JP4436747B2 - Electronic endoscope - Google Patents

Description

  The present invention relates to an electronic endoscope in which an imaging unit is incorporated at a distal end portion of an insertion portion of an endoscope.

  In general, an electronic endoscope includes an operation unit that is held and operated by an operator, an insertion unit that is inserted into a body cavity, and a connector unit that is connected to a light source device or an image processing device. The distal end portion of the insertion portion is provided with an objective lens for observing the inside of the body cavity, an imaging unit including a solid-state imaging device such as a CCD as an imaging means, and a distal end of a light guide that illuminates the inside of the body cavity.

  By the way, the structure in which the imaging unit is attached to the tip constituent member is formed with an imaging unit housing hole in the tip constituent member, and after the imaging unit is inserted into the housing hole, the imaging unit is fixed by a fixing screw screwed into the tip constituent member. It was something to do.

  By the way, conventionally, the optical window member (lens) arranged at the distal end portion of the endoscope is not only bonded with an adhesive between the lens and the lens frame in order to increase the fixing strength of the optical window member, By forming the inner diameter of the opening portion in the tip configuration portion into which the lens frame is fitted smaller than the outer diameter of the most advanced optical window member (lens) disposed here, the lens abutting portion is configured, and the imaging unit The position of the lens part was mechanically positioned and fixed. Further, the lens abutting portion here has a tapered abutting surface in consideration of the processability of the lens, the assemblability of the endoscope tip, or the diameter reduction of the endoscope tip. (See Patent Document 1).

On the other hand, in order to securely fix the imaging unit to the distal end configuration portion of the electronic endoscope, after the imaging unit is inserted into the imaging unit housing hole formed in the distal end configuration portion, a fixing screw screwed into the main body of the distal configuration portion Is fixed to the side peripheral surface of the imaging unit by being abutted and fixed (see Patent Document 2). The reason for adopting the screw fixing method in this way is to secure the fixing strength of the imaging unit against the tilt due to the bending operation and to easily remove the imaging unit at the time of repair.
JP 2002-085326 A JP 2003-260029 A

  In such a conventional imaging unit mounting method, when assembling the imaging unit of the electronic endoscope so that the specified position of the tip component, that is, the lens surface at the tip of the imaging unit is located at the tip surface of the tip component The following problems will occur.

  The inner diameter of the image pickup unit housing hole is slightly larger than the outer diameter of the image pickup unit to be incorporated, and a clearance is provided between the two, so that the image pickup unit can be advanced and retracted when the image pickup unit is assembled.

  On the other hand, a tapered abutting surface is formed at the opening of the imaging unit housing hole, and a tapered chamfered portion is formed at the entire periphery of the lens that abuts on the abutting surface. Therefore, when the imaging unit inserted into the imaging unit accommodation hole is tightened with a fixing screw, the imaging unit is moved in the fixing tightening direction of the fixing screw by the clearance in the imaging unit accommodation hole. This movement occurs in the direction in which the tapered contact surface and the tapered chamfer ride up (perpendicular to the axial direction of the imaging unit housing hole). For this reason, with the operation of tightening the fixing screw, the tapered abutting surface and the chamfered portion are pressed against each other and ride on each other, and the imaging unit may be retracted with respect to the tip component portion. As a result, so-called vignetting occurs in which the abutting portion of the tip component portion enters the effective angle of view of the objective lens system and the abutting portion is reflected in the peripheral portion of the endoscopic image, which hinders observation. There was a possibility.

  The present invention has been made in view of the above circumstances. Even if there is a clearance in the assembly portion between the imaging unit and the tip component, it is possible to secure a mechanical fixing structure of the lens and a screw fixing structure of the imaging unit. It is an object of the present invention to provide an electronic endoscope that prevents retreating with respect to the tip component portion of an image pickup unit when fixing a screw, which has been a problem in the past, while following the steps, and improving assembly and reducing optical performance.

The invention according to claim 1 includes imaging means for imaging a subject, imaging means mounting holes for arranging the imaging means, and fixing means for fastening and fixing the imaging means arranged in the imaging means mounting holes. In the electronic endoscope, a claw portion formed at the distal end opening of the imaging means mounting hole and partially protruding inward from the outer diameter of the optical window member provided at the distal end of the imaging means; A cutout portion is formed by cutting away the optical window member so as to avoid contact with the optical window member. The cutout portion is fastened to the image pickup means mounting hole by fastening the image pickup means by the fixing means. It is an electronic endoscope characterized by including what is arrange | positioned and located in the direction direction pressed .
According to a second aspect of the present invention, the optical window member has a tip edge formed as a tapered chamfered portion, and the abutting surface of the claw portion that comes into contact with the chamfered portion is along the tapered surface. The electronic endoscope according to claim 1, wherein the electronic endoscope is formed as an inclined surface.
According to a third aspect of the present invention, the fixing means is a fixing screw that is disposed so as to be substantially orthogonal to the central axis of the imaging means mounting hole and is screwed into a screw hole that communicates with the imaging means mounting hole. The electronic endoscope according to claim 1, wherein the electronic endoscope is provided.
According to a fourth aspect of the present invention, when the image pickup means is tightened, the fixing means abuts on the outer periphery of the image pickup means and fastens the image pickup means in the image pickup means mounting hole. The electronic endoscope according to claim 1, 2 or 3, wherein a force for moving the imaging means toward a normal mounting position of the hole is generated.
The invention according to claim 5, wherein the threaded member is a screw member in contact with the tip is flat on the outer periphery of the imaging means, the central axis of the central axis of the screw hole to screw the screw member and the imaging unit attachment hole When the screw member is screwed into the screw hole and the tip of the screw member is in contact with the outer periphery of the imaging means at one side region from the center position of the tip surface, the screw 4. The electronic endoscope according to claim 3, wherein the rotational force of the member generates a force for moving the imaging unit toward a normal mounting position of the imaging unit mounting hole.

  According to the present invention, when fixing the imaging unit to the tip member, there is no interference between the optical window member and the claw portion formed on the tip member even if the imaging unit moves in the tightening direction at the time of fixing. The imaging unit can be prevented from moving backward with respect to the tip member, and as a result, an electronic endoscope without vignetting around the observed image is obtained.

  Hereinafter, an electronic endoscope according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the electronic endoscope 1 of the present embodiment is connected to a long insertion portion 2, an operation portion 3 provided at the proximal end of the insertion portion 2, and the operation portion 3. The universal cable 4, the light guide connector 5 provided at the extending tip of the universal cable 4, the camera cable 6 connected to the light guide connector 5, and the extending tip of the camera cable 6. And a camera connector 7.

  The light guide connector 5 is connected to an illumination light source device (not shown). The camera connector 7 is connected to a camera control unit (hereinafter referred to as CCU) (not shown). A monitor (not shown) is connected to a CCU (not shown) to which the camera connector 7 is connected.

  An optical image of the test part is picked up by a solid-state image sensor of an image pickup unit as will be described later, and then signal processing is performed by the CCU, and the image of the test part is displayed as a video on the monitor.

  As shown in FIG. 1, the insertion portion 2 is provided with a distal end portion 8 at the most distal position, and a bendable bending portion 9 is provided adjacent to the proximal end of the distal end portion 8. The hard part 10 is continuously provided adjacent to the base end of the. An imaging unit 32 having a solid-state imaging device such as a CCD is incorporated in the distal end portion 8 as will be described later. Further, the rigid portion 10 is a long and rigid linear portion.

  A grip 11 that is gripped when the operator holds the endoscope 1 is formed at the insertion portion side portion of the operation portion 3. Two bending operation levers 12 and 13 as operation means for performing an operation for bending the bending portion 9 are provided at a portion of the operation portion 3 located closer to the grip 11 than the portion of the grip 11.

  A fixing lever 14 for fixing the bending operation levers 12 and 13 at a desired operation position (that is, fixing the bending state in a desired state) is provided at a portion adjacent to the bending operation levers 12 and 13. . In FIG. 1, only the fixing lever 14 for the bending operation lever 12 is shown, and the fixing lever for the other bending operation lever 13 is not shown. The grip 11 is provided with a plurality of remote switches 15 for remotely operating a video recording device such as a VTR (not shown) or a CCU (not shown).

  As shown in FIG. 1, a vent 16 is provided on the side wall surface of the light guide connector 5. The vent cap 16 has a valve function for selecting the internal / external communication state of the endoscope body. The vent cap 16 is normally closed and is in a watertight state in which water does not enter the endoscope 1. Then, air is supplied into the endoscope main body from the vent base 16 and the endoscope 1 is immersed in water, so that the water leakage inspection of the endoscope 1 can be performed depending on the presence or absence of leakage of bubbles. ing.

  As shown in FIG. 1, a protective sheath 17 mainly for protecting the bending portion 9 can be attached to the insertion portion 2. The protective sheath 17 includes a highly flexible tube-shaped sheath 18 and a mouth portion 19 provided at the base end of the sheath 18. Then, the insertion portion 2 of the endoscope 1 is inserted from the distal end portion 8 side through the opening portion of the mouth portion 19, and the insertion portion 2 is inserted into the sheath 18, and provided on the inner surface of the opening end portion of the mouth portion 19. The engaging convex portion 20 gets over the grip convex portion 21 provided on the distal end side of the grip 11 and engages with the operation portion 3 of the endoscope 1, whereby the protective sheath 17 is inserted into the insertion portion 2 of the endoscope 1. It can be fixedly attached to.

  As shown in FIGS. 2 to 5, the distal end portion 8 of the insertion portion 2 is provided with a distal end portion of a pair of light guides 31 and an imaging unit 32 as an illumination optical system. The light guide 31 is a light guide means made of an optical fiber or the like, and guides illumination light for illuminating a test portion in the body cavity from a light source device (not shown) and is arranged on the distal end surface of the distal end portion 8. Illumination light is illuminated from 33 toward the portion to be examined.

  In addition, the imaging unit 32 includes imaging means for imaging a subject. Specifically, as shown in FIG. 4A, an objective lens system 34 including an optical member such as a plurality of lenses as an objective optical system, This unit includes an imaging unit 35 that captures and captures an optical image of a portion to be examined by the objective lens system 34. The image pickup unit 35 incorporates a solid-state image pickup device (not shown) such as a CCD.

  The objective lens system 34 of the imaging unit 32 includes a lens group 36 as an observation optical lens incorporated in a metal rear lens frame 37 shown in FIG. 4 and is illuminated with illumination light emitted from the light guide 31. An optical image of the inspection unit is taken and formed on the solid-state image sensor of the imaging unit 35.

  Further, as shown in FIG. 4, a substantially cylindrical first lens frame 39 to which a disk-shaped first lens 38 made of an optical member is bonded and fixed is disposed at the tip side portion of the objective lens system 34. The first lens frame 39 is fixed to the rear lens frame 37 with an insulating frame 40 interposed between the first lens frame 39 and the rear lens frame 37. The rear lens frame 37 and the first lens frame 39 are exterior frame members that form the periphery of the objective lens system 34 of the imaging unit 32, and the outer periphery thereof forms the outer periphery of the imaging unit 32.

  The first lens 38 of the imaging unit 32 also serves as an observation window optical member, which is exposed on the distal end surface of the distal end portion 8 of the insertion portion 2. The insulating frame 40 is made of an electrically insulating material.

  As shown in FIGS. 4A and 4B, the front end surface of the first lens 38 is disposed so as to protrude forward from the front end of the first lens frame 39, and the corner of the protruding front end portion is tapered over the entire circumference. A chamfered portion 41 is formed.

  On the other hand, the main body member (tip member) of the distal end portion 8 in the insertion portion 2 is formed by a substantially cylindrical first distal tubular component 50 having an end surface portion 91 that becomes the distal end surface of the distal end portion 8. The light guide 31 and the imaging unit 32 are disposed and fixed in grooves and holes formed in the first tip tubular component 50.

  The light guide 31 is formed by, for example, a light guide fiber bundle. The fiber bundle can be freely deformed except for the vicinity of its tip, and its cross-sectional shape is not specified. However, as shown in FIGS. For example, a portion in the vicinity of the tip is formed in a rectangular shape.

  As shown in FIG. 4, an imaging cable 42 is connected to the rear portion of the imaging unit 32. The imaging cable 42 is led to the camera connector 7 through the insertion portion 2, the operation portion 3, the universal cable 4, the light guide connector 5 and the camera cable 6 of the endoscope 1 shown in FIG. The camera connector 7 is connected to a video processor or the like (not shown).

  Moreover, as shown in FIG.4 and FIG.8, the front-end | tip part 8 of the said insertion part 2 is comprised combining a some tubular member. The tubular member is roughly divided into the first distal tubular part 50 as a distal end body, and a substantially cylindrical second distal tubular part 60 (a mantle member) fitted to the first distal tubular part 50. ) And a substantially cylindrical third tip tubular part 70 as an exterior member fitted from the base end side to the outer periphery of the second tip tubular part 60.

  The first tip tubular component 50 has a tip portion formed as a wall portion, and an imaging unit housing hole 51 having a circular cross-sectional shape as shown in FIG. ) And is provided so as to penetrate in the longitudinal axis direction. Further, as shown in FIG. 4A, the imaging unit housing hole 51 is an attachment unit for an imaging unit that fits the distal end portion of the imaging unit 32 and places the imaging unit 32 at a specified position.

  Further, a gap is formed between the front end portion of the imaging unit 32 attached to the imaging unit housing hole 51 and the first tip tubular part 50, and this gap is watertight by an adhesive as will be described later. In the sealed state, the imaging unit 32 is fixed to the first tip tubular component 50.

  As shown in FIG. 2, a plurality of claw parts 52 protruding inwardly are provided partially at the opening edge of the imaging unit accommodation hole 51 at intervals. Here, the claw portion 52 includes three claw portions 52a, 52b, and 52c disposed in the lower portion and the left and right portions of the upper half, respectively, and the three claw portions 52a, 52b, and 52c are provided in the imaging unit storage hole 51. The positioning projections are arranged at intervals around the periphery of the opening. Each of the claw portions 52a, 52b, and 52c is formed integrally with the first tip tubular component 50 that is one of the frame members that form the main body portion of the tip portion 8.

  Then, the image pickup unit 32 is inserted into the image pickup unit housing hole 51, and the tip of the image pickup unit 32 is abutted against each claw portion 52, whereby the attachment position of the image pickup unit 32 in the central axis direction is determined. That is, the claw portion 52 constitutes a position restricting stopper means for determining the mounting position in the front-rear direction (center axis direction) of the imaging unit 32 that is inserted into the imaging unit housing hole 51 and disposed.

  Further, as shown in FIGS. 4A and 4B, each of the claw portions 52 protrudes so as to enter a region inside the outer diameter of the first lens 38 positioned at the forefront of the imaging unit 32. Yes.

  More specifically, the claw portions 52a, 52b, and 52c protrude from the tapered chamfered portion 41 formed on the outer peripheral portion of the disk-shaped first lens 38, respectively. The back surface of the claw portion 52, that is, the inner portion facing the chamfered portion 41 is formed as a tapered portion (inclined portion) 100 that matches the inclination of the tapered chamfered portion 41.

  Thus, since the tapered chamfered portion 41 and the tapered portion 100 come into contact with each other, there is no contact where the claw portion 52 is locally concentrated with respect to the chamfered portion 41 of the first lens 38, and a locally concentrated force is generated. Alleviating and preventing the first lens 38 from cracking. Further, since the claw portions 52a, 52b, and 52c are formed integrally with the first tip tubular component 50, the claw portions 52a, 52b, and 52c can be made as thin as possible and the protruding amount can be reduced. . For this reason, the chamfered portion 41 of the disk-shaped first lens 38 can be made small, and the effective outer diameter can be increased even with the first lens 38 having the same diameter, and the diameter of the distal end portion of the endoscope can be reduced.

  As shown in FIGS. 4 and 6, a screw hole 43 is formed in the side wall of the first tip tubular component 50, and the screw hole 43 penetrates to the image pickup unit storage hole 51 as an image pickup unit mounting portion. It is formed so as to communicate with the unit storage hole 51.

  In the present invention, as shown in FIG. 6, the screw hole 43 is located on a radial line 32 a in the vertical direction passing through the central axis O of the imaging unit storage hole 51 in which the imaging unit 32 is arranged, in a lower part of the tip 8. In the present embodiment, it is arranged as shown in FIG.

  That is, as shown in FIG. 9, the screw rotation center shaft 44a of the screw hole 43 does not coincide with the radial line 32a and is inclined with respect to the radial line 32a. The screw rotation center axis 44 a of the screw hole 43 coincides with the rotation center axis of the fixing screw 44 screwed into the screw hole 43. The central axis of the imaging unit 32 substantially coincides with the central axis O of the imaging unit storage hole 51 that stores the imaging unit 32.

  A flat tip screw 44 with a flat tip is screwed into the screw hole 43 from below the first tip tubular component 50. That is, the screw rotation center axis 44 a of the flat tip screw 44 is arranged so as to be shifted from the center axis O of the imaging unit housing hole 51. The screw rotation center axis 44a of the fixing screw and the center axis O of the image pickup unit housing hole 51 are not parallel and do not intersect with each other, so that they are arranged so as to intersect each other. Further, the axes are arranged so as to be substantially perpendicular (orthogonal).

  For this reason, when the flat tip screw 44 is screwed into the screw hole 43, the tip surface of the flat tip screw 44 partially abuts against the outer peripheral surface of the imaging unit 32. That is, the entire end surface 44b of the flat tip screw 44 does not uniformly hit the outer peripheral wall surface of the first lens frame 39 in the imaging unit 32, but one side of the end surface 44b of the flat tip screw 44 shown in FIG. Only the region 44c in the vicinity of the outer periphery hits the outer peripheral surface of the imaging unit 32 (FIG. 10B is a top view of the flat tip screw 44 viewed from the direction A in FIG. 10A).

  The normal flat-tip screw 44 uses a right-handed screw and is assumed to be used. The direction of the rotational force that the imaging unit 32 receives from the screw 44 when the screw end surface 44b of the flat tip screw 44 abuts on the outer peripheral surface of the imaging unit 32 depends on the region where the screw end surface 44b of the flat tip screw 44 contacts. Different. That is, as shown in FIG. 10B, when the screw end face center region 44d comes into contact, the screw works in the screw rotation direction. Assuming that the region 44c located on the right side of the paper surface from the center position of the screw end surface is in contact, it works upwardly on the paper surface. Further, if the region 44e located on the left side of the paper surface from the center position of the screw end surface comes into contact, it works toward the lower side of the paper surface.

  In the present embodiment, since the direction of the central axis of the screw hole 43 is tilted in the direction shown in FIG. 9, only the region 44 c of the flat tip screw 44 contacts the first lens frame 39 of the imaging unit 32. That is, only the upward force in the plane of the drawing in FIG. 10B is an effective force that acts on the first lens frame 39 and moves the imaging unit 32. Therefore, the arrangement state of the flat tip screw 44 has a relationship of generating a force in a direction to move the imaging unit 32 toward the distal end of the insertion portion when the flat tip screw 44 is applied to the first lens frame 39.

  When the flat tip screw 44 is screwed and rotated, the imaging unit 32 receives the tightening force and at the same time reaches the mounting position where the chamfered portion 41 of the first lens 38 located at the foremost position contacts the claw portion 52. When the chamfered portion 41 of the first lens 38 is pushed forward in a substantially straight line and reaches the proper mounting position where it abuts the claw portion 52, it stops and is positioned, and the imaging unit 32 is tightened to the proper mounting position. Fixed.

  After the screws are fixed, the filler 45 is filled in the remaining screw holes 43 as shown in FIG. By adopting such an attachment method, the imaging unit 32 is positioned and attached to the attachment position of the distal end portion 8 of the endoscope 1. The imaging unit 32 is attached to the distal end portion 8 of the endoscope 1 while being electrically insulated by the insulating frame 40.

  Further, with the imaging unit 32 assembled, an adhesive is poured into the gap between the imaging unit housing hole 51 and the imaging unit 32 from the notch 53 that avoids the claw 52 from the endoscope front end side. Watertightness between the one lens frame 39 and the first tip tubular part 50 is ensured.

  Further, since the notch 53 is formed so as to open larger than the outer diameter of the first lens 38, an adhesive is provided between the first lens frame 39 and the first tip tubular component 50. It is easy to pour in.

  One of the plurality of cutout portions 53 is disposed at the front of the application direction of the flat tip screw 44 that fixes the imaging unit 32 (that is, the central axis direction 44a of the flat tip screw 44). Yes. In the present embodiment, the notch 53a located on the upper side in FIG.

  Incidentally, there is usually a slight clearance in the fitting portion between the imaging unit housing hole 51 and the first lens frame 39 of the imaging unit 32. Therefore, when the flat tip screw 44 is applied to the first lens frame 39 to be fastened and fixed, the flat tip screw 44 is applied in the imaging unit housing hole 51 in addition to the influence of the screw rotational force of the flat tip screw 44. A current situation occurs in which the first lens frame 39 is biased in the pressing direction by the clearance. At this time, the first lens 38 is also biased together by the clearance in the screw contact pressing direction at the opening edge of the imaging unit housing hole 51.

  However, since the notched portion 53 (53a) is provided at the biased position and the claw portion 52 having the tapered portion 100 does not exist, the tapered chamfered portion 41 has an opening end such as the claw portion 52 or the like. It is possible to avoid interference by contacting the edge.

  As a result, the first lens 38 does not break due to interference with the claw portion 52 and the like. In addition, since the chamfered portion 41 and the claw portion 52 do not come into contact with each other, the phenomenon that the image pickup unit 32 is retracted does not occur, and the image pickup unit 32 is better fit.

  On the other hand, as shown in FIG. 8, in the lower outer peripheral portion of the first tip tubular component 50, a substantially rectangular groove in which the tip portion 31a of the light guide 31 having a substantially rectangular cross section formed by an adhesive or the like is disposed. Two right and left light guide receiving portions 54 are formed.

  As shown in FIGS. 2 and 8, the illumination window 33 (optical member) is provided on the surface exposed to the outside corresponding to the position where the light guide receiving portion 54 is formed at the distal end of the insertion portion 2. A stepped portion 55 is formed for placing the. The illumination window 33 is an optical member that can transmit illumination light such as flat glass, and has an irregular shape similar to the cross-sectional shape of the light guide 31 described later.

  As shown in FIGS. 2, 3, and 8, the step portion 55 has a shape substantially equal to the shape of the illumination window 33 and an end surface portion 91 that forms the distal end surface of the first distal tubular component 50. On the other hand, the end surface portion 91 of the first distal tubular part 50 is formed so as to be cut out with a hollow amount substantially equal to the thickness of the illumination window 33. Furthermore, two wedge-shaped claw portions 56 that face each other are formed on the step portion 55. A mounting portion for arranging the illumination window 33 is formed by the step portion 55 and the claw portion 56. On the other hand, as shown in FIG. 3, two chamfered portions 81 are formed in the illumination window 33 at positions corresponding to the claw portions 56.

  When the illumination window 33 is arranged on the step portion 55, the illumination window 33 is assembled at a predetermined position of the step portion 55 by slidingly engaging from the side of the first tip tubular component 50 toward the center thereof. . At this time, since the claw portion 56 contacts the chamfered portion 81 of the illumination window 33, the illumination window 33 is accommodated in the mounting portion without moving forward of the distal end of the endoscope.

  The portion of the first tip tubular component 50 where the stepped portion 55 is not cut out remains as a flange-like portion, and the flange portion 57 serves as an abutment positioning portion when the second tip tubular component 60 is assembled. . Further, as shown in FIG. 8, a positioning hole 58 for engaging the pin 46 for positioning the three components is provided at a predetermined position on the outer peripheral portion of the first tip tubular component 50.

  As shown in FIG. 8, the second tip tubular part 60 is made of metal and has a thin circular tube shape, one end of which is a stepped thick part 61, and the opening 66 has the first part in the first part. A contact portion 62 with which the flange portion 57 of the first tip tubular component 50 abuts is formed so that the end portions are flush with each other when the tip tubular component 50 is fitted in the longitudinal direction.

  As shown in FIGS. 2 and 8, in the present embodiment, the engaging portion 65 formed by the inner peripheral surface of the stepped thick portion 61 includes the arc portion 82 of the illumination window 33 (in other words, the mounting portion). The illumination window 33 is mechanically secured to the first and second tip components 50, 60.

  Similarly, as shown in FIG. 8, the second distal tubular part 60 is formed with a slit-like cutout portion 63 having a constant width cut out from the rear end side. Then, as shown in FIG. 7, by arranging the peripheral portion of the maximum outer diameter of the imaging unit 32 in the notch 63, interference between the imaging unit 32 and the second distal tubular part 60 is eliminated. The outer diameter of the insertion portion is kept small.

  Further, as shown in FIGS. 6, 8, and 9, the second distal tubular part 60 is provided with a hole 64 for engaging the pin 46 at a predetermined position. Then, the positions of the first tip tubular part 50 and the second tip tubular part 60 are determined by the pin 46.

  As shown in FIG. 8, the third tip tubular part 70 has a thin circular tube made of metal, and the tip-side tubular part fits snugly into the outer periphery of the second tip tubular part 60. A large-diameter cylindrical portion 71 having an inner diameter is formed. A rear end side portion of the third distal tubular part 70 is a stepped small diameter portion 72. A slit 73 is formed at the distal end portion of the large diameter tubular portion 71 of the third distal tubular component 70. The width of the slit 73 is substantially equal to the diameter of the small diameter portion 47 of the pin 46. Then, when the second tip tubular part 60 is fitted into the third tip tubular part 70 and the tip of the third tip tubular part 70 comes into contact with the stepped thick portion 61 of the second tip tubular part 60. The mutual positional relationship is determined by engaging the small-diameter portion 47 of the pin 46 in the slit 73 of the third tip tubular part 70.

  The other end portion of the third distal tubular part 70 has a stepped small diameter portion 72. As shown in FIG. 4, the stepped small diameter portion 72 includes a curved portion 9 of the insertion portion 2. One end portion of the node ring 74 that is located at the foremost part of the joint ring 74 is fitted, and both are bonded and fixed.

  Further, as shown in FIG. 1, at the distal end portion 8 of the insertion portion 2, the light guide 31 having one end portion fixed is fixed at the base end to the light guide connector 5. And the illumination light from the light source device which is not illustrated is guided to the front-end | tip of an insertion part through the light guide 31. FIG. The distal end portion of the light guide 31 is divided into right and left, and is substantially rectangular configured by the light guide receiving portion 54 of the substantially rectangular groove of the first distal tubular part 50 and the second distal tubular part 60 shown in FIG. Each is arranged in a shape space. At this time, as shown in FIG. 5, the rear end side of the first tip tubular component 50 is directed toward the outer peripheral side of the first tip tubular component 50 so as to include the entire light guide receiving portion 54. An inclined slope 59 is formed.

  Therefore, when the tip end of the light guide 31 is inserted into another member in the direction of the arrow shown in FIG. 8 and assembled, the tip end of the light guide 31 is brought into contact with the inclined surface portion 59 to be along the first tip tubular shape described above. It is easy to guide to a substantially rectangular space constituted by the component 50 and the second tip tubular component 60.

  The tip portion of the light guide 31 inserted through the substantially rectangular space is bonded and fixed in a state where it abuts against the illumination window 33 as shown in FIG. The illumination light sent through the light guide 31 is a recess formed by the first distal tubular component 50 and the second distal tubular component 60 at the end of the distal end portion 8 (that is, the light guide). The light is emitted to the portion to be examined through the illumination window 33 which is locked to the light emission end portion 31 and fixed in a watertight manner with an adhesive.

  Further, as shown in FIG. 5, the light guide 31 is disposed at the distal end portion 8 of the insertion portion 2, but a portion and a space avoiding the imaging unit 32 in the second distal tubular component 60. Since it is efficiently arranged by using, the diameter of the insertion portion 2 is reduced. In addition, by forming the light guide 31 in a substantially rectangular shape (flat), the useless space in the distal end portion 8 can be reduced.

  Furthermore, as shown in FIG. 5, the light guide molding portion is arranged in an S shape along the longitudinal direction so as to avoid the maximum outer diameter portion of the imaging unit 32, thereby improving the assemblability. Further, in order to make it difficult to break the strands of the light guide 31 even when the molded portion of the light guide 31 is subjected to stress during assembly or bending operation, the second tip tubular part 60 extends over the entire length in the longitudinal direction. The inner peripheral surface of the distal tubular part 60 and the side surface of the light guide 31 are bonded and fixed. With such a structure, the endoscope 1 has an insertion portion 2 that can be inserted into a subject.

  In the case of using the endoscope 1 described above, the illumination light emitted from the light source device enters the light guide 31, and the illumination light guided by the light guide 31 is an illumination window at the distal end of the endoscope. It radiates | emits from 33 and illuminates an affected part. Then, an optical image of the illuminated affected area is picked up by the image pickup unit 32, and after the signal processing by the CCU (not shown), the image is displayed on the monitor.

  As described above, in the endoscope 1 of the present embodiment, a flat-tip screw that is a fixing screw is used as a fixing means for fixing to the imaging means mounting portion, and the rotational force of the endoscope 1 is a regular value that defines the imaging unit as a tip component portion. Since it is used as a force for pushing into the position, there are the following various effects.

  First, there is no need for a special configuration (combination of a conventional V-groove and pointed screw) for fixing the imaging unit 32 while urging the imaging unit 32 toward the distal end side, and the lens frame and the like can be made compact. At the same time, the diameter of the distal end portion 8 of the endoscope 1 can be reduced.

  Further, when the imaging unit 32 is assembled to the distal end portion 8, the possibility that the imaging unit 32 tilts (causes a declination) with respect to the distal end portion 8 of the endoscope 1 is remarkably reduced, and illumination light distribution is poor. Can be prevented. The same effect can be obtained even when the fitting depth of the tip 8 with the hard component is shallow. And the hard length of the front-end | tip part 8 can be shortened, and the full length of the imaging unit 32 can be shortened.

  Further, as shown in FIGS. 4 and 6, a screw hole 43 is formed in the first distal tubular member 50 so as to be orthogonal to the imaging unit accommodation hole 51, and the screw hole 43 has a first hole. A screw 44 is screwed in from below the distal tubular member 50, and the screw 44 is applied to the first lens frame 39 fixed to the distal end side of the imaging unit 32 to place the imaging unit 32 in the first distal tubular member 50. To fix. After fixing the screw with the screw 44, the remaining screw hole 43 is filled with a filler 45 in order to ensure water tightness of the screwed portion. With such a configuration, the endoscope distal end 8 and the imaging unit 32 are electrically insulated by the insulating frame 40.

  When the imaging unit 32 is disposed in the imaging unit accommodation hole 51 of the distal end member, the claw portion 52 at the opening end of the imaging unit accommodation hole 51 has a chamfered portion 41 at the distal edge of the first lens 38 provided at the distal end of the imaging unit 32. Therefore, the mechanical fixing strength of the first lens 38 is excellent. Further, since the image pickup unit 32 can be fixed to the tip member reliably and easily by screw fixing, the image pickup unit 32 is excellent in assembling property, repairability, and mechanical fixing strength.

  Further, one of the notches 53 is provided in the direction in which the screw 44 that fixes the imaging unit 32 is applied, that is, in the direction in which the imaging unit 32 moves when pressed by the screw 44 (see FIG. 2). . In other words, the notch 53 is a screw application direction between the chamfered part 41 of the first lens 38 and the claw part 52 of the tip member due to the bias of the imaging unit 32 at the time of screw application (with respect to the imaging unit accommodation hole 51). Thus, it is possible to construct an endoscope that prevents interference in the substantially vertical direction), eliminates displacement (retraction) when the imaging unit is fixed, and has no vignetting around the image.

  In addition, by arranging the three claw portions at equal positions at intervals of approximately 120 °, the number of claws can be reduced as much as possible (reduction in labor for processing parts), and the entire periphery of the lens can be fixed in a balanced manner.

  The notch 53 not only prevents interference with the first lens 38, but can also be used as an injection port for pouring an adhesive between the lens frame and the distal tubular member from the distal end surface side of the insertion portion, thereby improving assemblability. Useful.

  The present invention is not limited to the above-described embodiments, and can be applied to other forms.

The perspective view which shows the whole structure of the endoscope which concerns on one Embodiment of this invention. The front view of the front-end | tip part in the insertion part of the said endoscope. The longitudinal cross-sectional view of the front-end | tip part of the insertion part in alignment with the KK line in FIG. (A) is a longitudinal cross-sectional view of the tip vicinity part of the insertion part in alignment with the AA in FIG. 2, (b) is a longitudinal cross-sectional view which expands and shows a part of front-end | tip of an objective optical system. The longitudinal cross-sectional view of the tip vicinity part of the insertion part in alignment with the OJ line in FIG. FIG. 5 is a cross-sectional view of a portion in the vicinity of the distal end of the insertion portion along the line BB in FIG. The cross-sectional view of the tip vicinity part of the insertion part which follows the CC line in Fig.4 (a). The disassembled perspective view of the component of the front-end | tip part in the said endoscope. The cross-sectional view of the tip vicinity part of the insertion part which follows the BB line in Fig.4 (a) which shows the other arrangement | positioning form of a screw hole. (A) is a perspective view which shows the relationship between the rotation direction of the flat tip screw which fixes the imaging unit in the said endoscope to a front-end | tip part, and a butting direction, (b) is the said flat tip screw from the A direction shown by (a). FIG. 6 is an explanatory diagram showing a relationship between a rotation direction of the flat tip screw and a direction of a force applied when contacting the imaging unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope 2 ... Insertion part 3 ... Operation part 8 ... Tip part 32 ... Imaging unit 38 ... Lens 39 ... Lens frame 44a ... Screw rotation center axis 44 ... Flat tip screw 44 ... Screw member 51 ... Imaging unit accommodation Hole 52 ... Claw 53 ... Notch 59 ... Slope

Claims (5)

In an electronic endoscope comprising an imaging means for imaging a subject, an imaging means mounting hole for arranging the imaging means, and a fixing means for fastening and fixing the imaging means arranged in the imaging means mounting hole.
A claw portion formed at the front end opening of the image pickup means mounting hole and partially protruding inward from the outer diameter of the optical window member provided at the front end of the image pickup means, and the optical window member And the notch is positioned on the direction side in which the imaging means is pressed against the imaging means mounting hole by tightening the imaging means by the fixing means. An electronic endoscope characterized in that the electronic endoscope includes the one arranged. The optical window member has a tip edge formed as a tapered chamfered portion, and an abutting surface of the claw portion contacting the chamfered portion is formed as an inclined surface along the tapered surface. The electronic endoscope according to claim 1.   The fixing means is a fixing screw that is disposed so as to be substantially orthogonal to a central axis of the imaging means mounting hole and is screwed into a screw hole that communicates with the imaging means mounting hole. The electronic endoscope according to claim 1 or 2. When the image pickup means is tightened, the fixing means is brought into contact with the outer periphery of the image pickup means and is fastened to the image pickup means attachment hole , and is directed to a normal attachment position of the image pickup means attachment hole separately from the force in the fastening direction. The electronic endoscope according to claim 1, 2 or 3, wherein a force for moving the imaging means is generated. The threaded member is a screw member in contact with the tip is flat on the outer periphery of the imaging unit, without intersecting the central axis of the screw hole to screw the screw member with respect to the central axis of the imaging unit attachment hole, When the screw member is screwed into the screw hole and the tip of the screw member is in contact with the outer periphery of the image pickup means at one end region from the center position of the tip surface, the rotational force of the screw member is applied to the image pickup means. 4. The electronic endoscope according to claim 3, wherein a force is generated to move the lens toward a normal mounting position of the imaging means mounting hole.

Images