JP2005043513A - Shutter driving device and lens frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shutter driving device in which the operating force characteristic of a plunger can be improved without lowering responsiveness, and to provided a lens barrel in which the shutter driving device is incorporated and a lens frame is little shaken. <P>SOLUTION: A focus unit 7 having the shutter driving device has a 2nd group guide frame 21 with a magnet 37, an LD (lens drive) base plate 22 which is integrally fixed on the 2nd group guide frame 21 and to which a plunger solenoid device 55 is attached, and a 2nd group frame 23 with an iron plate 38 supported to move relatively to the guide frame 21 and supporting a shutter blade driven by the plunger solenoid device 55. Since the frame 23 is supported to be biased through the iron plate 38 by the magnet 37 with respect to the guide frame 21, the frame 23 is supported without causing backlash in relative turning to the guide frame 21. Furthermore, the attractive force characteristic of the plunger solenoid device 55 is increased by the magnetic flux of the magnet 37. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter driving device applied to an actuator of a shutter device such as a camera, and a lens barrel in which the shutter driving device is incorporated.
[0002]
[Prior art]
Conventionally, there is a plunger solenoid device as a shutter driving device for driving a shutter device such as a camera. In this plunger solenoid device, the amount of suction force increases or decreases exponentially with respect to the plunger stroke. In view of this, Patent Document 1 proposes an electromagnetic mechanism (plunger solenoid device) that can move a long-displaced plunger with a more uniform operating force. This electromagnetic mechanism uses a plunger with a permanent magnet fixed to the tip, increases the magnetic flux generated by the permanent magnet, and biases the magnetic flux distribution toward the coil side to actuate the plunger's operating (attraction) force. It improves the characteristics.
[0003]
On the other hand, regarding a lens barrel having a shutter device, Patent Literature 2 proposes a lens barrel in which a shake prevention mechanism during shutter driving of a holding frame that holds the shutter device is incorporated. The lens barrel includes a first holding frame that holds the shutter device and a second holding frame that holds the first holding frame so as to be movable forward and backward. Permanent magnets are arranged for drawing in a direction intersecting the axis. The attraction force of the magnet prevents the first holding frame from shaking during the shutter opening / closing drive.
[0004]
[Patent Document 1]
Patent Document 1 is Japanese Patent Publication No. 63-46966.
[0005]
[Patent Document 2]
Patent Document 2 is Japanese Patent Laid-Open No. 6-242484.
[0006]
[Problems to be solved by the invention]
However, according to the electromagnetic mechanism proposed in Patent Document 1, since the permanent magnet is fixed to the plunger, the movable mass is increased by the amount of the permanent magnet. Therefore, for example, the responsiveness of the opening / closing operation of the shutter device is deteriorated, and there is a possibility that the shutter shake is likely to occur.
[0007]
On the other hand, in the lens barrel proposed in Patent Document 2, the first holding frame is prevented from shaking when the shutter is driven, and a good captured image without image shaking can be obtained. The effect of mounting is only to prevent the occurrence of the above-mentioned shake, and does not provide further effects.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a shutter driving device in which the plunger operating force characteristic can be improved without deteriorating responsiveness, and the shutter driving device is incorporated. Another object of the present invention is to provide a lens barrel with little lens barrel shake.
[0009]
[Means for Solving the Problems]
The shutter driving device according to claim 1 of the present invention includes a solenoid, a plunger driven by the solenoid, a magnet disposed in the vicinity of the solenoid, and a shutter blade driven by the movement of the plunger. In addition to the magnetic flux generated by the solenoid, the magnetic flux generated by the magnet acts on the plunger.
[0010]
According to a second aspect of the present invention, there is provided a shutter driving device including a solenoid, a plunger that is driven by the solenoid and is made of a magnetic material that is movable in the axial direction, a permanent magnet disposed in the vicinity of the solenoid, and the plunger. The shutter blades are driven by movement, and the magnetic flux generated by the magnet acts on the plunger in addition to the magnetic flux generated by the solenoid.
[0011]
According to a third aspect of the present invention, there is provided a lens barrel comprising: a solenoid; a plunger that is driven by the solenoid and is made of a magnetic material that is movable in the axial direction; a magnet disposed in the vicinity of the solenoid; and the movement of the plunger. A first blade that supports the solenoid, and a magnetic body that receives the magnetic flux of the magnet are arranged, guided by the first frame, and moved relative to the first frame. The second frame is guided by the first frame and moves relative to the first frame.
[0012]
According to a fourth aspect of the present invention, there is provided a lens barrel according to the first or second aspect of the invention, the first frame that supports the solenoid of the shutter drive unit, and the magnetic flux of the magnet. The magnetic body to be received is disposed, guided by the first frame, and has a second frame that moves relative to the first frame. The second frame is connected to the first frame. Guided and moved relative to each other while being offset.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are longitudinal sectional views of a lens barrel according to an embodiment of the present invention. FIG. 1 shows a zoom wide state capable of photographing, and FIG. 2 shows a zoom telephoto state capable of photographing. . In the following description, the subject side in the lens barrel is the front side, and the imaging side is the rear side (or the back side). The rotation direction of the member is indicated by the rotation direction when viewed from the front side.
[0014]
As shown in FIGS. 1 and 2, the lens barrel of the present embodiment is rotated with respect to the fixed frame 1, the first rotating frame 2 that is supported so as to be rotatable and movable back and forth with respect to the fixed frame 1, and the fixed frame. The float key 4 that is regulated and moves forward and backward together with the rotary frame 2, the second rotary frame 3 that rotates integrally with the rotary frame 2, and is driven forward and backward by the float key 4, and the rotation is restricted by the float key 4. And a float key 5 that moves forward and backward together with the rotary frame 3, a first group frame 6 that is rotationally restricted by the float key 5 and driven forward and backward by the rotary frame 3, and a rotational key that is restricted by the float key 5 and rotates. A focus unit 7 and a third group frame 8 constituting a lens barrel that is driven forward and backward by the frame 3, and an urging spring 9 formed by a compression spring that urges the focus unit 7 and the third group frame 8 in a separating direction; , Optical axis O As the photographing optical system, the first group lens 11 held by the first group frame 6, the second group lens 12 held by the second group frame 23, the third group lens 13 held by the third group frame 8, and the first group frame 6 And a bellows light shielding rubber 17 disposed between the focus units 7 and ring-shaped light shielding rubbers 18, 19, and 20 disposed between the frame members.
[0015]
The fixed frame 1 is provided with a female helicoid screw 1a and a rectilinear groove 1b that overlaps the helicoid screw on the inner peripheral portion thereof.
[0016]
The rotating frame 2 has a male helicoid screw 2a with a gear portion superimposed on the outer peripheral rear part thereof, and the male helicoid screw 2a is attached to the female helicoid screw 1a of the fixed frame 1 by screwing. The rotary frame 2 is rotationally driven through the gear portion by a long drive gear (not shown). The rotation frame 2 moves forward and backward in the direction of the optical axis O by the rotation.
[0017]
The float key 4 is coupled to the inner peripheral portion of the rotating frame 2 via a bayonet mechanism, and a protrusion 4a protruding from the outer peripheral rear portion is slidably fitted into the rectilinear groove 1b of the fixed frame 1 and attached. It has been. Therefore, the float key 4 moves forward and backward along the optical axis O together with the rotary frame 2 in a state where the rotation is restricted by the fixed frame 1.
[0018]
The rotating frame 3 has a guide pin 14 projecting to the outer periphery of the rear end slidably fitted into the rectilinear groove 2a of the rotating frame 2, and the male helicoid screw 3a is inserted into the female helicoid screw 4b on the inner periphery of the float key 4. It is attached in a screwed state. Therefore, the rotating frame 3 moves forward and backward in the direction of the optical axis O relative to the rotating frame 2 while rotating together with the rotating frame 2.
[0019]
The float key 5 is coupled to the rectilinear guide groove 4c that is coupled to the inner peripheral portion of the rotary frame 3 via a bayonet mechanism, and a projection 5a that protrudes from the outer peripheral rear portion overlaps the female helicoid screw 4b of the float key 4. It is slidably fitted and attached. Accordingly, the float key 5 moves forward and backward along the optical axis O together with the rotary frame 3 in a state where the rotation is restricted via the float key 4.
[0020]
The first group frame 6 has a rectilinear guide groove 6b slidably fitted in the rectilinear guide portion 5b of the float key 5, and the male helicoid screw 6a is screwed into the female helicoid screw 3b of the rotating frame 3, and the rotating frame 3 is attached. Therefore, the first group frame 6 moves back and forth in the direction of the optical axis O by the rotation of the rotating frame 3 while being restricted by the float key 5. A decorative plate 10 is bonded and fixed to the front surface of the first group frame 6.
[0021]
The focus unit 7 is a lens barrel with a built-in shutter driving device, has a guide rod 27, a second group guide frame 21 constituting the first frame, and a frame mounted on the front surface of the second group guide frame 21. A lid 26, a lens driving source, a shutter driving source, and the like are arranged, and are fixed integrally with the second group guide frame 21, and an LD (lens driving) base plate 22 constituting the first frame, and a second group guide. And a second group frame 23 as a second frame that is driven forward and backward relative to the frame 21. The second group frame 23 is provided with a shutter blade and a shutter lid on the front side, and a second group lens is held on the rear side.
[0022]
The focus unit 7 is supported by being linearly guided in the direction of the optical axis O in a state where the convex portion 21b of the second group guide frame 21 incorporated in the unit is fitted in the linear guide groove 5b inside the float key 5. . The focus unit 7 is relatively advanced and retracted with the rotation of the rotary frame 3 via the cam follower 15 of the second group guide frame 21 fitted into the cam groove 3 c of the rotary frame 3. A further detailed structure of the focus unit 7 will be described later.
[0023]
The third group frame 8 is supported in a state in which the convex portion 8a of the third group frame is fitted into the rectilinear guide groove 5c of the float key 5 and guided linearly in the direction of the optical axis O, and the cam groove 3d of the rotary frame 3 is supported. It is driven forward and backward relative to the rotary frame 3 through the cam follower 16 of the third group frame fitted into the frame.
[0024]
Next, each frame advancement / retraction operation in the lens barrel of the present embodiment having the above-described configuration will be described.
In the present lens barrel, in the non-photographing state, the lens frames such as the rotary frames 2 and 3 and the first group frame 6 are moved from the wide position extended position shown in FIG. It is carried over.
[0025]
At the time of shooting, the rotary frame 2, 3, the first group frame 6, the focus unit 7 and the third group frame are moved in accordance with the rotation of the rotary frame 2 at the position in the wide state or tele state shown in FIG. 1 or FIG. Are fed out in the direction of the optical axis O. That is, when the rotary frame 2 is rotationally driven by a lens drive gear (not shown), the rotary frame 2 is drawn forward through the female helicoid screw 1a of the fixed frame 1. The float key 4 is fed forward together with the rotating frame 2 without rotating. The rotating frame 3 is fed out while rotating together with the rotating frame 2, and the feeding position is drawn out through the female helicoid screw 4 a of the float key 4, so that the rotating frame 3 is drawn out further forward than the rotating frame 3. The float key 5 is fed out together with the rotary frame 3 in a state where the rotation is restricted by the float key 4. Further, the first group frame 6 is drawn forward from the rotary frame 3 via the female helicoid screw 3 b of the rotary frame 3 in a state in which the rotation is restricted by the float key 5. The focus unit 7 is drawn out by the cam groove 3 c of the rotating frame 3 in a state in which the rotation is restricted by the float key 5. The second group frame 23 built in the focus unit 7 is driven to move forward and backward relative to the second group guide frame 21 along the optical axis O direction by a focus drive mechanism section described later. Further, the third group frame 8 is drawn out by the cam groove 3d of the rotating frame 3 in a state in which the rotation is restricted by the float key 5.
[0026]
Next, a detailed configuration of the focus unit 7 will be described with reference to FIGS.
FIG. 3 is a perspective view of the focus unit. FIG. 4 is an exploded perspective view of the focus unit. FIG. 5 is a perspective view showing an assembled arrangement state of shutter blades and shutter drive levers in the second group frame of the focus unit. FIG. 6 is a perspective view of the second group frame as viewed from the rear, and shows the positional relationship between the iron plate member on the second group frame side, the plunger solenoid device on the LD base plate side, and the magnet member on the second group guide frame side. 7 and 8 are front views of the state of the shutter blades on the second group frame as viewed from the front (subject side). FIG. 7 shows the closed state of the shutter blades and the arrangement of the focus drive mechanism section. FIG. 8 shows the arrangement of the plunger solenoid device, the magnet, and the iron plate member on the cross section orthogonal to the optical axis, and FIG. 8 shows the opened state of the shutter blade. FIG. 9 is a cross-sectional view taken along the line AA of FIG. 7 and shows the focus driving mechanism portion of the second group frame.
[0027]
As shown in FIGS. 3 and 4, the focus unit 7 includes a second group guide frame 21, a lens and a shutter drive source, an LD base plate 22 that is integrally attached to the rear side of the second group guide frame 21, and shutter blades. , A light shielding blade, a second group lens, and the like are incorporated, and are attached to a front surface of the second group frame 23 and a second group frame 23 as a focus frame that is driven relative to the second group guide frame 21 in the optical axis O direction during focusing. It mainly includes a shutter lid 25, a frame lid 26 attached to the front surface of the second group guide frame 21, and a guide rod 27 that supports the second group frame 23 slidably in the optical axis O direction.
[0028]
The LD base plate 22 is a frame member having a central opening 22a, which is a driving source of shutter blades and light shielding blades on the front side thereof, and is a plunger solenoid device 55 constituting a shutter driving device and a focus driving source. Focus motor 41, focus drive gear train 46, focus drive mechanism for driving the second group frame 23 back and forth via focus drive gear train 46, focus motor rotation amount detection photo interrupter 61, and shutter blade movement A position detecting photointerrupter 63 and the like are incorporated. This LD ground plane 22 is temporarily fixed to the second group guide frame 21 with a hook 22c from the back side, and then a screw 71a through which the screw insertion hole 22b is inserted and a screw 71b through which the screw insertion hole 22d is inserted are two. The group guide frame 21 is screwed and fixed.
[0029]
The plunger solenoid device 55 includes a solenoid 58 made of a coil, a yoke 59 made of a magnetic material that supports the solenoid and is arranged on its side, a plunger 56 driven by the solenoid 58, and the solenoid and the plunger. A plunger spring 57 is provided as a second urging member that is interposed therebetween and urges the plunger in the protruding direction (the shutter blade closing direction). The plunger solenoid device 55 is attached to the LD base plate 22 via a yoke 59. The sliding direction of the plunger 56 is a direction along a plane perpendicular to the optical axis O. An end portion 29b of a shutter drive lever 29 described later abuts on the tip of the plunger 56.
[0030]
The focus motor 41 has an output shaft along a direction parallel to the optical axis O, and a pinion 42 is fixed to the output shaft. The pinion 42 meshes with the first gear 47 of the focus driving gear train 46. The rotation amount of the output shaft is detected by the output of the photo interrupter 61 that detects the rotation of the slit plate 62 attached to the shaft of the gear 48 in the focus drive gear train 46.
[0031]
The final stage gear 49 of the focus driving gear train 46 has a feed screw 50 integral with the gear, and is supported by a gear support shaft 51 that is an axis parallel to the optical axis O. Both ends of the gear support shaft 51 are rotatably supported by the LD base plate 22 by the shaft hole 22 c and the shaft hole 21 e of the second group guide frame 21. The feed screw 50 is screwed with a relative drive nut 52 described later. The detailed structure around the feed screw (focus drive mechanism) will be described later.
[0032]
The second group guide frame 21 is a frame member having a central opening 21a. As shown in FIG. 4 and the like, convex portions 21b are provided at three outer peripheral portions (two locations are shown). Each cam follower 15 is fixed. Further, the second group guide frame 21 is provided with a rod support hole 21c, a guide recess 21d, a hook portion 21f, and the like. The rod support hole 21c and the guide recess 21d are disposed at positions that are substantially opposed to each other with the optical axis O as the center.
[0033]
A magnet member 37 that is a permanent magnet is fixed to the magnet mounting portion 21 i of the second group guide frame 21. The magnet member 37 has a flat plate shape, and the front and back surfaces of the flat plate are magnetized surfaces, and the magnetized surface on the inner side (center opening 21a side) of the magnet member 37 is the second group frame 23 as shown in FIG. It is opposed to an iron plate member 38 (described later) fixed to the lens holding portion outer periphery 23k, and is disposed with a slight gap. The arrangement position of the magnet member 37 around the optical axis O is a position in the vicinity of the plunger solenoid device 55 on the line connecting the tip of the plunger 56 of the plunger solenoid device 55 attached to the LD base plate 22 and the optical axis O. And
[0034]
The second group frame 23 is a frame member having a shutter opening 23a in the center, and a second group lens and a shutter device are incorporated therein. That is, the second group frame 23 holds a second group lens 12 (FIGS. 1 and 2) on the rear side of the opening 23a, and a pair of shutters (shutter driving devices) on the front side that opens and closes the photographing optical path. A first shutter blade 31 and a second shutter blade 32 which are shutter blades are rotatably supported by a support pin 23d and a support pin 23e which are a pair of shafts. Further, a light shielding blade 33 that shields the leakage of photographing light as a shutter device is rotatably supported by a support pin 23f. Further, a shutter drive lever 29 is rotatably attached to a shaft portion 23g (FIGS. 4 and 7) protruding in the optical axis O direction at the upper portion on the back side. A sleeve 28 parallel to the direction of the optical axis O is bonded and fixed to the upper part of the second group frame 23. Further, a rotation-preventing guide convex portion 23 b that protrudes outward is provided at a position substantially opposite to the center of the optical axis O with respect to the sleeve 28 of the second group frame 23. On the surface of the lens holding portion outer periphery 23k of the second group frame 23, an iron plate member 38, which is a magnetic body, is fixed at a position facing the magnet member 37 on the second group guide frame 21 side with a slight gap. The iron plate 38 and the magnet member 37 on the second group guide frame 21 side are located in a triangular space formed by the lens holding portion outer periphery 23k, the shutter drive lever 29, and the plunger solenoid device 55.
[0035]
The support pins 23d and 23e are arranged at substantially equal distance positions on both sides of the pin insertion long hole 23c through which the shutter drive pin 29c of the shutter drive lever 29 is inserted. The support pin 23f is disposed at a position outside the support pin 23d with respect to the pin insertion long hole 23c, that is, at a position farther from the support pin 23d with respect to the opening 23a.
[0036]
First, the sleeve 28 is inserted into the second group frame 23 with a backlash. Then, the sleeve is positioned on the second group frame 23 with a jig or the like positioned so that the inner diameter portion of the sleeve is parallel to the optical axis O of the second group lens 12 and separated from the optical axis O by a predetermined distance. Bonded and fixed. A guide rod 27 that slidably supports the second group frame 23 is fitted into the sleeve 28.
[0037]
The shutter drive lever 29 is a driven member that is driven by the plunger 56 and is a drive member that rotationally drives the shutter blades including the light shielding blades. The shutter drive lever 29 is inserted through a shaft hole 29a that is rotatably fitted to the shaft portion 23g, an end portion 29b that contacts the tip of the plunger 56, and a pin insertion long hole 23c of the second group frame 23. And a shutter drive pin 29c that projects forward and engages the shutter blade and the light shielding blade.
[0038]
The shutter drive lever 29 is urged clockwise (as viewed from the front) by a shutter spring 30 as a first urging member. The urging direction is a direction in which the end portion 29c of the shutter drive lever 29 is in contact with the distal end side of the plunger 56, and a direction in which the shutter blades 31 and 32 and the light shielding blade 33 are opened. The biasing force of the shutter spring 30 against the shutter drive lever 29 is weaker than the biasing force of the biasing spring 57 on the plunger 56 side. Therefore, when the plunger solenoid device 55 is turned off, the shutter drive lever 29 is rotationally driven in the shutter closing direction via the plunger 56 by the biasing force of the biasing spring 57.
[0039]
Since the shutter drive lever 29 and the plunger 56 move relative to each other in the direction of the optical axis O during focus driving, the end portion 29b of the shutter drive lever 29 is light-tight in order to maintain a contact state with the tip of the plunger 56. It has a shape extending in parallel with the direction of the shaft hole 29a which is parallel to the direction of the axis O.
[0040]
The first shutter blade 31 has a light shielding portion that can open and close the shutter opening 23 a in cooperation with the second shutter blade 32. The shutter blade 31 is in a state in which the rotation pin hole 31 a is fitted into the support pin 23 d and the drive slot 31 b is fitted into the drive pin 29 c of the shutter drive lever 29 on the front side of the second group frame 23. It is supported so that it can rotate.
[0041]
The second shutter blade 32 has a light shielding portion having an opening edge portion 32 c that can open and close the shutter opening 23 a in cooperation with the first shutter blade 31. That is, the second shutter blade 32 forms an engagement portion (overlapping portion) on the opening 23 a in the shutter closed state with respect to the first shutter blade 31. The shutter blade 32 has a rotating pin hole 32 a fitted into the support pin 23 e in a state of being superimposed on the front surface of the shutter blade 31 on the front side of the second group frame 23, and the driving elongated hole 32 b is inserted into the shutter drive lever 29. The drive pin 29c is supported so as to be rotatable.
[0042]
The light shielding blade 33 blocks light leakage from the overlapping portion of the shutter blades 31 and 32 in a state where the shutter opening 23 a is shielded by the shutter blades 31 and 32, and the shutter opening 23 a together with the shutter blade 31 when the shutter is opened. A light-shielding portion that can be retracted from the The light shielding blade 33 is sandwiched between the shutter blades 31 in a state where the front edge of the second group frame 23 covers the opening edge 32c which is the edge of the light shielding portion on the front surface side of the shutter blades 32. Arranged in a state. In this attached state, the rotation pin hole 33a is fitted into the support pin 23f, and the drive elongate hole 33b is fitted into the drive pin 29c of the shutter drive lever 29 so as to be rotatable.
[0043]
A light shielding sheet 24 is further placed on the front surface of the light shielding blade 33 to cover it. The light shielding sheet 24 is provided with a central opening 24a having the same size as the shutter opening 23a, a relief hole 24c of the drive pin 29c, a relief 24b of the second group frame biasing spring 35, and the like.
[0044]
A shutter lid 25 is attached to the front surface of the second group frame 23 in which the shutter blades 31 and 32, the light shielding blade 33, and the light shielding sheet 24 are incorporated, and is latched by the latch pins 23h, 23i, and 23j of the second group frame 23. And unitized. The shutter cover 25 is provided with a relief hole 25c of the drive pin 29c, a relief portion 25b of the second group frame biasing spring 35, and the like.
[0045]
As described above, the unitized second group frame 23 is slidably fitted into the guide concave portion 21d of the second group guide frame 21 with respect to the second group guide frame 21 from the front side thereof. Installed. Further, in this mounted state, the frame lid 26 is fitted to the front surface of the second group guide frame 21 in a state where the frame lid 26 is positioned by the positioning pin of the guide frame, and the locking hole portion 26b of the frame lid 26 is inserted into the hook portion 21f of the second group guide frame 21. It is locked and set in a temporarily fixed state. Therefore, the guide rod 27 is inserted into the rod support hole 26c of the frame lid 26, and the tip portion is press-fitted into the rod support hole 21c of the second group guide frame 21 and fixed. In the fixed state, the second group frame biasing spring 35 is inserted into the guide rod 27 between the frame lid 26 and the second group frame 23 in a compressed state.
[0046]
In the assembled state of the focus unit 7, the second group frame 23 is relatively advanced and retracted (focus drive) relative to the second group guide frame 21 in the optical axis O direction according to the rotation of the focus motor 41. Next, the focus drive mechanism unit will be described.
[0047]
The main structure of the focus drive mechanism is shown in FIG. 9, which is a cross-sectional view taken along line AA of FIG. The final gear 49 that is rotationally driven by the focus motor 41 via the gear train 46 during the focus drive integrally includes a feed screw 50 and a gear support shaft 51. Both ends of the gear support shaft 51 are rotatably supported by the LD base plate 22 through the shaft hole 22 c and the shaft hole 21 e of the second group guide frame 21. A relative drive nut 52 is screwed to the feed screw 50. The nut 52 has a convex portion 52 a, and the convex portion 52 a is slidably fitted into the concave portion 21 h of the second group guide frame 21. Therefore, when the final gear 49 rotates, the nut 52 moves in a direction parallel to the optical axis O along the feed screw 50 in a state where the rotation is restricted.
[0048]
The second group frame 23 has a protrusion 23h having one apex protruding rearward and a single protrusion 23i having two apexes, and is always subjected to the rearward biasing force F0 by the biasing spring 35. ing. Therefore, the tops of the three points of the projecting portion 23 h and the projecting portion 23 i of the second group frame 23 are always in contact with the relative driving nut 52. When the output shaft of the focus motor 41 is rotationally driven during focusing, the second group frame 23 is pressed against the urging force of the urging spring 35 via the nut 52 as the final gear 49 rotates. It is driven back and forth along the Z direction (parallel to the optical axis O) relative to the group guide frame 21 and the LD base plate 22.
[0049]
During the relative movement of the second group frame 23 and when the shutter is opened and closed, the second group frame 23 is supported by the guide rod 27 fixed to the second group guide frame 21 and is formed by the recess 21 d of the second group guide frame 21. Although the rotation is restricted and held, there is a slight fitting backlash between the concave portion 21d and the guide convex portion 23b of the second group frame 23 fitted therein, and the second group frame 23 is slightly smaller than the second group guide frame 21. There is a possibility of rattling in the direction of rotation. However, since the iron plate member 38 fixed to the second group frame 23 receives an attractive force by the magnet member 37 fixed to the second group guide frame 21, the second group frame 23 rotates counterclockwise around the guide rod 27 (in FIG. And a slight relative rotation backlash at the time of movement or opening / closing of the shutter can be suppressed.
[0050]
When the second group frame 23 moves relative to the second group guide frame 21, the contact position of the tip of the plunger 56 with respect to the shutter drive lever tip 29c moves relative to the optical axis O.
[0051]
Next, the opening and closing operations of the shutter blades and the light shielding blades incorporated in the second group frame 23 will be described with reference to front views and the like in the shutter closed and open states of FIGS.
When the plunger solenoid device 55 is switched from the on state to the off state in order to switch to the shutter closed state, the shutter open state shown in FIG. 8 is switched to the shutter closed state shown in FIG. That is, when the solenoid device 55 is turned off, the plunger 56 protrudes from the suction position, and rotates the shutter drive lever 29 counterclockwise to the shutter closed position.
[0052]
When the shutter drive lever 29 rotates to the shutter closed position, the shutter blade 31 is driven counterclockwise about the support pin 23d by the drive lever 29, and at the same time, the shutter blade 32 is centered on the support pin 23e. Is rotated clockwise to the closed position. In this shutter closed state, the shutter opening 23a is in a closed state covered with the shutter blades 31 and 32 in cooperation.
[0053]
On the other hand, the light shielding blade 33 is rotationally driven by the shutter drive lever 29 to the closed position in the same counterclockwise direction as the shutter blade 31 around the support pin 23f. In this shutter closed state, the light shielding portion of the light shielding blade 33 covers the opening edge 32c of the shutter blade 32 in the closed position. Since the position of the support pin 23 f is located outside the drive pin 29 c with respect to the drive pin 29 c with respect to the light shielding blade 33, the rotational driving angle of the light shielding blade 33 is the rotational drive of the shutter blade 31. Less than angle.
[0054]
In the shutter closed state, the photographing light from the central opening 24 a of the light shielding sheet 24 does not directly reach the opening edge 32 c of the shutter blade 32, and does not pass through the gap of the light shielding blade 33. The part 32c cannot be reached.
[0055]
On the other hand, when the plunger solenoid device 55 is switched from the OFF state to the ON state to bring the shutter into the open state, the plunger 56 is sucked from the protruding position, and the shutter drive lever 29 is rotated clockwise by the biasing force of the shutter spring 30 as shown in FIG. To the shutter open position. When the shutter drive lever 29 rotates to the shutter open position, the shutter blade 31 rotates clockwise around the support pin 23d to the open position. At the same time, the shutter blade 32 rotates to the open position counterclockwise about the support pin 23e. Further, the light shielding blade 33 rotates to the open position clockwise around the support pin 23f. In this state, both the shutter blades 31 and 32 and the light shielding blade 33 are retracted from the shutter opening 23a, and the shutter is opened. Even in this shutter opening operation, the light shielding blade 33 rotates in the same direction as the shutter blade 31, and the rotation angle is smaller than that of the shutter blade 31.
[0056]
When the lens barrel of this embodiment is attached to a digital camera having an image sensor, the shutter device is held in the open state shown in FIG. 8 in a state before photographing, and the exposure ends after the photographing starts. Relatedly, the shutter device is switched to the closed state shown in FIG. On the other hand, when the lens barrel is mounted on a camera using a silver salt film, the shutter device is held in the closed state shown in FIG. 8 is switched back to the closed state shown in FIG. 7 when the exposure is completed.
[0057]
In the opening / closing operation described above, when a drive voltage is applied to the solenoid 58 of the plunger solenoid device 55 and energized, a magnetic flux is generated by the solenoid 55. The plunger 56 is attracted by the magnetic flux, and the magnetic flux passes through a magnetic circuit formed by the plunger 56 and the yoke 59. Further, in addition to the magnetic flux generated by the solenoid 55, the magnetic flux generated by the magnet member 37 fixed to the second group guide frame 21 is also applied to the magnetic circuit between the tip of the plunger 56 and the iron plate member 38 fixed to the second group frame 23. Pass through. The attractive force received by the plunger 56 due to the added magnetic flux slightly increases. Accordingly, the shutter blades 31 and 32 and the light shielding blade 33 receive a stronger suction force and are quickly and reliably rotated in the opening direction.
[0058]
FIG. 10 is a diagram showing the attractive force amount characteristics of the plunger solenoid device 55 with respect to the plunger stroke, in which the magnet member 37 and the iron plate member 38 are attached in the vicinity of the plungers of the second group guide frame 21 and the second group frame 23. The measured characteristic difference when not attached is shown. However, the magnetic pole on the outer side surface (the distal end side of the plunger 56) of the magnet member 37 attached to the second group guide frame 21 is opposite to the magnetic pole (S pole or N pole) at the distal end of the plunger when the solenoid is energized ( N pole or S pole). As shown in FIG. 10, an increase of about 0.01 N in the amount of attractive force due to the mounting of the magnet member in the usage range of the plunger 56 was found experimentally.
[0059]
Further, in the above opening / closing operation, when the plunger solenoid device 55 is driven on or off, the impact force due to the protrusion and withdrawal of the plunger 56 is received by the LD base plate 22 and the second group guide frame 21 to which the solenoid device is fixed. On the other hand, the second group frame 23 is supported by the second group guide frame 21 integrated with the LD base plate 22 through a guide rod 27 and a guide recess 21d so as to be able to move forward and backward indirectly. Therefore, the impact force due to the protrusion and withdrawal of the plunger 56 is not directly transmitted to the second group frame 23 that holds the second group lens 12, and the shutter blade shake due to the impact force is extremely small.
[0060]
As described above, according to the lens barrel of the present embodiment, the plunger solenoid device 55 that opens and closes the shutter blades is directly attached to the second group frame 23 that holds the second group lens 12 of the focus unit 7. Absent. Therefore, it is difficult for the second group lens to sway due to the impact of the plunger 56 during the opening / closing drive, and it is possible to obtain a good captured image with little shutter shake. Further, since the plunger solenoid device 55 is not attached to the second group frame 23, the weight of the second group frame 23 is light, the load resistance at the time of focusing driving is reduced, and quick focusing driving is possible.
[0061]
Further, by attaching the magnet member 37 and the iron plate member 38 to the second group guide frame 21 and the second group frame 23, the second group frame 23 is slightly moved when the relative movement with respect to the second group guide frame 21 or when the shutter is opened / closed. Relative relative rotation backlash is suppressed, and image-free shooting is possible.
[0062]
In addition, since the magnet member 37 and the iron plate member 38 are attached to the second group guide frame 21 and the second group frame 23 as described above, the amount of attracting force of the plunger 56 when the plunger solenoid device 55 is turned on is secondary. Increase. The increase in the amount of attracting force ensures that the shutter blades are opened. Or it becomes possible to reduce the ampere-turn of the solenoid 58, and a power saving and size reduction are attained. Since the magnet member 37 and the iron plate member 38 are fixed to the frame member separately from the plunger 56, there is no increase in mass of the plunger as in the electromagnetic mechanism described in Patent Document 1 described above, and the time lag at the time of suction and protrusion Does not occur.
[0063]
Further, since the magnet member 37 and the iron plate 38 are arranged in a triangular gap formed by the holding portion outer periphery 23k of the second group frame 23, the shutter drive lever 29, and the plunger solenoid device 55, the occupied area of the focus unit 7 is increased. There is no increase.
[0064]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a shutter driving device that can improve the plunger operating force characteristic without lowering the responsiveness, and there is little lens barrel shake in which the shutter driving device is incorporated. It becomes possible to provide a lens barrel.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a lens barrel according to an embodiment of the present invention in a zoom wide state where photographing is possible.
FIG. 2 is a longitudinal sectional view of the lens barrel in FIG. 1 in a zoom telephoto state where photographing is possible.
3 is a perspective view of a focus unit built in the lens barrel of FIG. 1. FIG.
4 is an exploded perspective view of the focus unit of FIG. 3. FIG.
5 is a perspective view showing an assembled arrangement state of shutter blades and shutter drive levers in the second group frame of the focus unit of FIG. 3; FIG.
6 is a rear perspective view of the second group frame of the focus unit of FIG. 3, and the positional relationship between the iron plate member of the second group frame, the plunger solenoid device on the LD base plate side, and the magnet member on the second group guide frame side. Indicates.
7 is a front view of the closed state of the shutter blades on the second group frame of the focus unit shown in FIG. 3 as viewed from the front (subject side), the arrangement of the focus drive mechanism, the plunger solenoid device and the magnet member; And the arrangement of the iron plate members on the cross section orthogonal to the optical axis are also shown.
8 is a front view of the open state of the shutter blades on the second group frame of the focus unit of FIG. 3 as viewed from the front.
9 is a cross-sectional view taken along the line AA of FIG. 7, showing a focus driving mechanism portion of the second group frame.
FIGS. 10A and 10B are diagrams showing the attractive force amount characteristics of the plunger solenoid device built in the focus unit of FIG. 3 with respect to the plunger stroke, with and without the magnet and the iron plate member being mounted in the vicinity of the plunger; And the characteristic difference.
[Explanation of symbols]
21 ... 2 group guide frame (first frame)
22 ... LD ground plate (first frame)
23 ... 2 group frame (2nd frame)
31, 32 ... Shutter blade 37 ... Magnet member (magnet)
38 ... Iron plate member (magnetic material)
56 ... Plunger 58 ... Solenoid

Claims (4)

A solenoid,
A plunger driven by the solenoid;
A magnet disposed in the vicinity of the solenoid;
A shutter blade driven by the movement of the plunger;
A shutter driving device comprising: A solenoid,
A plunger made of a magnetic material driven by the solenoid and movable in the axial direction;
A permanent magnet disposed in the vicinity of the solenoid;
A shutter blade driven by the movement of the plunger;
A shutter driving device comprising: A solenoid,
A plunger made of a magnetic material driven by the solenoid and movable in the axial direction;
A magnet disposed in the vicinity of the solenoid;
A shutter blade driven by the movement of the plunger;
A first frame that supports the solenoid;
A magnetic body that receives the magnetic flux of the magnet is disposed, guided by the first frame, and moved relative to the first frame;
Lens lens frame having The shutter driving device according to claim 1 or 2;
A first frame that supports the solenoid of the shutter driving device;
A magnetic body that receives the magnetic flux of the magnet is disposed, guided by the first frame, and a second frame that moves relative to the first frame;
Lens lens frame having

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