JP2010046424A - Endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope, capable of improving responsiveness when varying optical characteristics when a movable lens frame is moved forward and backward for zooming function or the like, and stably and securely moving the movable lens forward and backward without giving effects on inner members. <P>SOLUTION: The endoscope 2 is provided with a movable leans unit 32 provided on a camera unit 30 to move an optical lens 39 forward and backward along the optical axis for varying optical characteristics, a ferromagnetic shape memory alloy wire 56, connected to the movable lens unit at one end, and extended to an insert part 9, a magnetic coil 57 provided on the insert part for the ferromagnetic shape memory alloy wire to be inserted, and a variable control means to energize and de-energize a magnetic field on a magnetic field generating coil for varying distortion quantity of the ferromagnetic shape memory alloy wire. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an endoscope provided with an imaging unit that varies the optical characteristics of an objective optical system disposed in the endoscope.

As is well known, an electronic 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, an imaging unit that can change the focal length by moving the observation optical system in the direction of the photographic optical axis for a focusing function for adjusting the focus of a photographic image or a zooming function for performing wide zooming / tele zooming. Is used.
Such an imaging device which is an imaging unit capable of changing the focal length is used not only for an endoscope but also for various photographing machines.
For example, Patent Document 1 discloses a lens barrel and an imaging apparatus that can move only a part of lenses for focus adjustment. This conventional imaging device discloses a technique for moving the movable lens portion in the optical axis direction by utilizing the heat generated by the shape memory alloy spring.

  Further, for example, Patent Document 2 discloses a lens unit that reduces variations in operation in the autofocus function. This conventional lens unit discloses a technique in which a spring for setting an initial position of a lens barrel containing a lens group is formed of a shape memory alloy.

Further, the shape memory alloys used in Patent Document 1 and Patent Document 2 are those that change shape due to deformation (distortion) due to temperature change. For example, as disclosed in Patent Document 3 There has also been proposed a magnetic shape memory alloy that changes shape by deformation (distortion) due to magnetic force (magnetic field).
JP 2005-275270 A JP 2007-219409 A JP 2003-96529 A

  However, as described in Patent Document 1 and Patent Document 2, a conventional imaging unit (imaging device) is automatically operated by an actuator device using a shape memory alloy in which a strain amount (expansion / contraction amount) changes due to a temperature change. Because the optical characteristics are varied by moving the moving lens frame forward and backward for the focus function, zoom function, etc., the amount of strain changes according to the time when the shape memory alloy is heated or cooled, so the response speed of expansion and contraction However, there is a problem that the responsiveness of the moving and reciprocating movement of the moving lens frame is poor.

  In addition, since the magnetic shape memory alloy as described in Patent Document 3 changes the amount of distortion due to the generation and disappearance of a magnetic field and has good response to expansion and contraction, an actuator device that moves the moving lens frame of the imaging device forward and backward Suitable for However, using this magnetic shape memory alloy to move the moving lens frame forward and backward, the strain amount (stretching amount) of the magnetic shape memory alloy is much larger than the strain amount of the shape memory alloy whose shape changes due to temperature change. Therefore, there is a problem that it is difficult to obtain a moving amount for moving the moving lens frame as desired.

  In addition, in the conventional imaging device, since the shape memory alloy generates heat, the members around the shape memory alloy are thermally affected, which may cause a problem.

  Therefore, in view of the above circumstances, the present invention aims at improving the responsiveness when changing the optical characteristics by moving the moving lens frame forward and backward for the zooming function, etc. It is to realize an endoscope capable of moving a moving lens forward and backward stably and surely without affecting.

  In order to achieve the above object, a first endoscope of the present invention is an endoscope provided with a long insertion portion in which an imaging unit is built in a distal end portion and an operation portion connected to the insertion portion. A moving lens unit that is provided in the imaging unit and changes an optical characteristic by moving the optical lens back and forth in the optical axis direction, and one end of the moving lens unit is connected and extended to the insertion portion. A ferromagnetic shape memory alloy wire, a magnetic field generating coil provided in the insertion portion, through which the ferromagnetic shape memory alloy wire is inserted, and generating and extinguishing a magnetic field in the magnetic field generating coil; And a variable control means for variably controlling the amount of distortion.

  Further, the second endoscope of the present invention is an endoscope including a long insertion portion in which an imaging unit is built in a distal end portion, and an operation portion connected to the insertion portion, Provided in the imaging unit, the optical lens is moved back and forth in the optical axis direction to change the optical characteristics, and a part of the moving lens unit formed of a ferromagnetic material is disposed on the outer periphery of the moving lens unit. A magnet, a fixing member made of a magnetic material so as to abut against the magnet, and a ferromagnetic shape memory alloy wire extending to the insertion portion connected at one end; A magnetic field generating coil through which the magnetic shape memory alloy wire is inserted; and variable control means for variably controlling the amount of strain of the ferromagnetic shape memory alloy wire by generating and extinguishing a magnetic field in the magnetic field generating coil. And

  According to the present invention, the responsiveness when changing the optical characteristics by moving the moving lens frame forward and backward for the zooming function or the like is improved, and it is stably and reliably moved without affecting the internal members. An endoscope capable of moving the lens back and forth can be realized.

  The present invention will be described below with reference to embodiments based on the drawings.

(First embodiment)
First, the present invention will be described with reference to FIGS. 1 to 6 relate to the first embodiment of the present invention, FIG. 1 is a configuration diagram showing the entire electronic endoscope system, and FIG. 2 is an internal configuration of the distal end portion of the endoscope. 3 is a cross-sectional view showing the configuration of the image pickup unit in a state where the movable lens frame is at the wide end position, FIG. 4 is a cross-sectional view of the image pickup unit in which the range indicated by a circle IV in FIG. 3 is enlarged, and FIG. FIG. 6 is a cross-sectional view of the imaging unit in which the range indicated by a circle VI is enlarged, for explaining the action of the moving lens frame moving to the position.

  As shown in FIG. 1, an electronic endoscope system (hereinafter simply referred to as an endoscope system) 1 according to the present embodiment includes an electronic endoscope device (hereinafter simply referred to as an endoscope) 2, and a 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 in which the insertion portion 9 is extended. A universal cord 17 extending from the operation portion 10 is connected to the light source device 3 via a scope connector 18. Connected with. A coiled scope cable 19 is extended from the scope connector 18. An electric connector portion 20 is provided at the other end 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 connected in order from the distal end. A distal end opening, an observation window, a plurality of illumination windows, an observation window cleaning port, and an observation object cleaning port (not shown) are disposed on the distal end surface of the distal end portion 6.

  On the back side of the observation window, an imaging unit (described later) built in the distal end portion 6 is disposed. Further, on the back side of the plurality of illumination windows, a light guide bundle (not shown) that transmits illumination light from the light source device 3 and is inserted from the distal end portion 6 into the universal cord 17 is provided.

  The distal end portion 6 is provided with an observation window cleaning nozzle (not shown). The observation window cleaning nozzle constitutes an opening portion of a cleaning tube (not shown) that is inserted from the distal end portion 6 into the universal cord 17. These cleaning tubes are connected to a cleaning tank (not shown) in which cleaning water is stored, a compressor, and the light source device 3 side.

  The operation unit 10 includes an anti-bending portion 11 from which the insertion portion 9 extends, a forceps port 12 disposed on a side portion on the lower side, an operation portion main body 13 that constitutes a grip portion in the middle portion, and an upper side. Mainly an imaging function (for example, a zooming function) composed of a bending operation unit 16 including two bending operation knobs 14 and 15 provided, an air / water supply control unit 21, a suction control unit 22, and a plurality of switches. And a plurality of switch sections 23 for operating the. The forceps port 12 of the operation unit 10 constitutes one opening part of the treatment instrument channel 12b (see FIG. 2) that is mainly inserted into the insertion part 9 up to the distal end opening part of the distal end part 6.

Next, the configuration of the distal end portion 6 of the endoscope 2 will be mainly described below with reference to FIGS.
As shown in FIG. 2, the 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 24 and is fixed to the tip rigid member 24 by a set screw 27 from the side surface direction. Further, a watertight O-ring 28 is disposed on the outer peripheral portion on the front end side of the imaging unit 30. A tip cover 25 constituting the tip surface of the tip portion 6 is bonded and fixed so as to cover the tip portion of the tip rigid member 24.
Note that the distal end opening, which is a hole formed in the distal end cover 25, constitutes the opening of the treatment instrument channel 12b in the distal end 6 as described above. Also, a rubber tip insertion portion covering member 12a that integrally covers the outer periphery of the tip rigid member 24 and the bending piece 26 in the bending portion 7 is provided so as to form the outer shape of the tip portion 6 and the bending portion 7. It has been. The tip outer peripheral portion of the tip insertion portion covering member 12 a is fixed to the tip portion 6 by a pincushion bonding portion 29.

  Although not shown, the distal end rigid member 24 cleans the distal end portion of the light guide bundle that guides illumination light, the observation window of the distal end portion 6 and the like in addition to the imaging unit 30 and the treatment instrument channel 12b. The above-described observation window cleaning nozzle for supplying air into the body cavity, the distal end portion of the conduit communicating with the cleaning tube, and the distal end portions of a plurality of angle wires for bending the bending portion 7 It is fixed.

  The members such as the observation window cleaning nozzle, the cleaning tube, the light guide bundle, and the angle wire are well known in the art and will not be described in detail.

Next, the configuration of the imaging unit 30 will be described in detail below based on FIGS. 3 to 6.
The imaging unit 30 according to the present embodiment has a configuration in which an internal lens moves forward and backward for a focusing function or a zooming function that changes the focal length and changes the optical characteristics. In the present embodiment, the focal length is changed and the internal lens for changing the optical magnification is moved forward and backward. In the following description, switching between wide and tele is described as a zooming function.

  An imaging unit 30 shown in FIG. 3 includes a front group lens frame 34 that is a fixed lens frame that forms a front group lens unit 31 and holds a front group lens 35 that includes a plurality of objective lenses, and a plurality of objectives. A rear lens group frame 36 that is a fixed lens frame that holds a rear lens group 33 composed of lenses, and a moving lens unit 32 that is a moving body that is provided between the lens groups 35 and 33 and holds a moving lens 39. The outer lens frame 38, which is a ferromagnetic material formed from a ferromagnetic material, and the image sensor unit 46 having a CCD, a CMOS, and the like, which mainly form an outer shape, are mainly configured.

  In the imaging unit 30, the rear end portion of the front group lens frame 34 and the front end portion of the rear group lens frame 36 are fitted and joined. Further, a front end portion of an image sensor holding frame 41 that holds the image sensor unit 46 is inserted and fixed to the rear end portion of the rear group lens frame 36.

  The moving lens unit 32 is slidably disposed along the photographing optical axis O direction in the rear group lens frame 36 on the rear side of the front group lens unit 31. A magnet that is slidable parallel to the photographic optical axis O in a cover body 37 to be described later so as to sandwich the thick part of the rear lens group frame 36 on the lower outer peripheral side of the movable lens frame 38 of the movable lens unit 32. 40 is provided. Further, the magnet 40 gives a magnetic force that attracts the moving lens frame 38 formed of a ferromagnetic material of the moving lens unit 32 with the thick portion of the rear lens group frame 36 sandwiched therebetween. That is, in the moving lens unit 32, the moving lens frame 38 made of a ferromagnetic material is attracted by receiving the magnetic force of the magnet 40, and follows the forward / backward movement of the magnet 40, so that the inside of the rear lens group frame 36 is directed in the direction of the photographing optical axis O. Slide along.

  The image sensor unit 46 includes, in the image sensor holding frame 41, two optical members 42 and 43, an image sensor chip 45 with the image area 44 positioned on the front surface, and a laminated substrate 47 in order from the tip. Yes. The image sensor chip 45 and the multilayer substrate 47 are electrically connected by FPC.

  The laminated substrate 47 is connected to a plurality of communication lines of the main cable 51. The main cable 51 is inserted into the endoscope 2 and is electrically connected by the video processor 4 and the electrical connector unit 20 via the universal cord 17 and the scope cable 19.

  A reinforcing frame 48 is fitted on the outer periphery of the rear end of the image sensor holding frame 41, and a covering member 49, which is a heat-shrinkable tube, is provided on the outer periphery of the reinforcing frame 48 up to the tip of the main cable 51. Yes. A space formed by the reinforcing frame 48 and the covering member 49 from the rear end portion of the image sensor holding frame 41 provided with the image sensor chip 45 is filled with a protective agent such as an adhesive.

  In addition, an actuator holding portion that inserts and holds a tip portion of an actuator 62 that is a ferromagnetic shape memory alloy actuator device that moves the moving lens unit 32 forward and backward by the magnetic attraction force of the magnet 40 is provided at a rear lower portion of the rear group lens frame 36. 54 is formed so as to protrude downward.

  The actuator holding portion 54 is formed with a concave portion 54a, which has an outer shape capable of accommodating a wire fixing portion 52 of an actuator 62, which will be described later, which is attracted and fixed by the magnetic force of the magnet 40, from the front portion to the rear. A hole for holding and fixing the tip of the magnetic coil 57, which is a magnetic field generating coil of the actuator 62, is formed so as to open at the center of the recess 54a.

  In addition, a cover body 37 that holds a part of the front group lens unit 31 and integrally covers the magnet 40 and the actuator holding portion 54 is provided at the front lower portion of the rear group lens frame 36.

  Next, based on FIGS. 3 to 6, the configuration of the actuator 62 attached to the imaging unit 30 and the operation in which the moving lens unit 32 of the imaging unit 30 moves forward and backward along the imaging optical axis O by the actuator 62. This will be described in detail below.

  As shown in FIGS. 3 and 4, the actuator 62 is provided so as to contact the rear end surface of the magnet 40 and the front end surface of the actuator holding portion 54, and attracts the moving lens unit 32 by magnetic force to follow. The distal end portion is arranged and fixed on the compression coil spring 53 of a pressing spring that constitutes an elastic member that urges the front 40 forward, in this case toward the wide end, and the actuator holding portion 54 of the rear group lens frame 36, and the insertion portion extends to the operation portion 10. 9 is a magnetism generating means extending in the main body 9 and includes the above-described magnetic coil 57 made of a magnetic material, and a ferromagnetic shape memory alloy wire 56 inserted into the magnetic coil 57. It is configured. A recess 40 a is formed on the rear end surface of the magnet 40 so that the tip of the compression coil spring 53 abuts.

  The magnetic coil 57 of the actuator 62 is covered with a cover tube 58 at a rear end portion provided in the operation unit 10. In the cover tube 58, the rear end portion of the magnetic coil 57 is electrically connected to the conducting wire 61 a of the cable 61. Further, a block body 59 is fixed by caulking to the rear end portion of the ferromagnetic shape memory alloy wire 56 so as not to come into contact with the rear end portion of the magnetic coil 57.

  The cable 61 is inserted into the universal cord 17 from the operation unit 10 and is electrically connected by the video processor 4 and the electrical connector unit 20 via the scope cable 19 in the same manner as the main cable 51 of the imaging unit 30. Is done.

  The ferromagnetic shape memory alloy wire 56 is made of a shape memory alloy (Shape Memory Alloys, hereinafter referred to as “SMA”) made of a Co—Ni—Ga based Heusler type magnetic shape memory alloy or the like, and has a diameter of several tens of microns. (Hereinafter, the ferromagnetic shape memory alloy wire is abbreviated as a ferromagnetic SMA wire). The ferromagnetic SMA wire 56 is a shape memory alloy whose strain can be controlled by an external magnetic field (magnetic field) (magnetic field). Further, the ferromagnetic SMA wire 56 is inserted and disposed mainly in the magnetic coil 57 in a substantially non-tensioned state when a predetermined magnetic field (magnetic field) is not generated around the ferromagnetic SMA wire 56.

  Further, the cover body 37 is in contact with the front end surface of the magnet 40 in a state where the cover body 37 is fitted to the rear group lens frame 36, and restricts forward movement of the moving lens unit 32 that moves forward and backward following the magnet 40. And a restricting portion 37 a that defines the wide end position of the imaging unit 30.

  In order to restrict the movement of the moving lens unit 32 to the rear, the rear end surface of the wire fixing portion 52 attracted by the magnet 40 comes into contact with the front end surface serving as the bottom surface of the concave portion 54a of the actuator holding portion 54. The tele end position of the imaging unit 30 is defined.

  That is, the moving lens unit 32 is restricted from moving forward following the magnet 40 when the magnet 40 abuts on the restricting portion 37a of the cover body 37. Here, the viewing angle of the imaging unit 30 is controlled by each objective lens. Is set to have a predetermined wide angle optical characteristic (optical magnification). On the other hand, the moving lens unit 32 is configured such that the rear end surface of the wire fixing portion 52 that is attracted and fixed to the magnet 40 is accommodated in the concave portion 54a and comes into contact with one surface of the actuator holding portion 54 that becomes the bottom surface of the concave portion 54a. In this case, the optical characteristics (optical magnification) at which the viewing angle of the imaging unit 30 becomes a predetermined tele angle are set by each objective lens.

  As shown in FIG. 3, the endoscope 2 according to the present embodiment configured as described above has a magnetic coil that extends from the cable 61 when the moving lens unit 32 of the imaging unit 30 is positioned at the wide end. In this state, the energization to 57 is stopped.

  At this time, since the magnetic field (magnetic field) of the magnetic coil 57 extrapolated to the periphery disappears, the ferromagnetic SMA wire 56 is not distorted, that is, does not contract and is in a substantially non-tensioned state. The moving lens unit 32 is in a state where the ferromagnetic SMA wire 56 is magnetically contracted and the wire fixing portion 52 is not given a traction force to the rear, so that the magnet 40 attracted and fixed by the wire fixing portion 52 is also compressed. The coil spring 53 is pressed forward by the urging force of the coil spring 53 and moves forward following the magnet 40.

  In this way, the moving lens unit 32 that is attracted and followed by the magnetic force of the magnet 40 pressed forward by the urging force of the compression coil spring 53 moves toward the front indicated by the arrow W shown in FIG. When the front end surface comes into contact with the regulating portion 37 a of the cover body 37, the imaging unit 30 is stopped at the wide end position.

  With such a configuration of the imaging unit 30, a lens frame configuration in which the front group lens frame 34 and the rear group lens frame 36 are fitted in a closed (sealed) state can be obtained. An airtight structure can be provided around the optical lens. As a result, fogging of the optical lens can be prevented.

  Further, when the endoscope 2 is energized from the cable 61 to the magnetic coil 57, a predetermined magnetic field (magnetic field) is generated around the ferromagnetic SMA wire 56 by the magnetic coil 57, and this magnetic field (magnetic field) is generated. The received ferromagnetic SMA wire 56 magnetically contracts instantaneously with a predetermined strain amount. Then, the moving lens unit 32 of the imaging unit 30 follows the magnetic force of the magnet 40 to which the wire fixing part 52 is attracted and fixed against the forward biasing force of the compression coil spring 53, and the ferromagnetic SMA wire 56 contracts. In accordance with (strain), it is instantaneously pulled backward and moved as indicated by an arrow T shown in FIG.

  As described above, the moving lens unit 32 that is magnetically attracted to the magnet 40 follows the rear end face of the wire fixing portion 52 that is instantaneously pulled by the ferromagnetic SMA wire 56 and is attracted and fixed to the magnet 40. The actuator holding portion 54 comes into contact with the front end surface that is the bottom surface of the concave portion 54 a and stops at the tele end position of the imaging unit 30.

  In addition, ON / OFF operation of energization from the cable 61 to the magnetic coil 57 can be performed by one of the plurality of switch units 23 provided in the operation unit 10, and current is magnetically transmitted from the video processor 4 via the cable 61. Applied to the coil 57. That is, in this embodiment, by operating one of the plurality of switch units 23, the current from the video processor 4 is stopped from being applied from the cable 61 to the magnetic coil 57, which is a magnetic field generating coil, and a magnetic field is generated. The variable control means is configured to extinguish and control the amount of strain of the ferromagnetic SMA wire 56 to expand and contract.

  As described above, the endoscope 2 according to the present embodiment is not a conventional nonmagnetic shape memory alloy using a change in temperature, but a strong magnetic shape memory alloy whose amount of strain changes due to a magnetic field (magnetic field). The moving lens unit 32 is moved forward and backward by an actuator 62 using a magnetic SMA wire 56. Therefore, the amount of strain of the endoscope 2 is changed by the generation and disappearance of a magnetic field (magnetic field) as compared with a nonmagnetic shape memory alloy in which the thermal conductivity greatly affects the drive response as in the prior art. By using a magnetic shape memory alloy that can perform agile driving, the responsiveness of the moving lens unit 32 of the imaging unit 30 is greatly improved by switching between wide and telephoto here.

  Further, although the strain amount (stretching amount) of the magnetic shape memory alloy is very small compared to the strain amount of the shape memory alloy whose shape changes due to temperature change, the magnetic shape is almost completely within the insertion portion 9 of the endoscope 2. By providing the ferromagnetic SMA wire 56 which is a memory alloy, a stable amount of movement of the moving lens unit 32 of the imaging unit 30 can be sufficiently obtained.

  Further, the ferromagnetic SMA wire 56, which is a magnetic shape memory alloy, does not need to generate heat unlike the conventional nonmagnetic shape memory alloy, so that the surroundings in the imaging unit 30, the insertion portion 9, and the operation portion 10 are not necessary. There is no thermal influence on the members, and it is possible to prevent problems caused by the thermal effects on various members.

  Since the magnetic coil 57 through which the ferromagnetic SMA wire 56 is inserted is a flexible coil tube formed by winding a magnetic metal body, the flexibility of the insertion portion 9 is not hindered.

  As described above, the endoscope 2 of the endoscope system 1 according to the present embodiment has improved responsiveness when the optical characteristics are varied by moving the moving lens frame forward and backward for a zooming function and the like. It can be set as the structure which can move a moving lens forward and backward stably and reliably, without affecting a member.

(Second Embodiment)
Next, a second embodiment of the present invention will be described below based on FIG. 7 and FIG.
FIGS. 7 and 8 relate to the second embodiment of the present invention. FIG. 7 is a partial cross-sectional view showing the configuration around the moving lens of the imaging unit in the wide state, and FIG. 8 shows the movement of the imaging unit in the tele state. It is a fragmentary sectional view showing the composition around a lens.
In the following description, the same reference numerals are used for the same configurations as those of the imaging unit 30 of the endoscope system 1 according to the first embodiment described above, and detailed descriptions thereof are omitted.

  As shown in FIGS. 7 and 8, the imaging unit 30 of the endoscope 2 according to the present embodiment includes a connecting rod 69 and a distal end portion of the ferromagnetic SMA wire 56 that are fitted below the moving lens unit 32. The wire fixing portion 52 to be fixed is not attracted and fixed by a magnetic force, and the front surface portion of the wire fixing portion 52 comes into contact with the rear surface portion of the connecting rod 69 to move the moving lens unit 32 forward (in the direction of arrow W in FIG. 7). It is configured to move. That is, the connecting rod 69 is a non-magnet body instead of the magnet 40 of the first embodiment.

  Specifically, a ring member 71 for spring fastening is provided on the rear end surface, which is the bottom surface portion of the concave portion 54a formed in the actuator holding portion 54, and is pressed against the rear end surface of the wire fixing portion 52 and pressed forward. A coil spring 53 is provided in the recess 54a.

  Further, the cover body 37 is formed with a concave portion 37b that opens on the rear side along the advancing / retreating direction of the moving lens unit 32 on the lower side of the restricting portion 37a. A compression coil spring 55 that abuts the front end surface of the connecting rod 69 and urges the moving lens unit 32 rearward (in the direction of arrow T in FIG. 8) is disposed in the recess 37b.

In the rear group lens frame 36 of the imaging unit 30, a guide groove 36a that forms a guide groove is formed on the lower front side so that the connecting rod 69 connected to the moving lens unit 32 can advance and retreat.
Further, the cover body 37 is positioned at the front end portion of the rear group lens frame 36 that forms the guide groove 36a in a state of being fitted to the rear group lens frame 36, and abuts the forward movement of the movable lens unit 32. In this case, it has the restricting portion 37a described in the first embodiment that contacts the front end surface of the connecting rod 69 and defines the wide end position of the imaging unit 30.

  The rear lens group frame 36 is formed with a restricting portion 36b at the rear end portion of the guide groove 36a for restricting the rearward movement of the movable lens unit 32 by coming into contact with the rear end surface of the connecting rod 69.

  Since the imaging unit 30 of the present embodiment configured as described above has no distortion in the ferromagnetic SMA wire 56 when the magnetic field (magnetic field) in which the magnetic coil 57 is not energized is extinguished, The compression coil spring 53 presses the wire fixing portion 52 forward. At this time, the wire fixing portion 52 abuts on the connecting rod 69 by the urging force of the compression coil spring 53 and presses the moving lens unit 32 forward through the connecting rod 69.

  Then, the moving lens unit 32 moves forward against the urging force of the front side of the compression coil spring 55 in contact with the connecting rod 69 disposed on the cover body 37, and connects to the restricting portion 37a. Stops when it comes into contact. In other words, the imaging unit 30 is restricted from moving forward by the connecting rod 69 coming into contact with the regulating portion 37a of the cover body 37. Here, the viewing angle of the imaging unit 30 is set to a predetermined wide angle by each objective lens. Is switched to the optical characteristic (optical magnification).

  On the other hand, in the imaging unit 30, when the magnetic coil 57 is energized and a magnetic field (magnetic field) is generated, the ferromagnetic SMA wire 56 magnetically contracts with a predetermined strain amount, and the biasing force to the front of the compression coil spring 53. Against this, the wire fixing portion 52 is pulled backward. At this time, the wire fixing portion 52 is released from contact with the connecting rod 69 and is separated from the connecting rod 69.

  Then, only the rearward urging force of the compression coil spring 55 is applied to the moving lens unit 32, and the moving lens unit 32 moves rearward so that the connecting rod 69 comes into contact with the restricting portion 36b and stops. In other words, the imaging unit 30 is restricted from moving backward by the connecting rod 69 coming into contact with the regulating portion 36b of the rear lens group frame 36. Here, the viewing angle of the imaging unit 30 is predetermined by each objective lens. It is switched to the optical characteristic (optical magnification) that becomes the tele angle.

  As described above, the endoscope 2 according to the present embodiment has a configuration in which the ferromagnetic SMA wire 56 is not fixed to the moving lens unit 32 in the imaging unit 30. As a result, in a state where the moving lens unit 32 moves rearward and stops in contact with the restricting portion 36b, the ferromagnetic SMA wire 56 that is magnetically contracted is counteracted only by the forward biasing force of the compression coil spring 53. It takes power.

  Therefore, in addition to the urging force of the compression coil spring 53, an unreasonable load that pulls the stopped moving lens unit 32 is not applied to the ferromagnetic SMA wire 56 and the wire fixing portion 52. As a result, in addition to the effects of the first embodiment, the endoscope 2 of the present embodiment has the ferromagnetic SMA wire 56 itself in the actuator 62 of the imaging unit 30, and the ferromagnetic SMA wire 56 and the wire fixed thereto. The durability of the connection part with the part 52 can be improved.

(Third embodiment)
Next, a third embodiment of the present invention will be described below with reference to FIGS.
FIGS. 9 to 11 relate to a third embodiment of the present invention, FIG. 9 is a plan view showing an operation part of an endoscope, and FIG. 10 is for generating a magnetic field (magnetic field) by contacting with a magnetic field generating coil. FIG. 11 is a cross-sectional view of a state in which the permanent magnet that has been in contact is slid in order to extinguish the magnetic field (magnetic field) of the magnetic field generating coil.
In the following description, the same reference numerals are used for the same configurations as those of the imaging unit 30 of the endoscope system 1 according to the first embodiment described above, and detailed descriptions thereof are omitted.

  The endoscope 2 of the present embodiment is not configured to switch the generation and extinction of a magnetic field (magnetic field) by energizing and de-energizing the magnetic coil 57, but variable control for bringing the permanent magnet 66 into or out of contact with the magnetic coil 57. By using the means, the generation and extinction of the magnetic field (magnetic field) of the magnetic coil 57 is switched.

As shown in FIG. 9, an operation button 65 for sliding a permanent magnet 66 along a guide hole 67 formed in the longitudinal direction is provided on one surface of the operation unit main body 13 of the operation unit 10.
As shown in FIGS. 10 and 11, the operation button 65 has an outward flange shape outside the operation unit main body 13 and is connected to a cylindrical permanent magnet 66 provided in the operation unit main body 13. Yes.

  A cylindrical permanent magnet 66 is provided in the guide hole 67 so that the hole 59 can accommodate the magnetic coil 57 extending from the base end of the cover tube 58 and the block body 59 that fixes the ferromagnetic SMA wire 56 by caulking. Are arranged along.

  That is, when the operation button 65 is slid along the guide hole 67 in the direction of arrow T in FIG. 10, the rear end portion of the magnetic coil 57 and the block body 59 are accommodated in the hole portion of the permanent magnet 66. The permanent magnet 66 and the magnetic coil 57 are in contact with each other. In this state, the magnetic coil 57 is magnetized by the permanent magnet 66 from the rear end portion toward the front end to generate a magnetic field (magnetic field) around the ferromagnetic SMA wire 56. Then, the ferromagnetic SMA wire 56 that has received a magnetic field (magnetic field) magnetically contracts with a predetermined strain amount.

  In this way, the moving lens unit 32 of the imaging unit 30 resists the forward biasing force of the compression coil spring 53, or the magnetic attraction force of the magnet 40 in the first embodiment, or the second embodiment. Through the connecting rod 69, it is instantaneously pulled backward and moved in accordance with the contraction (strain) of the ferromagnetic SMA wire 56 (see FIGS. 5 and 6).

  As described above, the moving lens unit 32 that is instantaneously pulled by the ferromagnetic SMA wire 56 has the rear end surface of the wire fixing portion 52 that is attracted and fixed to the magnet 40 or connected to the connecting rod 69 as described above. It comes into contact with the front end surface serving as the bottom surface of the concave portion 54 a of the 54 and stops at the tele end position of the imaging unit 30.

  On the other hand, when the operation button 65 is slid along the guide hole 67 in the direction of the arrow W in FIG. 11, the rear end portion of the magnetic coil 57 housed in the hole portion of the permanent magnet 66 is moved. The permanent magnet 66 is not contacted. In this state, the magnetic coil 57 is demagnetized by the permanent magnet 66 and the magnetic field around the ferromagnetic SMA wire 56 disappears. Then, the ferromagnetic SMA wire 56 is in an original state (no distortion occurs, that is, a substantially non-tensioned state without contracting).

  Thus, the moving lens unit 32 is in a state in which the ferromagnetic SMA wire 56 is magnetically contracted and no magnetic attraction force of the magnet 40 or traction force to the rear via the connecting rod 69 is applied. The magnetic force of the magnet 40 pressed forward by the urging force via the wire fixing portion 52 or the forward movement via the connecting rod 69 moves forward.

  Thus, the moving lens unit 32 moves forward, and the front end surface of the magnet 40 or the connecting rod 69 comes into contact with the restriction portion 37a of the cover body 37 and stops at the wide end position of the imaging unit 30. It will be in a state (refer to Drawing 3, Drawing 4, and Drawing 7).

  Note that when the permanent magnet 66 is not in contact with the ferromagnetic SMA wire 56, the magnetic force around the permanent magnet 66 is moved by a sliding operation of the operation button 65 to a position where it does not affect the ferromagnetic SMA wire 56. The dimension of the guide hole 67 formed in the operation part main body 13 is set.

  Since the endoscope 2 according to the present embodiment configured as described above does not need to have an electrical configuration in addition to the effects of the first embodiment, it is only necessary to perform a sliding operation of the operation button 65. The imaging unit 30 can have a very simple configuration that can be switched between wide and tele.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described below with reference to FIGS.
FIGS. 12 to 15 relate to the fourth embodiment of the present invention, FIG. 12 is a partial cross-sectional view showing the imaging unit in the wide state, FIG. 13 is a partial cross-sectional view showing the imaging unit in the tele state, and FIG. FIG. 15 is a partial cross-sectional view showing an imaging unit in a tele state according to a modification. FIG.

  In the following description, the same reference numerals are used for the same components as those of the imaging unit 30 of the endoscope system 1 according to each of the above-described embodiments, and detailed descriptions thereof are omitted.

  The endoscope 2 according to the present embodiment has optical characteristics by, for example, desired wide / tele zooming even if the moving amount of the moving lens unit 32 in the imaging unit 30 is very small due to the precision optical lens design. It can be switched. As described above, in the case of the imaging unit 30 in which the moving amount of the moving lens unit 32 for switching the optical characteristics is small (the moving distance is short), the magnetic SMA wire 56 is made short (short) as shown in FIGS. ) Configuration.

  More specifically, as shown in FIGS. 12 and 13, the imaging unit 30 according to the present embodiment includes a moving lens unit 32 within a frame that overlaps with a front group lens frame 34 and a rear group lens frame 36. Are arranged so as to freely advance and retract. The moving lens unit 32 is urged forward by a compression coil spring 53 as indicated by an arrow W in FIG. 12, and stops in contact with the front lens group frame 34 at the wide end position in the imaging unit 30. In this state, the power supply to the magnetic coil 57, which is a magnetic field generating coil, is turned off.

  Further, the distal end portion of the ferromagnetic SMA wire 56 is fixedly connected to the moving lens frame 38. Further, an abutting pin 81 fixed to the rear lens group frame 36 is provided in the frame in which the moving lens unit 32 advances and retreats, and restricts the movement of the moving lens unit 32 to the rear.

  An outer peripheral portion of the magnetic coil 57 is provided in contact with the rear inner peripheral portion of the rear group lens frame 36. A cable 61 disposed on the main cable 51 is connected to the magnetic coil 57. When energization from the cable 61 to the magnetic coil 57 is turned on, a predetermined magnetic field (magnetic field) is generated by the magnetic coil 57. The generated magnetic field (magnetic field) is transmitted to the metal rear group lens frame 36 and the front group lens frame 34 which are magnetic materials, and a predetermined magnetic field (magnetic field) is generated around the ferromagnetic SMA wire 56.

  The ferromagnetic SMA wire 56 that has received this magnetic field (magnetic field) is magnetically contracted at a predetermined strain amount, although it is a small amount instantaneously. Then, the moving lens unit 32 of the imaging unit 30 moves while being instantaneously pulled backward as indicated by an arrow T shown in FIG. 13 against the forward biasing force of the compression coil spring 53.

  Then, the moving lens unit 32 stops when the moving lens frame 38 abuts against the abutting pin 81 and the rearward movement is restricted. At this time, the moving lens unit 32 is moved to the tele end position of the imaging unit 30.

  The endoscope 2 configured as described above has optical characteristics due to the desired zooming of wide / tele, even if the moving amount of the moving lens unit 32 in the imaging unit 30 is very small due to the design of the imaging unit 30 by the precision optical lens. When the configuration can be switched, the same effect as the first embodiment can be obtained, and the ferromagnetic SMA wire 56 can be simply configured to be short.

  As shown in FIGS. 14 and 15, the imaging unit 30 includes a magnetic coil outside the overlapping frame in which the front group lens frame 34 and the rear group lens frame 36 are fitted, and here on the outer periphery of the rear group lens frame 36. 57 may be provided and a cable 61 separated from the main cable 51 may be connected.

  The invention described in each of the above-described embodiments is not limited to the embodiments and modifications, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if several constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem to be solved by the invention can be solved, and the effect described in the effect of the invention can be obtained. A configuration from which this configuration requirement is deleted can be extracted as an invention.

The block diagram which shows the whole electronic endoscope system which concerns on 1st Embodiment, Sectional drawing which shows the internal structure of the front-end | tip part of an endoscope similarly Sectional drawing which shows the structure of the imaging unit with the moving lens frame in the wide end position Sectional drawing of the imaging unit which expanded the range shown by the circle IV of FIG. Same sectional view of the imaging unit for explaining the action of moving the moving lens frame to the tele end position, Sectional drawing of the imaging unit which expanded the range shown by the circle VI Same as above Cross sectional view showing the internal configuration of the distal end portion of the endoscope The fragmentary sectional view which shows the structure of the periphery of the moving lens of the imaging unit of the wide state which concerns on 2nd Embodiment FIG. 3 is a partial cross-sectional view showing the configuration around the moving lens of the imaging unit in the tele state The top view which shows the operation part of the endoscope which concerns on 3rd Embodiment Same as above, sectional view of a state in which a permanent magnet for generating a magnetic field in contact with the magnetic field generating coil is slid Same as above, a sectional view of a state in which the permanent magnet that has been in contact is slid in order to extinguish the magnetic field of the magnetic field generating coil The fragmentary sectional view which shows the imaging unit of the wide state which concerns on 4th Embodiment FIG. 13 is a partial sectional view showing the imaging unit in the tele state. Partial sectional view showing the imaging unit in the wide state according to the modified example The same fragmentary sectional view which shows the image pickup unit of the tele state of the modification

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Endoscope system 2 ... Endoscope 6 ... Tip part 7 ... Bending part 8 ... Flexible tube part 9 ... Insertion part 10 ... Operation part 16 ... Bending operation part 23 ... Switch part 26 ... Bending piece 30 ... Imaging unit 31 ... Front group lens unit 32 ... Moving lens unit 33 ... Rear group lens 34 ... Front group lens frame 35 ... Front group lens 36a ... Guide groove 36 ... Rear group lens frame 37 ... Cover body 37a ... Restricting part 38 ... Moving lens frame 39 ... Moving lens 40 ... Magnet 44 ... Image area 45 ... Image sensor chip 46 ... Image sensor unit 47 ... Laminated substrate 51 ... Main cable 52 ... Wire fixing part 53 ... Compression coil spring 54 ... Actuator holding part 56 ... Ferromagnetic shape memory alloy Wire 57 ... Magnetic coil 58 ... Cover tube 59 ... Block body 61 ... Cable 62 ... Actuator 66 ... Permanent magnet 69 ... Connecting rod ... photographing optical axis

Claims (6)

An endoscope provided with a long insertion part in which an imaging unit is built in a distal end part, and an operation part connected to the insertion part,
A moving lens unit that is provided in the imaging unit and changes the optical characteristics by moving the optical lens back and forth in the optical axis direction; and
A ferromagnetic shape memory alloy wire having one end connected to the moving lens unit and extending to the insertion portion;
A magnetic field generating coil provided in the insertion portion and through which the ferromagnetic shape memory alloy wire is inserted;
Variable control means for variably controlling the amount of strain of the ferromagnetic shape memory alloy wire by generating and extinguishing a magnetic field in the magnetic field generating coil;
An endoscope characterized by comprising: An endoscope provided with a long insertion part in which an imaging unit is built in a distal end part, and an operation part connected to the insertion part,
A moving lens unit that is provided in the imaging unit, changes the optical characteristics by moving the optical lens back and forth in the optical axis direction, and is partially formed of a ferromagnetic material;
A magnet disposed on the outer periphery of the moving lens unit;
A ferromagnetic shape memory alloy wire extending to the insertion portion, one end of which is connected to a fixture formed of a magnetic material so as to abut against the magnet;
A magnetic field generating coil provided in the insertion portion and through which the ferromagnetic shape memory alloy wire is inserted;
Variable control means for variably controlling the amount of strain of the ferromagnetic shape memory alloy wire by generating and extinguishing a magnetic field in the magnetic field generating coil;
An endoscope characterized by comprising:   The endoscope according to claim 1 or 2, wherein the ferromagnetic shape memory alloy wire provided in the insertion portion and the magnetic field generating coil are extended to the operation portion.   4. The variable control unit according to any one of claims 1 to 3, wherein the variable control means switches between applying and stopping current to the magnetic field generating coil to generate and extinguish a magnetic field around the ferromagnetic shape memory alloy wire. The endoscope according to item 1.   The variable control means switches between contact and non-contact of a permanent magnet to the magnetic field generation coil to generate and extinguish a magnetic field around the ferromagnetic shape memory alloy wire. The endoscope according to any one of the above. An elastic member for urging the moving lens unit in one direction along the photographing optical axis;
6. The device according to claim 1, wherein the ferromagnetic shape memory alloy wire contracts to pull the moving lens unit to the other against the biasing force of the elastic member. Endoscope.

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