JP5528024B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a lens barrel capable of a zoom operation and mounted on an imaging device such as a digital camera, and an imaging device including the lens barrel.

  As a conventional retractable zoom lens barrel of this type, a cam barrel that is cam-engaged with the inner peripheral surface of a fixed cam barrel and moves in the direction of the optical axis while rotating; And a straight guide cylinder that moves straight in the optical axis direction.

  The straight guide tube is provided with a member to be detected for detecting the initial position of the zoom lens. Then, when the rectilinear guide cylinder moves rectilinearly, the member to be detected is retracted from the slit portion of the photo interrupter fixed to the CCD holder or the like, and the zoom position is detected based on the signal output from the photo interrupter at the time of retracting ( Patent Document 1).

JP 2001-324664 A

  By the way, in the zoom lens barrel, in response to the recent demand for higher magnification, it is desired to increase the number of cylinders to be extended in order to extend the cylinder holding the lens to a position further away from the imaging plane. .

  However, when a large number of cylinders are provided in this manner, the shakiness in the optical axis direction of the helicoid mechanism, cam mechanism, etc. provided between the cylinders increases, and the moving position of the cylinder on the imaging plane side and the tip side are the most. The error from the moving position of the cylinder holding the lens increases.

  Therefore, as described in Patent Document 1, when a detection target member for detecting the initial position of the lens is provided on the straight guide cylinder closest to the imaging plane, the movement of the cylinder as the cylinder holding the lens is further away from the imaging plane. The influence of position error is increased. For this reason, the detection accuracy of the lens position is lowered, and the optical performance is adversely affected.

  Therefore, an object of the present invention is to provide a lens barrel and an imaging apparatus that can detect the lens position with high accuracy even when the lens moves to a position away from the imaging plane due to high magnification. To do.

In order to achieve the above object, a lens barrel of the present invention includes a first cam barrel, a holder attached to the first cam barrel and attached with detection means for detecting a zoom reset position, and the first barrel. By engaging with the first cam cylinder on the inner peripheral side of the cam cylinder, the second cam cylinder that moves in the optical axis direction while rotating, and the inner cam side of the second cam cylinder are arranged and rotated. A third cam cylinder that moves in the optical axis direction, a first straight guide cylinder that is coupled to the second cam cylinder and linearly moves in the optical axis direction, and a linear cam that is coupled to the third cam cylinder and linearly travels in the optical axis direction A second linear guide cylinder that moves, a plurality of lens holding frames that hold the lens and move straight in the optical axis direction, and a lens that is arranged closest to the subject among the plurality of lenses moves to the zoom reset position Detected part detected by the detecting means when And the detected member is provided on the second rectilinear guide tube, and in a zoom operation, between the lens arranged closest to the subject among the plurality of lenses and the second rectilinear guide tube Is characterized in that only the lens holding frame for holding the lens arranged closest to the subject is arranged.

  According to the present invention, even when the lens moves to a position away from the image forming plane due to high magnification, the lens position can be detected with high accuracy, so that stable optical performance can be maintained. .

It is sectional drawing in the accommodation state (collapsed state) of the lens barrel which is an example of embodiment of this invention. It is sectional drawing in the wide state of a lens-barrel. It is sectional drawing in the tele state of a lens-barrel. It is a disassembled perspective view of a lens barrel. It is a perspective view of an assembly of a CCD holder and a third group barrel. It is an expanded view of the internal peripheral surface of a fixed cam cylinder. It is an expanded view of the internal peripheral surface of a 1st movement cam cylinder. It is an expanded view of the outer peripheral surface of a 1st rectilinear guide cylinder. It is an expanded view of the internal peripheral surface of a 1st rectilinear guide cylinder. It is an expanded view of the internal peripheral surface of a 2nd movable cam cylinder. It is a disassembled perspective view of a first group barrel. It is a disassembled perspective view of a 1st moving cam cylinder and a 1st rectilinear guide cylinder. It is a disassembled perspective view of a 2nd movable cam cylinder and a 2nd rectilinear guide cylinder. (A) And (c) is a figure which shows the relationship between a drive pin and a penetration cam, (b) And (d) is a figure which shows the relationship between a follower pin and a cam groove.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of a lens barrel as an example of an embodiment of the present invention in a retracted state (collapsed state), FIG. 2 is a cross-sectional view of the lens barrel in a wide state, and FIG. 3 is a tele state of the lens barrel. 4 is an exploded perspective view of the lens barrel, and FIG. 5 is a perspective view of an assembly of the CCD holder and the third group barrel. In the present embodiment, a zoom lens barrel mounted on an imaging apparatus such as a digital camera is taken as an example.

  The lens barrel according to this embodiment includes a first group barrel 201 that holds the first lens group 101, a second group holder 202 that holds the second lens group 102, and a second group base 203 that includes a diaphragm / shutter. The unit includes a third group barrel 204 that holds the third lens group 103.

  The first group barrel 201 and the second group unit are a zooming lens group, and the second group unit includes a vibration-proof mechanism that corrects camera shake during photographing. The third group barrel 204 is a focus lens group for focusing on the subject.

  The lens barrel of the present embodiment includes a second moving cam cylinder 209, a second rectilinear guide cylinder 210, a first moving cam cylinder 207, a first rectilinear guide cylinder 208, a fixed cam cylinder 205, and a CCD holder 206.

  A CCD holder 206 is fastened to the fixed cam cylinder 205 with screws or the like. A CCD sensor 104 is attached to the CCD holder 206 via the CCD plate 11, and the optical filter 14 is disposed between the CCD mask 12 and the CCD rubber 13 on the object side of the CCD sensor 104. Has been.

  As shown in FIG. 5, the CCD holder 206 is attached with photo interrupters 36 and 37 for detecting the initial position of the lens during zooming and focusing. A zoom motor 212 is fixed to the CCD holder 206, and pulses generated by the zoom motor 212 are counted by the photo interrupters 38 and 39. The details of the photo interrupters 36, 37, 38, 39 will be described later. The rotational driving force of the zoom motor 212 is transmitted to the gear 211 via the gear train 213.

  A third lens barrel 204 is supported on the CCD holder 206 so as to be movable in the optical axis direction.

  That is, the AF guide shaft 31 extending in parallel with the photographing optical axis is press-fitted and fixed to the CCD holder 206, and the sub guide shaft 32 for restricting rotation is integrally formed with the CCD holder 206. A guide hole 204 a formed in the third group barrel 204 is slidably fitted to the AF guide shaft 31.

  The third group barrel 204 is urged toward the object side in the optical axis direction by the AF spring 33, and the object side of the third group barrel 204 is screwed into a screw (not shown) of the AF motor 34. An AF nut (not shown) is provided. When the screw of the AF motor 34 rotates, the third group barrel 204 moves forward and backward in the optical axis direction integrally with the AF nut.

  The third group lens barrel 204 is integrally formed with a light shielding plate 204 b, and the light shielding plate 204 b is disposed at a position where the light shielding plate 204 b can advance and retreat in the slit portion of the photo interrupter 37. Further, as shown in FIG. 5, the CCD holder 206 is provided with three springs 35 for urging the second group unit toward the subject side in the optical axis direction when retracted.

  FIG. 6 is a development view of the inner peripheral surface of the fixed cam cylinder 205.

  As shown in FIG. 6, three cam grooves 205a are formed at substantially equal intervals in the circumferential direction on the inner peripheral surface of the fixed cam cylinder 205, and three rectilinear guide grooves 205b parallel to the optical axis are formed. Has been.

  As shown in FIG. 4, a first moving cam cylinder 207 is arranged on the inner peripheral side of the fixed cam cylinder 205, and on the outer peripheral surface of the first moving cam cylinder 207, as shown in FIG. Three follower pins 207a that engage with the cam groove 205a of 205 are integrally provided.

  A gear portion 207g having gear teeth parallel to the photographing optical axis is formed on the outer peripheral surface of the first moving cam cylinder 207, and the rotation of the gear 211 is transmitted to the gear portion 207g. As a result, the first moving cam cylinder 207 moves in the optical axis direction while rotating by the cam engagement between the follower pin 207a and the cam groove 205a of the fixed cam cylinder 205.

  FIG. 7 is a development view of the inner peripheral surface of the first movable cam cylinder 207.

  As shown in FIG. 7, two group cam grooves 207b for moving the second group unit in the optical axis direction are formed on the inner peripheral surface of the first movable cam cylinder 207 at substantially equal intervals in the circumferential direction. Yes.

  Of the second group cam groove 207b, the lower shape in the optical axis direction of the cam groove 207f in the retracted region of the lens barrel is omitted, so that the entire length of the lens barrel when retracted is reduced. Can be shortened. A method of holding the second group unit by the first moving cam cylinder 207 during the collapse will be described later. Three cam grooves 207 c extending in the circumferential direction are formed at substantially equal intervals in the circumferential direction on the inner peripheral surface on the front end side of the first movable cam cylinder 207.

  In addition, on the inner peripheral surface on the rear end side of the first moving cam cylinder 207, two grooves 207d1 and 207d2, grooves 207d3 and 207d4, grooves 207d5 and 207d6 extending in the circumferential direction are formed at substantially equal intervals in the circumferential direction. .

  The distance between the grooves 207d1 and 207d2 in the optical axis direction is wider than the distance between the grooves 207d3 and 207d4 in the optical axis direction, and the distance between the grooves 207d3 and 207d4 in the optical axis direction is set wider than the distance between the grooves 207d5 and 207d6 in the optical axis direction. Has been.

  On the inner peripheral side of the first moving cam cylinder 207, a first rectilinear guide cylinder 208 is disposed so as to be slidable in the rotational direction with respect to the first moving cam cylinder 207 (FIG. 1).

  FIG. 8 is a development view of the outer peripheral surface of the first rectilinear guide tube 208.

  As shown in FIG. 8, the first rectilinear guide tube 208 is formed with three through cams 208e and first rectilinear guide grooves 208f at substantially equal intervals in the circumferential direction. As shown in FIGS. 7, 8, and 12, tapered pins 208 a that engage with the cam grooves 207 c of the first movable cam cylinder 207 are arranged at substantially equal intervals in the circumferential direction at the front end portion of the first rectilinear guide cylinder 208. In three places.

  By engaging the cam groove 207c of the first moving cam cylinder 207 and the taper pin 208a of the first rectilinear guide cylinder 208, the optical axis direction and the radial direction of the first moving cam cylinder 207 and the first rectilinear guide cylinder 208 are changed. While preventing rattling, impact resistance can be improved.

  In addition, rectangular pins 208b1 to 208b6 corresponding to the grooves 207d1 to 207d6 of the first moving cam cylinder 207 project from the rear end portion of the first rectilinear guide cylinder 208.

  Here, referring to FIG. 8, an area surrounded by the penetrating cam 208e and the first rectilinear guide groove 208f is X, and an area closer to the object side than the penetrating cam 208e is Y. Since the periphery of the region X is notched by the penetrating cam 208e and the first rectilinear guide groove 208f, the region X is supported only by the Z1 portion and the Z2 portion, and has lower impact resistance than the region Y.

  In the region Y, the taper pins 208a are arranged, and in the region X, the rectangular pins 208b1 to 208b6 are arranged. The rectangular pins 208b2, 208b4, 208b6 are arranged at the same height in the optical axis direction. The rectangular pins 208b1, 208b3, and 208b5 are arranged so that the intervals in the circumferential direction and the height in the optical axis direction are also different.

  Here, the width of the corresponding groove portions 207d1 to 207d6 is formed larger than the width of the rectangular pins 208b1 to 208b6, and gaps are formed in the concave and convex fitting portions between the rectangular pins 208b1 to 208b6 and the groove portions 207d1 to 207d6. ing.

  Therefore, when the first moving cam cylinder 207 rotates and moves in the optical axis direction, the rectangular pins 208b1 to 208b6 do not engage with the grooves 207d1 to 207d6. For this reason, the rectangular pins 208b1 to 208b6 function as a static pressure receiving portion when an impact such as a drop is applied and serve to ensure impact resistance, but do not hinder the zoom operation of the lens barrel.

  Further, on the outer peripheral portion of the first rectilinear guide tube 208, three rectilinear guide keys 208h are formed at approximately equal intervals in the circumferential direction. When the rectilinear guide key 208h is cam-engaged with the rectilinear guide groove 205b of the fixed cam cylinder 205, the rotation of the first rectilinear guide cylinder 208 is restricted when moving in the optical axis direction (FIGS. 5, 8, and 5). 12).

  In other words, the first moving cam cylinder 207 and the first rectilinear guide cylinder 208 are coupled together with little backlash in the optical axis direction and the radial direction. Then, when the first moving cam cylinder 207 rotates in the optical axis direction while rotating by the driving force from the gear train 213, the first rectilinear guide cylinder 208 also goes straight in the optical axis direction while being coupled with the first moving cam cylinder 207. Moving.

  FIG. 9 is a development view of the inner peripheral surface of the first rectilinear guide tube 208.

  On the inner peripheral surface of the first rectilinear guide tube 208, cam grooves 208c and 208d having the same shape as the penetrating cam 208e and having different phases in the circumferential direction, and a second rectilinear guide groove 208g parallel to the optical axis, respectively circulate. Three locations are formed at approximately equal intervals in the direction.

  The cam grooves 208c and 208d are divided in the retracted region by the first rectilinear guide groove 208f, and the cleaved portions are chamfered. The first rectilinear guide groove 208f is a guide groove for restricting rotation when the second group unit moves in the optical axis direction.

  Here, as shown in FIG. 4, in the second group unit, the three follower pins 203 a of the second group base 203 are engaged with the second group cam groove 207 b of the first movable cam cylinder 207. Further, the roots 203 b of the three follower pins 203 a are engaged with the first rectilinear guide grooves 208 f of the first rectilinear guide cylinder 208.

  When the first moving cam cylinder 207 rotates and moves in the optical axis direction, the second group unit moves straight in the optical axis direction along the cam groove 207b.

  As shown in FIGS. 1 and 4, the second movable cam cylinder 209 and the second rectilinear guide cylinder 210 are arranged on the inner peripheral side of the first rectilinear guide cylinder 208.

  As shown in FIG. 13, a follower pin 209 a that engages with cam grooves 208 c and 208 d of the first rectilinear guide cylinder 208 and a penetrating cam 208 e of the first rectilinear guide cylinder 208 are provided on the outer peripheral surface of the second movable cam cylinder 209. A drive pin 209b that penetrates is provided. The follower pin 209a has a tapered shape like the follower pins of other cylinders, but the drive pin 209b has a cylindrical shape.

  Further, the drive pin 209 b is engaged with the drive rectilinear groove 207 e of the first moving cam cylinder 207. The drive pin 209b rotates through the drive rectilinear groove 207e by the rotation of the first moving cam cylinder 207, and the second moving cam cylinder 209 follows the cam grooves 208c and 208d of the first rectilinear guide cylinder 208 in the first direction. It moves in the optical axis direction while rotating together with the moving cam cylinder 207.

  As described above, the cam grooves 208c and 208d formed on the inner peripheral surface of the first rectilinear guide cylinder 208 are divided into two parts, but it is engaged with the follower pin 209a of the second movable cam cylinder 209. The cam groove 208d in the photographing area. The cam groove 208c in the retracted region is formed larger than the shape of the follower pin 209a of the second movable cam cylinder 209 and does not function as a cam groove.

  Further, the penetrating cam 208e formed in the first rectilinear guide tube 208 is gradually changed before moving from the retracted region to the photographing region (wide position), and is engaged with the drive pin 209b of the second moving cam tube 209. It is only the retracted area. In the imaging region, the width of the penetrating cam 208e is gradually changed to be larger than the driving pin 209b and is not engaged with the driving pin 209b.

  That is, in the retracted area, the drive pin 209b of the second moving cam cylinder 209 is engaged with the penetrating cam 208e of the first rectilinear guide cylinder 208, and in the imaging area, the follower pin 209a of the second moving cam cylinder 209 is the first. It is in an engaged state with the cam groove 208d of the rectilinear guide tube 208.

  FIG. 10 is a development view of the inner peripheral surface of the second movable cam cylinder 209.

  Three cam grooves 209c and 209d for moving the first group barrel 201 in the optical axis direction are formed at substantially equal intervals in the circumferential direction on the inner peripheral surface of the second movable cam barrel 209. The cam grooves 209c and 209d are spaced apart from each other in the optical axis direction.

  Inside the second moving cam cylinder 209, a second rectilinear guide cylinder 210 is disposed so as to be slidable in the rotational direction with respect to the second moving cam cylinder 209.

  The sliding portion formed on the inner peripheral surface of the second movable cam cylinder 209 and the sliding portion formed on the outer peripheral surface of the second rectilinear guide cylinder 210 are relatively free from radial backlash. Can be rotated.

  Further, the upper surface of the sliding part formed on the inner peripheral surface of the second movable cam cylinder 209 and the lower surface of the sliding part formed on the outer peripheral surface of the second rectilinear guide cylinder 210 are connected to the bayonet. Is done. Accordingly, when the second moving cam cylinder 209 rotates and moves in the optical axis direction, the second rectilinear guide cylinder 210 also moves in the optical axis direction together with the second moving cam cylinder 209.

  At this time, the rectilinear guide key 210e formed on the outer peripheral portion of the second rectilinear guide tube 210 engages with the second rectilinear guide groove 208g formed on the inner peripheral surface of the first rectilinear guide tube 208, so that the second The rectilinear guide tube 210 is restricted from rotating when moving in the optical axis direction.

  Therefore, when the second moving cam cylinder 209 starts to rotate due to the rotational movement of the first moving cam cylinder 207, the second rectilinear guide cylinder 210 is bayonet-coupled with the second moving cam cylinder 209 and goes straight in the optical axis direction. Start moving. Here, in the present embodiment, the second rectilinear guide tube 210 corresponds to an example of a rectilinearly moving member of the present invention.

  Three guide grooves 210a are formed on the outer periphery of the second rectilinear guide tube 210 at approximately equal intervals in the circumferential direction for guiding the rectilinear movement when the first group barrel 201 moves in the optical axis direction. Further, the second straight guide tube 210 is integrally formed with a light shielding plate 210f (FIG. 13) corresponding to an example of the member to be detected of the present invention. The light shielding plate 210f is a slit of the zoom photo interrupter 36. It is arranged at a position where it can advance and retract.

  Here, the light shielding plate 210f enters the slit portion of the photo interrupter 36 when the lens barrel is retracted, and retreats from the slit portion of the photo interrupter 36 in the optical axis direction when the lens barrel is extended.

  As shown in FIGS. 1 and 4, a first group barrel 201 which is an example of a lens holding frame of the present invention is disposed on the inner peripheral side of the second movable cam barrel 209. As shown in FIG. 11, the first group barrel 201 includes three different types of follower pins 201a and 201b having different positions in the optical axis direction and the same phase in the circumferential direction at substantially equal intervals in the circumferential direction. The place is formed. The follower pin 201a is disposed closer to the object side than the follower pin 201b.

  The follower pin 201a is formed integrally with the first group barrel 201 and engages with the cam groove 209c of the second movable cam barrel 209. The follower pin 201b is formed of a metal pin or the like and is press-fitted into the first group barrel 201. It is fixed and corresponds to the cam groove 209d of the second moving cam cylinder 209. The cam groove 209d of the second movable cam cylinder 209 is wider than the shape of the follower pin 201b and does not function as a cam groove.

  That is, of the follower pins 201a and 201b, the follower pin 201a engages with the cam groove 209c, thereby preventing rattling in the optical axis direction, and the follower pin 201b plays a role of improving impact resistance at the time of impact such as dropping. Fulfill.

  Further, an engaging portion (not shown) that engages with a rectilinear guide groove 210a formed on the outer peripheral portion of the second rectilinear guide tube 210 is formed on the inner peripheral surface of the first group barrel 201. The unit serves as a guide when the first group barrel 201 moves in the optical axis direction.

  When the second moving cam barrel 209 rotates and moves in the optical axis direction, the first group barrel 201 moves straight in the optical axis direction without rotating through the cam groove 209c.

  Next, a lens barrier mechanism attached to the first group barrel 201 will be described with reference to FIG.

  As shown in FIG. 11, a lens barrier mechanism is provided at the front end of the first group barrel 201 to protect the photographing optical system by closing the photographing aperture when not photographing.

  The lens barrier mechanism includes a barrier blade 22 that protects the photographing optical system, a barrier moving ring 24 that drives the barrier blade 22 in the opening and closing direction, and a barrier spring 23 that biases the barrier blade 22 and the barrier moving ring 24 toward each other. Prepare. An imaging opening is formed on the object side of the barrier blade 22, and a barrier cover 21 that covers the barrier blade 22 is provided.

  The barrier moving ring 24 is provided with an extending piece 24a extending to the image plane side. When the extended piece 24a is in contact with the receiving portion 210b (see FIG. 13) of the second rectilinear guide tube 210, the barrier spring 23 biases the barrier blade 22 in the closing direction, and the barrier blade 22 causes the barrier cover to be closed. The photographing opening 21 is closed.

  When the extended piece 24a is separated from the receiving portion 210b of the second rectilinear guide tube 210, the barrier moving ring 24 starts to rotate by the biasing force of the barrier spring 23, and the blade contact portion 24b of the barrier moving ring 24 moves the barrier blade 22 away. Push to urge the barrier blade 22 in the opening direction. As a result, the photographing opening of the barrier cover 21 is opened.

  Next, the overall feeding operation and storage operation in the lens barrel will be described.

  FIG. 1 is a cross-sectional view of the lens barrel in a retracted state (collapsed state). At this time, the follower pin 201a of the first group barrel 201 is engaged with the cam groove 209c of the second movable cam barrel 209.

  Further, the second group unit is urged toward the subject side by the spring 35 in the optical axis direction, and is pressed against the upper surface of FIG. 7 in the optical axis direction of the cam groove 207f provided in the first movable cam cylinder 207. Is held by.

  Further, the photographing opening of the barrier cover 21 of the lens barrier mechanism attached to the first group barrel 201 is closed by the barrier blade 22.

  The driving force of the zoom motor 212 is transmitted to the gear 211 via the gear train 213 in order to shift the lens barrel from the housed state to the photographing state. As a result, the first moving cam cylinder 207 moves out in the direction of the optical axis while being rotated by the engagement between the follower pin 207a and the cam groove 205a formed on the inner peripheral surface of the fixed cam cylinder 205, and is drawn out.

  At this time, the first straight guide tube 208 is supported in a state in which the taper pin 208a and the cam groove 207c of the first moving cam tube 207 are bayonet-coupled, and there is no backlash in the optical axis direction and the radial direction.

  The first rectilinear guide cylinder 208 moves straight along the same locus as the first moving cam cylinder 207 in a state where the rotation is restricted by the fixed cam cylinder 205.

  When the first movable cam cylinder 207 is extended in the optical axis direction, the second group unit guided linearly by the first linear guide groove 208f of the first linear guide cylinder 208 is the follower pin 203a of the second group base 203 and the first movable cam cylinder. Due to the engagement of the cam groove 207b of 207, it moves straight in the optical axis direction. As a result, the lens barrel is held in the photographing state (wide state) as shown in FIG.

  When the second group unit enters the second group cam groove 207b by the rotation of the first moving cam cylinder 207 and starts to move straight in the optical axis direction, the second group unit is released from the bias of the spring 35, and the second group It moves along the cam groove 207b.

  Further, the second moving cam cylinder 209 is extended in the optical axis direction while rotating by the engagement of the drive pin 209b and the through cam 208e of the first rectilinear guide cylinder 208 by the extending operation of the first moving cam cylinder 207. Move the retracted area.

  The position of the driving pin 209b of the second moving cam cylinder 209 relative to the driving groove 207e of the first moving cam cylinder 207 in the retracted position is a position 209b1 in FIG. 7, and at this time, all the three driving pins 209b are connected to the driving groove 207e. Is engaged.

  In the retracted region, as shown in FIG. 14B, the follower pin 209a of the second moving cam cylinder 209 and the cam groove 208c of the first rectilinear guide cylinder 208 are not engaged. As shown in FIG. 14A, the drive pin 209b is engaged with the penetrating cam 208e in the optical axis direction but is not restricted in the radial direction. Shaking occurs in the radial direction between the movable cam cylinder 209.

  In this case, since the retracted region is a non-photographable region, there is no problem even if there is a slight backlash between the first rectilinear guide tube 208 and the second moving cam tube 209. By providing this, it is possible to reduce the driving load of the lens barrel when moving from the retracted area to the imaging area.

  Here, as shown in FIG. 7, the drive groove 207e of the first moving cam cylinder 207 is notched by the groove portions 207d1, 207d3, and 207d5 of the first moving cam cylinder, and the second moving cam cylinder 209 from the retracted state. As it goes out, it passes through this notch.

  However, the groove portions 207d1, 207d3, and 207d5 are formed so that the heights in the optical axis direction are different at the three locations, and the other two drive grooves 207e and drive pins are formed even in the region where the one drive groove 207e is notched. Since it is always engaged with 209, the zoom operation is not affected.

  Further, as shown in FIG. 7, the positions 209b2 and 209b3 are the positions of the drive pins 209b of the second moving cam cylinder 209 in the wide state and the tele state, respectively, but in the photographing region, the drive pins 209b and the drive grooves 207e. Is always engaged at all three locations. For this reason, a smoother zoom operation is possible.

  When the second moving cam cylinder 209 rotates and moves in the optical axis direction, the cam grooves 208c and 208d of the first rectilinear guide cylinder 208 are separated by the first rectilinear guide groove 208f before the wide position, and therefore the follower pin 209a Once comes out of the cam groove 208c. When the second movable cam cylinder 209 further moves in the optical axis direction, the follower pin 209a enters the cam groove 208d again.

  In the region where the cam grooves 208c and 208d are divided, the through cam 208e gradually changes and becomes wider, and as shown in FIG. 14C, it does not engage with the drive pin 209b. Conversely, the follower pin 209a and the cam groove 208d are engaged with each other as shown in FIG. 14D, and the second movable cam cylinder 209 is held in the imaging region (wide position) (FIG. 2).

  Further, the cam grooves 208c and 208d are chamfered at the divided portions, so that the follower pin 209a can perform a smooth zoom operation without being caught even when entering the cam groove 208d.

  Since the follower pin 209a is a taper pin, the second moving cam cylinder 209 does not shake in the optical axis direction and the radial direction with respect to the first rectilinear guide cylinder 208 in the photographing state in which the follower pin 209a and the cam groove 208d are engaged. Retained.

  The second rectilinear guide cylinder 210 is bayonet-coupled to the second moving cam cylinder 209 and is restricted in rotation by a second rectilinear guide groove 208g formed in the first rectilinear guide cylinder 208. Therefore, when the second moving cam cylinder 209 rotates and moves in the optical axis direction, the second rectilinear guide cylinder 210 moves linearly in the optical axis direction together with the second moving cam cylinder 209 and is held at the wide position.

  Further, when the second movable cam barrel 209 is extended in the optical axis direction, the first group barrel 201 guided linearly through the rectilinear guide groove 210a of the second rectilinear guide barrel 210 has the follower pin 201a and the second movable cam barrel 209. The cam groove 209c engages to move straight in the optical axis direction.

  When the first group barrel 201 starts moving in the optical axis direction, the first group barrel 201 moves away from the second rectilinear guide barrel 210 by the cam trajectory of the second movable cam barrel 209.

  When the first group barrel 201 and the second rectilinear guide cylinder 210 are separated, the extended piece 24a that is in contact with the receiving portion 210b at the time of retracting is separated from the receiving portion 210b, and the urging force of the barrier spring 23 is released. As a result, the barrier moving ring 24 rotates and the barrier blades 22 are opened, and the first lens barrel 201 is further moved in the optical axis direction and held in the wide position (FIG. 2).

  That is, the extension position of the first lens group 101 with respect to the CCD sensor 104 is determined by the forward movement amount of the first rectilinear guide barrel 208, the forward movement amount of the second movable cam barrel 209, and the cam extension amount of the second movable cam barrel 209. Determined as the total value.

  The extension position of the second lens group 102 with respect to the CCD sensor 104 is determined as a sum value of the forward movement amount of the first moving cam cylinder 107 and the cam extension amount of the first moving cam cylinder 107.

  When the zoom motor 212 is further driven from the wide state that is the imaging region, as described above, the first group barrel 201 that holds the first lens group 101 and the second group unit that holds the second lens group 102 are on the optical axis. To the tele state shown in FIG.

  Further, a cam groove 208d which is an accuracy cam of the first rectilinear guide tube 208 is formed in the region Y as shown in FIGS. Since the taper pin 208a is arranged behind the cam groove 208d, the second moving cam cylinder 209 is in a relationship with little tilt with respect to the first moving cam cylinder 207.

  In other words, the first lens group 101 of the first group barrel 201 that engages with the second moving cam cylinder 209 and the second lens group 102 of the second group unit that engages with the first moving cam cylinder 207 also tilt each other. It can be reduced.

  Also, in the imaging region from the wide position to the tele position, the third group barrel 204 holding the third lens group 103 is moved in the optical axis direction by driving the AF motor 34 according to the subject distance, and focusing is performed. Made.

  When the power is turned off and the zoom motor 212 is rotated in the reverse direction, the lens barrel is moved to the retracted position by performing a retracting operation reverse to that at the time of extension. In the middle of the movement to the storage position, the follower pin 209a of the second moving cam cylinder 209 is removed from the cam groove 208d, and again enters the cam groove 208c to be in a retracted state.

  Further, since the chamfered portion is provided at the divided portion of the cam groove 208c, the follower pin 209a can be smoothly retracted without being caught even when entering the cam groove 208c.

  Next, a drive control example of the zoom operation in the lens barrel of the present embodiment will be described.

  When the power is turned on, the control unit (not shown) determines whether or not the lens barrel is in the retracted position. Here, when the control unit does not detect a signal output from the photo interrupter 36 when the light shielding plate 210f provided on the second straight guide tube 210 is retracted from the slit of the photo interrupter 36 fixed to the CCD holder 206, The lens barrel is determined to be in the retracted position.

  When the lens barrel is in the retracted position, the control unit drives the zoom motor 212 to start the zoom operation. As a result, the driving force of the zoom motor 212 is transmitted from a gear (not shown) attached to the motor shaft to the first moving cam cylinder 207 via the gear train 213 and the gear 211, and the first moving cam cylinder 207 rotates. To do.

  Next, the control unit determines whether or not the first lens group 101 has moved to the zoom reset position. This determination is made based on whether or not the light shielding plate 210f provided on the second rectilinear guide tube 210 has been retracted from the slit of the photo interrupter 36 fixed to the CCD holder 206.

  That is, the control unit detects a signal output from the photo interrupter 36 when the light shielding plate 210f is retracted from the slit of the photo interrupter 36, and the first lens 101 group moves to the zoom reset position based on the detection signal. It is determined that

  In addition, when a signal indicating that the light shielding plate 210f is retracted from the slit of the photo interrupter 36 is not detected within a predetermined time, the control unit determines that the first lens group 101 has not moved to the zoom reset position. Perform error handling.

  Incidentally, three blades are integrally formed on a gear (not shown) attached to the motor shaft of the zoom motor 212, and these blades pass through slits of the two photo interrupters 38 and 39.

  The control unit detects the number of rotations of the zoom motor 212 by performing pulse conversion on a signal output when two photo interrupters detect passage of a blade and counting the pulses.

  At this time, the number of rotations of the zoom motor 212 at the zoom stop position such as the wide position and the tele position of the lens barrel is stored in advance in the memory with reference to the zoom reset position of the lens barrel.

  From the above, when it is determined that the lens barrel is driven to the zoom reset position, the zoom count is reset, and the lens barrel moves to the wide position. After the lens barrel moves to the wide position, the third group barrel 204 starts to move to the focus reset position.

  When the third group barrel 204 starts to move, the light blocking plate 204b of the third group barrel 204 is retracted from the slit portion of the focus photo interrupter 37. As a result, the output signal of the focus photo interrupter 37 is switched, and the control unit determines that the third group lens barrel 204 has been extended to the focus reset position, and the movement is completed.

  At this time, the control unit determines whether the third group lens barrel 204 has reached the focus reset position within a predetermined time.

  Then, when the signal of the focus photo interrupter 37 is not switched within a predetermined time, the control unit determines that some trouble has occurred and performs error processing. When it is determined by the control unit that the third group barrel 204 has reached the focus reset position within a predetermined time, the third group barrel 204 reaches the wide standby position and the preparation for photographing is completed.

  Here, in a series of zoom operations, only the first group barrel 201 is interposed between the first lens group 101 and the second rectilinear guide barrel 210, and the zoom reset position is detected in the second rectilinear guide barrel 210. A light shielding plate 210f is provided. This makes it possible to maintain stable optical performance even in a configuration with many cylinders.

  As described above, in the present embodiment, the second linear guide tube 210 that linearly guides the first group barrel 201 in the optical axis direction is shielded to detect the initial position of the first lens group 101 in the optical axis direction. A plate 210f is provided.

  Therefore, the light shielding plate 210f is disposed in the vicinity of the first lens group 101, and even if the number of cam cylinders and rectilinear guide cylinders is increased for higher magnification, It is possible to reduce the influence of an error from the moving position of the one moving cam cylinder 207. Thereby, the detection accuracy of the initial position of the first lens group 101 can be increased, the first lens group 101 can be stopped at an accurate position, and the optical performance of the lens barrel can be improved.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

  For example, in the above-described embodiment, the case where the light shielding plate 210f is provided in the second rectilinear guide tube 210 is illustrated, but the present invention is not limited to this. It may be attached to further increase the detection accuracy of the lens position.

  In the above embodiment, a zoom lens barrel configured by three groups has been exemplified. However, the present invention may also be applied to a zoom lens barrel configured by two groups or four groups.

101 First lens group 201 First group barrel 205 Fixed cam barrel 207 First moving cam barrel 208 First rectilinear guide barrel 209 Second movable cam barrel 210 Second rectilinear guide barrel 210f Light shielding plate

Claims (2)

A first cam cylinder, a holder attached to the first cam cylinder and attached with detection means for detecting a zoom reset position, and cam engagement with the first cam cylinder on the inner peripheral side of the first cam cylinder doing, the second cam barrel moves in the optical axis direction while rotating, it is disposed on the inner peripheral side of the second cam barrel, and a third cam barrel to move in the optical axis direction while rotating, the second A first linear guide cylinder coupled to the two cam cylinders and linearly moving in the optical axis direction; a second linear guide cylinder coupled to the third cam cylinder and linearly moved in the optical axis direction; and a lens, respectively. A plurality of lens holding frames that move straight in the optical axis direction; a detected member that is detected by the detection means when a lens that is arranged closest to the subject among the plurality of lenses moves to the zoom reset position; With
The detected member is provided in the second rectilinear guide tube ,
In the zoom operation, only the lens holding frame that holds the lens arranged closest to the subject is arranged between the lens arranged closest to the subject among the plurality of lenses and the second rectilinear guide tube. A lens barrel characterized by that . An imaging apparatus comprising the lens barrel according to claim 1 .