FIG. 2 is a longitudinal sectional view of a distal end portion of the insertion section of the endoscope according to the first embodiment.

FIG. 3A is a front view of a distal end of an insertion section of the endoscope according to the first embodiment, and FIG. 3B is a perspective view of the distal end.

4A is a sectional view of a portion of the hood in a direction A shown in FIG. 3, and FIG. 4B is a sectional view of a portion of the hood in a direction B shown in FIG.

5 (a) and 5 (b) are longitudinal sectional views of a front end portion taken along line XX in FIG. 2;

FIG. 6 is a longitudinal sectional view of a distal end portion of the insertion section of the endoscope according to the first embodiment.

FIG. 7 is a front view of a distal end portion of an insertion section of the endoscope according to the second embodiment.

FIG. 8 is a longitudinal sectional view of the distal end portion of the insertion section of the endoscope according to the second embodiment passing through the center of the optical axis of the objective optical system unit.

FIG. 9A is a front view of a distal end of an insertion section of an endoscope according to a third embodiment, and FIG. 9B is a perspective view of the distal end.

FIG. 10 is an explanatory diagram of a use state of a distal end portion in an insertion section of an endoscope according to a third embodiment.

FIG. 11 is a front view of a distal end portion of an insertion section of an endoscope according to a fourth embodiment.

FIG. 12 is a longitudinal sectional view of a distal end portion of an insertion section of an endoscope according to a fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... endoscope, 8 ... insertion part, 12 ... front-end | tip part, 19 ... front-end | tip end surface, 20 ... objective optical system unit, 21 ... viewing angle, 23
... tip cover, 22 ... hood.

Claims (1)

[Claims] 1. An endoscope having a hood integrated with a distal end portion at a peripheral portion of a distal end portion where an objective optical system unit is disposed, wherein the hood is located at a peripheral portion of the distal end portion and is located at a position closer to the objective optical system than an end surface of the distal end portion. An endoscope formed by projecting by a predetermined amount that does not enter the observation field of view of the unit, and changing at least a hood thickness or a hood projection height according to the size of the observation field.