JP2008061295A - Motor unit, lens driving apparatus, lens barrel and image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving apparatus in which one of two moving lens groups moves with rotation of a lead screw, the other lens group moves with a prescribed play with respect to rotation of the lead screw and which can easily be assembled while a position relation of the desired lens group is secured and to provide a lens barrel having the lens driving apparatus. <P>SOLUTION: In the lens driving apparatus, the lead screw has a first male screw part and a second male screw part different in diameters. A minor diameter of the first male screw part is formed to be larger than a major diameter of the second male screw part. A part where screwing with a female screw member is released is formed between the first male screw part and the second male screw part or between two end parts of the lead screw. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens barrel having a motor unit including a lead screw on which a plurality of different leads are formed and a lens driving device configured to move two lens groups by the motor unit.

  2. Description of the Related Art Conventionally, cameras equipped with a variable focal length photographing lens (hereinafter also referred to as a zoom lens) are commercially available. The zoom lens is configured to change the focal length (zooming) by moving a plurality of lens groups constituting the optical system to a desired position along the optical axis and changing the interval therebetween.

  There are roughly two types of methods for moving a plurality of lens groups along the optical axis. The lens frame is engaged with the linear guide, and the lens frame is moved linearly by rotating the cam barrel, and the optical axis is used. A shaft is arranged almost in parallel, and this shaft is used as a guide shaft for rectilinear guide. A sleeve through which the guide shaft passes is formed in the lens frame, and the lens frame is slid directly along the guide shaft using a motor and a lead screw. There is something that lets you move straight ahead.

  The latter, which uses the lead screw to move the lens frame directly along the guide shaft, has a simple structure, so it is often used for lens barrels that do not require a retracting mechanism. There are a lead screw for moving one lens group and a lead screw for moving the other lens group as a driving device that moves the lens frame directly using, from one lead screw to the other lead screw. A lens driving device that transmits power using gears and a belt and moves two lens groups with one motor is known (for example, see Patent Document 1).

  In addition, the two shafts with cam grooves are arranged in series with play in the rotational direction, and the lens group that engages the cam grooves of each shaft is driven to perform zooming and focusing with a single motor There is known a lens barrel that performs the above (see, for example, Patent Document 2).

  The lens driving device described in Patent Document 1 can be applied to zooming but cannot perform focusing. Therefore, a driving source such as a motor for focusing is separately required, and when applied to a lens barrel, In addition to an increase in cost, there is a problem of an increase in size. Further, in the configuration of the lens barrel described in Patent Document 2, the play is an amount within one rotation of the shaft, and the amount of movement of the lens group for focusing can be reduced. It is difficult to ensure sufficient accuracy (resolution).

Therefore, in the Japanese Patent Application No. 2005-350417, the applicant of the present application has a single motor and a lead screw that is rotated in conjunction with the rotation of the motor. A lens barrel with a lens driving device configured to move with the rotation of the lead screw and the other lens group to move with a predetermined play amount with respect to the rotation of the lead screw is proposed. .
JP 2001-124974 A JP-A-4-317015

  The lens barrel proposed by the applicant of the present application in Japanese Patent Application No. 2005-350417 is capable of continuously changing the focal length in small increments with a single driving source, and securing a sufficient amount of focusing movement and resolution. A lens barrel having a small, low-cost lens driving device can be obtained.

  In this lens barrel, it is necessary to move the two lens groups while maintaining a desired positional relationship, and in a state where the two female screw members to be screwed into the lead screw are respectively in a predetermined position with respect to the lead screw, It is necessary to attach the motor unit to the main cylinder. Further, when the female screw member is screwed into the lead screw, when one of them is rotated and screwed, it cannot be assembled unless some condition is satisfied between the two female screw members and the lead screw. There's a problem.

  In view of the above problems, the present invention provides a single motor, a lead screw integrally formed with two types of male screw portions of different leads that rotate in conjunction with the motor, and two types of male screw portions, respectively. An object of the present invention is to obtain a low-cost motor unit, a lens driving device including the motor unit, and a lens barrel, in which a female screw member is easily assembled, and a motor unit having two female screw members to be screwed together Is.

  The above object is achieved by the invention described below.

  1. A motor, a lead screw integrally formed with a plurality of male screw portions of different leads rotating in conjunction with the motor, and a plurality of female screw members respectively screwed into the plurality of male screw portions of the lead screw , Wherein the female thread member screwed into the male thread part on the side close to the motor is larger in diameter than the male thread part far from the motor. unit.

  2. A motor, a lead screw integrally formed with a plurality of male screw portions of different leads rotating in conjunction with the motor, and a plurality of female screw members respectively screwed into the plurality of male screw portions of the lead screw A motor unit having the motor and a fixed frame that holds the lead screw, wherein a rotation locking portion of a female screw member that is screwed to the lead screw and the rotation locking are part of the fixed frame A motor unit characterized in that a portion where rotation cannot be locked is formed continuously with the portion.

  3. A plurality of lens groups, a single motor for moving two lens groups of the plurality of lens groups in the optical axis direction, and two types of male screw portions of different leads that rotate in conjunction with the motor. A motor unit having an integrally formed lead screw and two female screw members screwed into the male screw part, and a lens drive configured to move two lens groups by each of the female screw members An apparatus for driving a lens, wherein a female thread member screwed into a male thread part on a side closer to the motor has a larger diameter than a male thread part on a side far from the motor.

  4). At least one of the three positions between the two end portions of the lead screw and the plurality of male screw portions is formed with a portion where screwing with the female screw member is released. 4. The lens driving device according to 3.

  5. A plurality of lens groups, a single motor for moving two lens groups of the plurality of lens groups in the optical axis direction, and two types of male screw portions of different leads that rotate in conjunction with the motor. A motor unit having an integrally formed lead screw and two female screw members screwed into the male screw part, and a lens drive configured to move two lens groups by each of the female screw members The motor unit includes a fixed frame that holds the motor and the lead screw, a rotation locking portion of a female screw member that is screwed into the lead screw, and a part of the fixed frame; A lens driving device characterized in that a portion where rotation cannot be locked is formed continuously with the rotation locking portion.

  6). 6. The lens driving device according to any one of 3 to 5, wherein the female screw member has a rotation locking portion formed at a plurality of positions.

  A lens barrel comprising the lens driving device according to any one of 7.3 to 6.

  An imaging apparatus comprising the lens barrel described in 8.7.

  According to the present invention, a single motor and a lead screw in which two types of male screw portions of different leads rotating in conjunction with the motor are integrally formed, and two types of male screw portions are respectively screwed. Assembling of the female screw member of the motor unit having the two female screw members is facilitated, whereby a low-cost motor unit can be obtained. Further, by providing the motor unit, it is possible to obtain a low-cost lens driving device and a lens barrel.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  First, a lens barrel according to the present embodiment and an imaging apparatus including the lens barrel will be described.

  FIG. 1 is a diagram illustrating an example of an internal arrangement of main constituent units of a camera 100 that is an example of an imaging apparatus including a lens barrel according to the present embodiment. FIG. 3 is a perspective view of the camera 100 as viewed from the subject side.

  As shown in the figure, in the camera 100, a lens barrel 50 according to the present invention that includes a foldable imaging optical system capable of zooming is arranged vertically on the right side as shown in the figure, and an opening 51 takes in a subject light flux. Has been placed. The opening 51 is provided with a lens barrier (not shown) that is in an open state that exposes the opening 51 and a closed state that covers the opening 51.

  Reference numeral 52 denotes a flash light emission window. Reference numeral 53 denotes a flash unit including a reflector, a xenon tube, other main capacitors, a circuit board, and the like disposed behind the flash light emission window. Reference numeral 54 denotes a card-type image recording memory. A battery 55 supplies power to each part of the camera. The image recording memory 54 and the battery 55 can be inserted and removed from a lid (not shown).

  A release button 56 is disposed on the upper surface of the camera. When the first button is pushed, a shooting preparation operation of the camera, that is, a focusing operation and a photometric operation are performed, and a shooting exposure operation is performed by pushing the second button. A main switch 57 is a switch for switching the camera between an operating state and a non-operating state. When switched to the operating state by the main switch 57, the lens barrier (not shown) is opened and the operation of each part is started. When the main switch 57 is switched to the non-operating state, the lens barrier (not shown) is closed and ends the operation of each unit.

  On the back side of the camera, an image display unit 58 configured by an LCD, an organic EL, or the like and displaying an image and other character information is disposed. Although not shown, a zoom button for zooming up and down, a playback button for playing back a captured image, a menu button for displaying various menus on the image display unit 58, and a desired function are selected from the display. An operation member such as a selection button is arranged.

  Although not shown, each part is connected between these main constituent units and a circuit board on which various electronic components are mounted is arranged to drive and control each main constituent unit. Yes. Similarly, although not shown, an external input / output terminal, a strap attaching portion, a tripod seat, and the like are provided.

  FIG. 2 is a cross-sectional view showing an example of a foldable imaging optical system capable of zooming, which is included in the lens barrel 50 according to the present embodiment. This figure is a cross-sectional view taken along a plane including two optical axes before and after bending.

  As shown in the figure, OA is the optical axis before bending, and OB is the optical axis after bending.

  Reference numeral 1 denotes a first lens group. The first lens group 1 includes a lens 11 that is disposed toward a subject with an optical axis OA, a prism 12 that is a reflecting member that bends the optical axis OA in a substantially right angle direction, and a prism 12. The lens 13 is disposed with the optical axis OB bent by the optical axis as the optical axis. The first lens group 1 is a lens group fixed to the main body 9.

  Reference numeral 2 denotes a second lens group, which is incorporated in the second lens group frame 2k. The second lens group is a lens group that moves together with the second lens group frame 2k during zooming (hereinafter also referred to as zooming).

  Reference numeral 3 denotes a third lens group, which is fixed to the main body 9. The third lens group 3 is a lens group that does not move.

  Reference numeral 4 denotes a fourth lens group, which is incorporated in the fourth lens group frame 4k. The fourth lens group is a lens group that moves integrally with the fourth lens group lens frame 4k at the time of zooming, and also moves alone to perform focus adjustment (hereinafter also referred to as focusing).

  Reference numeral 5 denotes a fifth lens group, which is fixed to the main body 9. The fifth lens group 5 is a lens group that does not move.

  Reference numeral 7 denotes an optical filter in which an infrared light cut filter and an optical low-pass filter are stacked, and is assembled to the main cylinder 9. Reference numeral 8 denotes an image sensor, and a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, or the like is used. The image sensor 8 is assembled to the main body 9. The FPC is a flexible printed circuit board that is connected to the image sensor 8 and connected to other circuits in the camera. S is an aperture shutter unit, which is fixed to the main cylinder 9. Reference numeral 10 denotes a lid member assembled to the main body 9.

  FIG. 3 is a plan view showing a schematic structure inside the main barrel 9 of the lens barrel 50 provided with the lens driving device according to the present embodiment. The figure schematically shows the lens barrel 50 shown in FIG. 2 with the lid member 10 removed and the lens driving device according to the present embodiment arranged outside the lens barrel for the sake of simplicity. It is.

  As shown in the figure, the lens barrel 50 has a sleeve 2s formed integrally with the second lens group frame 2k and a sleeve 4s formed integrally with the fourth lens group frame 4k. A guide shaft 15 is provided. Further, the guide shaft 16 penetrates the rotation locking portion 2m formed integrally with the second lens group lens frame 2k and the rotation locking portion 4m formed integrally with the fourth lens group lens frame 4k. Is provided. Accordingly, the second lens group lens frame 2k and the fourth lens group lens frame 4k are slidable along the guide shafts 15 and 16 in the direction of the optical axis OB. Each sleeve is fitted with a guide shaft, and the guide shafts 15 and 16 are disposed substantially in parallel with the optical axis OB, and are fixed to the main body 9 by bonding or the like at both ends thereof.

An engaging portion 2t is integrally formed with the sleeve 2s. The female screw member 23 screwed with the lead screw and moved in the direction of the optical axis OB along the guide shaft 15 by the rotation of the lead screw has play in the direction of the optical axis OB as shown in the figure. And are configured to engage. Specifically, the inner width t ₂ of the engaging portion 2 t is formed larger than the thickness t ₁ of the female screw member 23. That is, in the figure, (t ₂ -t ₁ ) corresponds to the play amount.

  The sleeve 4s is integrally formed with an engaging portion 4t, and is engaged with a female screw member 24 that is screwed with the lead screw and moved in the optical axis OB direction along the guide shaft 15 by the rotation of the lead screw. Match.

In the stepping motor 20 (hereinafter also referred to as a motor), a lead screw 20r that is a male screw member is disposed on an extension line of the rotating shaft. The lead screw 20r is formed with a first male screw portion 20r ₁ and a second male screw portion 20r ₂ having different pitches and screw advance directions on one shaft. The lead screw 20r having the first and second male screw portions 20r ₁ and 20r ₂ may be individually manufactured, joined and integrated, or an integrated shaft may be processed.

The female screw member 23 is screwed with the first male screw portion 20r ₁ of the lead screw 20r, and moves the second lens group lens frame 2k engaged with a predetermined play amount in the direction of the optical axis OB. Similarly, female screw member 24 is combined second threaded and male threaded portion 20r ₂ of lead screw 20r, moving the fourth lens group holding frame 4k which engages the optical axis OB direction.

  As a result, the second lens group 2 and the fourth lens group 4 approach the third lens group 3 from both sides with different movement amounts due to the rotation of the stepping motor 20 in a predetermined direction, and the stepping motor 20 rotates in the reverse direction. Accordingly, the third lens group 3 is moved away from the third lens group 3 by different moving amounts.

  32 is a photo interrupter. The photo interrupter 32 detects the initial position for positioning the second lens group frame 2k by detecting the switching position of the presence or absence of the shielding portion formed on the second lens group frame 2k. This photo interrupter preferably detects the initial position of the lens group moved with a play amount, that is, the second lens group frame 2k in this example.

  The position control of each lens group is performed by controlling the rotation direction and the rotation amount of the stepping motor 20 based on the initial position. The initial position detection of the lens group lens frame may be a photo reflector.

  That is, in the prior art, an initial position detection means is required for each lens group lens frame. However, in this embodiment, only one initial position detection of the lens group lens frame is required, which saves space and costs. Is possible.

  FIG. 4 is an internal cross-sectional view of the sleeve 2s cut along a plane perpendicular to the optical axis OB. This figure shows only the sleeve 2s side of the second lens group frame 2k.

  As shown in the figure, a guide shaft 15 which is a member fixed to the main body 9 passes through a hole 2h formed in the sleeve 2s, and a friction member 21 biased by a compression coil spring 22 is guided by the guide shaft 15. The shaft 15 is pressed.

Accordingly, as shown in FIG. 2, the engaging portion 2t and the female screw member 23 formed on the sleeve 2s have a play amount of (t ₂ -t ₁ ), and the engaging portion 2t and the female screw Even when the member 23 is in the separated state, the second lens group frame 2k can maintain the stopped state by this frictional force. The female screw member 23 abuts on the engaging portion 2t, and applies a force to overcome the frictional force to the engaging portion 2t, thereby moving the second lens group lens frame 2k in the optical axis OB direction.

  FIG. 5 is a diagram showing a lens group position control method when the second lens group and the fourth lens group of the lens barrel 50 according to the present embodiment are moved from the wide angle side to the telephoto side. 4A is a movement diagram of the second lens group and the fourth lens group, and FIGS. 4B to 4E are engaging portions 2t of the sleeve 2s and the female screw member 23, and the sleeve 4s and the female lens. It is a figure which shows the position of the screw member.

  As shown in FIG. 5A, the second lens group 2 and the fourth lens group 4 are moved so as to approach the third lens group 3 so that the magnification is changed from wide angle (W) to telephoto (T). To do.

The width between the broken line A and the second solid line indicating the position of the second lens group 2 shown in FIG. 4A corresponds to the play amount (t ₂ −t ₁ ) measured as described above. When the female screw member 23 moves by the play amount, the female screw member 24 and the fourth lens group 4 move from the broken line C to the position of the broken line B. Hereinafter, a description will be given with reference to FIGS.

It is assumed that the initial state is a wide angle (W) state, and the female screw member 23 is in a position in contact with the engaging portion 2t on the first lens group 1 side (position Aw). First, the motor is driven so that the female screw member 23 is moved from the Aw position to the 2w position. As a result, the female screw member 23 moves by an amount corresponding to the play amount (t ₂ −t ₁ ) and comes into contact with the other end of the engaging portion 2t. The second lens group frame 2k remains stopped. At this time, the female screw member 24 and the fourth lens group lens frame 4k move from the Cw position to the Bw position. The state at this position is shown in FIG.

  Further, the motor is driven in the same direction, and the female screw member 23 is moved to a position of 2 ma and stopped. As a result, the second lens group frame 2k approaches the third lens group 3 and is in a position necessary for the focal length MA. At this time, the female screw member 24 and the fourth lens group frame 4k move from the position Bw to the position Bma. The state at this position is shown in FIG.

  Next, the motor is driven in reverse to move the female screw member 24 and the fourth lens group frame 4k from the Bma position to the 4ma position. At this time, the female screw member 23 moves from the position of 2ma in the direction of Ama. However, as shown in FIG. 4D, the female screw member 23 and the engaging portion 2t are moved within the play amount, so that they are separated from each other. Thus, the second lens group frame 2k remains stopped. This state is a state in which the second lens group 2 and the fourth lens group 4 have a focal length MA and the focus is adjusted with respect to a subject at infinity.

  Thereafter, the motor is driven so as to move the female screw member 24 between 4ma and Bma, so that the fourth lens group lens frame 4k is stopped while the second lens group lens frame 2k is stopped. Focusing can be performed by moving in the state as shown in FIG. That is, the hatching area between the solid line and the broken line B of the fourth lens group 4 in FIG. 4A is the focusing area of the fourth lens group.

  As described above, zooming from the wide-angle side to the telephoto side can be performed by the movement of FIGS. 7B to 7D, and focusing can be performed by the movement of FIGS.

  FIG. 6 is a diagram showing drive control when the second lens group and the fourth lens group of the lens barrel 50 according to the present embodiment are moved from the telephoto side to the wide angle side. 4A is a movement diagram of the second lens group and the fourth lens group, and FIGS. 4B to 4E are engaging portions 2t of the sleeve 2s and the female screw member 23, and the sleeve 4s and the female lens. It is a figure which shows the position of the screw member.

  The state will be described from the state in which the female screw member 23 is at the position 2ma and the state in which the female screw member 24 is at the position Bma (the state shown in FIG. 5B).

  First, the motor is driven so that the female screw member 23 is moved from the 2ma position to the Ama position and the female screw member 24 is moved from the Bma position to the Cma position. The state at this position is shown in FIG.

  Further, the motor is driven in the same direction, and the female screw member 23 is moved to the Amb position and stopped. As a result, the second lens group frame 2k moves in a direction away from the third lens group 3, and becomes a position necessary to obtain the focal length MB. At this time, the female screw member 24 and the fourth lens group frame 4k move from the position of Cma to the position of Cmb. The state at this position is shown in FIG.

Next, the motor is driven in the reverse direction to move the female screw member 24 and the fourth lens group frame 4k from the Cmb position to the 4mb position. At this time, the female screw member 23 moves in the direction of 2 mb from the position of Amb. However, as shown in FIG. 5E, the female screw member 23 and the engaging portion 2t are within the play amount (t ₂ -t ₁ ). The second lens group lens frame 2k remains stopped because of the movement. This state is a state in which the second lens group 2 and the fourth lens group 4 have a focal length MA and the focus is adjusted with respect to a subject at infinity.

  Thereafter, by driving the motor so as to move the female screw member 24 between 4 mb and Bmb, focusing is performed by moving only the fourth lens group frame 4k while stopping the second lens group frame 2k. It can be carried out.

  As described above, zooming from the wide-angle side to the telephoto side is performed by the movement of FIGS. 7B to 7D, and the focus adjustment to the infinite object is performed by the movement of FIGS. From FIG. 5E, focusing can be performed by moving only the fourth lens group 4k.

  Hereinafter, the motor unit of the lens driving device according to the present embodiment will be described. In the following drawings, in order to avoid duplication of explanation, the same reference numerals are given to the same functional members. The motor unit is a unit in which the motor 20, the lead screw 20r, and the fixed frame 25 shown in FIG.

  FIG. 7 is a diagram illustrating an example of a motor unit of the lens driving device according to the present embodiment. FIG. 2A is a diagram showing the entire motor unit, and FIG. 2B is a cross-sectional view taken along the line FF shown in FIG.

As shown in FIG. 5A, both end portions of the lead screw 20r, in which the first male screw portion 20r ₁ and the first male screw portion 20r ₂ are formed, which are different in at least one of the screw advance direction and the pitch. 35 and 36 and the portion 37 between the first male screw portion 20r ₁ and the second male screw portion 20r ₂ have a small diameter so that the screw engagement with the female screw member 23 or 24 is released. Is formed. It should be noted that this narrow diameter portion is a portion indicated by 37 between the first male screw portion 20r ₁ and the second male screw portion 20r ₂ , or a portion indicated by 35 and 36 at both ends of the lead screw. What is necessary is just to be formed.

Further, as shown in the figure, when the mountain diameter of the first female screw member 23 is T and the mountain diameter of the _second male screw portion 20r ₂ is Y, T> Y is satisfied. Therefore, the first female screw member 23 can be a second male threaded portion 20r ₂ through the second male threaded portion 20r ₁ without screw connection. In such a configuration, the fixed frame 25 and the lead screw 20r, when the first, assemble the second female screw member 23 and 24, either of the bearing portion 25h ₁ or 25h ₂ fixed frame 25 the lead screw 20r Meanwhile the threading, the first in this state, the second female screw member 23, 24 a screw coupled to the lead screw 20r, further, through the distal end of the lead screw 20r to the other bearing part 25h ₁ or 25h ₂ fixed frame 25 Can be assembled. If the configuration is not as described above, for example, it is necessary to divide the lead screw into two bodies, screw the first and second female screw members 23 and 24 respectively, and then connect the lead screws integrally, etc. Decrease accuracy, increase costs, etc.

Further, a magnet Mg constituting the motor is integrally fixed to the motor 20 side of the lead screw 20r. For this reason, since it cannot pass from the motor 20 side to the bearing part of the fixed frame 25, it is preferable that the diameter of the male screw part (corresponding to 20r _{2 in the} figure) on the side far from the motor 20 is formed thin.

Further, the female screw member 23 is rotationally locked by a fixed frame 25 as shown in FIG. 5B, and moves straight by the rotation of the _first male screw portion 20r1. The female screw member 24 is similarly rotationally locked, and moves linearly by the rotation of the _second male screw portion 20r2.

As described above, the first to the crest diameter of the female screw member 23 is formed to be larger than the second male threaded portion 20r ₂ crest diameter, a first male screw portion 20r ₁ and the second male screw portion 20r ₂ or at the two ends of the lead screw 20r, a portion where the screwing with the female screw member is released is formed, so that the positioning reference of the fixed frame 25 with respect to the main body 9 is at the position indicated by A. If it is assumed that the female screw member 24 is positioned at a position L ₀ away from the positioning reference and the interval between the female screw member 23 and the female screw member 24 is set to L, the female screw member is placed on the portion having the small diameter. 23, the female screw member 24 is in a standby state, and the other of the female screw member 23 and the female screw member 24 is screwed and moved to reach a desired position. By screwing the member, the female screw member 24 is positioned. The position of the L ₀ from determined criteria, the spacing of the female screw member 23 and the female threaded member 24 can be L, the can be ensured the positional relation of the lens groups, the easily assembled capable lens driving device Can be obtained.

  FIG. 8 is a diagram illustrating another example of the motor unit of the lens driving device according to the present embodiment. FIG. 2A is a diagram showing the entire motor unit, FIG. 2B is a cross-sectional view taken along line FF shown in FIG. 1A, and FIG. It is sectional drawing cut | disconnected by the GG line | wire shown to a). In the figure, only the parts different from the motor unit shown in FIG. 7 will be described.

  As shown in FIG. 5B, the female screw member 23 is formed with projections 23t in 90 ° increments. One of the protrusions 23t is engaged with a long groove-shaped rotation locking groove 25m formed in the fixed frame 25 as shown in FIG. Further, a portion 25t where rotation cannot be locked is formed continuously with the rotation locking groove 25m.

Thus, by forming the protrusions 23t at plural locations at intervals of 90 degrees in the female screw member as a rotation locking unit, in 1/4 increments of the pitch of the lead screw 20r _1, the female screw for the female screw member 24 The position and spacing of the member 23 can be adjusted. That is, even if the lead screws 20r ₁ and 20r ₂ are out of phase, the position and interval of the female screw member 23 relative to the female screw member 24 can be adjusted with an error of ¼ or less of the pitch. Such a configuration can also be applied to the female screw member 24, and is not limited to 90 ° increments, but can be adjusted in 45 ° increments (adjustable in 1/8 pitch increments), 60 ° increments (1/6 pitch increment). It is possible to set it in steps of 72 degrees (adjustable in steps of 1/5 of the pitch). By adopting such a configuration, even if the relative rotational direction phase of the _first and second male threaded portions 20r ₁ and 20r ₂ deviates from the design requirement, the error is reduced to 1 / n (the pitch). n can be adjusted to be equal to or less than the deviation of the number of rotation restricting portions.

  In the above-described embodiment, the camera is described as an example of the imaging device. However, the present invention is also applicable to a camera module built in a portable terminal such as a PDA or a cellular phone. Further, although the bending optical system has been described, the present invention can also be applied to a lens barrel that includes an optical system having no reflecting surface.

It is a figure which shows an example of the internal arrangement | positioning of the main structural unit of the camera which is an example of the imaging device provided with the lens barrel which concerns on this Embodiment. It is sectional drawing which shows an example of the bending imaging optical system which can be changed in magnification included in the lens barrel which concerns on this Embodiment. It is a top view which shows schematic structure inside the main barrel of the lens barrel provided with the lens drive device concerning this Embodiment. FIG. 5 is an internal cross-sectional view of a sleeve 2s cut along a plane perpendicular to the optical axis OB. It is a figure which shows the lens group position control method at the time of moving the 2nd lens group and 4th lens group of the lens barrel which concerns on this Embodiment from a wide angle side to a telephoto side. It is a figure which shows drive control at the time of moving the 2nd lens group and 4th lens group of the lens barrel which concerns on this Embodiment from the telephoto side to the wide angle side. It is a figure which shows an example of the motor unit of the lens drive device which concerns on this Embodiment. It is a figure which shows another example of the motor unit of the lens drive device which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 2k 2nd lens group frame 3 3rd lens group 4 4th lens group 4k 4th lens group frame 5 5th lens group 7 Optical filter 8 Image sensor 9 Main trunk 10 Lid Member 15, 16 Guide shaft 20 Stepping motor 20r Lead screw 23, 24 Female screw member 25 Fixed frame OA, OB Optical axis 50 Lens barrel 100 Camera

Claims (8)

A motor, a lead screw integrally formed with a plurality of male screw portions of different leads rotating in conjunction with the motor, and a plurality of female screw members respectively screwed into the plurality of male screw portions of the lead screw A motor unit comprising:
A motor unit characterized in that a female thread member screwed into a male thread part on the side close to the motor has a larger diameter than a male thread part on a side far from the motor. A motor, a lead screw integrally formed with a plurality of male screw portions of different leads rotating in conjunction with the motor, and a plurality of female screw members respectively screwed into the plurality of male screw portions of the lead screw A motor unit having the motor and a fixed frame for holding the lead screw,
A motor unit characterized in that a part of the fixed frame is formed with a rotation locking part of a female screw member screwed to the lead screw and a part where rotation locking is impossible. A plurality of lens groups, a single motor for moving two lens groups of the plurality of lens groups in the optical axis direction, and two types of male screw portions of different leads that rotate in conjunction with the motor. A motor unit having an integrally formed lead screw and two female screw members screwed into the male screw part, and a lens drive configured to move two lens groups by each of the female screw members A device,
A lens driving device characterized in that a crest diameter of a female thread member screwed into a male thread section on the side close to the motor is larger than a crest diameter of a male thread section on a side far from the motor. At least one of the three positions between the two end portions of the lead screw and the plurality of male screw portions is formed with a portion where screwing with the female screw member is released. The lens driving device according to claim 3. A plurality of lens groups, a single motor for moving two lens groups of the plurality of lens groups in the optical axis direction, and two types of male screw portions of different leads that rotate in conjunction with the motor. A motor unit having an integrally formed lead screw and two female screw members screwed into the male screw part, and a lens drive configured to move two lens groups by each of the female screw members A device,
The motor unit includes a fixed frame that holds the motor and the lead screw, and a rotation locking portion and a rotation locking portion of a female screw member that is screwed into the lead screw are part of the fixed frame. A lens driving device characterized in that a portion where rotation cannot be locked is formed. The lens driving device according to any one of claims 3 to 5, wherein the female screw member has a rotation locking portion formed at a plurality of positions. A lens barrel comprising the lens driving device according to claim 3. An imaging apparatus comprising the lens barrel according to claim 7.

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