JP2000206422A - Endoscope provided with objective lens moving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a control cable from interfering with a signal cable or both cables from being pressed each other and to protect a weak member such as a wiring by constituting an endoscope, so that the extending direction of an arm part is offset by a prescribed angle with respect to the center line of a curve in the vertical directions of an angle part. SOLUTION: The vertical directions in an observation field is a direction along a line Y-Y linking the top and bottom operation wires 26, and this line is the center line of the curve in the vertical directions of the angle part 3b. The signal cable 52 made to be pulled out of a substrate 33b in a solid-state image pickup element assembly 33 is arranged on or near the line Y-Y at least on the edge side of the angle part 3b. In order to successively provide a lens support frame 35 and a pivotally support member, the axial line A of the arm part linking a projection part 35b from the frame 35 and a movable lens frame and a nut part is inclined by the specified angle θ with respect to the line Y-Y from a center position C, whereby a control cable 41 is offset in a rotating direction with respect to the line Y-Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective optical system which is provided in an insertion portion of an endoscope used for medical purposes and constitutes an observation portion, and has an observation depth, an imaging magnification, a viewing angle and the like. The present invention relates to an endoscope with an objective lens moving mechanism in which at least one lens constituting an objective optical system is moved in a direction of an optical axis by remote control in order to make at least one of them variable.

[0002]

2. Description of the Related Art In general, an endoscope used for medical purposes or the like is a universal endoscope which is detachably connected to an insertion portion into a body cavity, a light source device, and the like, to a main body operation portion which is grasped and operated by an operator. It is roughly configured by providing a series of cords. The insertion portion is composed of a distal end main body, an angle portion, and a flexible portion from the distal end side in terms of its structure and function, and the flexible portion has most of the length from the portion connected to the main body operation portion,
It has a structure that bends in any direction along the insertion path. The distal end main body is provided with an illuminating section, an observation section, and the like on the distal end surface thereof, and has an opening for a treatment instrument lead-out section for leading out a treatment instrument such as forceps. In order to bend, it can be bent by remote control from the main body operation unit side.

As described above, at least the illumination section and the observation section are provided in the distal end body, and the exit section of the light guide made of an optical fiber bundle faces the illumination section, and this light guide is inserted into the insertion section. Through the main body operation unit and into the universal cord. Further, an objective optical system is mounted on the observation unit. When the objective optical system is configured as an electronic endoscope, a solid-state imaging device is arranged at an image forming position in the objective optical system. Here, the observation unit is usually arranged at a substantially central position in a vertical cross section of the distal end body, and one or a plurality of illumination units are provided at positions close to the observation unit. As a result, an observation field is formed at the center position of the insertion portion, and illumination light is applied to the entire field range centered on the observation field. In particular, when a hood is attached to the distal end of the insertion section, the observation field of view is prevented from being shaken by the hood to a minimum.

When a solid-state imaging device is provided in the observation unit, a signal cable is pulled out from a substrate on which the solid-state imaging device is mounted. However, since the substrate is provided near the center of the insertion unit, the signal cable is At least a portion from the tip main body to the angle portion substantially passes through the center position. There is also a configuration in which a prism is incorporated in the objective optical system and the optical axis thereof is bent by 90 °.
In this case, the solid-state imaging device and its substrate are arranged at positions offset from the center of the insertion portion, so that the position where the signal cable is pulled out from the substrate is away from the center of the insertion portion.
It is generally arranged on or near the vertical centerline of curvature of the angle portion. Further, in an optical endoscope using an image guide, the image guide extends in the optical axis direction of the objective optical system. It is located at the center or in the vicinity thereof.

[0005] The objective optical system provided in the observation section includes an objective lens group, which is composed of a plurality of lenses. Depending on the observation site, the purpose of the treatment, and the like, it is desirable to change the depth of focus with respect to the observation target portion, the imaging magnification, the viewing angle, and the like. Therefore, one or more lenses of the objective lens group are formed as movable lenses that can be moved in the optical axis direction, and by moving this movable lens, the depth of focus, the imaging magnification, the viewing angle, and the like can be adjusted. Is conventionally known. For this purpose, the fixedly held lens is provided on the fixed lens frame, the movable lens is mounted on the movable lens frame, and the movable lens frame is arranged in the fixed lens frame, and the fixed lens frame is guided. To move the movable lens frame in the optical axis direction.

As a driving means for moving the movable lens in the optical axis direction, for example, it has been proposed to use a piezoelectric element, a shape memory alloy, and an artificial muscle. However, usually, a control cable is used. The distal end of the control cable is connected to the movable lens, and the proximal end of the control cable is extended into the main body operation unit. The control cable is configured to remotely move the movable lens in the optical axis direction. . And, as a specific configuration of the control cable,
The transmission member is inserted into a flexible sleeve. As the transmission member, a wire for push-pull operation or a flexible shaft for rotational driving is used.

When a wire is used as the transmission member,
The tip of this wire is directly connected to the movable lens frame, and the wire is pushed and pulled to move the movable lens. When a flexible shaft is used, a screw shaft is connected to the tip of the flexible shaft, and a nut for screwing the screw shaft is provided in the movable lens frame, so that the rotation of the flexible shaft is used for the linear movement of the movable lens. Convert. When a wire is used as the transmission member, the outer diameter of the control cable can be reduced. However, the drive can be performed only in one direction, that is, in the direction in which the wire is pulled. Force means must be applied. On the other hand, the flexible shaft is composed of a close contact coil in which a metal wire is wound in a close contact spiral shape,
When rotating in the forward and reverse directions, the coil is generally formed in two layers, inside and outside. When the flexible shaft is rotated around the axis inside the sleeve, the rotational force is transmitted to the tip without fail, and the movable lens can be reciprocated between the forward position and the retracted position. Since no force acts in the direction of expansion and contraction, the flexible shaft is superior in controllability from the viewpoint of stable operation and the like. However, when the flexible shaft is used, the diameter of the control cable is slightly increased, and it is undeniable that the control cable is slightly harder in the bending direction than when the wire is used.

[0008]

In any case, the distal end of the control cable is connected to the movable lens frame, but the control cable extends from the inside of the insertion portion to the main body operation portion.
Since the movable lens frame to which the control cable is connected forms an observation unit together with the solid-state imaging device and the like, the control cable is arranged at a position close to the signal cable (or image guide) drawn from the solid-state imaging device. Therefore, the control cable and the signal cable must be drawn out so as not to interfere with each other. All of these are flexible in the bending direction, and the portion from the base end of the angle portion to the soft portion in the insertion portion can be directed in any direction, so it is not particularly difficult to secure the installation space. However, at the position near the connecting portion between the angle portion and the distal end portion main body, the position is restricted to the position of the observation portion.

The angle portion can be bent vertically and horizontally by remote control. If the control cable and the signal cable are close to each other, they may come into contact with each other during the bending operation. Comparing the stiffness of the control cable and the signal cable in the bending direction, the control cable is usually stiffer, and when bent, the signal cable bends easily against bending. Will be pressed against the signal cable. As a result, there is a higher possibility that the wiring constituting the signal cable is broken. In addition, in the vertical and horizontal bending directions of the angle part, particularly in the vertical direction, the control cable and the signal cable are arranged in the vertical direction because the vertical and horizontal bending directions are greatly bent to 180 ° or more. An extremely large compression force will act.

The present invention has been made in view of the above points, and an object of the present invention is to prevent a control cable from interfering with or pressing against a signal cable or the like drawn from a solid-state image sensor. And to effectively protect the fragile member such as the wiring.

[0011]

In order to achieve the above-mentioned object, the present invention provides a fixed lens mounted on a fixed lens frame and a movable lens frame which slides on the inner surface of the fixed lens frame. An objective optical system having at least one movable lens is provided, a nut portion screwed to a screw shaft is continuously provided on the movable lens frame, and the screw shaft is rotated by a remote control using a control cable. In an endoscope provided with a distal end body in which an observation portion enabling a movable lens to be movable in an optical axis direction is connected to an angle portion, a support portion is integrally provided on the fixed lens frame, and a screw shaft is provided on the support portion. Is provided so as to be rotatable and immovable in the axial direction so as not to be movable in the axial direction, and arm portions are continuously provided between the fixed lens frame and the support portion and between the movable lens frame and the nut portion, respectively.
It is characterized in that the extending direction of the arm portion is offset by a predetermined angle with respect to the vertical center line of curvature of the angle portion.

Here, if both arms are configured to be offset by substantially the same angle with respect to the vertical and horizontal bending center lines of the angle portion, the signal can be obtained regardless of the vertical or horizontal bending operation. It is possible to prevent the cable and the drive cable from being pressed against each other.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, it is assumed that the objective optical system is configured as an electronic endoscope using a solid-state imaging device and the optical axis of the objective optical system is bent by 90 ° by a prism. The present invention can be applied to an optical endoscope in which an image guide is arranged at a position, and can be applied to an electronic endoscope which does not incorporate a prism even if a solid-state imaging device is used.

First, FIG. 1 shows a schematic configuration of the entire endoscope. As is apparent from FIG. 1, the endoscope 1 is generally configured by connecting an insertion section 3 into a body cavity or the like to a main body operation section 2 and pulling out a universal cord 4 from the main body operation section 2. Things. The insertion section 3 connected to the main body operation section 2 is divided into a front end main body 3a, an angle section 3b, and a flexible section 3c in order from the front end side in terms of function and structure.

The distal end body 3a is made of a hard member,
As shown in FIG. 2, an illumination unit 10, an observation unit 11, a treatment tool lead-out unit 12, and a cleaning nozzle 13 are provided on the tip surface, and a jet water supply unit 14 is further opened. In addition,
Although the illustrated illumination unit 10 is provided at three locations so as to surround the observation unit 11, any number of the illumination units 10 may be provided, and the jet water supply unit 14 is not necessarily provided. The angle portion 3b can be operated to bend in up, down, left and right directions by an angle knob 5 provided on the main body operation portion 2 so as to direct the distal end portion main body 3a in a desired direction. Further, the flexible portion 3c is
The flexible portion 3c has a structure that is flexible in the bending direction and has crush resistance, and therefore bends in any direction along the insertion path. .

FIG. 3 shows a cross section of a portion on the distal end side of the insertion portion 3. As is apparent from this figure, the distal end portion main body 3a has a main body block 20 made of, for example, a metal, and a through hole is formed in a required portion of the main body block 20 so as to penetrate in the axial direction. An insulating cap 21 is attached to the tip end surface of the main body block 20, and is fixed to the main body block 20 by a set screw 22. Angle part 3b
A node ring structure in which a number of angle rings 23 are sequentially pivoted by pivot pins 24 is provided. A metal net and fluoro rubber, E
A cover member 25 including a skin layer made of PDM, urethane rubber or the like is provided. Further, four operation wires 26 extend from the inside of the angle portion 3b toward the flexible portion 3c, and these operation wires 26 form a pair at the top and bottom and at the left and right, respectively. When one is pulled and the other is extended, the angle portion 3b is bent vertically, and when one of the pair of left and right operation wires is pulled and the other is extended, the angle portion 3b is curved left and right.

The tip ring 23a located at the leading end of the multiple connected angle rings 23 constituting the angle portion 3b is connected to the main body block 20.
Therefore, in the insertion portion 3, the portion from the distal end surface of the insulating cap 21 to the position of the pivotal connection between the distal end ring 23a of the angle portion 3b and the other angle ring 23 pivotally connected thereto is a hard portion. I have.

As is well known, the illumination unit 10 irradiates the illumination light transmitted to the light guide toward the inside of the body cavity, and can observe the inside of the body cavity under the illumination light. The observation of the inside of the body cavity is performed by the observation unit 11, and the observation unit 11 is disposed approximately at the center of the distal end surface of the distal end main body 3 a of the insertion unit 3. As a result, the center position of the insertion section 3 substantially coincides with the center of the observation field of view, which is advantageous in terms of the operation of inserting the insertion section 3 into the body cavity and the like. In the case of wearing, for example, blurring of the observation visual field is suppressed to a minimum. The configuration of the observation unit 11 provided at the distal end of the distal end body 3a will be described with reference to FIGS.

First, in FIG. 4, reference numeral 30 denotes a lens assembly constituting an objective optical system, and this lens assembly 30 is provided with an observation unit mounting portion 11a provided on the main body block 20.
(See FIG. 3). The lens assembly 30 includes an objective lens group 31. The lens assembly 30 includes an objective lens group 31. The objective lens group 31
The optical path from is bent downward by 90 ° by the prism 32. Then, the objective lens group 31
A solid-state image sensor assembly 33 composed of a solid-state image sensor 33a joined to the prism 32 and its substrate 33b is arranged at the image forming position. A filter 3 having desired characteristics is provided between the objective lens group 31 and the prism 32.
4 and an aperture (not shown) in addition to these.
Are provided.

As is clear from FIGS. 5 and 6, a part (one or a plurality) of lenses 31a constituting the objective lens group 31 is a movable lens movable in the optical axis direction, and the remaining lenses are movable. 31b is a fixed lens. The fixed lens 31b is fixedly mounted on a lens support frame 35 constituting a fixed lens frame.
2 is joined to the surface. The movable lens 31a is mounted on the movable lens frame 36, and the movable lens frame 36
Is moved along the inner surface of the lens support frame 35, whereby the movable lens 31a moves in the optical axis direction.

In order to accurately match the optical axes of the movable lens 31a and the fixed lens 31b, the movable lens frame 36 provided with the movable lens 31a
It is movable in the optical axis direction, and is fixedly held in other directions, that is, in a direction orthogonal to the optical axis and in a falling direction. In addition, in order to minimize the sliding resistance when moving in the optical axis direction, at least two sliding contact surfaces 36a are formed on the outer peripheral surface of the movable lens frame 36, and only the sliding contact surfaces 36a are formed. By contacting the inner surface of the lens support frame 35, the contact area between the movable lens frame 36 and the lens support frame 35 is reduced. Thus, in the illustrated example, two sliding contact surface portions 36a are provided at two positions, which have a positional relationship of 180 ° with each other and have a predetermined width in the circumferential direction. An arm 37 is connected to the movable lens frame 36, and the arm 37 is led out through a slit 35a provided in the lens support frame 35 in the optical axis direction. Is provided with a nut portion 38 in series. Here, the width dimension of the arm portion 37 substantially matches the groove width of the slit 35a, thereby restricting the movement of the movable lens frame 36 in the rotation direction.

With the above configuration, the movement of the movable lens frame 36 other than in the direction of the optical axis is almost completely restricted. By moving the nut portion 38 in a direction parallel to the optical axis, the movable lens frame 36 moves in the optical axis direction. The reason why the movable lens 31a can be moved in the optical axis direction is to change at least one of the observation depth, the imaging magnification, the viewing angle, and the like. Here, the movable lens frame 36 is positioned at least at both end positions of the movement stroke, but may be arranged at an intermediate position in order to arbitrarily set an imaging magnification and the like.

The movable lens 31a is moved by remote control on the main body operation unit 2. To this end, a protrusion 35b is continuously provided on the lens support frame 35, and a substantially cylindrically-shaped support member 39 is continuously provided on the protrusion 35b, and the support member 39 is movable. It functions as a support for holding the driving means of the lens frame 36. The driving means includes a nut 38 connected to the tip of the arm 37.
And a control shaft 41 for driving the screw shaft 40 to rotate. The screw shaft 40 includes a screw rod portion 40a and a rotation shaft portion 40b, and the rotation shaft portion 40b is formed through an insertion hole 3 formed in the shaft support member 39.
9a is rotatably inserted so as not to move in the axial direction. The threaded rod portion 40a projects a predetermined length forward from the shaft support member 39 by a predetermined length.
Is screwed into the protruding portion of the screw rod portion 40a.

The control cable 41 is formed by inserting a flexible shaft 43 composed of a double close coil into a sleeve 42 having flexibility. The tip of the flexible shaft 43 is connected to the screw shaft 4 by the connecting member 44.
0, and the end of the sleeve 42 is
At 5, it is fixed to the shaft support member 39. Therefore, when the proximal end of the flexible shaft 43 is rotated around the axis in the sleeve 42, the rotation is transmitted to the screw shaft 40, and the screw shaft 40 rotates, thereby connecting the nut portion 38 and the nut portion 38 thereto. The movable lens frame 36 moves. And
In order to regulate the moving stroke range of the nut portion 38,
A stopper member 46 is screwed into the distal end of the screw rod portion 40a, and a stopper step 40c is provided on the proximal end side. Therefore, the nut portion 38 is provided with the stopper step 40.
4 can be displaced between the forward position shown in FIG. 4 abutting on c and the retracted position shown in FIG. As a result, the depth of focus and the imaging magnification of the objective lens group 31 and the viewing angle can be changed. For example, when the movable lens 31a to which the movable lens 31a is attached is located at the position shown in FIG. 4 where the nut portion 38 connected to the movable lens 31a contacts the stopper step 40c, the imaging magnification is reduced and the movable lens 31a is brought into contact with the stopper member 46. The arrangement of 6 increases the imaging magnification and narrows the viewing angle. In addition, the depth of focus of the movable lens 31a at each of these positions also changes.

The control cable 41 extends from the insertion section 3 into the main body operation section 2, and the base end of the flexible shaft 43 is connected to the rotating shaft 47.
2 is fixedly held by a casing or the like of the main body operation unit 2. A driven gear 48 is connected to the rotating shaft 47 and meshes with a driving gear 50 provided on an output shaft of a motor 49. When the driving gear 50 is driven to rotate by the motor 49, the driven gear 48 is driven. As a result of the rotation of the gear 48 following the rotation, the rotation shaft 47 and the flexible shaft 43 connected thereto rotate around the axis,
The screw shaft 40 connected to the flexible shaft 43 is driven to rotate by remote control, and the movable lens 31a moves in the optical axis direction. And this motor 49
The body operation section 2 is provided with a toggle switch 5 for controlling the operation of the motor 49. By operating the toggle switch 5, ON / OFF control of the motor 49 is performed.

From the above, the driving mechanism of the movable lens 31a constituting the objective lens group 31 is controlled by the control cable 41
And the flexible shaft 43 of the control cable 41
And a nut portion 38 connected to the movable lens 31a and screwed to the screw shaft 40. When the flexible shaft 43 is rotated, the rotation is transmitted to the screw shaft 40, and this screw shaft 4
The rotation of 0 causes the nut portion 38 to move in the axial direction. Therefore, the screw shaft 40 and the nut portion 38 constitute a means for converting the rotational motion into the linear motion.

As described above, the movable lens 31a is moved by operating the control cable 41 to rotate the screw shaft 40. The movable lens 31a is always moved along the optical axis of the entire objective lens group 31, that is, fixed. It is necessary to keep the state where the optical axis coincides with the lens 31b.
The sliding contact surface portion 36a of the movable lens frame 36 is
For this reason, the sliding surfaces 36a provided at two places are both slid along the inner surface of the lens support frame 3.
5 in a substantially surface contact state. In addition, it is necessary to hold the movable lens 31a so as not to be displaced in the rotation direction unnecessarily during the movement. For this reason, the arm portion 37 is moved with respect to the slit 35a of the lens support frame 35 in the width direction, that is, in the rotation direction. It is inserted with almost no gap. As a result, the movable lens 31a is positioned extremely accurately, and movement other than in the optical axis direction is almost completely restricted.

Incidentally, the driving force of the movable lens 31a is:
It acts on a nut part 38 provided continuously with one arm part 37 extended from the movable lens frame 36. As described above, since the movement of the movable lens frame 36 other than the optical axis is restricted, there is some backlash in the screw fitting portion between the nut portion 38 and the screw shaft 40 on the driving side, that is, the back. By providing a lash, machining errors, assembling errors, and the like are absorbed on the screw fitting portion side. In addition, in order to minimize the deviation of the axis line between the nut portion 38 and the screw shaft 40, the length of the screw fitting portion is increased so that the sliding resistance during the movement of the movable lens frame 36 is reduced. Thus, the movable lens frame 36 is restricted so as not to generate a force in the falling direction due to a delay in following the movement of the nut portion 38. For this purpose, the movable lens frame 36
An overhang portion 38a is provided on a nut portion 38 provided continuously with the arm portion 37 in the above, so that the overall length of the nut portion 38 is increased. The length of the overhang portion 38a in the axial direction is such that when the movable lens 31a is arranged at a position separated from the fixed lens 31b, it comes into contact with the stopper step 40c. Also works. And the screw rod part 4 in the screw shaft 40
The base end portion of Oa extends into the shaft support member 39. For this reason, the shaft support member 39 is connected to an insertion hole 39a in which the rotating shaft portion 40b is located. An accommodating portion 39b capable of accommodating the screw rod portion 40a having a larger diameter than the insertion hole 39a is formed. However, it is not always necessary to connect the overhanging portion 38a to the nut portion 38 in the case where the displacement of the axis line due to the backlash does not occur.

The shaft support member 39 is a hard member, and therefore needs to be arranged inside the hard portion at the distal end of the insertion portion 3. Here, at the distal end of the insertion portion 3, in addition to the distal end body 3a, the distal end ring 2 forming the angle portion 3b
It is a hard portion that does not bend due to external force or the like up to the position of the pivot pin 24 that connects the 3a and the next angle ring 23. The solid-state imaging device unit 33 constituting the observation unit 11 is a hard member. In order to protect the solid-state imaging device unit 33, the portion up to the base end of the substrate 33b is located in the hard portion. There must be. The end of the substrate 33b is connected to the prism 3 of the lens support frame 35.
It is located considerably behind the junction to 2. Therefore,
There is a considerable distance from the base end of the lens support frame 35 to the end of the above-described hard portion, and the shaft support member 39 is extended toward the angle portion 3b to extend to the end position of the substrate 33b. .

The control cable 41 has its distal end connected to a screw shaft 40 as a driving means of the movable lens frame 36 and a shaft support member 39 for supporting the screw shaft 40, and passes through an angle portion 3b and a flexible portion 3c. The control cable 41 extends to the inside of the operation unit 2, and the distal end of the control cable 41 is generally disposed near the base end of the solid-state imaging device assembly 33. Here, the substrate 33 constituting the solid-state imaging device assembly 33
A large number of wirings are connected to b, and these wirings are
A lead-out portion 51 from the substrate 33b or a position near the lead-out portion serves as a wiring lead-out portion 51 fixed with a sealing material. Also,
Each wire led out from the wire lead-out portion 51 is inserted into a thin film tape or tube to become a single signal cable 52, and the signal cable 52 is loosely bound at least in the angle portion 3b. As a result, the flexibility of the signal cable 52 becomes extremely good, and the resistance to the bending operation of the angle portion 3b decreases.

Since the signal cable 52 is loosely bound, its cross-sectional shape becomes large, and if a large compressive force is applied, there is a possibility that the wiring inserted therein will be disconnected. On the other hand, the control cable 41 is
In the same manner as in the case of FIG. The control cable 41 has a certain degree of rigidity in order to accurately transmit rotation. If the control cable 41 and the signal cable 52 are arranged close to each other in the angle portion 3b, the difference in resistance between the control cable 41 and the signal cable 52 in the bending direction when the angle portion 3b is bent. Causes relative movement between the control cable 41 and the signal cable 5.
2 come into contact with each other, and as the bending angle increases, they are pressed against each other. Due to the compression force generated at this time, there is a possibility that the wiring constituting the signal cable 52 may be disconnected. In order to avoid or relieve the compression, it is necessary to separate the cables 41 and 52 from each other. However, in this case, the internal space of the insertion section 3 must be increased.

Incidentally, the angle portion 3b is bent up and down and left and right, but the direction of the observation visual field depends on the bending direction of the angle portion 3b. As shown in FIG. 7, the vertical direction in the observation field of view is a direction along a line YY connecting the upper and lower operation wires 26, 26, and this line is a vertical center line of the angle portion 3b in the vertical direction. Also,
The left-right direction is a line XX connecting the left and right operation wires 26, 26.
This line becomes a substantially curved center line in the left-right direction of the angle portion 3b. The center of the optical axis in the objective lens group 31 is bent by 90 ° by the prism 32, whereby the center of the optical axis is directed downward substantially on the curved center line YY in the vertical direction. Therefore, the solid-state imaging device assembly 3
3. Signal cable 5 pulled out from substrate 33b
2 at least on the tip side of the angle portion 3b
It will be arranged on or near the curved center line YY in the vertical direction.

From the above, in order to connect the lens support frame 35 and the shaft support member 39 continuously, the protruding portion 35b from the lens support frame 35, the movable lens frame 36 and the nut portion 38
By tilting the axis A of the arm portion 37 connecting the control cable 41 from the center position C by a predetermined angle θ with respect to the vertical bending center line Y-Y, the control cable 41 is connected to the bending center line Y-
It is configured to be offset in the rotation direction with respect to Y. The offset amount is set in relation to the length of the axis A.
When projected in the direction parallel to −Y, the signal cable 52
Are set as small as possible, and desirably, are set so as to be positions where they hardly overlap or completely do not overlap.

At the same time, even if the control cable 41 is projected in a direction parallel to the center line XX in the horizontal direction, the control cable 41 is prevented from overlapping the signal cable 52 as much as possible. Here, as shown in FIG.
When the optical axis is bent by using the control cable 4 in the left-right direction, the possibility that the projection portion of the control cable 41 in the left-right direction overlaps with the signal cable 52 is small.
In order to keep the distance between the control cable 1 and the signal cable 52 as large as possible, the control cable 41 is prevented from being offset in the rotation direction to a position near the center line XX in the horizontal direction. Accordingly, the control cable 41 is located on the opposite side of the signal cable 52 with respect to the curved center line XX, and is substantially the same amount or less than the curved center lines XX and Y-Y. It is most desirable to offset to a position slightly deviated in the curved center line YY direction.

The prism 32 has a substantially square or rectangular shape in the longitudinal sectional direction of the distal end portion main body 3a, and its corner is formed with a chamfered portion 32a to prevent cracking or chipping. Is provided. Therefore,
By disposing the control cable 41 at a position near the chamfered portion 32a, the control cable 41 can be smoothly pulled out.

With the above configuration, when the control cable 41 and the signal cable 52 relatively move within the angle portion 3b when the angle portion 3b is bent, the hardness of the control cable 41 and the signal cable 52 in the bending direction is reduced. Based on the difference, mutual interference does not occur. That is, when the angle portion 3b is bent in the vertical direction, the signal cable 52 is displaced upward or downward along the vertical bending center line Y-Y, but the control cable 41 is offset from this position in the horizontal direction. Therefore, the direction of the movement is displaced in a direction almost passing the signal cable 52. As a result, compression of the signal cable 52 by the control cable 41 and disconnection of the wiring constituting the signal cable 52 caused by the compression can be reliably prevented. The same applies to the case where the angle portion 3b is curved in the left-right direction.

In the above-described embodiment, the prism is incorporated in the objective optical system, and the solid-state image pickup device is used as the image pickup means. The present invention can also be applied to a configuration in which the incident end of the image guide faces the image position. In this case, since the signal cable and the image guide substantially pass through the center position at the angle portion, the pull-out position of the signal cable is displaced downward on the vertical bending center line Y-Y using the prism. Different from the case where the vertical center of curvature Y-
In the direction along Y and the direction along the curved center line XX in the left-right direction, the possibility that the control cable and the signal cable or the image guide interfere with each other increases accordingly.
It is desirable to extend the control cable so that it is not projected in the direction parallel to the curved center line XX in the left-right direction, that is, at an angle of 45 ° with respect to the center of the distal end body.

[0038]

According to the present invention, the control cable is prevented from interfering with or pressing against a signal cable or the like drawn out of the solid-state imaging device, and the fragile members such as the wiring are effectively reduced. It has effects such as protection.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an endoscope showing one embodiment of the present invention.

FIG. 2 is an external view showing a distal end surface of an insertion portion of the endoscope in FIG. 1;

FIG. 3 is a longitudinal sectional view of the vicinity of a distal end of an insertion portion.

FIG. 4 is a longitudinal sectional view showing an observation unit and a drive mechanism of a movable lens thereof.

FIG. 5 is an exploded perspective view of the lens assembly.

FIG. 6 is a sectional view similar to FIG. 4, showing a state in which the movable lens is advanced.

FIG. 7 is a configuration explanatory view showing a positional relationship between a signal cable and a control cable in a vicinity of a distal end of an insertion portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endoscope 2 Main body operation part 3 Insertion part 3a Tip main part 3b Angle part 3c Flexible part 10 Illumination part 11 Observation part 12 Treatment tool derivation part 20 Main body block 30 Lens assembly 31 Objective lens group 35 Lens support frame 35a Slit 35b Projection Part 36 Movable lens frame 36a Sliding contact surface part 37 Arm part 38 Nut part 38a Overhang part 39 Shaft support member 39a Insertion hole 39b Housing part 40 Screw shaft 40a Screw rod part 40b Rotating shaft part 41 Control cable 51 Wiring lead part 52 Signal cable

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H040 AA00 BA02 BA03 BA21 CA00 CA11 CA23 CA24 DA03 DA14 DA18 DA19 DA42 DA56 DA57 EA01 GA03 4C061 AA00 BB02 CC06 DD03 FF40 JJ06 JJ11 LL02 NN01 PP06 PP12 RR06 RR17

Claims (2)

[Claims] 1. A fixed lens mounted on a fixed lens frame,
An objective optical system having at least one movable lens mounted on a movable lens frame that slides on the inner surface of the fixed lens frame is provided, and a nut portion screwed to a screw shaft is connected to the movable lens frame. Then, by rotating the screw shaft by remote control using a control cable, an endoscope provided at an end portion main body connected to an angle portion with an observation portion capable of moving the movable lens in the optical axis direction. A support is integrally provided on the fixed lens frame, and a screw shaft is inserted through the support so as to be rotatable and immovable in the axial direction, and between the fixed lens frame and the support and the movable lens frame. And the nut portion are connected to each other, and the extending direction of the arm portion is offset by a predetermined angle with respect to the vertical center line of the angle portion. You Endoscope with an objective lens moving mechanism. 2. The objective lens moving mechanism according to claim 1, wherein the two arm portions are offset by substantially equal angles with respect to the vertical and horizontal curved center lines of the angle portion. With endoscope.