JP3475778B2 - Structure for fixing observation means of electronic endoscope - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in an electronic endoscope provided with an image pickup means, fixedly holds an observation means including an objective optical system and an image pickup means at a predetermined position of a distal end forming portion of an insertion portion. The present invention relates to a structure for fixing an observation means of an electronic endoscope.

[0002]

2. Description of the Related Art An electronic endoscope is composed of an objective optical system having an objective lens and an image pickup means as an observation means attached to a distal end forming portion of an insertion portion to be inserted into a body cavity or the like. The image pickup means is arranged at the image forming position of the objective optical system,
It is configured by mounting a solid-state image sensor such as a CCD on a circuit board. If necessary, electronic components such as chip components are mounted on this circuit board, and a required number of cables are pulled out, and these cables are extended from the insertion section to the main body operation section and into the universal cord. To be done. A connector is provided at the base end of the universal cord, and the connector is detachably connected to the processor so that the drive signal is transmitted to the solid-state image sensor and the video signal from the solid-state image sensor is captured. Has become. Therefore, the observing means is configured to have a hard portion in a portion from the tip of the lens barrel to which the objective lens is attached to the circuit board, and a flexible portion formed of a cable drawn from the circuit board. .

The insertion portion of the endoscope is generally composed of a flexible portion that bends in an arbitrary direction along the insertion path from the side connected to the main body operation portion, and the distal end of this flexible portion is remote. An angle portion that can be bent by operation is provided. The tip forming section is connected to the tip of the angle section, and the tip forming section is provided with an illumination window and an observation window. The angle portion is for orienting the tip forming portion in a desired direction, and the angle portion has a node ring structure in which angle rings are sequentially pivoted. Since the tipmost angle ring of the angle rings, that is, the tip ring is connected to the tip forming portion, the tip ring cannot be bent. Therefore, the portion from the tip forming portion to the tip ring in the angle portion is the tip hard portion.

Since the insertion portion is inserted into the patient's body, there is a great demand for reducing the diameter of the insertion portion and shortening the axial length of the hard tip portion. This is because if the diameter of the insertion portion becomes large, it becomes difficult to pass through a narrowed portion, and if the distal end hard portion becomes long, it becomes difficult to pass through a sharply curved path. As described above, since the tip ring constitutes a part of the hard tip portion, the hard portion of the observing means is housed in a portion including the tip ring, so that the length and outer dimension of the hard tip portion as a whole are The diameter is kept as small as possible.

The solid-state image pickup device and its circuit board constituting the image pickup means are generally rectangular and are the largest members of various members provided in the insertion portion.
Therefore, the arrangement of this circuit board and the solid-state image sensor mounted on the circuit board has a great influence on the outer diameter of the insertion portion. If the solid-state image pickup device and its circuit board are arranged in a direction orthogonal to the optical axis of the objective optical system, a large space is required to mount this image pickup means, and the diameter of the insertion portion is increased. Therefore, a solid-state image sensor and a circuit board for the solid-state image sensor constituting the image pickup means are arranged widely in parallel with the optical axis of the objective optical system. When the image pickup means is arranged parallel to the optical axis of the objective optical system, it is necessary to bend the optical axis by approximately 90 °, and a prism is used for this purpose. This prism is arranged between the objective lens and the solid-state image sensor, and in the case of this configuration, the objective lens and the prism form an objective optical system.

The objective lens is mounted on the lens barrel,
The lens barrel is a cylindrical member, and a through hole is formed in the tip forming portion, and the lens barrel is inserted into the through hole and fixedly held. The width of the circuit board is usually larger than the outer diameter of the lens barrel, and the circuit board is arranged closer to the center of the insertion portion than the lens barrel. In the insertion part,
In addition to the observation means having the above configuration, at least a light guide as an illumination means is provided, and a treatment tool insertion channel for inserting a treatment tool such as forceps, and further for cleaning the lens surface of the observation means A fluid passage or the like may be attached. Since the light guide, the treatment tool insertion channel, and the fluid passage have a substantially uniform outer diameter over the entire length, the portion where the image pickup means is provided, particularly the portion where the circuit board is arranged, is the most filled portion in the insertion portion. The rate will be high. However, since this part is provided in the distal end hard part of the insertion part, if the above-mentioned members can be mounted, they will not interfere with each other even if there is little space between them. So
There is no particular hindrance.

[0007]

As described above, among the members that are inserted into the insertion portion, the member that has no directivity in the insertion direction is inside the rigid tip portion if the fixed position in the distal end forming portion is fixed. The position at is fixed. However, the rigid portion located in the distal end hard portion of the image pickup means is large in size and has a complicated shape. Therefore, when the rigid portion is fixed to the distal end constituent portion, it must be provided with directionality. In particular, the ratio of the width dimension of the circuit board to the diameter of the inner circumference of the insertion portion is considerably large, so that the directionality of the imaging means including the solid-state image sensor and the circuit board must be set very strictly. There is a risk of interfering with other members, for example, the treatment instrument insertion channel, and it will not fit in the insertion portion. In particular, the treatment instrument insertion channel is formed of a tube material having a large diameter so that the treatment instrument as large as possible can be inserted therethrough. Although the treatment instrument insertion channel itself is flexible, it has a considerably high rigidity.If the imaging means is pressed with this treatment instrument insertion channel, the solid-state image sensor is damaged or the electronic components mounted on the circuit board are damaged. There is a possibility that the cable may be broken or the cable may be broken.

Therefore, the observation means is fixed to the tip forming portion by providing a through hole in the tip forming portion and inserting the lens barrel into the through hole. Since this lens barrel has a cylindrical outer periphery, it may be attached at a position slightly deviated from the proper position in the rotational direction when fixing the lens barrel. The circuit board is tilted at an angle with respect to the proper position. As a result, when other members are inserted into the insertion portion, there is a high possibility of interfering with them, and there is a possibility that a fragile solid-state image sensor may be damaged, a cable may be disconnected, and the like. You may have to re-install. In addition, even if the members do not interfere with each other in the mounted state, if the solid-state image sensor and its circuit board are mounted in a state in which there is no proper gap with respect to other members such as the treatment tool insertion channel, When the angle portion is bent during use of the endoscope, the members may be pressed against each other, resulting in damage or the like.

The endoscope is not necessarily provided with the treatment instrument insertion channel, and there are some endoscopes which are not provided with the treatment instrument insertion channel, such as those which are inserted into a thin body cavity tube. In this type of endoscope, there is an increasing demand for reducing the diameter of the insertion portion and shortening the length of the hard portion. As described above, since the circuit board of the solid-state image pickup device that constitutes the observation means is the largest built-in object, this circuit board influences the outer diameter of the insertion portion. Therefore, the inner space of the tip forming section should have a minimum diameter on condition that the circuit board can be mounted, that is, the diameter of the inner space of the tip forming section should be slightly larger than the widthwise dimension of the circuit board. To be set. However,
Since the objective optical system by the observation means is arranged so as to be as close to the center position of the insertion section as possible, the circuit board is at a position offset to some extent from the center position of the insertion section. In such a structure, in order to make the diameter of the insertion portion as small as possible, the both ends of the circuit board are mounted so as to be substantially in contact with the inner surface of the hard end portion. Therefore, even if the circuit board is slightly tilted, it may come into contact with the inner surface of the tip hard portion or be pressed by this inner surface, which may also damage the circuit board or break the cable.

The present invention has been made in view of the above points, and an object of the present invention is to easily, accurately and accurately place an observing means attached to a distal end constituent portion of an insertion portion at an appropriate position. It is to be able to fix in the positioned state.

[0011]

In order to achieve the above-mentioned object, the present invention provides an observation means including an objective optical system and an image pickup means arranged at an image forming position of the objective optical system. In the structure for fixing the distal end hard part continuously provided to the angle part of the insertion part of the endoscope, the objective optical system is held.
Therefore, the cross section inserted into the through hole of the hard tip is circular.
And the base end side of the part that is inserted into this through hole.
And a holding member having an abutting portion having a flat surface,
It is formed on the proximal end side of the through hole of the distal end hard portion, and
The reference surface consisting of a flat surface with which the contact portion abuts, and the tip hard
From the side facing the reference surface of the holding member.
Screw the pressing screw to press the contact part against the reference surface.
It is characterized by having a configuration having the screw holes .

Here, the screw hole is formed so as to be opened on the outer peripheral surface of the hard tip portion, and the screw hole forming portion is covered with an outer skin layer extending from the angle portion. The observation means can be fixed at an appropriate position simply by screwing in the mounting screw and pushing it in.
Also, the screw hole portion can be sealed. When an objective optical system including an objective lens and a prism for bending the optical axis of the objective lens by 90 ° is used, a lens barrel having the objective lens attached thereto and a prism frame connected to the prism are provided. And the solid-state imaging device is assembled so as to be bonded to the prism. Thereby, the focus can be adjusted by moving the lens barrel in the optical axis direction with respect to the prism frame. The lens barrel is fixed with a lens barrel fixing screw at a position in focus with respect to the prism frame.A screw hole for screwing this lens barrel fixing screw is provided in the prism frame. A portion where the screw hole is formed is used as a screw mounting portion so as to project from the prism frame, and a flat side surface is formed on this screw mounting portion, and this flat side surface functions as an abutting surface pressed against the reference surface. preferable.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Thus, FIGS. 1 to 6 show the first embodiment of the present invention, and FIGS.
0 shows the second embodiment of the present invention, and FIG. 11 shows the third embodiment.

First, FIG. 1 shows the entire structure of an endoscope. In FIG. 1, reference numeral 1 denotes a main body operating portion, and the main body operating portion 1 has an insertion portion 2 to be inserted into a body cavity or the like. , And the universal cord 3 is pulled out from the main body operation unit 1. Although not shown, the universal cord 3 is adapted to be connected to a light source device and a processor. The insertion portion 2 is a flexible portion 2a that is bent in an arbitrary direction along the insertion path from the side where the insertion portion 2 is connected to the main body operation portion 1, and an angle portion 2b is provided at the tip of the flexible portion 2a. Further, a tip forming portion 2c is continuously provided at the tip of the angle portion 2b.

Next, FIGS. 2 and 3 show the structure of the tip forming portion 2c. Although a direct-viewing endoscope is shown in these drawings, the present invention is not limited to the direct-viewing endoscope and may be configured as a side-viewing endoscope or a perspective endoscope.

In the direct-view endoscope, as is apparent from FIG. 2, the illumination window 4 and the observation window 5 are provided on the tip surface of the tip forming portion 2c.
Are provided so that the inside of the body cavity can be inspected. Here, in the illustrated one, the illumination window 4
Are provided in two sets, and these are arranged on both left and right sides of the observation window 5. Further, a treatment instrument lead-out portion 6 through which forceps and other treatment instruments are inserted is provided below the observation window 5,
Further, 7 is a fluid jet nozzle, and this fluid jet nozzle 7 is adapted to jet a cleaning liquid, pressurized air or the like toward the observation window 5 when the observation window 5 is soiled.

As is apparent from FIG. 3, the tip forming portion 2c is composed of a tip body 10 and an insulating cover 11 fitted and fixed to the tip surface of the tip body 10. It The angle portion 2b is continuously provided to the tip forming portion 2c, and for this reason, the base end side of the tip body 10 has a small diameter portion 1a.
0a, and the angle portion 2b is attached to the small diameter portion 10a.
Of the angle rings forming the node ring structure in (1), the tip ring 12 located at the tip is fitted and fixed in a connected state by means such as a set screw or welding. Further, the outer skin layer 13 of the angle portion 2b passes through the connecting portion of the tip ring 12, and the insulating cover 11 in the tip body 10 is provided.
Is extended to a position where it abuts against the end surface of the tip end portion, and the end portion is fixed to the outer peripheral surface of the tip end portion main body 10.
A spool and an adhesive are used as 4. Therefore, in the distal end portion of the insertion portion 2, the distal end forming portion 2 c including the distal end portion main body 10 and the insulating cover 11 extends from the distal end ring 12 to the distal end ring portion 12.
The part up to the base end of the part constitutes a non-bendable tip hard part.

4 and 5 show cross sections at the XX and YY positions in FIG. As is clear from these figures, the distal end body 10 has a plurality of through holes. An opening is also formed in the insulating cover 11 at the same position. Reference numerals 20 and 20 denote light guide insertion portions, and a light guide 21 reaching the illumination window 4 is inserted into the light guide insertion portion 20. The tip of the light guide 21 faces the illumination lens 22 provided on the insulating cover 11. Reference numeral 23 denotes a treatment instrument insertion passage, and a connection pipe 24 is inserted into the treatment instrument insertion passage 23. The connection pipe 24 projects from the base end side of the distal end portion main body 10 and has a protruding portion. The treatment instrument insertion channel 25 is fitted and fixed to the. Here, the treatment instrument insertion channel 25
Has a bendable flexibility, but is relatively thick from the viewpoint of buckling prevention, and is made of a tube material having a high rigidity. Further, 26 is a fluid passage, which communicates with the fluid injection nozzle 7. Although illustration is omitted, an air / water feeding tube is connected to the fluid passage 26, and a connection pipe 27 for connecting the air / water feeding tube is inserted into the fluid passage 26.

An observation means 29 is attached to the observation window 5.
The observing means 29, as shown in FIG.
The objective optical system 30 includes an objective lens 32 including a plurality of lenses mounted on a lens barrel 33, and the optical axis of the objective lens 32 is bent by approximately 90 °. The prism 34 is provided for this purpose. Moreover, the objective lens 32 is movably connected to the prism 34 so as to move toward and away from the prism 34 to enable focus adjustment. For this purpose, the prism 34
A prism frame 35 is joined to the incident surface side of the lens barrel 33, and the lens barrel 33 is connected to the prism frame 35 so that the position thereof can be adjusted in the optical axis direction. Therefore, after the focus adjustment is performed, the lens barrel 33 and the prism frame 35 have a fixed relationship, and the objective lens 3 serving as the objective optical system is thereby provided.
2 and a holding member that holds the prism 34.

Further, the image pickup means 31 has a solid-state image pickup element 36 composed of a CCD or the like. The image pickup surface of the solid-state image pickup element 36 is joined to the prism 34, and the opposite surface is the circuit board 37. It is joined. Further, a cable 38 is drawn out from the circuit board 37, and a chip component 39 including a resistor and a capacitor is mounted on the surface of the circuit board 37 opposite to the joint surface of the solid-state imaging device 36. Of these chip components 39, the chip component indicated by 39a is sealed with resin.

The observation means 29 is constructed as described above, but the portion from the tip of the lens barrel 33 to the rear end of the circuit board 37 is a hard member, and the cable 38 extended from this circuit board 37. Is a flexible member. Lens barrel 3
3 is fixed by inserting it into a through hole 40 formed from the tip body 10 to the insulating cover 11. Further, the parts from the prism frame 35 to the solid-state image pickup device 36 and the circuit board 37 thereof are arranged from the tip end portion main body 10 to the angle portion 2
A cable 38 that extends into the tip ring 12 that constitutes b and is connected to the circuit board 37 is pulled out from the angle portion 2b to the flexible portion 2a side. Then, as is apparent from FIG. 4, by engaging the fixing screw 41 with the side surface of the lens barrel 33, the entire observing means 29 is fixed so as not to be excessively displaced. Further, the image guide 21 and the connection pipe 2 inserted into the treatment instrument insertion passage 23.
4. The connection pipe 27 inserted into the fluid passage 26 is also fixed with the same fixing screws 42 to 44. Then, a sealing material is filled in the screw holes of the fixing screws 41 to 44.

By using the prism 34, the solid-state image pickup device 36 and its circuit board 37 extend substantially parallel to the objective lens 32. Therefore, the distal end portion body 10 has a circular outer shape at the portion where the through hole 40 for mounting the lens barrel 33 is formed, but as shown in FIG. 5, the proximal end portion is at the central portion. Are divided into left and right divided block portions 10b and 10c each having a curved surface on the outer side and a flat surface having a step on the inner side, and the space formed between them is the solid-state image sensor 36 and its circuit board. Three
7 is the mounting portion 45 in which it is located. In addition, the light guide 21 and the treatment instrument insertion channel 25 are also attached to the mounting portion 4.
It is designed to pass 5.

In order to reduce the diameter of the insertion portion 2, the circuit board 37 is arranged at a position close to the treatment instrument insertion channel 25 in the mounting portion 45. Therefore, if the entire imaging means is not accurately positioned, it may interfere with the treatment instrument insertion channel 25 or the wall surface of the distal end portion main body 10. In particular, since the cable 38 is pulled out to the circuit board 37 and the chip parts 39, 39a are mounted on the side facing the treatment instrument insertion channel 25, these should not interfere with the treatment instrument insertion channel 25 or the like. Must be fitted.

Since the observing means 29 is fixed to the distal end forming portion 2c by inserting the cylindrical lens barrel 33 into the through hole 40 and using the screw 41, the observing means 29 should be attached in an arbitrary direction in the rotating direction. You can Therefore, it may be attached in a state in which it is deviated from the regular position in the rotational direction by an angle. Then, the solid-state imaging device 36 and the circuit board 37
Is tilted. However, the treatment instrument insertion channel 2
Since there is a relatively large space in the stage before 5 and the like are connected to the tip end main body 10, even if the circuit board 37 is slightly inclined, its attachment does not hinder. In this state, the treatment instrument insertion channel 25, etc.
If you try to connect it to 0, it will contact the circuit board 37,
It may come into contact with the chip parts 39, 39a.

The circuit board 37 is the treatment instrument insertion channel 25.
Since it is arranged at a position extremely close to the position, even if there is a slight deviation, it will interfere with the circuit board 37, the chip parts 39, 39a and the treatment instrument insertion channel 25, etc. , Circuit board 37
It may be damaged by applying pressure to the chip parts 39, 3
9a may be damaged, and the cable 38 may be broken. Further, if the circuit board 37 is extremely displaced, the treatment tool insertion channel 25 and the like cannot be assembled. Further, even if the circuit board 37 or the chip parts 39, 39a and the treatment instrument insertion channel 25 do not interfere with each other, there is almost no gap between them and the angle portion 2b is curved when they are substantially in contact with each other. When the treatment instrument insertion channel 25 is bent, a compressive force acts due to the bending of the treatment instrument insertion channel 25, which may also cause damage or disconnection.

From the above, strict positioning of the observing means 29 depends on the circuit board 37 and the chip parts 39,
It is important for protection of the cable 39a and the cable 38, and by strict positioning of the cable 39a, it is possible to effectively utilize the space in the portion having the highest filling rate, and thus it is advantageous in reducing the diameter of the insertion portion 2. Become. Therefore, by providing a positioning mechanism for the lens barrel 33 having no directivity in the rotation direction between the lens barrel 33 and the tip end body 10, the solid-state imaging device 36 having the directivity in the rotation direction and the circuit board thereof. The 37 can be positioned easily and extremely accurately.

As described above, the lens barrel 33 can be brought into focus by displacing the lens barrel 33 in the direction in which the lens barrel 33 approaches and separates from the prism 34. When the lens barrel 33 and the prism frame 35 are fixed so that the lens barrel 33 and the prism frame 35 are not displaced when the positional relationship is brought into focus, the lens barrel fixing screw 46 is provided as shown in FIG. The lens barrel 33 and the prism frame 35 are fixed by using them. This fixing is performed by the prism frame 35.
A lens barrel fixing screw 46 is screwed into and the tip of the screw is engaged with the outer surface of the lens barrel 33. For this purpose, a screw mounting portion 47 is continuously provided at the tip end side portion of the lens frame 35, and a screw hole is formed in the screw mounting portion 47.

Using this screw mounting portion 47, the lens barrel 3
Positioning in the rotational direction of 3 is performed. For this reason, the screw mounting portion 47 has a rectangular shape that projects from the prism frame 35 to the side opposite to the side where the solid-state image sensor 36 is joined. However, the protruding height of the screw mounting portion 47 does not exceed the height of the prism 35, and the width dimension does not exceed the width dimension of the prism 35.
Alternatively, by making the size slightly smaller than those dimensions, it is not necessary to provide an extra space in the mounting portion 45 of the tip body 10. Then, flat surfaces are formed on both the left and right sides of the screw mounting portion 47 so that one side surface functions as a contact surface 47a serving as a contact portion and the other side surface functions as a pressing surface 47b. On the other hand, the tip body 1
The left and right divided block parts 10 constituting the mounting part 45 of 0
A reference surface 48 is formed on the inner surface of the divided block portion 10b on one side of b and 10c on the side facing the contact surface 47a of the screw mounting portion 47. The divided block portion 10c on the opposite side is provided with a screw hole 49 penetrating to the side surface portion.

Therefore, the pressing screw 50 is screwed into the screw hole 49 provided in the divided block portion 10c, and the screw mounting portion 4
7 by pressing the pressing surface 47b of the contact surface 4
7a can be brought into pressure contact with the reference surface 48, and as a result, the image pickup means can be attached to the distal end forming portion 2c so that the prism frame 35 is at a predetermined position in the rotation direction. As a result, the solid-state image sensor 36 and its circuit board 37 are always arranged at a fixed position.

Therefore, when the observation means 29 is attached to the insertion portion 2, the tip end main body 1 constituting the tip end forming portion 2c.
0 is separated from the insulating cover 11 and the angle portion 2b, and the lens barrel 33 is attached to the through hole 40 of the tip body 10.
Insert it to the specified position. The lens barrel 33 and the prism frame 35 are integrally fixed by the lens barrel fixing screw 46. Then, the lens barrel fixing screw 4
The screw mounting portion 47 provided with 6 is located in the mounting portion 45 formed between the divided block portions 10b and 10c of the tip end body 10. In this state, the divided block unit 1
When the pressing screw 50 is screwed into the screw hole 49 provided in 0c, it abuts the pressing surface 47b of the screw mounting portion 47,
The screw mounting portion 47 is displaced so as to incline toward the divided block portion 10b side around the optical axis center of the lens barrel 33. As a result, the contact surface 47a of the screw mounting portion 47 comes into contact with the reference surface 48 of the divided block portion 10b, and by tightening the pressing screw 50, the prism frame 35 moves to the tip portion main body 10 in a predetermined manner. It is fixed while it is positioned in position. Therefore, when the prism frame 35 is fixed, the reference surface 48 and the contact surface 47 are formed so that the solid-state imaging device 36 and its circuit board 37 are in proper positions. Tightening keeps them in place at all times.

The focus adjustment can be performed before assembling into the tip body 10, but even when the prism frame 35 is positioned and fixed to the tip body 10, the divided block 10 is used.
Since it is possible to insert and remove the lens barrel fixing screw 46 into and from the screw mounting portion 47 by inserting a jig such as a driver from between b and 10c, focus adjustment can be performed at this stage as well. Further, the screw 41 is screwed into the tip body 10 and the tip of the screw 41 is engaged with the lens barrel 33, whereby the observation means 29 can be completely fixed. The prism frame 35 is fixedly held by the tip body 10 by the pressing screw 50, and the lens barrel 33 is fixed to the prism frame 35 by the lens barrel fixing screw 46. The fixing of the lens barrel 33 is not always essential, but the observation means 29 is held more stably by using the screw 41.

Since the members other than the observing means 29 have a circular cross section, the positions of the respective members within the cross section are fixed when the members are fixed to the tip end main body 10. When mounted in such a proper position, all the members have a fixed positional relationship, and the members interfere with each other or are pressed against each other in the narrow space of the mounting portion 45. It is possible to effectively protect the solid-state imaging device 36 and its circuit board 37, which are members rationally arranged and vulnerable to external force, the cable 38, and the chip parts 39, 39a, etc. Therefore, it is not necessary to provide a space in consideration of an error when mounting each member, and thus the diameter of the insertion portion 2 can be reduced. Moreover, it becomes possible to position the observation means 29 by a simple operation of screwing the pressing screw 50, and it is possible to prevent unreasonable assembly due to the positional displacement, and to eliminate the need for reassembly and the like. Assembling is also good.

The screw hole 49 is opened in the side surface of the tip end main body 10. Therefore, if the airtightness of the portion where the screw hole 49 is formed is not ensured, a contaminant or the like will enter the insertion portion 2. Since the outer skin layer 13 of the angle portion 2b passes through the portion where the screw hole 49 is formed, is joined to the base end portion of the insulating cover 11, and is fixed by the fixing portion 14 including the bobbin, When the entire insertion portion 2 is assembled as a whole, the screw hole 49 is covered with the outer skin layer 13, so that its airtightness can be secured. Further, the pressing screw 5 is inserted into the screw hole 49.
If the sealing material is filled after screwing 0, a higher degree of airtightness can be secured.

Next, FIGS. 7 to 10 relate to the second embodiment of the present invention. In this embodiment, the observation means is substantially the same as that of the first embodiment. However, the insertion portion of the endoscope has a small diameter with only an illumination window and an observation window.

As is apparent from FIG. 7, the observation means 60 is composed of an objective optical system 61 and an image pickup means 62, and the objective optical system 61 has a lens barrel 64 in which an objective lens 63 is incorporated. The prism 65 and the lens barrel 64 are connected to each other via a prism frame 66. Further, a solid-state image sensor 67 is joined to the prism 64, the solid-state image sensor 67 is mounted on a circuit board 68, and a cable 69 is pulled out from the circuit board 68. Further, the circuit board 68 has a chip component 70.
Etc. are installed.

The insertion portion 71 of the endoscope to which the observing means 60 having the above-mentioned structure is attached is the one except that the observing means 60 is provided with the image guide 72. The diameter can be reduced. As shown in FIG. 9, the widest circuit board 68 is attached to the insertion portion 71.
It is located near the center of. However, observation means 6
In order to prevent the observation field of view of 0 from being too far from the center of the insertion portion 71, the circuit board 68 is set to the insertion portion 71.
Although it is close to the center of the
The distance D is offset from the center of.

Here, in the illustrated insertion portion 71, a tip forming portion 71a is formed by connecting a connecting cylinder member 74 to a tip portion main body 73, and an angle portion 71b is connected to the tip forming portion 71a. Although not shown in the drawing, a flexible portion is connected to the angle portion 71b. A through hole 75 through which the lens barrel 64 is inserted is formed in the distal end portion main body 73, and a concave portion is formed at the proximal end side. This concave portion is the proximal end side of the lens barrel 64 in the observing means 60. And the prism frame 66. Further, the solid-state image sensor 67 and the circuit board 68 thereof are arranged inside the connecting cylinder member 74.

In this structure, it is substantially the width of the circuit board 68 that determines the outer diameter of the insertion portion 71. That is, the circuit board 68 is arranged inside the connecting cylinder member 74, and the thickness of the connecting cylinder member 74 is determined from the viewpoint of strength and the like, and the left and right ends of the circuit board 68 are substantially in contact with the inner surface of the connecting cylinder member 74. When mounted in this state, the inner diameter becomes the smallest. Therefore, as in the first embodiment described above, the circuit board 68 is tilted from the normal position and the tip portion main body 7 is inclined.
3 is connected to the distal end body 7
I cannot connect to 3.

From the above, as is apparent from FIG. 8, the lens barrel for fixing the lens barrel 64 to the prism frame 66 to which the lens barrel 64 is connected so that its position can be adjusted in the optical axis direction. A screw mounting portion 78 to which the fixing screw 77 is mounted is provided in series, and one side surface of the screw mounting portion 78 is a contact surface 78a and the other side surface is a pressing surface 78b.
In addition, the screw mounting portion 7 of the mounting portion 76 in the tip portion main body 73
The wall surface facing 8 is formed as a reference surface 79, and a screw hole 80 is formed on the opposite side to the reference surface 79 so that the pressing screw 81 can be screwed into the screw hole 80. In the figure, 8
Reference numeral 2 is a retaining screw for preventing the tip body 73 from deviating from the connecting cylinder member 74.

With this structure, after the observing means 60 is assembled in the tip end body 73, the pressing screw 81 is screwed into the screw hole 80, and the contact surface 78a of the screw mounting portion 78 is changed to the reference surface 79. Since the circuit board 68 is always arranged at a fixed position by being pressed against, the connecting cylinder member 74 can be reliably connected to the tip end body 73, and the circuit board 68 and the like can be connected when the connecting cylinder member 74 is connected. It won't damage it. Here, as is clear from FIG.
Unlike the first embodiment described above, the screw mounting portion 78
Project to the circuit board 68 side. Therefore, the width dimension of the screw mounting portion 78 needs to be sufficiently smaller than the width dimension of the circuit board 68. However, the height direction of the screw mounting portion 78 can be slightly projected from the circuit board 68.

As the observing means, as shown in FIG. 11, the lens barrel 90 is inserted into the holding cylinder 91 without using the prism, and the solid-state image pickup element 92 is directly bonded to the holding cylinder 91. The observing means 93 thus configured may be used in some cases. Focus adjustment is performed by advancing and retracting the lens barrel 90 with respect to the holding barrel 91. For this purpose, the holding barrel 91 is provided with a screw mounting portion 95 to which the lens barrel fixing screw 94 is mounted. Therefore, the surface on one side of the screw mounting portion 95 serves as the contact surface 95a, and the surface on the other side serves as the pressing surface 95b. And the above-mentioned first,
Similar to the second embodiment, the contact surface 95a is attached to the tip end body.
The solid-state image sensor 92 and its circuit board 96 are always in a fixed direction by providing a reference surface that contacts with the pressing surface 95b and a screw hole into which a pressing screw that presses the pressing surface 95b is screwed. Can be installed.

[0042]

As described above, according to the present invention, the tip hardness
By forming an abutting portion on the holding member that is inserted into the through hole of the quality portion ,
A reference surface against which the contact portion is pressed is formed on the wall surface of the mounting portion of the observation means of the distal end hard portion, and the contact portion is pressed against the reference surface on the side facing the reference surface of the mounting portion. Since the screw hole into which the pressing screw is screwed is formed, the observation means attached to the hard end of the insertion part is attached to the tip.
It can be securely fixed to the hard part, and the contact part is pressed against the reference surface.
By making contact with each other, positioning in the rotation direction is easy and
There is an effect that it can be accurately performed .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electronic endoscope.

FIG. 2 is an external view showing a distal end surface of an insertion portion.

FIG. 3 is a vertical cross-sectional view of the distal end portion of the insertion portion showing the observation means fixing structure according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line XX of FIG.

5 is a cross-sectional view taken along line YY of FIG.

FIG. 6 is an external perspective view of the observation means according to the first embodiment.

FIG. 7 is a vertical cross-sectional view of the distal end portion of the insertion section showing the observation means fixing structure according to the second embodiment of the present invention.

8 is a sectional view taken along line P-P of FIG.

9 is a sectional view taken along line QQ of FIG.

FIG. 10 is an external perspective view of the observation means according to the second embodiment.

FIG. 11 is an external perspective view of an observation means according to a third embodiment.

[Explanation of symbols]

2 Insertion part 2b Angle part 2c Tip structure part 4 Illumination window 5 Observation window 10 Tip part body 10b, 10c Divided block part 11 Insulation cover 12 Tip ring 13 Outer skin layer 29, 60, 93 Observation means 30, 61
Objective optical system 31, 62 Imaging means 32, 63
Objective lens 33, 64, 90 Lens barrel 34, 65
Prism 35,66 Prism frame 36,67
Solid-state image sensor 37, 68 Circuit board 38, 69
Cables 39, 39a, 70 Chip parts 40 Through holes 45, 76 Mounting parts 47, 7
8, 95 screw mounting portions 47a, 78a, 95a abutting surfaces 47b, 7
8b, 95b Pressing surface 48, 79 Reference surface 49, 80
Screw holes 50, 81 Pressing screw 74 Connection tube member 91 Holding tube

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-253181 (JP, A) JP-A-4-317622 (JP, A) JP-A-6-70882 (JP, A) JP-A-9- 173288 (JP, A) Actual development 3-18801 (JP, U) Actual development Sho 64-30522 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61B 1/00-1 / 32

Claims (4)

(57) [Claims] 1. An observation means including an objective optical system and an image pickup means arranged at an image forming position of the objective optical system is fixed to a distal end hard portion connected to an angle portion of an insertion portion of an electronic endoscope. The objective optical system is held and inserted into the through hole of the distal end hard portion.
The part with a circular cross section and the through hole
Abutting part that is provided on the base end side of the closed part and has a flat surface
And a holding member having, and a base end side of the through hole of the distal end hard portion,
A reference surface, which is a flat surface with which the contact portion abuts, and a reference surface of the holding member, which is provided in the distal end hard portion, and is opposed to the reference surface.
Press to press the contact part against the reference surface from the opposite side
An observation means fixing structure for an electronic endoscope, characterized in that the structure has a screw hole into which a manual screw is inserted . 2. The screw hole is formed so as to be opened on the outer peripheral surface of the distal end hard portion, and the portion where the screw hole is formed is covered with an outer skin layer extending from the angle portion. The observation means fixing structure for an electronic endoscope according to claim 1. 3. The objective optical system includes an objective lens and a prism for bending an optical axis of the objective lens by approximately 90 °, and the image pickup means is joined to the prism. The observation means fixing structure for an electronic endoscope according to claim 1. Wherein said retaining member comprises a prism frame provided coupled to said prism, by moving in the optical axis direction the lens barrel relative to the prism frame, configurations and none can focus adjustment A screw mounting portion into which a lens barrel fixing screw is screwed in order to fix the lens barrel at a predetermined position with respect to the prism frame is integrally provided on the prism frame, and the contact portion is The observation means fixing structure for an electronic endoscope according to claim 1, wherein the structure is formed by a flat side surface of the screw mounting portion.