JP5717457B2 - Lens barrel and digital camera - Google Patents

Description

  The present invention relates to a structure of a lens barrel of an imaging apparatus such as a digital camera.

  The digital camera's optical system is a varifocal lens that is part of the photographic lens, most of which has the rearmost lens as the focus lens and is driven with high precision and compensates for it. A feeling of operation has been obtained and the miniaturization of the camera has been achieved.

  Therefore, the focus lens needs to be combined with a focus mechanism that operates accurately and quickly so as to accurately compensate for the movement of the focus position of the varifocal lens and not cause the user to feel that the operation is slow.

  Therefore, a stepping motor is adopted as the drive motor of the focus mechanism in order to drive accurately. In particular, a direct drive system is adopted in which a mechanism intervening in the middle is omitted, a lead screw is provided on the rotating shaft of the stepping motor, and a nut is provided on the lens holding frame on the lens side. This is for shortening the drive control time so that an accurate drive amount can be obtained even in open loop control.

  However, there is always play in the joints such as the lead screw and nut, which hinders high accuracy.

  Therefore, Patent Document 1 discloses a technique for removing play play between the lead screw and the nut by making the nut into two parts and repelling them with a spring. The lens holding frame shows a first guide shaft that ensures accuracy in the optical axis direction and a second guide shaft that prevents the lens holding frame from rotating about the first guide shaft.

JP 2002-287001 A

  In the prior art disclosed in the above-mentioned patent document, play play between the lead screw and the nut can be removed. However, there is a case where the accuracy of the stop position or the control position is insufficient due to vibration accompanying the driving of the lens holding frame. This is because in order for the lens holding frame to move along the first guide shaft, play of the lens holding frame and the first guide shaft requires play play. Further, in order to prevent the lens holding frame from rotating with the second guide shaft, play play is also required between the rotation of the lens holding frame and the rotation stopping groove of the lens holding frame.

To achieve the above object, a lens barrel of the present technical idea, a lead screw which is given rotational motion by a driving source, a nut engaging said lead screw, the rotation of the lead screw that engages the nut Accordingly, the lens holding frame that moves along the optical axis direction, the first guide shaft and the second guide shaft that guide the movement of the lens holding frame in the optical axis direction, the first guide shaft, and the first guide shaft. An outer frame that holds the two guide shafts, and when viewed from the optical axis direction, the lens holding frame is located on the second guide shaft and is positioned on the opposite side of the lead screw with the first guide shaft interposed therebetween. And a biasing means charged with movement of the lens holding frame in the optical axis direction ,
The biasing means is attached to the hanging portion of the lens holding frame and the hanging portion of the outer frame so as to be inclined with respect to the optical axis,
When viewed from the optical axis direction, the hanging portion of the lens holding frame is located closer to the optical axis than the straight line connecting the first guide shaft and the lead screw .

  The lens barrel according to another aspect of the present invention includes a lead screw that is rotated by a drive source, a nut that engages with the lead screw, and a lens, and the lead that engages with the nut. A lens holding frame that moves along the optical axis direction toward the subject side as the screw rotates clockwise as viewed from the subject side of the screw, and first and second guide shafts that guide the movement of the lens holding frame in the optical axis direction And an outer frame that holds the first and second guide shafts, and the lens holding frame that is positioned on the opposite side of the lead screw with the first guide shaft interposed therebetween. An urging unit that is abutted and charged with movement of the lens holding frame in the optical axis direction, the urging unit being fixed to the lens holding frame and the outer frame while being inclined with respect to the optical axis. And have.

  According to the present invention, it is possible to provide a lens barrel in which the lens holding frame is stabilized and the accuracy of the stop position and the control position is improved.

It is sectional drawing of a lens-barrel. It is a front view which shows a focus mechanism. It is a perspective view which shows a focus mechanism. It is sectional drawing which shows a spring hook. This is a conventional example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<About the sectional view of the lens barrel>
FIG. 1 is a cross-sectional view of a lens barrel of a digital camera according to an embodiment of the present invention.

  In FIG. 1, there is an image sensor 1 that converts an image formed on the rear end of a lens barrel into an electric signal.

  The imaging element 1 is bonded to the sensor plate 2 and fixed to the outer frame 3 that also serves as a sensor holder with a screw (not shown). The imaging element 1 images reflected light from a subject that has passed through the lens barrel.

  The outer frame 3 incorporates a focus mechanism constituted by a third lens group 4 and a lens holding frame 5 of the photographing lens. The focus mechanism will be described later in detail in the embodiments.

  A fixed cylinder 6 is attached to the outer frame 3 with a screw (not shown), and a motor and a gear for performing a zooming operation for changing the focal length of the optical system and a storing operation of the lens barrel are incorporated.

  Of these gears, the last gear rotates the drive gear 7a of the cam cylinder 7, and a cam pin (not shown) of the cam cylinder 7 moves in the direction of the optical axis while rotating along the cam groove 6a of the fixed cylinder 6.

  There is a straight cylinder 8 inside the cam cylinder 7. The rectilinear cylinder 8 has a key 8a, which is in a key groove 6b (not shown) of the fixed cylinder 6. The rectilinear cylinder 8 and the cam cylinder 7 are rotatably held by the cam cylinder 7 by a method (not shown), are constrained to rotate by the key 8a, and move in the optical axis direction together with the cam cylinder 7 without rotating.

  The cam cylinder 7 includes a second group cam 7 b that drives a second group lens holder 10 that holds the second group lens 9, and a first group cam 7 c that drives the first group lens holder 13 that holds the first group lens 11 and the lens barrier 12. There is.

  The second group lens holder 10 is moved in the direction of the optical axis in the cam cylinder 7 by the cam pin 10a of the second group lens holder 10 tracing the second group cam 7b and subject to the restriction of rotation around the optical axis by the rectilinear cylinder 8. To do.

  The first group lens holder 13 is outside the rectilinear cylinder 8, and the rotation direction is restricted by a locking portion (not shown). A cam pin (not shown) of the first group lens holder 13 is driven by the first group cam 7c and moves in the cam cylinder 7 in the optical axis direction.

  The second group cam 7b and the first group cam 7c of the cam barrel change the optical axis positions of the second group lens 9 and the first group lens 11 to form a varifocal lens having a variable focal length.

<About the focus mechanism>
Next, the focus mechanism will be described. FIG. 2 is a front view showing the focus mechanism as seen from the subject side. FIG. 2A is a diagram including an outer frame 3 that also serves as a sensor holder. FIG. 2B is a view in which the outer frame 3 is removed to make the main configuration easy to see. However, in FIG. 2B, the second guide shaft 3a is left and illustrated.

  As shown in FIGS. 2A and 2B, a focus mechanism is incorporated in the outer frame 3. A second guide shaft 3 a is integrated with the outer frame 3. The second guide shaft 3 a is located in the guide groove 5 e of the lens holding frame 5.

  A stepping motor, which is a drive source 14, is fixed to the outer frame 3, and a first guide shaft 15 is provided on the right side thereof. In addition, although the stepping motor is illustrated and demonstrated as the drive source 14, it may be a voice coil motor or a DC motor, for example.

  Here, there is a spring hook 5 f of the lens holding frame 5 on the opposite side of the drive source 14 across the first guide shaft 15. The biasing means 16 is hung on the spring hook 5f. Therefore, the urging force is charged as the lens holding frame 5 moves in the optical axis direction. In addition, although demonstrated here also using a coil spring as the biasing means 16, rubber | gum may be sufficient.

  The drive source 14, the first guide shaft 15, and the spring hook 5 f of the lens holding frame 5 are arranged outside the fixed cylinder 6. This is to make the lens barrel compact. On the other hand, in order to be as close to the optical axis as possible, they are arranged close to each other so as to stick to the fixed cylinder 6. In this regard, when the diameter of the lens barrel is larger than the diameter of the lens, the driving source 14, the first guide shaft 15, and the spring hook 5 f of the lens holding frame 5 may be arranged inside the fixed cylinder 6. .

  The lens holding frame 5 holds the third group lens 4 at the center of the optical axis. The lens holding frame 5 is guided in the optical axis direction so as not to be tilted by the first guide shaft 15, and is prevented from rotating by the second guide shaft 3a. As a result, the optical axis of the third group lens 4 moves without being inclined with respect to the optical axis of the lens barrel.

  FIG. 3 is a perspective view showing the focus mechanism. FIG. 3A is a view of the focus mechanism as viewed from the upper left. FIG. 3B is a view in which the mounting plate of the drive source 14 is removed to make the nut 19 and the lead screw 18 easier to see. FIG. 3C is a diagram in which the outer frame 3 is also removed in order to facilitate understanding of the shape of the lens holding frame 5. In this embodiment, the nut 19 is formed of a nonmetallic resin. This is because it is easier to make complex shapes than sheet metal.

  As shown in FIG. 3A, the drive source 14 is attached to the support metal plate 14 a and is fixed to the outer frame 3 with screws 17.

  Positioning is performed by a shaft 3b for positioning the supporting sheet metal 14a visible in FIG. 3B excluding the supporting sheet metal 14a, and screws 17 are screwed into the screw holes 3c and fixed.

  A lead screw 18 is provided on the rotation shaft of the drive source 14, and the lead screw 18 receives a rotational motion from the drive source 14. In this regard, the lead screw 18 may not be provided directly on the rotating shaft of the drive source 14, but the rotating force may be transmitted from the rotating shaft to the lead screw 18 via a gear. However, when this gear is used, the sound noise increases and the backlash tends to occur.

  A nut 19 is screwed into the lead screw 18. The nut 19 is sandwiched between the nut holding portions 5 a of the lens holding frame 5. The urging means 16 urges the lens holding frame 5 in the optical axis direction to bring the nut 19 and the lead screw 18 into contact with each other.

  Here, the lead screw 18 and the nut 19 will be described as right-hand screws. Therefore, when the lead screw 18 is rotated in the clockwise direction toward the paper surface, the nut 19 is drawn out in the direction of the arrow Z. The direction of the arrow Z is the direction on the subject side where the subject is present, and is opposite to the imaging side where the image sensor 1 is located.

  The nut 19 can be composed of a molded product of resin such as a steel plate, a brass plate, or a plastic. The softer the material, the quieter the drive noise tends to be, so the place of plastic molded products such as plastics becomes quieter. This is because in the case of a plastic molded product, the lead screw 18 and the plastic are in contact with each other, and the friction between them is reduced.

  The lens holding frame 5 has a pair of upper and lower bearings 5 b along the optical axis that is fitted to the first guide shaft 15. By holding with this bearing, the lens holding frame 5 can move in the optical axis direction without tilting. The pair of bearings are used to prevent the optical axis of the third lens group 4 from being inclined with respect to the optical axis of the lens barrel.

  The first guide shaft 15 is press-fitted and fixed in a guide shaft hole 3 b provided in the outer frame 3. Although not shown, the guide shaft hole 3b is provided in a pair so that the lower end of the first guide shaft 15 is also press-fitted.

  The lens holding frame 5 is connected to a lens holding portion 5d to which the third group lens 4 is attached with an arm portion 5c. The arm portion 5c is positioned below the cam barrel 7 and the straight advance barrel 8 when the lens barrel is retracted.

  Therefore, in order to shorten the length of the storage state of the lens barrel, a retracting hole for the arm portion 5c is provided in the outer frame 3, and the arm portion 5c is retracted here when the lens barrel is stored. The arm portion 5c is required to have rigidity for maintaining the positional accuracy of the third group lens 4. On the other hand, the arm portion 5c has a thickness that allows the accuracy to be maintained in order to shorten the length of the lens barrel in the retracted state. . As a result, when the third lens group 4 is moved in the optical axis direction, the lens holding portion 5d vibrates with an amplitude that affects the focus accuracy. In this regard, as will be described later, the vibration is suppressed by friction between the second guide shaft 3a and the guide groove 5e. Around the lens holding portion 5d of the lens holding frame 5, there is a rotation-preventing guide groove 5e fitted to the second guide shaft 3a. The lens holding frame 5 is held by the first guide shaft 15 and is prevented from rotating by sandwiching the second guide shaft 3a in the guide groove 5e. As a result, the optical axis of the third group lens 4 can be moved without being inclined with respect to the optical axis of the lens barrel.

  There is a spring hook 5 f in the vicinity of the bearing 5 b on the upper side of the lens holding frame 5, and a biasing means 16 is hung between the spring hook 3 c of the outer frame 3. The positional relationship between the spring hook 3c of the outer frame 3 and the spring hook 5f of the lens holding frame 5 is such that the biasing means 16 is slanted rather than being positioned in the horizontal direction on the optical axis. Therefore, the moment of a component having an angle with respect to the optical axis direction is generated by the biasing means 16.

  FIG. 4 is a BB cross section of FIG. The BB cross section is intended to be a cross-sectional view showing how to apply the spring. The spring hook 5f, the urging means 16, and the spring hook 3c are inclined with respect to the optical axis direction when viewed from the side as shown in FIG.

  Further, as shown in FIG. 2, the spring hook 5f of the lens holding frame 5 is closer to the optical axis than the line L obtained by extending the line connecting the lead screw 18 and the first guide shaft 15.

  By urging the biasing means 16 obliquely and by setting the spring hook 5f to the optical axis side from the line L, the lens holding frame 5 receives a rotational moment in the same direction as pushing the third group lens 4 toward the subject side. ing. This will be described in detail below.

<Receiving rotational moment in the same direction>
First, static balance and play play will be explained.

  The lens holding frame 5 holds the third group lens 4, is supported by the first guide shaft 15 and the second guide shaft 3a, and is movable in the optical axis direction.

  Since the lens holding frame 5 is pulled by the urging means 16, the nut holding portion 5 a presses the nut 19 toward the outer frame 3. Accordingly, the lower surface of the screw of the nut 19 is in a state where a force is applied to press the upper surface of the screw of the lead screw 18.

  Here, the biasing means 16 is applied obliquely, and its inclination is about 1/10 degree, so that the force on the plane perpendicular to the optical axis is 1/10 of the spring force. Assuming that the force of the biasing means 16 is x gram, x / 10 gram is a component force in a vertical plane, and the length of the arm of the spring hook 5f is about ymm. Therefore, the rotational moment created by the lens bias spring 16 is xy / 10. Gram x mm.

  Here, part of the rotational moment is also applied to the lead screw 18 and the first guide shaft 15. This is because when the lead screw 18, the nut 19, and the nut holding portion 5 a receive only a force less than the maximum static friction due to the frictional force, they function as if they are integrated. On the other hand, the engagement of the lead screw 18, the nut 19, and the nut holding part 5 a is slightly backlash. For this reason, the presence of the backlash and the above-described integral view allow a part of the rotational moment to be applied to the lead screw 18 and the first guide shaft 15. Accordingly, the clockwise rotational moment acts as a rotational force with the first guide shaft 15 as a fulcrum between the lens holding frame 5 and the spring hook 5f.

  The rotational moment is also applied to the first guide shaft 15 and the second guide shaft 3a. A moment in the clockwise direction is applied to the lens holding frame 5 with the first guide shaft 15 as a fulcrum as shown in FIG. This clockwise moment acts on the second guide shaft 3a via the guide groove 5e. The direction of the moment is a direction in which play of play with the push guide groove 5e is approached from the spring hooking 5f side of the line connecting the optical axis and the second guide shaft 3a. This is because a clockwise rotational moment with the first guide shaft 15 as a fulcrum works due to the relationship of the size of play play as described above.

  Furthermore, when the biasing means 16 is applied obliquely as shown in FIG. 4, the lens holding frame 5 receives a small rotational moment in the same direction as when the third group lens 4 is pushed toward the subject. This is because the spring hook 5 f of the lens holding frame 5 is slightly on the optical axis side from the line L connecting the lead screw 18 and the first guide shaft 15. Therefore, it is because a clockwise rotational moment with the first guide shaft 15 as a fulcrum still works. In addition, when the biasing means 16 is applied obliquely as shown in FIG. 4, the bearing 5b on the upper side of the lens holding frame 5 has a moment acting with the first guide shaft 15 directed in the optical axis direction, causing play play. It is done. However, this moment is small because the acting arm is short compared to the moment acting on the plane perpendicular to the optical axis. Therefore, the bearing 5b on the lower side of the lens holding frame 5 is also loosened so as to be pushed in the direction of the optical axis of the first guide shaft 15 by the moment force acting on the surface perpendicular to the optical axis.

<About operation>
Next, the operation will be described. The drive source 14 is energized, and the lead screw 18 is rotated clockwise as viewed in FIG. 2 (viewed from the subject side). Then, since the nut 19 is held against the lens holding frame 5 so as not to rotate, it is pushed up against the urging force of the urging means 16 in the direction of the arrow Z (subject side) in FIG. Therefore, the urging force of the urging means 16 is charged as the nut 19 moves toward the subject. In this embodiment, the driving that requires the accuracy of the lens holding frame 5 and the third group lens 4 is one direction in which the lens holding frame 5 and the third group lens 4 move to the subject side. Movement to the imaging side is unstable driving with no accuracy.

  Here, the arm portion 5 c has only a marginal rigidity for maintaining the positional accuracy of the third group lens 4. Therefore, the lens holding frame 5 is increased in speed from a stationary state by driving of the driving source 14 and then maintained at a constant speed, and then vibrates in the process of decreasing the speed for braking. During the acceleration for increasing the speed and during the deceleration for stopping, the third lens group 4 can cause vibrations that oscillate in the optical axis direction. A countermeasure against this vibration will be described later.

  Further, as described above, the lens holding frame 5 receives a rotational moment in the clockwise direction about the first guide shaft 15 as a fulcrum in the present embodiment from the lead screw 18 toward the FIG. 2 during driving. Therefore, when the drive source 14 is smoothly turned, a moment in the clockwise direction toward the lens holding frame 5 is applied to the lens holding frame 5, and the first guide shaft 15 is pushed in the direction of the optical axis of the lens. Here, the reason why the lens holding frame 5 receives the rotational moment from the lead screw 18 in the clockwise direction with the first guide shaft 15 as a fulcrum toward the FIG. 2 during driving will be described again. That is, since the play between the lead screw 18, the nut 19, and the nut holding portion 5a is larger than the play between the first guide shaft 15 and the guide shaft 5b, the first guide shaft 15 serves as a fulcrum for rotation. The first guide shaft 15 serves as a fulcrum for rotation, and the lens holding frame 5 exerts a rotational force in the clockwise direction in FIG. In other words, the second guide shaft 3a is loosely moved with respect to the guide groove 5e in the direction of pressing from the first guide shaft 15 side of the line connecting the optical axis and the second guide shaft 3a.

  This direction is a direction in which the moment in the static balance generated by applying the biasing member 16 obliquely is not canceled.

  In addition, a lead component with respect to the driving force in the axial direction of the lead screw is transmitted to the lens holding frame 5 as a rotational force. The lead of the lead screw 18 has an angle at which a frictional force that does not move the lens holding frame 5 is generated by the urging force of the urging means 16 even when the drive source 14 is not driven. This is because, even in the photographing state, when the movement of the third group lens 4 in the optical axis direction is not necessary, the energization to the drive source 14 may be stopped. In such a case, when the third lens group 4 moves according to the urging force of the urging means 16, the focus lens position of the photographic lens moves. This is because such movement results in an unsightly image in live view display. The driving force is substantially the same as the force of the biasing means 16 applied and the weight of the lens holding frame 5 and the third group lens 4.

  Here, it is assumed that the lead screw gives a frictional force proportional to the force of the urging means 16 and the weight of the lens holding frame 5 and the third group lens 4.

  Since the urging means 16 is directly applied to the lens holding frame 5, the force is stable. Even if the rotational moment transmitted from the drive source 14 is unstable, the fluctuation is absorbed, and one wall of the guide groove 5e is formed by the second guide shaft. 3a can be pressed stably.

  In the present embodiment, due to the rigidity of the lens time frame 5, the guide groove 5e and the lens holding portion 5d move substantially the same. Accordingly, at this time, the one wall of the guide groove 5e receives a frictional force in the direction opposite to the movement of the one wall of the guide groove 5e, that is, the movement of the lens holding portion 5d.

  This frictional force absorbs vibration energy generated in the lens holding portion 5d during acceleration driving, so that deceleration can be started in a stable state with little vibration. Further, this frictional force is also stably applied to the vibration generated in the lens holding portion 5d during deceleration after the movement of the drive source 14 is stopped. Therefore, this frictional force takes away vibration energy that can be generated in the lens holding frame 5 and accelerates the convergence of vibration.

  Here, in order to shorten the total length of the lens barrel when the lens barrel is stored, the nut 19 and the bearing 5b on the lower side of the lens holding frame 5 and the guide groove 5e are positioned so as to stick to the outer frame 3 in the stored state. It is in. Therefore, the nut 19 and the lower bearing 5b and the guide groove 5e of the lens holding frame 5 are located on substantially the same plane perpendicular to the optical axis. Therefore, the rotational moment generated when the lead screw 18 and the nut 19 are driven is the function that the third group lens 4 and the lens holding part 5d regulate and stabilize the vibration caused by the low rigidity of the arm part 5c. There is no. This is because the nut 19 and the bearing 5b and the guide groove 5e on the lower side of the lens holding frame 5 are located on substantially the same plane perpendicular to the optical axis, so that the balance of force is achieved in this plane.

  In this regard, as described above, a part of the rotational moment is applied to the first guide shaft 15, so that play play between the first guide shaft 15 and the bearing 5b is eliminated. Further, as described above, play play between the second guide shaft 3a and the guide groove 5e is removed. Therefore, the following two effects can be obtained.

  The first is to generate a force that stably pushes play play in one direction in a stationary state after driving. When there is a pressing force, the vibration of the lens holding frame is stopped by the friction force between the rotation of the lens holding frame and the second guide shaft. Therefore, it is possible to avoid changing the position where the lens stops at the timing when the vibration stops, and the stop position becomes stable. In addition, there is no time inaccuracy until braking.

  The second is not to make the driving state unstable. Basically, if a mechanism with backlash is moved with a rectangular wave type driving force that is not necessarily smooth like a stepping motor, the lens holding frame will move while resonating with the backlash. Become. This vibration can prevent the rotation of the lens holding frame and the second guide shaft from rubbing and take away vibration energy by the frictional force so that the amplitude does not increase.

  In the above description, it has been described that the rotational moment in the clockwise direction toward FIG. 2 is generated on the surface perpendicular to the optical axis by applying the biasing means 16 obliquely. In this respect, for example, a twisting moment may be applied to one end of a coil spring that constitutes the biasing means 16 to apply a rotational moment similar to that applied to the biasing means 16 obliquely. In this way, a sufficient space is provided for providing the biasing means 16 obliquely. However, labor and confirmation work during assembly are complicated.

  Further, when the third group lens 4 is moved in the direction opposite to that described above, that is, on the imaging side, after the third group lens 4 is extended, depending on the focal length of the next photographing lens or the focus position based on the subject distance, the lens It is necessary to move the holding frame 5 to the subject side (the side opposite to the imaging side). At this time, it is once moved to the image pickup side, and after the movement, the stop position of the third lens group 4 ends with an operation of moving to the subject side. Thereby, a play of play is absorbed, and a lens driving mechanism with high accuracy and quick convergence of vibration after driving is configured.

  Here, in the above description, when the third group lens 4 is moved to the subject side, the reason given for the case where the accuracy of the stop position and control position of the third group lens 4 is moved to the imaging side is given. explain. In the case of the inner focus lens, when the third group lens 4 that is a focus lens is on the image pickup side, the lens is focused on the infinity side. On the other hand, when the third lens group 4 which is a focus lens is on the subject side, the focus is on the near side. On the other hand, when performing AF control, so-called contrast AF is performed from a subject at infinity, thereby shortening the time until focusing on the subject. This is because experientially searching for the contrast from infinity requires a shorter time to capture the main subject. Therefore, the above-described lens barrel is also configured to provide accuracy when the third lens group 4 moves from the imaging side, which is the infinity side, toward the subject side, which is the near side.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  In particular, the left-handed lead screw or nut is used to configure the system counterclockwise, or to tilt the spring so that a counterclockwise moment is generated to ensure accuracy in the retraction direction, etc. Range.

DESCRIPTION OF SYMBOLS 1 Image pick-up element 2 Sensor plate 3 Outer frame 3a 2nd guide shaft 3b Guide shaft hole 3c Spring hook 4 3rd group lens 5 Lens holding frame 5a Nut holding part 5b Bearing 5c Arm part 5d Lens holding part 5e Guide groove 5f Spring hook 6 Fixed Tube 6a Cam groove 6b Key groove 7 Cam tube 7a Drive gear 7b 2nd group cam 7c 1st group cam 8 Linear cylinder 8a Key 9 2nd group lens 10 2nd group lens holder 10a Cam pin 11 1st group lens 12 Lens barrier 13 1st group lens holder 14 Drive source 15 First guide shaft 16 Biasing means 17 Screw 18 Lead screw 19 Nut

Claims (4)

A lead screw which is given rotational motion by a driving source, a nut engaging said lead screw, a lens holding frame that moves along the optical axis direction along with the rotation of the lead screw that engages the nut, the A first guide shaft and a second guide shaft that guide the movement of the lens holding frame in the optical axis direction, an outer frame that holds the first guide shaft and the second guide shaft, and a view from the optical axis direction. The lens holding frame is brought into contact with the second guide shaft, and the lens holding frame is moved in the optical axis direction, on the opposite side of the lead screw across the first guide shaft. An urging means to be charged along with the lens barrel ,
The biasing means is attached to the hanging portion of the lens holding frame and the hanging portion of the outer frame so as to be inclined with respect to the optical axis,
When viewed from the optical axis direction, the lens holding frame hanging portion is positioned closer to the optical axis than the straight line connecting the first guide shaft and the lead screw. When viewed from the optical axis direction, the first rotational moment generated by the biasing unit with respect to the lens holding frame and the second rotational moment generated by the drive source with respect to the lens holding frame are in the same direction. The lens barrel according to claim 1. 3. The lens barrel according to claim 2, wherein the urging unit is twisted and the first rotation moment is generated with respect to the lens holding frame . 4. A digital camera in which the lens barrel according to any one of claims 1 to 3 and an image sensor that captures reflected light from a subject that has passed through the lens barrel are incorporated.

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