JP5412590B2 - Endoscope imaging unit - Google Patents

Description

  The present invention relates to an endoscope imaging unit that can change the optical characteristics of an objective optical system disposed in an 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.
For example, Patent Document 1 discloses a technique for changing the optical characteristics of such an imaging unit provided in an endoscope by moving a moving lens frame back and forth for a zooming function or the like.

This patent document 1 includes an objective optical system unit having a front lens group frame, a rear lens group frame, and a movable lens frame that moves back and forth along the photographing optical axis in the rear lens group frame. A mirror imaging device is disclosed. This conventional imaging unit is fixed to the tip end body by a fixing screw screwed to the tip end body from the circumferential direction on the outer periphery of the objective optical system unit.
For example, Patent Document 2 discloses an endoscope including an actuator unit that controls the moving lens frame to move forward and backward using a spring and a shape memory alloy wire.

JP 2003-230532 A JP 2007-229155 A

  However, as described in Patent Document 1 and Patent Document 2, a conventional imaging unit including a moving lens frame that moves back and forth has a backlash that fits between the moving lens frame and the fixed lens frame. The moving lens frame has a problem in that the front and rear stop positions vary, and the movable lens frame does not stop at a position that satisfies the desired optical characteristics. As a result, the moving lens frame and the fixed lens frame are required to have accuracy in manufacturing, and there is a problem in that the yield decreases.

  Furthermore, if the moving lens frame is loosely fitted with the fixed lens frame, there is also a problem that image shaking occurs during forward / backward movement. In addition, even if the deflection angle of the objective optical system is adjusted, the moving lens frame of the imaging unit may not stop at the desired position in endoscopes used in any posture, and the desired optical characteristics can be stabilized. There was also a problem that it could not be reproduced.

  In an imaging unit having a zooming function of wide zooming / tele zooming, accuracy of the stop position at the wide end where the moving lens frame has a large viewing angle is required. That is, at the wide end where the viewing angle becomes large, there is also a problem that vignetting occurs if the reproducibility of the stop position of the moving lens frame is poor.

  Therefore, in view of the above-described circumstances, the present invention aims to stably reproduce desired optical characteristics so that image shaking does not occur during forward and backward movement, and a moving lens frame is fixed. It is to realize an imaging unit for an endoscope that improves the reproducibility of stopping at the wide end position and prevents the occurrence of vignetting.

  In order to achieve the above object, an endoscope imaging unit according to one aspect of the present invention is fitted and fixed by a distal end body and a fixing member of an endoscope, and can change the optical characteristics of an objective optical system. In the unit, a fixed lens frame that holds at least one lens, a movable lens frame that is provided in the fixed lens frame so as to be movable forward and backward in the direction of the photographic optical axis, and that holds a moving lens; An urging member for urging in a first direction along the axis; and an actuator for extending the movable lens frame in a second direction along the imaging optical axis against the urging force of the urging member; And the actuator is configured to bias at least the contact member and the contact member in the second direction opposite to the first direction along the imaging optical axis. A moving body. The frame has a contacted surface configured to contact the contact member, and the contact member biased in the second direction by the biasing body is the contacted surface. When a pressing force is applied to the contact surface by contacting the contact surface, the pressing force applied from the contact member to the contact surface is changed to a third direction substantially orthogonal to the photographing optical axis. And the second direction along the photographing optical axis, and the movable lens frame is pressed to the third direction side substantially orthogonal to the photographing optical axis, It is drawn out in the second direction along the photographing optical axis.

  According to the present invention, it is possible to stably reproduce desired optical characteristics so as not to cause image shaking during forward / backward movement, and to improve the reproducibility of stopping the moving lens frame at a certain wide end position. An endoscope imaging unit that prevents the occurrence of field vignetting can be realized.

The block diagram which shows the whole electronic endoscope system of one embodiment of this invention Sectional drawing which shows the internal structure of the front-end | tip part of an endoscope similarly Sectional view showing the configuration of the imaging unit Sectional view showing the configuration of the actuator Partial sectional view showing the configuration of the imaging unit FIG. 5 is a sectional view taken along line VI-VI in FIG. VII-VII sectional view of FIG. VIII-VIII sectional view of FIG. Partial sectional view showing the surface side of the TAB substrate Partial sectional view showing the back side of the TAB substrate Sectional view showing cable The perspective view which shows one structure of an imaging unit same as the above Partial sectional view showing one configuration of the imaging unit The fragmentary sectional view which shows one structure of the imaging unit of a modification same as the above A perspective view showing the moving lens unit Sectional view showing the moving lens unit at the tele end position Sectional view showing the moving lens unit at the wide end position The partial sectional view which shows an example of the slope part of the same FIG. 18 is a partial cross-sectional view showing an example of a slope portion of the receiving rod different from FIG. FIG. 17 and FIG. 18 are partial cross-sectional views showing an example of a slope portion of the receiving rod different from FIG. Sectional drawing which shows the moving lens unit of the wide end position of a modification Sectional drawing which shows the moving lens unit of the wide end position of the modification different from FIG. Sectional drawing which showed an example structure of a moving lens frame, and cut | disconnected the imaging unit from the horizontal direction Sectional drawing which showed an example structure of a rear group lens frame, and cut | disconnected the imaging unit from the horizontal direction

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

  First, the present invention will be described with reference to FIGS. 1 to 24 relate to an embodiment of the present invention, FIG. 1 is a block diagram showing the entire electronic endoscope system, and FIG. 2 is a cross-sectional view showing the internal configuration of the distal end portion of the endoscope. 3 is a sectional view showing the configuration of the imaging unit, FIG. 4 is a sectional view showing the configuration of the actuator, FIG. 5 is a partial sectional view showing the configuration of the imaging unit, and FIG. 6 is a sectional view taken along line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5, FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5, FIG. 9 is a partial cross-sectional view showing the front side of the TAB substrate, and FIG. 11 is a sectional view showing the cable, FIG. 12 is a perspective view showing one configuration of the imaging unit, FIG. 13 is a partial sectional view showing one configuration of the imaging unit, and FIG. 14 shows one configuration of the imaging unit of the modification. FIG. 15 is a perspective view showing a moving lens unit, and FIG. FIG. 17 is a cross-sectional view showing the movable lens unit at the wide end position, FIG. 17 is a cross-sectional view showing the moving lens unit at the wide end position, FIG. FIG. 20 is a partial cross-sectional view showing an example of a slope part of a receiving part different from those in FIGS. 17 and 18, and FIG. 21 is a movement of the wide end position of a modified example. 22 is a cross-sectional view showing a lens unit, FIG. 22 is a cross-sectional view showing a moving lens unit at a wide end position according to a modification different from FIG. 21, and FIG. FIG. 24 is a sectional view showing an example of the configuration of the rear lens group frame, and is a sectional view of the imaging unit cut from the lateral direction.

  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. A light guide bundle (not shown) that transmits illumination light from the light source device 3 and is inserted into the universal cord 17 from the distal end portion 6 is provided on the back side of the plurality of illumination windows. .

  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 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 below with reference to FIG.
As shown in FIG. 2, the imaging unit 30 is disposed inside the distal end portion 6. The imaging unit 30 is fitted and disposed in the distal end rigid member 24 that is a rigid distal end main body, and is firmly fixed to the distal end rigid member 24 together with an adhesive by a set screw 27 that is a fixing member from the side. 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.
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 portion 6. 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.

  In addition to the imaging unit 30 and the treatment instrument channel 12b, the distal end rigid member 24 cleans the light guide bundle that guides the illumination light, the observation window of the distal end portion 6, and the like, and feeds it into the body cavity. In addition, the above-described observation window cleaning nozzle and a conduit communicating with the cleaning tube and an angle wire for bending the bending portion 7 are arranged (all not shown).

  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 10.
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 internal lens that changes the optical magnification is moved forward and backward by changing the focal length, and in the following description, a zooming function for switching between wide and tele is described. Further, as will be described later, the imaging unit 30 has optical characteristics set so that the state in which the moving lens unit 32 moves forward and stops is wide, and the state in which the moving lens unit 32 moves backward and stops becomes tele. ing.

  As shown in FIG. 3, the imaging unit 30 forms a front group lens unit 31 from the tip, and a first fixed lens frame that holds a front group lens 35 that is a first lens group including a plurality of objective lenses. A front group lens frame 34, a rear group lens frame 36 serving as a second fixed lens frame for holding a rear group lens 33 serving as a second lens group composed of a plurality of objective lenses, and each of these lens groups 35, The movable lens frame 38 which is provided between the movable lens unit 32 and which forms the outer shape of the movable lens unit 32 which is a movable body holding the movable lens 39, and the solid-state imaging device unit 46 having a CCD, a CMOS, etc. Has been. The rear group lens 33 and the rear group lens frame 36 constitute a rear group lens unit that is a second fixed lens unit.

  In this imaging unit 30, the proximal end portion of the front group lens frame 34 and the distal end portion of the rear group lens frame 36 are fitted and joined. A screw receiving tube 37 of a tubular body, which is a deformation preventing member of the rear group lens frame 36, is fitted in the state sandwiched between the front group lens frame 34 and the rear group lens frame 36 and on the outer periphery of the front end portion of the rear group lens frame 36. It is fixed.

  The screw receiving tube 37 is extended upward as viewed in the drawing, and has a restricting portion 37a for abutting and restricting the forward movement of the moving lens unit 32, and in the inner peripheral direction on the tip side. An inward flange-shaped rib 37b extending toward the end is formed. The front group lens frame 34 is inserted and disposed so that the rib 37b contacts the outer periphery of the front group lens frame 34.

Note that the imaging unit 30 of the present embodiment has a thin film sheet 34a of, for example, 50 μm for fine adjustment of optical settings such as focusing out and adjusting the angle of view between the front lens unit 31 and the screw receiving tube 37. A single layer or a plurality of layers are provided (see FIG. 5).
Further, the distal end portion of the solid-state image sensor holding frame 41 that holds the solid-state image sensor unit 46 is inserted and fixed to the proximal end portion of the rear group lens frame 36. The solid-state image sensor holding frame 41 is fitted to the rear group lens frame 36 so as to be extrapolated. With such a configuration, it is not necessary to grip the shield side of the solid-state imaging device unit 46 as in the past when focusing out at the time of assembly, and a hard part can be gripped. An increase in the declination can be suppressed. That is, when the solid-state image sensor holding frame 41 and the rear lens group frame 36 are fitted together, the deviation in the deflection angle is reduced when the focus is taken out, so that one-side blur on the image can be suppressed.

  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. The moving lens frame 38 of the moving lens unit 32 is integrally provided with a receiving rod 40 that is a contacted portion that extends upward (hereinafter simply referred to as “upward”) as viewed in the drawing. Is formed.

  In addition, the receiving rod 40 is formed with an inclined surface portion 40a serving as a contacted surface that comes into contact with and comes into contact with a contact member 63 of an actuator 62 described later in the inner peripheral direction of the moving lens frame 36 from the front to the rear. Has been. The catch 40 is inserted into a notch 36a that is a guide groove formed in the rear group lens frame 36, and protrudes from the outer periphery of the rear group lens frame 36 so that the entire inclined surface 40a is exposed. .

  As described above, the moving lens unit 32 is restricted from moving forward when the receiving rod 40 abuts against the restricting portion 37 a of the screw receiving tube 37. On the other hand, the moving lens unit 32 is restrained from moving backward by the receiving ring 40 abutting against an adjusting ring 32a that is a fitting tube that is screwed onto the middle outer periphery of the rear lens group frame 36 and is fitted. Is done.

  The adjustment ring 32a is rotationally adjusted around the photographing optical axis O when it is fixed to the rear group lens frame 36, and the tip of the adjustment ring 32a can be finely adjusted so that the movement stroke restricting position to the rear side of the moving lens unit 32 can be finely adjusted. This is a tubular member whose end face on the side is cut obliquely and has different lengths in the direction of the photographic optical axis O.

  That is, the adjustment ring 32 a has a thread groove formed on the inner peripheral surface thereof, and is screwed into the screw groove formed on the outer peripheral surface of the rear group lens frame 36. When the adjustment ring 32a is rotated in the direction of the photographic optical axis O, the adjustment ring 32a advances and retreats along the photographic optical axis O with respect to the rear group lens frame 36. Fine adjustments can be made.

  Further, in the movable lens unit 32, a proximal end portion of a compression coil spring 66 that is a pressing spring that constitutes a biasing body that is arranged in parallel to the photographing optical axis O and that biases it forward is housed in the receiving rod 40. Has been. The distal end portion of the compression coil spring 66 is accommodated in the restricting portion 37 a of the screw receiving tube 37. As described above, the movable lens unit 32 is provided in the rear lens group frame 36 in a state in which it is urged by the compression coil spring 66 so as to be always extended backward.

  In addition, the solid-state image sensor unit 46 includes, in order from the tip, in the solid-state image sensor holding frame 41, two optical members 42 and 43, a solid-state image sensor chip 45 having an image area (not shown) on the front surface, and TAB (Tape). An Attached Bonding) substrate 47. The solid-state image sensor chip 45 and the TAB substrate 47 are electrically connected by an integrally formed FPC configuration.

  The TAB substrate 47 has electronic components mounted on the upper surface side, and is connected to a plurality of communication lines of the cable 51 on the lower surface side. The cable 51 is inserted and arranged inside the endoscope 2 and is electrically connected by the video processor 4 and the electrical connector portion 20 via the universal cord 17 and the scope cable 19 shown in FIG. The Further, a cable holding member 50 is extrapolated at the distal end portion of the cable 51 by thread winding adhesion, and a covering member 49 described later is provided so as to integrally cover the distal end portion of the cable holding member 50.

  A reinforcement frame 48 is fitted on the base end side of the solid-state image sensor holding frame 41, and a heat shrinkable tube that integrally covers the cable holding member 50 up to the distal end portion of the cable 51 on the outer periphery of the reinforcement frame 48. The above-described covering member 49 is provided. In addition, in the space formed by the reinforcing frame 48 and the covering member 49 from the base end portion of the solid-state image sensor holding frame 41 provided with the solid-state image sensor chip 45 to the cable holding member 50, an adhesive or the like is used. Filled with protective agent.

  In addition, an actuator holding portion 36b for inserting and holding an actuator 62, which is a shape memory alloy actuator device for moving the moving lens unit 32 forward and backward, is formed on the rear upper portion of the rear group lens frame 36 so as to protrude upward. .

Next, the configuration of the actuator 62 attached to the imaging unit 30 will be described with reference to FIGS.
As shown in FIGS. 3 to 8, the actuator 62 includes a hard and long guide tube 53 inserted into the actuator holding portion 36 b of the rear lens group frame 36 and a shape inserted into the guide tube 53. A memory alloy wire 56, a compression coil spring 57 of a pressing spring which is an urging body inserted and arranged in the guide tube 53 and which is externally inserted into the shape memory alloy wire 56 and constitutes an elastic member, and the shape memory alloy wire 56 An insulating spring stopper tube 58 made of an insulating tube inserted into the proximal end portion of the guide tube 53, a block body 59 for caulking and fixing the proximal end of the shape memory alloy wire 56, and a guide tube 53, a rod 64 that is a tubular body that is inserted and disposed in the distal end portion of 53 so that the distal end portion of the shape memory alloy wire 56 is inserted and disposed, and a distal shell that is fixed to the distal end portion of the rod 64. Have Jo between the contact member 63, a is mainly composed.

  Further, the guide tube 53 is covered with a cover covering member 55 that is a heat shrinkable tube after the distal end portion. Further, the restricting portion 37 a of the screw receiving tube 37 and the outer portion of the actuator holding portion 36 b of the rear group lens frame 36 are covered with the receiving rod 40, the rod 64, and the contact member 63 of the moving lens frame 38. A cover member 65 having a U-shaped cross section is fitted (see FIGS. 5 to 8). Further, the restricting portion 37a and the actuator holding portion 36b are formed in an arc shape in the outer peripheral portion in the extending direction.

  The shape memory alloy wire 56 is made of a shape memory alloy (Shape Memory Alloys, hereinafter referred to as “SMA”) that shrinks when heated and expands when cooled (natural cooling to room temperature), and has a diameter of several tens of microns. (Hereafter, the shape memory alloy wire is abbreviated as SMA wire).

  The guide tube 53 described above is disposed in such a manner that its distal end position is aligned with the distal end surface of the actuator holding portion 36b, and is adhesively fixed to the actuator holding portion 36b. Further, the guide tube 53 is precisely fitted to the actuator holding portion 36b so as to be parallel to the photographing optical axis O so that the longitudinal axis satisfies the optical characteristics (optical magnification) set by the imaging unit 30.

  The SMA wire 56 inserted and disposed in the guide tube 53 and the rod 64 is folded back so as to penetrate from the side of the contact member 63 (see FIGS. 4 and 8). As shown in FIG. 4, the SMA wire 56 is folded back by the contact member 63 and then inserted into the insulating tube 67. One end of the SMA wire 56 is fixed by crimping to the block body 59. The portion is fixed by caulking to the other block body 59.

  A rod 64 is inserted into the distal end portion of the guide tube 53 so as to be able to advance and retreat, the distal end of the compression coil spring 57 abuts on the base end surface of the rod 64, and the rod 64 moves forward together with the abutting member 63 provided at the distal end. It is energized to be paid out.

  In other words, the compression coil spring 57 extrapolated to the SMA wire 56 is disposed in the guide tube 53 so that the end portions thereof are in contact with each other between the rod 64 and the insulating spring stopper tube 58. The compression coil spring 57 has a proximal end abutted against the distal end surface of the fixed insulating spring stopper tube 58 and the distal end abutted against the proximal end surface of the rod 64. It is energized to pay out.

  One block body 59 that fixes both ends of the SMA wire 56 described above has a shape larger than the hole diameter of the insulating spring stopper tube 58 and is disposed in contact with the proximal end surface of the insulating spring stopper tube 58. The The block body 59 is electrically connected to the strand 60a of the current application side cable 60 by soldering or the like. The other block body 59 is electrically connected to the strand 60a of the cable 60 on the current feedback side by soldering or the like.

Then, the connecting portion between the block body 59 and the electric cable 61 is covered with an insulating tube 55 that integrally covers from the distal end portion of the guide tube 53 so that insulation is maintained. The cable 60 is disposed up to the scope connector 18 of the universal cord 17 of the endoscope 2 shown in FIG. 1, and the current applied to the cable 60 is supplied from the video processor 4 via the scope cable 19. Is done.
Further, as described above, the rear lens group frame 36 has a guide groove so that the receiving lens 40 of the moving lens unit 32 can move straight forward and backward in the upper front side as viewed toward the plane of FIG. 3 and FIG. The notch part 36a which comprises is formed. As described above, the screw receiving tube 37 fitted to the rear lens group frame 36 restricts the forward movement of the movable lens unit 32 by the base end surface, and here, the wide end with the front end surface of the receiving rod 40 as a reference. It has a restricting portion 37a that defines the end position.
Further, on the outer peripheral portion of the rear lens group frame 36, there is an adjustment ring 32a that regulates the rearward movement of the movable lens unit 32 and defines the tele end position with reference to the base end surface of the receiving rod 40. It is fitted.

  In other words, the moving lens unit 32 has its distal end surface of the receiving rod 40 abutting against the base end surface of the restricting portion 37a, so that forward movement is restricted. Here, the viewing angle of the imaging unit 30 is controlled by each objective lens. An optical characteristic (optical magnification) that provides a predetermined maximum wide angle is set. On the other hand, the movable lens unit 32 is restricted from moving backward by the base end surface of the receiving rod 40 coming into contact with the distal end surface of the adjustment ring 32a. Here, the viewing angle of the imaging unit 30 is controlled by each objective lens. An optical characteristic (optical magnification) that provides a predetermined maximum tele angle is set.

  Further, when the contact member 63 provided at the tip of the rod 64 of the actuator 62 is biased forward by the compression coil spring 57, the contact member 63 comes into contact with the inclined surface portion 40a of the receiving rod 40 as the contact member. The moving lens unit 32 is extended forward and moved against the rearward biasing force of the compression coil spring 66 on the side. The moving lens unit 32 stops at the wide end position when the distal end surface of the receiving rod 40 comes into contact with the proximal end surface of the restricting portion 37a.

  On the other hand, when a current is applied to the SMA wire 56, the temperature of the SMA wire 56 increases and contracts, and the abutting member 63 is pulled backward against the forward biasing force of the compression coil spring 57. . Then, the contact member 63 moves backward so as to be separated from the inclined surface portion 40 a of the receiving rod 40. Since the receiving rod 40 receives a rearward biasing force by the compression coil spring 66 on the distal end side, the movable lens unit 32 extends and moves rearward. Then, the movable lens unit 32 stops at the tele end position when the base end surface of the receiving rod 40 comes into contact with the front end surface of the adjustment ring 32a.

  In addition, the imaging unit 30 of the present embodiment has a configuration in which the moving lens unit 32 is stopped only at two positions of the wide end position and the tele end position by the actuator 62 and the two optical magnifications of wide and tele are switched. It has become.

  In the actuator 62 of the present embodiment, a shape memory alloy resistance control circuit in which the application of current to the SMA wire 56 is controlled to be stopped and the expansion and contraction state drive control of the SMA wire 56 is provided in the video processor 4 as in the conventional case. It is the structure performed by the part. Since this shape memory alloy resistance control circuit unit employs a conventional configuration, its detailed description is omitted.

Next, the configuration of the TAB board 47 provided in the solid-state image sensor unit 46 of the imaging unit 30 and the cable 51 connected to the TAB board 47 will be described below with reference to FIGS.
As shown in FIG. 9, the TAB substrate 47 is cut so that a connection portion 47 a that is electrically connected to the solid-state image sensor chip 45 has a small width on the front end side. As described above, the TAB substrate 47 has a configuration in which a mounting area of electronic components to be mounted is ensured and electrical connection can be made in response to downsizing of the solid-state imaging device chip 45.

  In addition, the various electronic components mounted on the TAB substrate 47 have an arrangement layout of electronic components so that they do not fall off when bending stress is applied to the flexible TAB substrate 47. Specifically, various electronic components are arranged in a plurality of rows in the longitudinal direction of the TAB substrate 47 along the photographing optical axis O direction, so that the TAB substrate 47 does not bend between adjacently arranged electronic components. Another electronic component is arranged on an extension line in the longitudinal direction or short direction between the electronic components.

  That is, the various mounted electronic components are continuously arranged adjacent to each other on an extension line between other electronic components in which bending stress is easily applied to the TAB substrate 47. Thereby, even if a bending stress is applied to the TAB substrate 47, it is difficult to be deformed, so that the mounted electronic component is prevented from falling off.

  Further, the electronic components mounted on the TAB substrate 47 are arranged so that the longitudinal direction thereof matches the longitudinal direction of the TAB substrate 47. Thereby, it can be set as the structure which prevented the width direction of the TAB board | substrate 47 becoming large and prevented the diameter increase of the solid-state image sensor unit 46. FIG.

Further, in accordance with various electronic components mounted on the surface of the TAB substrate 47, as shown in FIG. 10, each cable land to which various signal cables 51A including a GND line are electrically connected to the back surface of the TAB substrate 47 is provided. It is arranged. Specifically, various signal cables 51A for transmitting digital signals and analog signals are provided on the back side corresponding to (projected) the surface area of the TAB substrate 47 on which mainly digital electronic components and analog electronic components are mounted. The arrangement area of each cable land to be electrically connected is determined.
With such a configuration, it is possible to reduce image noise, reduce the oversight rate when various signal cables 51A are electrically connected to the respective cable lands by soldering, and prevent erroneous connection.

  As shown in FIG. 11, the cable 51 has a plurality of signal cables 51a to 51l (L) inserted therein (various signal cables 51A in FIGS. 9 and 10). Of these signal cables 51a to 51l (L), the signal cable 51a is a Vout cable, and the three signal cables 51h to 51j are digital signal cables.

  The signal cable 51a for Vout and the three signal cables 51h to 51j for digital signals are inserted and arranged in the cable 51 so as to be separated as much as possible to prevent electromagnetic interference. , Measures to reduce noise between each other are adopted.

  The imaging unit 30 according to the present embodiment described above is screwed and penetrated into the distal end rigid member 24 in a concave portion 37c which is a screw receiving portion formed on the outer peripheral surface of the screw receiving tube 37 shown in FIG. When the end portion of the set screw 27 hits and is pressed, as shown in FIG. 13, the set screw 27 is inserted and fixed to the distal end rigid member 24 that is the distal end portion main body.

  The screw receiving recess 37c is formed at the outer peripheral position of the screw receiving tube 37 in the vicinity of the rib 37b. That is, the screw receiving pipe 37 is prevented from being deformed due to a distortion in the inner circumferential direction due to a pressing force which is a fixing force of the set screw 27. Further, the screw receiving tube 37 disperses the pressing force (fixing force for fixing) from the set screw 27 on the inner peripheral end surface of the rib 37b and the inner peripheral surface on the base end side from the rib 37b.

  At this time, since the rib 37b has a large thickness in the direction orthogonal to the photographing optical axis O, the rib 37b is hardly deformed, so that an unnecessary load is prevented from being applied to the front lens group frame 34. Further, since the pressing force from the set screw 27 is dispersed also in the rear lens group frame 36 that is pressed in surface contact with the inner peripheral surface of the screw receiving tube 37, an excessive load is prevented from being applied.

  From the above, since the screw receiving tube 37 is inserted into and fixed to the rear group lens frame 36 in which the movable lens unit 32 advances and retreats inside by the set screw 27 screwed through the distal end rigid member 24, it is directly as conventional. Therefore, the pressing force (fixing force) from the set screw 27 is not applied, and the influence of strain deformation in the inner circumferential direction is reduced or prevented. As a result, the imaging unit 30 is configured to prevent the advance / retreat operation failure of the moving lens unit 32 that moves back and forth within the rear group lens frame 36.

  That is, when the rear lens group frame 36 is distorted or deformed in the inner peripheral direction, contact friction between the outer peripheral portion of the moving lens frame 38 of the moving lens unit 32 and the inner peripheral surface of the rear lens group frame 36 increases. The moving lens frame 38 is caught or the like, and the smooth forward / backward movement in the rear group lens frame 36 is prevented. Therefore, the imaging unit 30 fixed to the distal end rigid member 24 prevents the rear group lens frame 36 from deforming in the inner circumferential direction, and the distal end rigid member 24 and the main rigid member 24 so that the movable lens unit 32 can move forward and backward smoothly. Further, a screw receiving tube 37 is interposed between the rear lens group frame 36 and the rear group lens frame 36.

  As shown in FIG. 14, the rib 37 b (see FIG. 13) is not provided in the screw receiving tube 37, but a simple tubular member, the outer peripheral surface of the maximum outer shape portion of the front group lens frame 34, and the rear group lens frame 36. It is good also as a structure which surface-contacts an outer peripheral surface integrally with an inner peripheral surface. At this time, the screw receiving concave portion 37 c of the screw receiving tube 37 is preferably formed in the vicinity of the maximum outer shape portion of the front group lens frame 34.

  Next, mainly based on FIGS. 15 to 17, the moving lens unit 32 is advanced and retracted forward and backward in the rear lens group frame 36 by the actuator 62 of the imaging unit 30, particularly from the tele end position on the rear side to the front side. The operation of moving to the wide end position will be described in detail.

  The imaging unit 30 is in a state where a current is applied to the SMA wire 56 in the actuator 62 when the moving lens unit 32 is stopped at the tele end position. The SMA wire 56 is in a state where the temperature rises and contracts due to the application of electric current, and the rod 64 is pulled backward together with the contact member 63 against the urging force of the compression coil spring 57. In this state, since the abutting member 63 of the actuator 62 is not in contact with the receiving rod 40 of the moving lens frame 38, the moving lens unit 32 is urged rearward from the front side by the compression coil spring 66 and contacts the adjustment ring 32 a. Stops touching.

  When application of current to the SMA wire 56 of the actuator 62 is stopped from the tele state, the SMA wire 56 is naturally cooled and stretched to an initial length state. Then, as shown in FIG. 16, the contact member 63 moves forward together with the rod 64 by the compression coil spring 57 that biases the rod 64 of the actuator 62 forward.

  As shown in FIGS. 15 and 17, the abutting member 63 moved forward contacts the inclined surface 40 a of the receiving rod 40 of the moving lens frame 38, and urges the moving lens unit 32 from the front to the rear. The whole moving lens unit 32 is pressed to the front side along the photographing optical axis O in the rear lens group frame 36 against the compression coil spring.

  Further, when the tip bullet-shaped contact member 63 is in contact with the inclined surface portion 40a of the receiving rod 40 by the spherical surface and the entire moving lens unit 32 is moved forward, the moving lens unit 32 is As shown in FIG. 17, the pressing force (stress) is dispersed in the X-axis direction on the front side and the Y-axis direction on the lower side of the paper, which is a direction substantially orthogonal to the photographing optical axis O, and is viewed toward the paper. A stress F is applied in the direction of about 45 ° obliquely to the lower left.

  In the moving lens unit 32, the distal end surface of the receiving rod 40 comes into contact with the proximal end surface of the restricting portion 37a, and the forward movement is restricted and stops. This state is an optical characteristic (optical magnification) at which the viewing angle of the imaging unit 30 becomes a predetermined maximum wide angle by each objective lens in the present embodiment.

  Even when the moving lens unit 32 is stopped at the wide end position, the spherical surface of the contact member 63 is in contact with the inclined surface portion 40a of the receiving rod 40 being pushed forward, , A stress F of approximately 45 ° diagonally to the lower left as shown in FIG. 17 is always applied. In other words, the moving lens unit 32 of the imaging unit 30 stops at the wide end position while being always pressed in the forward X-axis direction and here in the downward Y-axis direction.

  As described above, the imaging unit 30 of the present embodiment has the moving lens unit even when the moving lens frame 38 of the moving lens unit 32 and the rear lens group frame 36 that is a fixed lens frame are loosely fitted. 32 can stably stop at a wide end position satisfying desired optical characteristics, here, wide. As a result, even if the moving lens frame 38 and the rear lens group frame 36 are manufactured with a little accuracy, the moving lens unit 32 can be stably stopped at a predetermined wide end position, so that the yield is improved. There is an advantage.

  Further, even if the moving lens frame 38 and the rear lens group frame 36 are loosely fitted, the image pickup unit 30 is always on the front side (X-axis direction) and the photographing optical axis O. Since the movement is performed in a state of being pressed in the substantially perpendicular direction (Y-axis direction perpendicular to the X axis parallel to the photographing optical axis O), here, the lower side in FIG. 17, image shake may occur during forward and backward movement. Is prevented. Thus, the imaging unit 30 has a configuration in which the moving lens unit 32 is always subjected to stress in one direction on the outer side with respect to the front side. Therefore, in the endoscope 2 used in any posture, the moving lens unit 32 moves forward. Since it stops at the desired wide end position when it is extended, the desired optical magnification (wide zooming) can be stably reproduced.

  Note that, as described above, as a reason for improving the reproducibility of the moving lens unit 32 only during wide zooming, the imaging unit 30 is required to have an accuracy of the stop position at the wide end of the moving lens unit 32 that has a particularly wide viewing angle. Because. That is, the imaging unit 30 of the present embodiment can be configured to improve the reproducibility of the stop position of the moving lens unit 32 and prevent the occurrence of field vignetting in wide zooming in which the viewing angle increases. .

  As described above, the imaging unit 30 for the endoscope according to the present embodiment has the distal end rigid member that is the distal end body without hindering the slidability of the movable lens unit 32 including the movable lens frame 38 that moves forward and backward. 24, and the reproducibility of the stop position at the fixed wide end and the production yield can be improved.

  Further, the inclined surface portion 40a of the receiving rod 40 of the movable lens frame 38 may be a flat surface, but as shown in FIG. Thus, it is good also as a recessed part shape of a cross-section circular arc. Furthermore, the inclined surface 40a of the receiving rod 40 has a concave shape with a V-shaped cross section as shown in FIG. 19 or a trapezoidal cross section as shown in FIG. 20 in order to reduce contact friction with the contact member 63. It is good also as a recessed part shape. As shown in FIG. 21, the inclined surface portion 40 a of the receiving rod 40 may have a circular arc shape in which the moving lens frame 38 is notched from the inner peripheral direction to the outer peripheral direction as it goes forward.

The contact member 63 has a configuration in which the tip surface having a tip shell shape is a spherical surface in order to further reduce contact friction with the inclined surface portion 40a having various cross-sectional shapes.
Further, as shown in FIG. 22, a leaf spring 70 is provided at the tip of the rod 64 so that the movable lens unit 32 is always orthogonal to the front side (X-axis direction) and the outer peripheral direction (X-axis parallel to the photographing optical axis O). (Y-axis direction), here, a configuration of pressing downward in FIG.

  Specifically, the distal end portion of the leaf spring 70 is formed in an arc shape in the outer peripheral direction of the moving lens frame 38, and the arc surface of the arc-shaped leading end portion is in contact with the rear corner of the receiving rod 40 of the moving lens frame 38. In contact therewith, the movable lens unit 32 is always pressed toward the front side in one direction of the outer periphery. In addition, the receiving part 40 is not formed with the inclined surface part 40a, and an arcuate surface 40b is formed at a corner part where the leaf spring 70 abuts.

  In addition, as shown in FIGS. 15 to 17, the movable lens frame 38 of the movable lens unit 32 according to the present embodiment has protrusions 38a at the outer peripheral portions at both ends in the circumferential direction. That is, since the moving lens frame 38 slides within the rear group lens frame 36, the friction during the forward and backward movement of the moving lens unit 32 is reduced by reducing the contact area with the inner peripheral surface of the rear group lens frame 36. In order to reduce, it has the structure in which the protrusion part 38a was formed in the outer peripheral part of both ends.

  Further, in place of such a protrusion 38a, as shown in FIG. 23, in a direction in which the stress F of the moving lens frame 38 is applied so that the moving lens unit 32 smoothly moves forward and backward within the rear lens group frame 36. For example, a plurality of protrusions 38b (only two are shown here) may be provided on the outer peripheral portion on the lower side, for example, at a line-symmetrical position along the Y axis in the drawing through the photographing optical axis O.

  The protrusion 38b of the moving lens frame 38 shown in FIG. 23 has a protruding shape that makes substantially point contact with the inner peripheral surface of the rear lens group frame 36, and the moving lens frame 38 moves forward and backward stably within the rear lens group frame 36. It is preferable to form a plurality of such positions as possible.

  Further, as shown in FIG. 24, in the direction in which the stress F of the rear lens group frame 36 is applied, here, a part of the inner peripheral surface on the lower side passes through the photographing optical axis O and extends along the Y axis in the drawing. You may form the two plane parts 36c in a line symmetrical position.

  The flat portion 36c of the rear lens group frame 36 in FIG. 24 is formed along the longitudinal direction, so that the outer peripheral portion of the moving lens frame 38 is in line contact, and the friction when the moving lens unit 32 moves back and forth is reduced. Can do.

  In the present embodiment, the actuator 62 that moves the moving lens unit 32 forward is exemplified by the configuration using the SMA wire 56 as the driving means. Other drive means for moving forward along the axis O may be used.

  In addition, the imaging unit 30 of the present embodiment is set to the wide end position at the position where the moving lens unit 32 moves forward and stops, but the moving lens unit 32 is moved backward by the actuator 32 without being limited thereto. The position of moving to and stopping may be the wide end position.

  In other words, the direction in which the moving lens unit 32 is urged by the compression coil spring 66 that is the urging member, and the driving direction in which the actuator 62 moves out the moving lens unit 32 are along the photographic optical axis O described in the above embodiment. Alternatively, the front and rear directions may be reversed.

  That is, the direction in which the moving lens unit 32 is urged by the compression coil spring 66 and the direction in which the moving lens unit 32 is extended by the actuator 62 may be the front or rear as opposed directions, depending on a predetermined optical setting. The moving lens unit 32 may be configured to always receive stress in one direction of the outer periphery at the wide end position. In the endoscope 2 used in any posture, the movable lens unit 32 stops at the desired wide end position, and performs the desired optical operation. What is necessary is just to comprise so that magnification (wide zooming) can be reproduced stably.

  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 endoscope imaging unit of the present invention described above has the following characteristics.

(Appendix 1)
In the endoscope imaging unit that is fitted and fixed by the distal end body and the fixing member of the endoscope and can change the optical characteristics of the objective optical system,
A first fixed lens frame holding a first objective lens group;
A second fixed lens frame that is fitted in the first fixed lens frame and holds the second objective lens group;
A movable lens frame that is provided in the second fixed lens frame so as to be movable forward and backward in the direction of the photographic optical axis, and holds the movable lens;
A biasing member that biases the moving lens frame to one side along the photographing optical axis;
An actuator for extending the movable lens frame to the other along the photographing optical axis against the urging force of the urging member;
A contact member provided on the actuator and contacting the moving lens frame;
A contacted portion provided on the moving lens frame and in contact with the contact member;
A contact surface that is formed in the contacted portion and disperses a pressing force applied from the contact member in a direction substantially orthogonal to the imaging optical axis;
An imaging unit for an endoscope, comprising:

(Appendix 2)
The endoscope imaging unit according to appendix 1, wherein the contacted surface is a slope formed on the movable lens frame.

(Appendix 3)
The endoscope imaging unit according to appendix 1 or appendix 2, wherein the abutment member has a spherical surface that abuts against the abutted surface.

(Appendix 4)
The optical magnification of the maximum wide zooming is set at a position where the moving lens frame moves and stops when the movable lens frame is extended to the other side by the actuator. Imaging unit for endoscope.

DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope system 2 ... Electronic endoscope 6 ... Tip part 9 ... Insertion part 24 ... Tip rigid member 27 ... Set screw 30 ... Imaging unit 31 ... Front group lens unit 32 ... Moving lens unit 32a ... Adjustment ring 33 ... rear group lens 34 ... front group lens frame 34a ... thin film sheet 35 ... front group lens 36 ... rear group lens frame 36a ... notch part 36b ... actuator holding part 37 ... screw receiving tube 37a ... regulating part 37b ... rib 37c ... concave part 38 ... Moving lens frame 39 ... Moving lens 40 ... Receptacle 40a ... Slope portion 41 ... Solid-state image sensor holding frame 45 ... Solid-state image sensor chip 46 ... Solid-state image sensor unit 47 ... TAB substrate 52 ... Actuator holder 53 ... Guide tube 55 ... cover covering member 55 ... insulating tube 56 ... shape memory alloy wire 57 ... compression coil spring 58 ... spring stopper tube 62 ... actuator 6 ... contact member 64 ... rod 66 ... compression coil spring 67 ... insulating tube

Claims (7)

In the endoscope imaging unit that is fitted and fixed by the distal end body and the fixing member of the endoscope and can change the optical characteristics of the objective optical system,
A fixed lens frame holding at least one lens;
A movable lens frame which is provided in the fixed lens frame so as to be movable back and forth in the direction of the photographing optical axis and holds the movable lens;
A biasing member that biases the moving lens frame in a first direction along the photographing optical axis;
An actuator for extending the moving lens frame in a second direction along the photographing optical axis against the urging force of the urging member;
With
The actuator includes at least a contact member and a biasing body configured to bias the corresponding contact member in the second direction opposite to the first direction along the photographing optical axis; Have
The movable lens frame has a contacted surface configured to contact the contact member, and the contact member urged in the second direction by the urging member is the contacted member. When a pressing force is applied to the contacted surface by contacting the contact surface, the pressing force applied from the contact member to the contacted surface is substantially perpendicular to the photographing optical axis. And the second direction along the photographic optical axis.
The endoscope is characterized in that the movable lens frame is extended in the second direction along the photographing optical axis in a state where the movable lens frame is pressed toward the third direction substantially orthogonal to the photographing optical axis. Imaging unit.   The endoscope imaging unit according to claim 1, wherein the contacted surface is a slope formed on the movable lens frame.   The imaging unit for an endoscope according to claim 1, wherein the contact member has a spherical surface that is in contact with the contacted surface.   4. The optical magnification of maximum wide zooming is set at a position where the moving lens frame moves and stops when the moving lens frame is extended in the second direction by the actuator. 5. The endoscope imaging unit according to claim 1. The actuator has a shape memory alloy wire that moves in the first direction against the biasing force of the biasing body by contracting in the first direction by energization,
The contact member is urged in the second direction by the urging body when the shape memory alloy wire extends in the second direction by stopping energization. The endoscope imaging unit according to claim 4. The actuator has a drive source that generates a driving force in the first direction and moves the contact member in the first direction against the urging force of the urging body by the driving force. ,
5. The apparatus according to claim 1, wherein when the generation of the driving force of the driving source is stopped, the abutting member is biased in the second direction by the biasing body. The endoscope imaging unit according to claim 1.   The endoscope according to any one of claims 1 to 6, wherein the contacted surface is formed on a contacted part formed integrally with the movable lens frame. Imaging unit.

Images