JP6465438B2 - Imaging unit and endoscope - Google Patents

Description

  The present invention relates to an imaging unit capable of changing optical characteristics of an observation optical system and an endoscope provided with the imaging unit.

  As is well known, an endoscope is widely used for observation, treatment, etc. of a living body (inside a body cavity) or inspection, repair, etc. in an industrial plant facility. In recent years, in this type of endoscope, the focal length is changed by moving the observation optical system in the direction of the photographic optical axis because of a zooming function that adjusts the focus of the captured image or the magnification adjustment such as wide / telephoto. Some image pickup units are used. In addition, the technique of the imaging unit which can change a focal distance in this way is used not only for an endoscope but for various photographing machines.

  Here, particularly in endoscopes that require a reduction in size, focus switching is performed when the moving lens unit (moving lens frame) provided in the observation optical system is at a predetermined advanced position and retracted position. The imaging unit of the system is widely adopted. In such a focus switching type imaging unit, in order to achieve an appropriate focusing state even when there is a processing tolerance of each lens, the advance position of the moving lens frame is generally fixed at the time of assembling the imaging unit. It is adjusted by finely adjusting the relative position of the lens frame or the like.

  On the other hand, as a technique for adjusting the retracted position of the moving lens frame, for example, in Patent Document 1, a screw portion is formed on the outer periphery of the abutting member of the pipe unit with which the moving lens frame abuts at the retracted position, A technique is disclosed in which the retracted position of the moving lens frame is adjusted by finely adjusting the screwed state of the threaded portion with respect to the lens cylinder unit (fixed lens frame).

JP 2001-258823 A

  By the way, in this type of imaging unit, in order to realize a smooth forward and backward movement of the moving lens frame within the fixed lens frame, it is common to provide a predetermined clearance at each part between the moving lens frame and the fixed lens frame. It is. For example, in this type of imaging unit, in general, an operating rod protruding from the moving lens frame in order to operate the moving lens frame in the optical axis direction, and a fixed lens for guiding the operating rod along the optical axis direction A predetermined clearance is provided between the slit formed in the frame.

  However, such a clearance may cause shakiness of the moving lens frame in the fixed lens frame, and it may be difficult to arrange the moving lens frame at a predetermined adjustment position with good reproducibility. For example, the clearance between the operating rod and the slit is mainly a cause of rattling around the optical axis of the moving lens frame in the fixed lens frame, and the moving lens frame can be arranged at a predetermined adjustment position with high reproducibility. May be difficult.

  In particular, in an imaging unit such as an endoscope in which an observation optical system is configured using a fine optical member, such a slight shift of the moving lens frame is optically accompanied with an increase in the number of pixels of the imaging element. The characteristics may be affected, and it may be difficult to obtain a high-quality captured image.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an imaging unit and an endoscope that can obtain a high-quality captured image by arranging a moving lens frame at an adjustment position with high reproducibility. .

An imaging unit according to an aspect of the present invention includes a focus switching observation optical system including a fixed lens and a moving lens, a fixed lens frame that holds the fixed lens, and a direction along the imaging optical axis of the observation optical system. It is arranged in the fixed lens frame so as to be able to move forward and backward, and protrudes to the outer peripheral side of the fixed lens frame through a moving lens frame that holds the moving lens and a slit provided in the fixed lens frame. As described above , one of the photographing optical axes is brought into contact with the operation rod that is projected in the outer diameter direction of the moving lens frame and transmits the power for moving the moving lens frame forward and backward, and the operation rod of the moving lens frame. by restricting the movement in the direction, and a stopper member that is positioned and fixed to the fixed lens frame so as to hold the movable lens to a position to realize one focal length of the observation optical system, A guide projection provided on one of the contact surface of the contact surface or the stopper member of the operating rod of the serial movement lens frame, the contact surface or the stopper member of the operating rod of the movable lens frame Provided on either one of the contact surfaces, when the contact surface of the operating rod comes into contact with the contact surface of the stopper member , it engages with the guide projection and causes the operating rod to move against the stopper member. And a guide recess for guiding to the contact position.

  An endoscope according to an aspect of the present invention includes the imaging unit at a distal end portion of an insertion portion that is inserted into a subject.

  According to the present invention, it is possible to obtain a high-quality captured image by arranging the moving lens frame at the adjustment position with high reproducibility.

Explanatory drawing which shows the whole structure of the endoscope according to the first embodiment of the present invention. Sectional drawing which shows internal structure of a front-end | tip part and a curved part same as the above. Same as above, sectional view showing the imaging unit in a state where the moving lens unit has moved to the forward advance position Same as above, a sectional view showing the imaging unit in a state where the moving lens unit is moved to the rearward retracted position. The perspective view which shows a stopper member from diagonally forward same as the above Same as above, perspective view showing relationship between stopper member and adjustment ring The perspective view which shows the assembly | attachment process of a stopper member and an adjustment ring same as the above. Same as above, perspective view of imaging unit Same as above, sectional view taken along line IX-IX in FIG. The main part sectional drawing which shows the relationship between the projection for guides and the recessed part for guides concerning a modification same as the above Sectional drawing of the principal part of an observation optical system unit concerning the 2nd Embodiment of this invention. Same as above, exploded perspective view showing the main part of the observation optical system unit

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to the first embodiment of the present invention, FIG. 1 is an explanatory view showing the overall configuration of the endoscope, FIG. 2 is a sectional view showing the internal configuration of the distal end portion and the bending portion, and FIG. FIG. 4 is a sectional view showing the imaging unit in a state in which the moving lens unit is moved to the rearward retracted position, and FIG. 5 is a perspective view showing the stopper member obliquely from the front. 6 is a perspective view showing the relationship between the stopper member and the adjustment ring, FIG. 7 is a perspective view showing the assembly process of the stopper member and the adjustment ring, FIG. 8 is a perspective view of the imaging unit, and FIG. It is principal part sectional drawing which follows the -IX line.

  As shown in FIG. 1, an electronic endoscope system (hereinafter simply referred to as an endoscope system) 1 according to this embodiment includes an electronic endoscope apparatus (hereinafter simply referred to as an endoscope) 2 as an endoscope. The light source device 3, the video processor 4, and the color monitor 5 are electrically connected.

  The endoscope 2 includes an insertion portion 9 and an operation portion 10 provided with the insertion portion 9. A universal cord 17 extending from the operation portion 10 is connected to the light source device 3 via a scope connector 18. It is connected to the.

  A coiled scope cable 19 is extended from the scope connector 18. An electric connector portion 20 is provided on the other end side of the scope cable 19, and the electric connector portion 20 is connected to the video processor 4.

  The insertion portion 9 includes a distal end portion 6, a bending portion 7, and a flexible tube portion 8 that are arranged in order from the distal end side. On the distal end surface of the distal end portion 6, a known distal end opening, an observation window, a plurality of illumination windows, an observation window cleaning port, and an observation object cleaning port are disposed (all not shown).

  An imaging unit, which will be described later, is disposed in the distal end portion 6 on the back side of the observation window. Moreover, the front end side of the light guide bundle which is not illustrated is arrange | positioned at the back side of the several illumination window. The light guide bundle is inserted and arranged in the universal cord 17 from the insertion portion 9 through the operation portion 10, and when the scope connector 18 is connected to the light source device 3, the illumination light from the light source device 3 is transmitted to the illumination window Can be transmitted.

  The observation window cleaning port and the observation object cleaning port constitute openings of two cleaning tubes (not shown) that are inserted from the distal end portion 6 into the universal cord 17. These cleaning tubes are connected to a cleaning tank in which cleaning water is stored and a compressor (both not shown) on the light source device 3 side.

  The operation part 10 includes a bend preventing part 11 from which the insertion part 9 extends, a forceps port 12 disposed on the side part on the lower side, an operation part main body 13 constituting a grip part in the middle part, and an upper side A bending operation section 16 comprising two bending operation knobs 14 and 15 provided on the air supply / water supply control section 21, a suction control section 22, and a switch section that mainly operates an imaging function. 23 and an operation lever 24 for operating a zoom function for adjusting a magnification such as a focusing function or a wide / tele, for example, by moving a moving lens provided in an imaging unit, which will be described later, forward and backward. Is provided.

  The forceps port 12 of the operation unit 10 constitutes an opening portion of a treatment instrument channel (not shown) that is mainly inserted into the insertion portion 9 up to the distal end opening portion of the distal end portion 6.

  Next, the configuration of the distal end portion 6 of the endoscope 2 will be mainly described with reference to FIG.

  As shown in FIG. 2, an imaging unit 30 is disposed inside the distal end portion 6. The imaging unit 30 is inserted and disposed in a hard tip rigid member 25, and is fixed to the tip rigid member 25 by a set screw (not shown) from the side surface direction.

  In addition, an O-ring 28 for ensuring watertightness with the distal end hard member 25 is disposed on the outer peripheral portion on the distal end side of the imaging unit 30. Further, a distal end cover 25 a constituting the distal end surface of the distal end portion 6 is bonded and fixed to the distal end side of the distal end rigid member 25.

  Note that the distal end opening, which is a hole formed in the distal end cover 25a, constitutes the opening of the treatment instrument channel 12b in the distal end 6 as described above.

  A plurality of bending pieces 26 constituting the bending portion 7 are connected to the proximal end side of the distal end rigid member 25, and the outer circumferences of the distal end rigid member 25 and the bending piece 26 are integrated by the distal end insertion portion rubber member 12a. Is covered. The distal end outer peripheral portion of the distal end insertion portion rubber member 12 a is fixed to the distal end rigid member 25 by a pincushion bonding portion 29.

  In addition, about members, such as the washing tube arrange | positioned at the front-end | tip part 6, the light guide bundle for illumination, since they are conventionally well-known structures, those description is abbreviate | omitted.

  Next, a detailed configuration of the imaging unit 30 will be described with reference to FIGS. 3 to 7.

  As shown in FIGS. 3, 4, and 7, the imaging unit 30 of the present embodiment includes a solid-state imaging element unit 31 and an observation optical system unit 32 that is connected to the distal end side of the solid-state imaging element unit 31. Configured.

  The solid-state image sensor unit 31 has a solid-state image sensor holding frame 35, and the solid-state image sensor holding frame 35 has an optical member 36 such as a cover glass on the front side of a solid-state image sensor chip 37 made of CCD, CMOS, or the like. Is held through. A laminated substrate 38 is electrically connected to the back side of the solid-state imaging device chip 37 via an FPC (not shown), and a plurality of communication lines branched from the cable 39 are connected to the laminated substrate 38. . The cable 39 is inserted into the endoscope 2 and is electrically connected to the video processor via the electrical connector unit 20.

  In addition, a reinforcing frame 40 is connected to the outer peripheral portion of the base end of the solid-state image sensor holding frame 35, and a heat shrinkable tube 41 that covers the distal end portion of the cable 39 is provided on the outer periphery of the reinforcing frame 40. In the space formed by the reinforcing frame 40 and the heat-shrinkable tube 41 from the base end portion of the solid-state image sensor holding frame 35, the solid-state image sensor unit 31 is watertightly held, and an adhesive for protecting it is used. The protective agent 42 is filled.

  The observation optical system unit 32 of this embodiment has a focus switching type observation optical system 33 that realizes a focusing function or a zooming function by changing an optical characteristic (focal length) by moving an internal lens forward and backward. It is configured.

  More specifically, the observation optical system unit 32 includes a front group lens unit 45 positioned on the distal end side, a rear group lens unit 46 connected to the proximal end side of the front group lens unit 45, and the rear group. The lens unit 46 includes a moving lens unit 48 that can move back and forth in the direction of the photographic optical axis O, and an actuator 49 that moves the moving lens unit 48 back and forth.

  The front group lens unit 45 includes a front group lens frame 55 that is a fixed frame, and a front group lens 56 a that includes a plurality of fixed lenses held by the front group lens frame 55.

  The rear group lens unit 46 includes a rear group lens frame 57 that is a fixed frame whose front end is externally fitted to the front group lens frame 55, and a plurality of rear group lens units 46 that are held on the photographing optical axis O on the base end side of the rear group lens frame 57. And a rear lens group 56b made of a fixed lens.

  A solid-state image sensor holding frame 35 is fitted on the proximal end side of the rear group lens frame 57, thereby connecting the solid-state image sensor unit 31 and the observation optical system unit 32.

  Further, the rear lens group frame 57 is provided with a slit 57 a that penetrates the inner and outer peripheral sides of the rear lens group frame 57. The slit 57 a extends in the same direction as the photographing optical axis O direction, and the front end side of the slit 57 a is opened at the front end of the rear group lens frame 57. The rear lens group frame 57 is provided with a holding rod 57b that protrudes in the outer diameter direction on the proximal end side of the slit 57a. The holding rod 57b is provided with an actuator holding hole 57c that passes through the optical axis O in the coaxial direction. Is provided.

  Further, the rear group lens frame 57 is provided with a stopper member 58 that is positioned and fixed in a state of being applied to the outer peripheral surface of the rear group lens frame 57. As shown in FIGS. 5 and 6, the stopper member 58 of the present embodiment includes a C-ring-shaped ring portion 58 a that is applied in a state of being in direct surface contact with the outer peripheral surface of the rear lens group frame 57, and the ring portion. And a pipe-shaped stopper portion 58b integrally formed with the 58a. The stopper member 58 is bonded to the outer peripheral surface of the rear lens group frame 57 in a state where the stopper portion 58b is positioned so as to face the holding rod 57b at a predetermined position in the photographing optical axis O direction. It is fixed by doing.

  Here, for example, an adjustment ring 59 is interposed between the holding rod 57b and the stopper member 58 in order to accurately position the stopper member 58 in the photographing optical axis O direction with reference to the holding rod 57b. The adjustment ring 59 is formed of a C-ring-like member whose width D in the photographic optical axis O direction linearly changes along the circumferential direction, one end abuts against the stopper member 58, and the other end is a holding rod. It arrange | positions so that 57b may be contact | abutted. The adjustment ring 59 is rotated about the photographing optical axis O along the outer peripheral surface of the rear lens group frame 57 to change the relative position between the stopper member 58 and the holding rod 57b. The position of the photographic optical axis O direction on the rear group lens frame 57 of the stopper member 58 is adjusted. In this case, in order to accurately move the stopper member 58 following the adjustment ring 59, it is desirable to provide the stopper member 58 with a protrusion 58c for making a substantially point contact with the adjustment ring 59.

  As shown in FIGS. 3 and 4, a front stopper portion 60 is provided on the front end side of the rear lens group frame 57 so as to face the stopper portion 58 b. In the present embodiment, the front stopper portion 60 is integrally formed with the front group lens frame 55, and the front stopper portion 60 includes a spring receiving portion facing the through hole 58d of the stopper portion 58b and the actuator holding hole 57c of the holding rod 57b. 60a is recessed.

  The moving lens unit 48 includes a moving lens frame 65 that is a moving frame, and a moving lens 66 that is held by the moving lens frame 65.

  In the present embodiment, the moving lens frame 65 is disposed in the rear group lens frame 57 that is a fixed frame, and can move forward and backward in the direction along the photographing optical axis O. The movable lens frame 65 is provided with an operating rod 65a protruding in the outer peripheral direction. The operation rod 65a protrudes to the outer peripheral side of the rear group lens frame 57 through the slit 57a of the rear group lens frame 57 and faces the stopper portion 58b (holding rod 57b) and the front stopper portion 60. The operating rod 65a is provided with a bearing portion 65b facing the spring receiving portion 60a on the surface facing the front stopper portion 60, and a shaft member 67 protruding into the spring receiving portion 60a is provided on the bearing portion 65b. Is retained. Further, a return spring 68 having one end side held in the spring receiving portion 60a is wound around the outer periphery of the shaft member 67, and the operation rod 65a is attached to the base end side (the holding rod 57b side) by the return spring 68. It is energized.

  In order to reduce the sliding resistance of the moving lens frame 65 with respect to the rear lens group frame 57, a predetermined clearance is provided between the slit 57a and the operating rod 65a (see FIG. 9). Further, a cover 69 for watertightly closing the slit 57a is provided on the projecting end side of the holding rod 57b, the stopper portion 58b, the front stopper portion 60, and the operation rod 65a.

  The actuator 49 has a guide tube 70 whose tip side is held in the actuator holding hole 57c of the holding rod 57b. In this guide tube 70, there is provided a push rod 71 that can be projected and retracted from the tip of the guide tube 70, and a contact member that comes into contact with and separates from the operating rod 65a at the tip of the push rod 71. The head portion 72 is fixed. In this case, in order to prevent the head portion 72 from being caught or the like and realize a good protrusion / retraction operation (advancement / retraction movement) of the push rod 71, the head portion 72 is in any state when the push rod 71 protrudes or is retracted. In this case, it is desirable that at least a part of the head portion 72 is set to a length arranged in the through hole 58d of the stopper portion 58b.

  The push rod 71 is connected to a distal end side of a drive wire 73 inserted into the guide tube 70, and a shape memory element 74 made of a shape memory alloy is connected to the proximal end side of the drive wire 73. . Further, in the guide tube 70, a push spring 75 for urging the push rod 71 toward the front stopper portion 60 with an urging force stronger than that of the return spring 68 is wound around the outer periphery of the drive wire 73. Yes.

  For example, the shape memory element 74 is set to be shrunk when heated and stretched when cooled, and is held in the guide tube 70 in a stretchable state. Further, the shape memory element 74 is provided with a heat source such as a Peltier element (not shown). The heat source can heat or cool the shape memory element 74 according to the operation state of the operation lever 24. Yes. The shape memory element 74 is not limited to a type that expands and contracts by heating or cooling using a heat source such as a Peltier element, and for example, a type that heats and contracts the shape memory alloy by energization is adopted. It is also possible.

  Then, when the shape memory element 74 is extended by cooling, the shape memory element 74 operates the drive wire 73 in a direction in which the urging force of the push spring 75 is released (that is, a direction on the distal end side along the photographing optical axis O). Thus, the distal end side of the push rod 71 protrudes from the guide tube 70 and presses the operating rod 65a against the urging force of the return spring 68. As a result, the operating rod 65a moves to a position where it comes into contact with the front stopper 60. Along with the movement of the operating rod 65a, the moving lens frame 65 moves the moving lens 66 to the advance position for realizing a preset first focal length (first optical characteristic) (see FIG. 3). .

  In this case, for example, as shown in FIGS. 3 to 5 and 9, the front stopper portion 60 is provided with a guide protrusion 60 b on the contact surface with the operating rod 65 a. In the present embodiment, the guide protrusion 60b is formed by a tapered taper protrusion whose cross-sectional area gradually decreases toward the tip. Further, the operating rod 65a is provided with a guide recess 65c that can be engaged with the guide protrusion 60b on the contact surface with the front stopper 60. In the present embodiment, the guide recess 65c is formed by a narrow taper-shaped recess whose opening area gradually decreases toward the bottom.

  The guide protrusions 60b and the guide recesses 65c are set to be engaged when the operating rod 65a comes into contact with the front stopper 60. At the time of these engagements, the guide projection 60b guides the guide recess 65c to a predetermined engagement position by sliding the tapered surface of the guide recess 65c along the taper surface of the guide projection 60b. . Thereby, the operating rod 65a is always brought into contact with the front stopper 60 at the same position.

  On the other hand, when the shape memory element 74 is contracted by heating, the shape memory element 74 operates the drive wire 73 in a direction against the urging force of the push spring 75 (that is, a direction on the base end side along the photographing optical axis O). As a result, the distal end side of the push rod 71 is retracted into the guide tube 70. As a result, the operating rod 65a is urged by the return spring 68 and moves to a position where it comes into contact with the stopper portion 58b. Along with the movement of the operating rod 65a, the moving lens frame 65 moves the moving lens 66 to a retracted position for realizing a preset second focal length (second optical characteristic) (see FIG. 4). .

  In this case, for example, as shown in FIGS. 3, 4, and 9, a guide protrusion 58 e is provided on the stopper portion 58 b on the contact surface with the operating rod 65 a. In the present embodiment, the guide protrusion 58e is formed by a tapered tapered protrusion whose sectional area gradually decreases toward the tip. The operating rod 65a is provided with a guide recess 65d that can engage with the guide protrusion 58e on the contact surface with the front stopper 60. In the present embodiment, the guide recess 65d is formed by a bottom taper-shaped recess whose opening area gradually decreases toward the bottom.

  The guide protrusion 58e and the guide recess 65d are set to be engaged when the operating rod 65a comes into contact with the stopper portion 58b. At the time of these engagements, the guide recess 58d guides the guide recess 65d to a predetermined engagement position by sliding the tapered surface of the guide recess 65d along the taper surface of the guide protrusion 58e. . Thereby, the operating rod 65a is always in contact with the stopper portion 58b at the same position.

  Here, in the imaging unit 30 configured in this way, the advance position of the moving lens 66 for realizing the first focal length is, for example, the relative position of each fixed frame or the like when the observation optical system unit 32 is assembled. Is adjusted finely. That is, when the observation optical system unit 32 is assembled, the front group lens frame 55 and the operation lens 65a in a state where the operating rod 65a is in contact with the front stopper 60 and the guide recess 65c is engaged with the guide protrusion 60b. The rear group lens frame 57 is positioned relative to each other while confirming optical characteristics, and is fixed via an adhesive or the like.

  On the other hand, the retracted position of the moving lens 66 for realizing the second focal length is, for example, a stopper on the rear group lens frame 57 after the front group lens frame 55 and the rear group lens frame 57 are positioned and fixed. Fine adjustment is performed by adjusting the position of the member 58 in the photographing optical axis O direction by using the adjustment ring 59. That is, when adjusting the retracted position of the moving lens 66, for example, as shown in FIG. 7, the stopper member 58 and the adjustment with respect to the outer peripheral surface of the rear group lens frame 57 positioned and fixed to the front group lens frame 55 are adjusted. A ring 59 is fitted. After that, in a state where the operating rod 65a is in contact with the stopper portion 58b and the guide recess 58d is engaged with the guide protrusion 58e, the stopper member 58 is rotated by the adjustment ring 59 while checking the optical characteristics. And is fixed through an adhesive or the like (see FIG. 8).

  According to such an embodiment, the guide projection 58e provided on the stopper portion 58b of the stopper member 58 and the operating rod 65a of the moving lens frame 65 are provided so that the moving lens frame 65 contacts the stopper member 58. (Ie, when the operating rod 65a of the moving lens frame 65 abuts against the stopper portion 58b of the stopper member 58), the movable lens frame 65 is brought into a predetermined contact with the stopper member 58 by engaging with the guide projection 58e. By having the guide recess 65d that guides the position, the moving lens frame 65 can be arranged at the retreat side adjustment position with high reproducibility, and a high-quality captured image can be obtained.

  That is, for example, the retracted position of the moving lens 66 for realizing the second focal length is that the stopper member 58 is positioned while checking the optical characteristics in a state where the operating rod 65a is in contact with the stopper portion 58b. In this case, the contact position between the operating rod 65a and the stopper portion 58b is adjusted by finely adjusting the position of the stopper member 58 in a state where the guide recess 58d is engaged with the guide protrusion 58e. In addition, the stopper member 58 can be positioned (adjustment of the second focal length of the moving lens 66) with the strict definition. At the time of use, when the stopper member 58 and the operating rod 65a are brought into contact with each other, the guide recess 58d is engaged with the guide protrusion 58e so that each portion between the rear lens group frame 57 and the movable lens frame 65 is engaged. Even when there is rattling due to clearance or the like, the moving lens frame 65 is arranged with high reproducibility at a predetermined adjustment position including the rotation position around the photographing optical axis O to obtain a high-quality captured image. be able to.

  In this case, the contact position between the operating rod 65a and the stopper member 58 can be accurately defined by forming the guide protrusion 58e and the guide recess 65d in a tapered shape.

  The positioning of the stopper member 58 is finely adjusted by rotating the adjustment ring 59. The adjustment ring 59 is rotated independently of the stopper member 58. Therefore, the guide protrusion 58e. The positioning of the stopper member 58 can be adjusted with the guide recess 65d always engaged.

  Similarly, the guide projection 60b provided on the front stopper 60 and the operating rod 65a of the moving lens frame 65 are provided when the moving lens frame 65 contacts the front stopper 60 (that is, the moving lens frame 65). A guide recess 65c that engages with the guide projection 60b and guides the movable lens frame 65 to a predetermined contact position with respect to the front stopper 60 (when the operating rod 65a is in contact with the front stopper 60). , The moving lens frame 65 can be arranged at the adjustment position on the advance side with good reproducibility, and a high-quality captured image can be obtained.

  That is, for example, the advancing position of the moving lens 66 for realizing the first focal length is the front stopper 60 (front) while confirming the optical characteristics in a state where the operating rod 65a is in contact with the front stopper 60. This is done by positioning the group lens frame 55). At this time, the position of the front stopper 60 is finely adjusted in a state where the guide recess 65c is engaged with the guide projection 60b, whereby the rear group lens. Even when there is rattling due to clearance or the like at each part between the frame 57 and the moving lens frame 65, the moving lens frame 65 is placed at a predetermined adjustment position including the rotation position around the photographing optical axis O. It is possible to obtain a high-quality captured image by arranging with good reproducibility.

  In this case, the contact position between the operating rod 65a and the front stopper 60 can be accurately defined by forming the guide protrusion 60b and the guide recess 65c into a tapered shape.

  Here, the shape of the guide protrusions 60b and 58e is not limited to the tapered shape, and may be, for example, a partially spherical or partially spheroidal protrusion as shown in FIG. Further, the shape of the guide recesses 65c and 65d is not limited to a tapered shape, and may be, for example, a partially spherical or partially spheroidal recess as shown in FIG. Although not shown, the arrangement of the guide protrusion and the guide recess may be the reverse of that shown in the above-described embodiment.For example, the guide recess is provided in the front stopper 60 and the stopper member 58. It is also possible to provide guide projections corresponding to these on the operation rod 65a.

  Next, FIGS. 11 and 12 relate to a second embodiment of the present invention, FIG. 11 is a cross-sectional view of the main part of the observation optical system unit, and FIG. 12 is an exploded perspective view showing the main part of the observation optical system unit. In this embodiment, instead of the stopper member 58 that is positioned and fixed on the outer peripheral surface of the rear group lens frame 57, a stopper member 80 that is positioned and fixed on the inner peripheral surface of the rear group lens frame 57 is adopted. It differs mainly from the first embodiment described above. In addition, about the structure similar to the above-mentioned 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 11, a stopper member 80 is disposed inside the rear group lens frame 57 on the proximal end side with respect to the moving lens frame 65 and on the distal end side with respect to the rear group lens 56b. Yes.

  For example, as shown in FIGS. 11 and 12, the stopper member 80 is formed integrally with a ring portion 80a applied in a state of being in direct surface contact with the inner peripheral surface of the rear lens group frame 57, and the ring portion 80a. The stopper portion 80b is configured.

  Here, like the operation rod 65a of the moving lens frame 65, the stopper portion 80b is configured by a rod-shaped member that protrudes outside the rear group lens frame 57 via the slit 57a. An adjustment ring 59 is disposed on the base end side of the stopper portion 80b, and the stopper portion 80b is substantially outside the rear group lens frame 57 via the protrusion portion 80c protruding from the stopper portion 80b. Point contact. Further, a through hole 80d facing the actuator holding hole 57c is provided in the vicinity of the protruding end portion of the stopper portion 80b.

  The stopper member 80 is bonded to the inner peripheral surface of the rear lens group frame 57 in a state where the stopper portion 80b is positioned so as to face the holding rod 57b at a predetermined position in the photographing optical axis O direction. It is fixed by.

  Here, a guide projection 80e is provided on the stopper portion 80b on the contact surface with the operating rod 65a. In the present embodiment, the guide protrusion 80e is formed by a taper-shaped protrusion whose sectional area gradually decreases toward the tip. The operating rod 65a is provided with a guide recess 65d that can engage with the guide protrusion 80e on the contact surface with the front stopper 60. In the present embodiment, the guide recess 65d is formed by a bottom taper-shaped recess whose opening area gradually decreases toward the bottom.

  The guide protrusions 80e and the guide recesses 65d are set to be engaged when the operating rod 65a is brought into contact with the stopper portion 80b. At the time of these engagements, the guide projection 80e guides the guide recess 65d to a predetermined engagement position by sliding the tapered surface of the guide recess 65d along the taper surface of the guide projection 80e. . Thereby, the operating rod 65a is always in contact with the stopper portion 80b at the same position.

  In the imaging unit 30 configured as described above, the retracted position of the moving lens 66 for realizing the second focal length is, for example, after the front lens group frame 55 and the rear lens group frame 57 are positioned and fixed. The position of the stopper member 80 in the rear optical group lens frame 57 in the direction of the photographing optical axis O is finely adjusted by adjusting it using the adjustment ring 59. That is, in the state in which the operating rod 65a is in contact with the stopper portion 80b and the guide recess 65d is engaged with the guide protrusion 80e, the adjustment ring 59 is rotated while checking the optical characteristics of the stopper member 80. And fixed through an adhesive or the like.

  According to such an embodiment, substantially the same effects as those of the first embodiment described above can be achieved. In this case, by disposing the ring portion 80a of the stopper member 80 on the inner peripheral surface side of the rear lens group frame 57, as shown in FIG. 11, only the stopper portion 80b is at the retracted position of the movable lens frame 65. In addition, the moving lens frame 65 can be brought into contact with the ring portion 80a, and the positioning of the moving lens frame 65 can be realized with higher accuracy.

  Here, for example, in order to improve the accuracy of the contact position between the stopper member 80 and the movable lens frame 65, for example, a guide projection is provided on the ring portion 80a, and the guide projection engages with the guide projection. It is also possible to provide a recess in the moving lens frame 65.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention.

  For example, in each of the embodiments described above, an example in which a guide concave portion is provided on the movable lens frame 65 side and a guide protrusion is provided on the stopper member (front stopper portion 60, stopper portion 58b, and stopper portion 80b) side. As described above, the present invention is not limited to this, and it is also possible to provide a guide projection on the movable lens frame 65 side and provide a guide recess on the stopper member side.

  Further, for example, in each of the above-described embodiments, the configuration in which the guide protrusion and the guide recess that are engaged with each other are provided at the advanced position and the retracted position of the movable lens frame 65, but the present invention is not limited thereto. However, the present invention is not limited to this, and it is possible to provide the guide projection and the guide recess only in either the advanced position or the retracted position.

DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope system 2 ... Endoscope 3 ... Light source device 4 ... Video processor 5 ... Color monitor 6 ... Tip part 7 ... Bending part 8 ... Flexible tube part 9 ... Insertion part 10 ... Operation part 11 ... Breaking prevention Part 12 ... Forceps port 12a ... Tip insertion part rubber member 12b ... Treatment instrument channel 13 ... Operation part main body 14, 15 ... Bending operation knob 16 ... Bending operation part 17 ... Universal cord 18 ... Scope connector 19 ... Scope cable 20 ... Electric connector Part 21 ... Air / water control part 22 ... Suction control part 23 ... Switch part 24 ... Operation lever 25 ... Tip rigid member 25a ... Tip cover 26 ... Bending piece 28 ... Ring 29 ... Pincushion bonding part 30 ... Imaging unit 31 ... Solid imaging Element unit 32... Observation optical system unit 33... Observation optical system 35. Child holding frame 36 ... Optical member 37 ... Solid-state imaging device chip 38 ... Laminated substrate 39 ... Cable 40 ... Reinforcement frame 41 ... Heat-shrinkable tube 42 ... Protective agent 45 ... Front group lens unit 46 ... Rear group lens unit 48 ... Moving lens unit 49 ... Actuator 55 ... Front group lens frame 56a ... Front group lens 56b ... Rear group lens 57 ... Rear group lens frame 57a ... Slit 57b ... Holding rod 57c ... Actuator holding hole 58 ... Stopper member 58a ... Ring portion 58b ... Stopper portion 58c ... Projection part 58d ... Through hole 58e ... Guide projection 59 ... Adjustment ring 60 ... Front stopper 60a ... Spring receiving part 60b ... Guide projection 65 ... Moving lens frame 65a ... Operating rod 65b ... Bearing part 65c ... Guide recess 65d ... Guide recess 6 ... Moving lens 67 ... Shaft member 68 ... Return spring 69 ... Cover 70 ... Guide tube 71 ... Push rod 72 ... Head part 73 ... Drive wire 74 ... Shape memory element 75 ... Push spring 80 ... Stopper member 80a ... Ring part 80b ... Stopper part 80c ... Projection part 80d ... Through hole 80e ... Projection for guide

Claims (4)

A focus switching observation optical system including a fixed lens and a moving lens;
A fixed lens frame for holding the fixed lens;
A movable lens frame disposed in the fixed lens frame so as to be movable back and forth in a direction along the imaging optical axis of the observation optical system, and holding the movable lens;
An operation in which power is transmitted through the slit provided in the fixed lens frame so as to protrude toward the outer peripheral side of the fixed lens frame in the outer diameter direction of the moving lens frame and to move the moving lens frame forward and backward.桿,
By restricting the movement in one direction of the photographing optical axis by the contact with the operating rod of the movable lens frame, so as to hold the movable lens to a position to realize one focal length of the observation optical system A stopper member positioned and fixed to the fixed lens frame ;
A guide projection provided on one of the contact surface of the operating rod and the contact surface of the stopper member of the movable lens frame;
Provided on the other of the contact surface of the operating rod and the contact surface of the stopper member of the movable lens frame, the guide when the contact surface of the operation rod contacts the contact surface of the stopper member An imaging unit comprising: a guide recess that engages with a projection for guiding the operating rod to a predetermined contact position with respect to the stopper member. The guide protrusion is a tapered protrusion,
The imaging unit according to claim 1, wherein the guide recess is a tapered recess that can be engaged with the guide protrusion. The guide protrusion is a partial spherical or partial spheroidal protrusion,
2. The imaging unit according to claim 1, wherein the guide recess is a recess having a partial spherical shape or a partial spheroidal shape that can be engaged with the guide protrusion.   An endoscope comprising the imaging unit according to any one of claims 1 to 3 at a distal end portion of an insertion portion to be inserted into a subject.

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