JP2009075170A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, easily-assembled imaging device wherein a diaphragm is variable in accordance with the movement of a movable lens by employing a simple constitution. <P>SOLUTION: The imaging device includes: a movable lens unit 60 having a movable lens frame 61 that holds the movable lens 63, and a magnetic member 62; a fixed lens frame 33 wherein a plurality of objective optical systems 31 and 34 are arranged, which holds the movable lens frame so as to freely move backward and forward in a photographing optical axis direction; a diaphragm unit 35 for adjusting the photographing light amount by moving a diaphragm blade 74 formed of a magnetic body; and a ferromagnetic body 38 for moving the diaphragm blade with magnetic force in accordance with the backward and forward movement of the movable lens frame. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus with variable optical performance, and more particularly to an imaging apparatus used for medical equipment such as an endoscope.

  In recent years, endoscopes have been widely used in the medical field and the industrial field. Further, in such endoscopes, a conventional fiberscope type endoscope that observes an observation image with an eyepiece using an image fiber, or an endoscope tip part, an endoscope operation part There is an electronic endoscope in which a solid-state image sensor is arranged on a monitor and an observation image is displayed on a monitor.

  These endoscopes are equipped with a movable lens mechanism for focus and zoom functions that move the movable lens in the direction of the optical axis without changing the focal point and continuously change the angle of view, magnification, etc. There is something. The technique of such a movable lens mechanism is applied not only to an endoscope, for example, the technique disclosed in the lens driving device described in Patent Document 1 or the imaging device described in Patent Document 2. .

The lens driving device described in Patent Document 1 discloses a technique for moving a lens movable body in the optical axis direction by a magnetic action. In addition, the imaging device disclosed in Patent Document 2 discloses a technique for opening and closing a shutter and a diaphragm by a magnetic action.
JP 2005-227705 A JP 2006-276798 A

  However, in a configuration including a movable lens by changing an optimum focal position, such as a conventional lens driving device or an imaging device, the optimum brightness is adjusted, that is, the amount of light in the optical system is adjusted. A variable aperture for adjustment is provided.

  As described above, the conventional imaging optical system including the movable lens mechanism and the variable aperture mechanism has a very complicated structure, and it is difficult to adjust the driving mechanism of the parts, and there is a problem that the assembling property is poor.

  In particular, an endoscope, which is a medical device, is inserted into a body cavity or the like, so that the diameter of the endoscope is desired. For this reason, even if the components of the imaging device itself are made very small, not only the assemblability is deteriorated but also the size reduction of the imaging device may be hindered depending on the complicated structure form.

  Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is a small and easy assembly that can change the diaphragm according to the movement of the movable lens with a simple configuration. It is to realize an imaging device.

  In order to achieve the above object, an imaging apparatus according to the present invention includes a movable lens frame that holds a movable lens, a movable lens unit that includes a magnetic member, and a plurality of objective optical systems, and photographs the movable lens frame. A fixed lens frame that can be moved forward and backward in the direction of the optical axis, an aperture unit that adjusts the amount of photographing light by movement of the aperture blades formed of a magnetic material, and the aperture blades that are magnetically moved according to the forward and backward movement of the movable lens frame. And a ferromagnetic material that moves by the above.

  According to the present invention, it is possible to realize a small-sized imaging device that can be easily assembled with a simple configuration that can change the diaphragm in accordance with the movement of the movable lens.

  Embodiments of the present invention will be described below with reference to the drawings. In the embodiment of the present invention, a rigid electronic endoscope used in, for example, laparoscopic surgery in an endoscope apparatus that is a medical apparatus that is inserted into a body cavity and observes a living tissue. An example of the imaging device built in the mirror will be described below.

(First embodiment)
First, the image pickup apparatus according to the first embodiment will be described with reference to FIGS.
1 to 10 relate to a first embodiment of the present invention, FIG. 1 is a diagram showing a configuration of a rigid electronic endoscope, and FIG. 2 is an image pickup disposed in a distal end portion of the rigid electronic endoscope. 3 is a sectional view taken along line III-III in FIG. 2, FIG. 4 is an exploded perspective view of the diaphragm unit, FIG. 5 is a front view of the diaphragm unit, FIG. 6 is a sectional view taken along line VI-VI in FIG. Is a sectional view showing a state in which the movable lens unit is located rearward, FIG. 8 is a sectional view taken along the line VII-VII in FIG. 7, FIG. 9 is a sectional view showing a state in which the movable lens unit is located in the front, and FIG. It is XX sectional drawing.

  As shown in FIG. 1, a rigid electronic endoscope 1 (hereinafter simply referred to as an endoscope) 1 includes an insertion portion 2, an operation portion 3 connected to the proximal end of the insertion portion 2, and the operation portion. 3, a universal cord 4 extending from 3, a scope connector 5 disposed at a base end of the universal cord 4, an electrical connector 6 provided at an end of a cable extending from a side portion of the scope connector 5, It is mainly composed.

  The insertion portion 2 of the endoscope 1 includes, in order from the distal end, a distal end portion 11, a bending portion 12 connected to the distal end portion 11, and a rigid tube provided between the bending portion 12 and the operation portion 3. And a portion 13. The hard tube portion 13 of the present embodiment is formed from a non-flexible hard tube formed from stainless steel or the like. Note that an imaging device (described later) having an imaging optical system is built in the distal end portion 11.

  The operation unit 3 of the endoscope 1 according to the present embodiment includes two bending operation levers 14 and 15 for performing a bending operation of the bending unit 12 by a turning operation, and switches 16 for performing various operations. Is provided. The bending operation levers 14 and 15 are configured to bend in four directions or two directions when the bending portion 12 of the insertion portion 2 is rotated. Further, the plurality of switches 16 arranged in the operation unit 3 are operated when executing a predetermined endoscope function, for example, an operation of an imaging device disposed in the distal end portion 11 or the like. .

  Although not shown, in the endoscope 1 of the present embodiment, the scope connector 5 is connected to a light source device incorporating illumination light generating means such as a halogen lamp, and the electrical connector 6 is connected to a video processor. The

  Illumination light from the light source device is transmitted by a light guide bundle that is inserted from the universal cord 4 to the distal end portion 11 and irradiated from the distal end portion 11 toward the subject. The video processor is connected to a monitor, and outputs an endoscopic image captured by the endoscope 1 to the monitor for display.

Next, the imaging apparatus according to the present embodiment disposed in the distal end portion 11 of the endoscope 1 will be described in detail below with reference to FIGS. 2 and 3.
As shown in FIG. 2, the imaging device 20 according to the present embodiment includes a lens unit 30, an imaging element unit 40 fitted behind the lens unit 30, the lens unit 30, and the outer periphery of the imaging element unit 40. And a movable lens driving mechanism 50 disposed along a part of the movable lens driving mechanism 50.

  The lens unit 30 includes a front lens group 31 that constitutes a front objective optical system including an observation lens disposed on the distal end surface of the distal end portion 11 and a nonmagnetic material that holds the front lens group 31. A substantially cylindrical shape that holds a rear group lens 34 that is a lens group and is connected to the rear end portion of the front group lens fixed frame 32 and is connected to the rear end of the front group lens fixed frame 32 to form a rear objective optical system. A rear lens group fixing frame 33, which is a fixed lens frame formed of a non-magnetic material, and a movable lens unit 35 that is movably disposed in the rear lens group fixing frame 33 and that has a diaphragm unit 35 fitted and fixed to the tip portion. And a lens unit 60.

  The rear lens group fixing frame 33 is fitted with a permanent magnet (hereinafter simply abbreviated as a magnet) 38, which is a ferromagnetic body, on the outer peripheral portion on the front end side. Here, a permanent magnet is used as the magnet 38 and is disposed on the upper side of the rear lens group fixing frame 33 as viewed toward the paper surface of FIG.

  The movable lens unit 60 includes a movable lens frame 61 formed of a nonmagnetic material, a magnetic member 62 formed of a ring-shaped magnetic material fitted to the base end of the movable lens frame 61, and the movable lens frame 61. And a movable lens 63 held on the surface. The movable lens unit 60 is linearly guided in a movable lens frame 61 so as to be movable back and forth along the photographing optical axis O.

  The image sensor unit 40 includes a holding frame 41 that holds an optical component 42 such as a cover glass, and a solid-state image sensor 43 that is an image sensor such as a CCD or CMOS that is bonded to the optical component 42 so that the light receiving unit side is surface-bonded. And an FPC (flexible printed circuit board) 44 in which electronic components electrically connected to the solid-state imaging device 43 are mounted and a plurality of communication lines 45 are electrically connected by soldering. ing.

  The holding frame 41 has a distal end portion fitted and fixed to the rear group lens fixing frame 33 of the lens unit 30, and a heat shrinkable tube 46 that covers and protects the solid-state imaging device 43 and the like on the outer peripheral portion of the proximal end. ing. The heat shrinkable tube 46 is filled with a protective adhesive so as to cover the solid-state imaging device 43, the FPC 44, and the communication line 45.

  The movable lens driving mechanism 50 includes a frame 51 in which a guide groove 51a that is a concave groove parallel to the photographing optical axis O is formed, and a magnet holding base that is formed from a nonmagnetic material that is guided straight in the guide groove 51a. 52, a movable magnet 53 of a permanent magnet which is a ferromagnetic material fitted to the upper part of the magnet holding table 52, a spring 54 for urging the magnet holding table 52 forward, and a base end of the magnet holding table 52 SMA (Shape Memory Alloys) wire 55 joined to the part, a metal, for example, stainless steel pipe 56 fitted to the base end of frame 51, and SMA wire 55 are inserted inside, An insulating tube 57 such as an insulative peak (PEEK) tube inserted in the pipe 56, and an electric wire provided at the base end of the insulating tube 57 to which the SMA wire 55 is joined. An electrode caulking 58; a power cable 59 electrically connected to the electrode caulking 58; and an insulating sheath 65 covering the power cable 59 together with the electrode caulking 58 from the proximal end portion of the insulating tube 57. Configured. The SMA wire 55 is joined to the base end portion of the magnet holding base 52, and then folded back and extended rearward as a GND (ground) wire 55a.

  As shown in FIG. 3, the frame 51 has a substantially U-shaped cross section, and the upper end portion is engaged with the rear group lens fixing frame 33 of the lens unit 30. In this fitted state, a space surrounded by the outer surface of the rear lens group fixing frame 33 and the inner surface of the frame 51 is formed. Within this space, the magnet holding base 52 is linearly guided by the guide groove 51 a and moves forward and backward in a direction parallel to the photographing optical axis O together with the movable magnet 53.

  The forward and backward movement of the magnet holding base 52 is caused by supplying power from the power cable 59 to the SMA wire 55 connected to the rear end portion of the magnet holding base 52 via the electrode caulking 58, and the SMA wire 55 itself generates heat. Then, the magnet holder 52 is pulled backward against the forward biasing force of the spring 54. Thereby, the magnet holding stand 52 moves backward.

  When the power supply to the SMA wire 55 is stopped, the SMA wire 55 returns to room temperature, and the magnet holding base 52 is moved forward by receiving a forward biasing force by the spring 54. When the magnet holding base 52 is moved forward, the front end surface thereof comes into contact with the contact member 39 fitted to the front end of the frame 51 and the forward movement is restricted.

  The SMA wire 55 is electrically connected to a GND (ground) wire 55a (see FIG. 3) which is folded back by the magnet holding base 52 and covered with an insulating tube 55b extending rearward.

  Thus, the magnet holding base 52 moves forward and backward in a parallel direction along the photographing optical axis O together with the movable magnet 53. At this time, the magnetic member 62 provided at the base end portion of the movable lens frame 61 is attracted by receiving the magnetic force from the movable magnet 53 from the outside of the rear lens group fixing frame 33, and interlocks with the forward / backward movement of the movable magnet 53. Then, together with the movable lens frame 61, it moves back and forth in a parallel direction along the photographic optical axis O within the rear group lens fixed frame 33.

  In other words, in the movable lens unit 60, the magnetic member 62 of the movable lens frame 61 holding the movable lens 63 receives the magnetic action from the movable magnet 53, and moves forward and backward within the rear group lens fixed frame 33.

  The forward / backward movement distance of the movable lens unit 60 is set by a focal length corresponding to a predetermined zoom / tele state of the image pickup apparatus 20 that varies as the movable lens 63 moves along the photographing optical axis O.

  In the rearward movement of the movable lens unit 60, the inner peripheral surface of the rear lens group fixing frame 33 is brought into contact with the base end surface of the magnetic member 62 disposed at the base end of the movable lens frame 61 so that the movable position is set. A restricting convex portion 33a protruding in the restricting inner diameter direction is formed. Further, when the movable lens unit 60 is movable forward, the movement of the movable lens frame 61 is restricted by contacting the proximal end surface of the front lens group fixing frame 32 with the distal end surface of the movable lens frame 61.

  That is, the movable lens unit 60 has a photographing optical axis in a range from a position where the movable lens frame 61 contacts the front group lens fixed frame 32 to a position where the magnetic member 62 contacts the restriction convex portion 33a of the rear group lens fixed frame 33. A movable range along O is defined.

  Further, the movable lens unit 60 is moved forward and backward in the space of the sealed rear group lens fixing frame 33 whose front end is sealed by the front group lens 31 and the front group lens fixing frame 32 and closed by the rear group lens 34. To do. That is, the imaging apparatus 20 of the present embodiment is configured to move the movable lens unit 60 in the space of the rear lens group fixing frame 33, in which the movable lens driving mechanism 50 is sealed, by magnetic action. It has a structure with good moisture resistance.

  In addition, the imaging apparatus 20 according to the present embodiment is configured to be switched between two states, for example, a wide state in which the movable lens unit 60 is positioned in the front and a tele state in which the movable lens unit 60 is positioned in the rear. In order to adjust the optimal amount of light according to the distance, the aperture diameter φ of the aperture of the aperture unit 35 is variable.

Next, based on FIGS. 4 to 6, the diaphragm unit 35 of the present embodiment in which the aperture diameter φ of the diaphragm is variable will be described in detail below.
As shown in FIG. 4, the aperture unit 35 is provided with an aperture 71a at the center, and a fixed aperture plate 71 formed of a disc-like nonmagnetic material and an aperture frame 72 formed of an annular nonmagnetic material. And two holding plates 73, which are substantially semicircular non-magnetic plates constituting the diaphragm blade restraint, and a magnetic body in which an aperture hole 74a is formed on the upper side and a notch 74b is formed on the lower side. The movable diaphragm blade 74 is formed, and a spring 75 that is an urging member having one end fixed to the upper end portion of the movable diaphragm blade 74.

  In the fixed aperture plate 71, the formed aperture 71a allows only a part of the imaging light to pass through, and the aperture diameter of the aperture 71a satisfying a predetermined optical performance by adjusting the imaging light quantity in the optical system of the present embodiment. φA (see FIG. 6) is set. The fixed diaphragm plate 71 is subjected to surface processing such as PTFE for reducing sliding frictional resistance with the movable diaphragm blade 74.

  The diaphragm frame 72 substantially coincides with the outer shape of the fixed diaphragm plate 71 whose outer peripheral surface is circular, and has a predetermined thickness larger than that of the movable diaphragm blade 74 and the holding plate 73.

  Although two holding plates 73 will be described later, the two holding plates 73 are arranged to face each other, and at both ends of the movable diaphragm blades 74 in a state where the movable diaphragm blades 74 are in contact with the fixed diaphragm plate 71 on one surface side of the facing edge at this time. A guide groove 73a is formed in which the portion is in surface contact and slidably held and guided straight up and down. Surface treatment such as PTFE for reducing sliding frictional resistance with the movable diaphragm blade 74 is also applied to the surface of the guide groove 73a.

  The movable diaphragm blade 74 is subjected to surface processing such as PTFE for reducing sliding frictional resistance. The diaphragm aperture 74a formed in the movable aperture blade 74 allows only a part of the photographic light to pass through and adjusts the photographic light quantity in the optical system of the present embodiment, thereby opening the aperture hole 71a satisfying a predetermined optical performance. An opening diameter φB (see FIG. 6) smaller than the diameter φA is set.

  In addition, the movable diaphragm blade 74 extends to the lower side opposite to the upper side where the spring 75 is provided, and is formed with a notch 74b whose upper part is cut into an arc shape. The cutout 74 b has a larger shape than the aperture hole 71 a of the fixed aperture plate 71.

  The above-described fixed diaphragm plate 71 has a diaphragm frame 72 fixed to a circumferential portion of one surface thereof. The movable diaphragm blade 74 is arranged so as to be in surface contact with one surface of the fixed diaphragm plate 71 to which the diaphragm frame 72 is fixed.

  The other end of the spring 75 opposite to the one end fixed to the movable diaphragm blade 74 is fixed to the inner surface of the diaphragm frame 72 by bonding or the like. The movable diaphragm blades 74 and the fixed diaphragm plate 71 and the two diaphragm plates 74 are engaged with the guide grooves 73a of the fixed diaphragm plate 71 by the two holding plates 73 and are held down by the fixed diaphragm plate 71. The holding plate 73 is slidable vertically. The two holding plates 73 are fixed to the diaphragm frame 72 in a state of being separated by a predetermined distance that does not block the diaphragm holes 71a and 74a.

  As shown in FIGS. 5 and 6, the assembled aperture unit 35 of the present embodiment has the movable lens unit 60 as shown in FIG. 2 so that the movable aperture blades 74 are located on the front side. The movable lens frame 61 is internally fitted and fixed to the tip portion.

  Next, in the imaging apparatus 20 of the present embodiment configured as described above, the movable diaphragm blade 74 of the diaphragm unit 35 that is interlocked with the advance / retreat movement of the movable lens unit 60 along the photographing optical axis O is as follows. Now, the action of moving in the vertical direction will be described in detail below with reference to FIGS.

  First, in the imaging apparatus 20 according to the present embodiment, in the tele state located at the rear as shown in FIGS. 7 and 8, as described above, current is applied to the SMA wire 55, and the SMA wire 55 contracts. As a result, the magnet holding base 52 provided with the movable magnet 53 is pulled backward against the forward biasing force of the spring 54.

  Then, in the movable lens unit 60, the magnetic member 62 is attracted to the movable magnet 53 by a magnetic action, and moves backward in the rear lens group fixing frame 33 in conjunction with the movable magnet 53. In the movable lens unit 60, the base end surface of the magnetic member 62 comes into contact with the restricting convex portion 33a of the rear group lens fixing frame 33 and the rearward movement is restricted, and the tele-state position of the set predetermined focal length is set. Stop at.

  At this time, as shown in FIG. 8, the movable diaphragm blades 74 of the diaphragm unit 35 here have an upward biasing force acting on the movable magnet 53 side by the upper spring 75 so that the lower end of the diaphragm frame 72 is abutted against the diaphragm frame 72. It will be in contact. In this state, the movable aperture blade 74 overlaps so that the aperture hole 74a coincides with the center of the aperture hole 71a of the fixed aperture plate 71 and covers the periphery of the aperture hole 71a. That is, at this time, the aperture unit 35 has an aperture amount that adjusts the amount of photographing light by the aperture diameter φB of the aperture hole 74a of the movable aperture blade 74.

  On the other hand, when the imaging device 20 is in the wide state located in the front in the present embodiment shown in FIGS. 9 and 10, as described above, the application of the current to the SMA wire 55 is stopped, The SMA wire 55 returns to the normal temperature, and the magnet holding base 52 provided with the movable magnet 53 is pushed forward and moved by the urging force of the spring 54.

  At this time, the movable lens unit 60 is moved forward in the rear lens group fixing frame 33 in conjunction with the movement of the movable magnet 53 by the magnetic member 62 receiving the magnetic action of the movable magnet 53. Then, the movable lens unit 60 is restricted from moving forward by the front end surface of the movable lens frame 61 coming into contact with the base end surface of the front group lens fixed frame 32, and stops at the zoom position at the set focal length. To do.

  At this time, as shown in FIG. 10, the movable diaphragm blades 74 of the diaphragm unit 35 are magnets provided on the upper portion of the rear lens group fixing frame 33 against the urging force of the upper spring 75 toward the lower side. It is drawn to 38 and moves upward. That is, when the diaphragm unit 35 moves forward together with the movable lens unit 60, the diaphragm unit 35 moves to a position close to the magnet 38 of the rear lens group fixing frame 33. Under the magnetic action, it is pulled upward while being guided straight in the guide groove 73a of the holding plate 73.

  In this state, in the movable aperture blade 74, the aperture hole 74a is moved above the aperture hole 71a of the fixed aperture plate 71, and the aperture hole 71a is exposed by the notch 74b. That is, at this time, the aperture unit 35 has an aperture amount obtained by adjusting the photographing light amount by the aperture diameter φA of the aperture hole 71a of the fixed aperture plate 71.

  As described above, in the imaging device 20 of the present embodiment, the movable diaphragm blades of the diaphragm unit 35 according to the movement of the movable lens unit 60 back and forth along the photographing optical axis O according to the two states of tele and zoom. 74 moves up and down while being guided straight in the guide groove 73 a of the holding plate 73.

  That is, when the diaphragm unit 35 moves forward together with the movable lens unit 60, the movable diaphragm blade 74 formed of a magnetic material comes close to the magnet 38. Therefore, the biasing force of the spring 75 is received by the magnetic force from the magnet 38. It is attracted with a greater force and moves upward. On the other hand, when the diaphragm unit 35 moves rearward together with the movable lens unit 60, the movable diaphragm blade 74 moves away from the magnet 38, the magnetic force from the magnet 38 decreases, and the biasing force of the spring 75 wins and moves downward. To do.

  Note that the magnet 38 is positioned further forward than the position where the movable magnet 53 has moved to the front side, which is the wide position, in the front-rear direction of the photographic optical axis O, that is, the front-rear direction of the long axis of the imaging device 20. Thus, they are arranged at point-symmetrical positions with respect to the photographing optical axis O. In this embodiment, even if the magnetic movable diaphragm blade 74 receives the urging force of the spring 75 and the magnetic force from the movable magnet 53 at the position where it has moved forward in the wide state, the magnetic force of the magnet 38 is sufficient. The position of the magnets 38 and 53, the magnetic force that the magnets 38 and 53 act on the movable diaphragm blade 74, and the biasing force of the spring 75 are set. Further, even when the magnetic movable diaphragm blade 74 receives a magnetic force from the magnet 38 at a position where it moves backward in the tele state, the magnet 38 can be sufficiently moved downward by the biasing force of the spring 75. , The magnetic force acting on the movable diaphragm blade 74 of the magnet 38 and the biasing force of the spring 75 are set.

  As described above, in the imaging apparatus 20 having the tele-zoom function according to the present embodiment, the movable lens unit 60 in the sealed space is moved to the photographing optical axis O by the magnetic action of the movable lens driving mechanism 50. It has a structure with good moisture resistance by moving forward and backward along, and has a simple structure in which the aperture is opened and closed by the aperture unit 35 that varies the amount of light to be photographed according to the tele state or the zoom state. be able to. In particular, the imaging apparatus 20 according to the present embodiment has a simple variable aperture structure by the diaphragm unit 35, and therefore, even if it is small in size, it is very easy to assemble.

(Second Embodiment)
Next, a second embodiment of the present invention will be described below based on FIGS. 11 to XX.
FIGS. 11 to 15 relate to the second embodiment of the present invention, FIG. 11 is a partial cross-sectional view showing the configuration of the imaging apparatus, and FIG. 12 is a cross-sectional view showing a state where the movable lens unit is located rearward. 13 is a sectional view taken along line XIII-XIII in FIG. 12, FIG. 14 is a sectional view showing a state where the movable lens unit is positioned forward, and FIG. 15 is a sectional view taken along line XV-XV in FIG. In the following description, the same reference numerals are used for the same configurations as those of the imaging device 20 of the first embodiment described above, and detailed descriptions of those configurations are omitted.

  In the imaging apparatus 20 of the present embodiment, the aperture unit 35 is fitted and fixed to the proximal end portion of the front lens group fixing frame 32. Further, the movable lens frame 61 of the movable lens unit 60 has a magnet 81 that is a ferromagnetic material fitted and disposed at the top of the tip portion. Further, the rear lens group fixing frame 33 is on the lower outer peripheral side on the front end side, and a magnet 82 that is a ferromagnetic material is fitted and disposed immediately below the aperture unit 35.

  That is, the imaging apparatus 20 of the present embodiment has a configuration in which the aperture unit 35 fixed to the movable lens unit 60 in the first embodiment is disposed on the front group lens fixed frame 32.

  As shown in FIG. 12, the imaging device 20 configured as described above has a movable aperture blade 74 of the aperture unit 35 as shown in FIG. In response to the magnetic force of the magnet 82 provided immediately below the aperture unit 35, the magnet 82 is attracted downward on the magnet 82 side, and the lower end of the aperture frame 72 comes into contact. In this state, the movable aperture blade 74 overlaps so that the aperture hole 74a coincides with the center of the aperture hole 71a of the fixed aperture plate 71 and covers the periphery of the aperture hole 71a. That is, at this time, the aperture unit 35 has an aperture amount that adjusts the amount of photographing light by the aperture diameter φB of the aperture hole 74a of the movable aperture blade 74.

  On the other hand, as shown in FIG. 14, in the present embodiment, the imaging device 20 also has a movable diaphragm blade 74 of the diaphragm unit 35 directly below as shown in FIG. The magnet 82 is attracted and moved upward by receiving the magnetic force of the magnet 81 provided at the upper end of the movable lens frame 61 against the force attracted downward by the magnetic force of the magnet 82. That is, when the movable lens unit 60 moves forward, the diaphragm unit 35 moves to an upper position where the magnet 81 of the movable lens frame 61 approaches, so that the movable diaphragm blade 74 formed of a magnetic material is magnetized by the magnet 81. In response, the guide plate 73 is drawn upward while being guided straight in the guide groove 73a of the holding plate 73.

  In this state, in the movable aperture blade 74, the aperture hole 74a is moved above the aperture hole 71a of the fixed aperture plate 71, and the aperture hole 71a is exposed by the notch 74b. That is, at this time, the aperture unit 35 has an aperture amount obtained by adjusting the photographing light amount by the aperture diameter φA of the aperture hole 71a of the fixed aperture plate 71.

  That is, when the movable lens unit 60 moves forward, the movable diaphragm blade 74 formed of a magnetic material receives the magnetic force from the magnet 81 and moves with a magnetic force larger than the magnetic force of the magnet 82. It is attracted and moves upward. On the other hand, when the movable lens unit 60 moves backward, the movable diaphragm blade 74 moves away from the magnet 81, the magnetic force from the magnet 81 decreases, the magnetic force of the magnet 82 wins, and moves downward.

  Accordingly, the magnet 81 of the movable lens unit 60 has a larger magnetic force than the magnet 82 disposed on the rear lens group fixing frame 33 provided at a point-symmetric position where the movable lens unit 60 has moved forward. A magnetic force capable of attracting the movable diaphragm blade 74 against the magnetic force is set.

  The diaphragm unit 35 of the present embodiment has a configuration in which the movable diaphragm blade 74 moves forward and backward in the direction orthogonal to the photographing optical axis O, here up and down, by the two magnets 81 and 82. As shown in FIGS. 13 and 15, the spring 75 provided in the first embodiment is not required.

  The imaging device 20 according to the present embodiment described above can achieve the same effects as those of the first embodiment, and it is not necessary to provide the spring 75 in the aperture unit 35. Therefore, the magnetic force of the two magnets 81 and 82 can be obtained. Just by setting the force relationship, the configuration is simple.

  Note that the aperture unit 35 described in each of the above-described embodiments is an example, and may have a configuration as shown in FIGS. 16 is a front view showing the configuration of the aperture unit according to the first modification, FIG. 17 is a sectional view taken along the line XVII-XVII in FIG. 16, and FIG. 18 is according to the second variation, and shows the configuration of the aperture blade. FIG. 19 is a front view showing the configuration of the diaphragm blade according to the third modification.

  For example, as shown in FIGS. 16 and 17, the diaphragm unit 35 is different from the embodiments in the configuration of the movable diaphragm blade 74A. Specifically, the movable diaphragm blade 74A is made of a magnetic material, and an extended end portion of an arm portion extended from a circular outer peripheral portion in which a diaphragm hole 74a is formed is fixed by a fixed diaphragm plate. 71 is arranged so as to be rotatable with respect to 71.

  A spring stopper member 87 is disposed on the arm portion of the movable diaphragm blade 74 </ b> A, and one end of a spring 86 is connected to the spring stopper member 87. The spring 86 urges the movable diaphragm blade 74 </ b> A downward, and the other end is fixed to the inner surface of the diaphragm frame 72.

  Further, a blade stop member 85 that abuts and defines the position of the movable diaphragm blade 74A biased by the spring 86 at the position where the diaphragm hole 74a of the movable diaphragm blade 74A overlaps the diaphragm hole 71a. Is provided.

  Also in the aperture unit 35 configured as described above, the movable aperture blade 74A is moved in accordance with the forward / backward movement of the movable lens unit 60 and the forward movement of the imaging device 20 in the tele state as in the above-described embodiments. Thus, a force attracted upward is received by the magnetic force from the adjacent ferromagnetic material, and the spring 86 rotates upward around the blade shaft 84 against the urging force of the spring 86.

  On the other hand, as the movable lens unit 60 moves backward in the wide state of the image pickup apparatus 20, the movable diaphragm blade 74A decreases in magnetic force due to the ferromagnetic material, and is pulled downward by the spring 86 and rotated. The stop is brought into contact with the member 85 and stopped at a position where the stop hole 74a overlaps the stop hole 71a.

  In this way, the aperture unit 35 constitutes a mechanism for changing the aperture diameter φ of the aperture. Also in the aperture unit 35 configured in this way, the same operational effects as those of the above-described embodiments can be obtained.

  As shown in FIG. 18, the movable diaphragm blade 74 should have a slit 74c that connects the diaphragm hole 74a and the notch 74b. The slit 74c is formed at a position where the photographing optical axis O passes when the movable diaphragm blade 74 moves forward and backward.

  By providing the slit 74c in the movable diaphragm blade 74 in this way, the photographing optical axis O is not interrupted for a moment when the movable diaphragm blade 74 moves back and forth. -It can be prevented from disappearing for a moment when switching to wide. Further, the imaging device 20 can prevent the photographed image from disappearing even if the movable diaphragm blade 74 does not advance or retreat accurately and stops during the retreat due to some trouble.

  Furthermore, the notch 74b formed in the movable diaphragm blade 74 only needs to be able to completely expose the diaphragm hole 71a of the fixed diaphragm plate 71 when moved upward of the movable diaphragm blade 74. For example, FIG. As shown, any shape may be used such that the upper part is formed in a substantially semicircular shape and extends vertically downward.

  In each of the above-described embodiments, the ferromagnetic body that moves the movable diaphragm blade 74 to a magnetic action has a simple configuration, and thus a permanent magnet is used. However, the present invention is not limited to this. good.

  Furthermore, the movable diaphragm blade 74 is made of a magnetic material, but may itself be a ferromagnetic material. In this case, the polarity of attraction and repulsion with each magnet may be set in accordance with the movable direction. .

  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 some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem to be solved by the invention can be solved and the described effect can be obtained. The deleted configuration can be extracted as an invention.

The figure which shows the structure of the rigid electronic endoscope which concerns on the 1st Embodiment of this invention. Sectional drawing of the imaging device arrange | positioned in the front-end | tip part of a rigid electronic endoscope similarly FIG. 2 is a sectional view taken along line III-III in FIG. The exploded perspective view of the aperture unit Same as above, front view of aperture unit FIG. 5 is a sectional view taken along line VI-VI in FIG. Sectional drawing which shows the state in which the movable lens unit was located back VII-VII sectional view of FIG. Sectional drawing which shows the state in which the movable lens unit was located ahead XX sectional view of FIG. 8, a sectional view of the distal end portion of the electronic endoscope The fragmentary sectional view which shows the structure of the imaging device which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the state in which the movable lens unit was located back XIII-XIII sectional view of FIG. Sectional drawing which shows the state in which the movable lens unit was located ahead XV-XV sectional view of FIG. The front view which shows the structure of the aperture unit which concerns on a 1st modification. XVII-XVII sectional view of FIG. The front view which shows the structure of the aperture blade which concerns on a 2nd modification The front view which shows the structure of the aperture blade which concerns on a 3rd modification

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rigid electronic endoscope 2 ... Insertion part 11 ... Tip part 20 ... Imaging device 30 ... Lens unit 31 ... Front group lens 32 ... Front group lens fixing frame 33a ... Restriction convex part 33 ... Rear group lens fixing frame 34 ... Rear Group lens 35 ... diaphragm unit 38 ... permanent magnet 39 ... contact member 40 ... image sensor unit 41 ... holding frame 42 ... optical component 43 ... solid-state image sensor 50 ... movable lens drive mechanism 52 ... magnet holder 53 ... movable magnet 54 ... Spring 55 ... SMA wire 59 ... Power cable 60 ... Movable lens unit 61 ... Movable lens frame 62 ... Magnetic member 63 ... Movable lenses 71a, 74a ... Diaphragm hole 71 ... Fixed aperture plate 72 ... Diaphragm frame 73a ... Guide groove 73 ... Holding plate 74c ... slit 74 ... movable diaphragm blades φ, φA, φB ... aperture diameter

Claims (7)

A movable lens frame that holds a movable lens, and a movable lens unit that includes a magnetic member;
A plurality of objective optical systems, and a fixed lens frame that holds the movable lens frame so as to be movable back and forth in the direction of the photographing optical axis;
A diaphragm unit that adjusts the amount of photographing light by moving a diaphragm blade formed of a magnetic material;
A ferromagnetic body that moves the diaphragm blades by a magnetic force in accordance with the advancing and retreating movement of the movable lens frame;
An image pickup apparatus comprising:   The imaging apparatus according to claim 1, further comprising a movable lens driving mechanism that moves the magnetic member of the movable lens frame forward and backward by a magnetic force from the outside of the fixed lens frame. The aperture unit is disposed on the movable lens frame,
The ferromagnetic body is disposed in the fixed lens frame, and the diaphragm unit moves forward and backward in the optical axis direction together with the movable lens frame, thereby moving the diaphragm blades by magnetic force. The imaging device according to claim 1 or 2. The aperture unit is disposed on the fixed lens frame,
The ferromagnetic body is disposed on the movable lens frame, and moves together with the movable lens frame in the photographic optical axis direction to move the diaphragm blades by magnetic force, or The imaging device according to claim 2.   The imaging apparatus according to any one of claims 1 to 4, wherein the movable lens frame and the fixed lens frame are formed of a nonmagnetic material. The movable lens driving mechanism is
A moving magnet that attracts the magnetic member of the movable lens;
A shape memory alloy wire that contracts and retracts the moving magnet by the supply of electric power;
A biasing member that biases the moving magnet forward;
The imaging device according to claim 2, wherein the imaging device is an actuator constituted by: The fixed lens frame has a sealed space whose front and rear are sealed by the plurality of objective optical systems,
The imaging apparatus according to any one of claims 1 to 6, wherein the movable lens unit is disposed in the sealed space so as to be movable forward and backward in the direction of the photographing optical axis.

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