JP2007133262A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lens driving device capable of preventing backlash in respective parts caused during advance/retreat driving with space-saving constitution composed of a small number of components. <P>SOLUTION: The lens driving device is equipped with: a meshing member 2 screwed on a lead screw 6; an energizing member 3 supported by a shaft 3a in a direction parallel with an optical axis in a lens holder 1; and a spring 5 generating elastic force in two directions, that is, a direction parallel with the optical axis and a direction perpendicular to the optical axis. The meshing member 2 is held by the abutting part 1d of the lens holder 1 and the abutting part 3c of the energizing member 3. In such a state that the rotation stopping dowel 1d of the lens holder 1 and the energizing dowel 3b of the energizing member 3 are engaged with the notched part 2b of the meshing member 2, the meshing member 2 is energized in the direction parallel with the optical axis by the abutting part 3c of the energizing member 3 and energized in the direction perpendicular to the optical axis by the energizing dowel 3b thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive device that moves a movable lens connecting member of a zoom system or a focus system in an optical axis direction in, for example, a video camera, a still camera, and other imaging apparatuses.

  In recent years, with the miniaturization of video cameras or still cameras, the miniaturization of their photographic optical systems has been remarkably performed. The downsizing of the photographic optical system greatly contributes to the downsizing of the image pickup element and the reduction of the driving distance of the movable lens by increasing the optical sensitivity of the lens. However, as the sensitivity of the lens increases, the influence on the photographed image increases, for example, the focus is greatly shifted by a minute lens position change and the zoom magnification is changed. Therefore, in order to further reduce the size of the imaging apparatus while increasing the sensitivity of the lens, it is essential to improve the positional accuracy of the lens and the positioning accuracy in the optical axis direction.

  The main causes that hinder the improvement of the positional accuracy and the feeding accuracy of the lens include vibration generated in the driving unit and fitting backlash due to a gap provided in the driving unit and the holding unit. For this reason, various drive units having a structure for preventing these problems have been proposed as conventional techniques.

Conventional lens drive devices using lead screws include those using a rack as a meshing member (for example, see Patent Document 1) and those using a nut as a meshing member (for example, see Patent Document 2 and Patent Document 3). is there.
Hereinafter, the structure of a conventional lens driving device using a lead screw will be described with reference to FIGS. 10 to 12, 13 and 14.

  FIG. 10 is a perspective view of a conventional lens driving device using a rack as a meshing member. The main members will be described. In FIG. 10, reference numeral 101 denotes a fixed lens barrel that holds the first group lens L1. Reference numeral 105 denotes a second group lens holder, which holds a second group lens L2 that performs zooming. The second group lens holder 105 is held movably in the optical axis direction by two guide bars 106a and 106b held by the fixed barrel 101 and the rear barrel 102 at the front and rear.

  Reference numeral 109 denotes a zoom motor, in which a drive portion and an output screw portion are integrally held on a U-shaped sheet metal. The zoom motor 109 is fixed to the fixed barrel 101 with screws. On the other hand, a rack 110 is attached to the second group lens holder 105, and the rack 110 is driven in the optical axis direction by meshing with a screw portion of the zoom motor 109.

  At this time, the rack 110 is urged by the spring 111 in the meshing direction and the optical axis direction, and the meshing backlash (backlash between the lead screw and the meshing portion) and thrust backlash (backlash between the meshing member rack and the lens holder). I try to get rid of. The rack 110 is attached by fitting the shaft portion 110a into the hole portion 105a formed in the second group lens holder 105 so as to extend in the optical axis direction. The second lens group holder 105 and the fourth lens barrel 107 can be rotated about the shaft 110a. For this reason, even if the parallelism between the guide bars 106a and 106b and the motor output shaft is deviated, the second group lens holder 105 can be smoothly moved. The rack 110 is urged by the spring 111 in one direction of rotation, and the meshing portion of the rack 110 is in pressure contact with the motor output screw. For this reason, the meshing part of the rack 110 and the male screw of the motor output shaft can be reliably meshed.

Next, the backlash removing structure of the moving barrel of this conventional example will be described.
FIG. 11 is a plan view showing a holding structure of the second lens group holder 105, and the sleeve portion has a fitting hole 105c through which the guide bar 106b is inserted. Further, the rear portion of the sleeve portion has a fitting hole 105d, which is engaged with the guide bar 106b by the two fitting holes 105c and 105d, thereby enabling the second group lens holder 105 to move smoothly. .

  In FIG. 11, a U-shaped groove 105e that fits into the guide bar 106a is provided at the lower right in the drawing. As the two guide bars, the fitting holes 105c and 105d, and the U-shaped groove 105e slide stably, the second group lens holder 105 uses the optical axis of the second group lens L2 as the optical axis of the other optical system. It is possible to move in the direction of the optical axis while keeping the same.

  On the other hand, FIG. 12 is a diagram showing in detail the configuration of the rack 110 and the spring 111. The tooth portion 110b meshes with the motor screw 109a, and at the same time, the inclined surface 110c is attached in the meshing direction by the spring 111 to prevent the meshing play. It is energized. Since the inclined surface 110c is arranged at a predetermined angle with respect to the tooth portion 110b, as a result, an urging force that pulls the second group lens holder 105 in the F direction shown in FIG. 11 (the urging force of the lens holder against the guide bar). Is occurring. With such an urging force, the sliding position of the guide bar and the second lens group holder 105 can be kept stable even when the camera is directed upward, for example, and image shaking during shooting can be prevented. It becomes possible to prevent.

  FIG. 13 is a perspective view of a conventional lens driving device using a nut as a meshing member. In FIG. 3, reference numeral 201 denotes a lens that constitutes a part of the photographing lens system, and is held by the lens holder 202. The lens holder 202 is slidably engaged with a fitting bar 203 extending along the optical axis direction, and a bush 204 is fitted and fixed in a corresponding hole 202 a of the lens holder 202. Reference numeral 205 denotes a lead screw. A magnet rotor 206 as a stepping motor rotor is fixed to one end of the lead screw, and is screwed into a nut 207 inserted into a corresponding groove 202b of the lens holder 202.

  The nut 207 is provided with a notch 207a, which engages with the rotation stop dowel 202f of the lens holder 202 and restricts the rotation of the nut 207 around the optical axis. A known yoke or coil (not shown) is disposed around the magnet rotor 206 to form a stepping motor unit. A U-shaped groove 202c that is slidably engaged with the anti-vibration bar 208 is provided at a position substantially symmetrical with the fitting bar 203 across the optical axis of the lens holder 202, and the lens holder 202 is fitted to the fitting bar 203. Rotating around the center is prevented.

  209 is coaxial with the outer periphery of the lead screw 205 and is disposed in the corresponding hole 202d of the lens holder 202, abuts against the flange 202e at the bottom of the hole, and moves the holding member 202 rearward of the optical axis, that is, in the direction A in FIG. A biasing spring that biases. Although not touched in the text, both ends or one ends of the fitting bar 203, the lead screw 205, the anti-vibration bar 208, and the one-sided spring 209 are appropriately held by front and rear ground plates (not shown). The biasing spring 209 biases the lens holder 202 in the optical axis direction, thereby biasing the meshing backlash and the thrust backlash simultaneously.

  FIG. 14 is a side sectional view of a conventional lens driving device using a nut as a meshing member. The main members will be described. In FIG. 14, reference numeral 301 denotes a lens holder that holds the moving lens group 301f, and 302 denotes a lead screw that is driven to rotate as an output shaft of the stepping motor unit 306. A U groove portion 301c is formed at one end of the lens holder 301 in the lens radial direction, and the U groove portion 301c is fitted to a guide bar 305 extending in the optical axis direction so as to be movable in the optical axis direction. At the other end of the lens holder 301 in the lens radial direction, a nut attachment portion 301e and two sleeve portions 301a and 301b disposed on both sides of the nut attachment portion 301e in the optical axis direction are formed. A hole having an inner diameter that is somewhat larger than the outer diameter of the lead screw 302 is formed in the nut mounting portion 301e. In addition, one end surface of the nut attachment portion 301e is a slope inclined with respect to the radial direction of the lead screw 302. In addition, a sleeve hole is formed in the sleeve portions 301a and 301b, and a lead screw 302 is fitted and inserted into the sleeve hole.

  Thus, the U-groove portion 301c of the lens holder 301 is fitted to the guide bar 305, and the sleeve portions 301a and 301b are fitted to the lead screw 302, so that the lens holder 301 and the moving lens group 301f are orthogonal to the optical axis direction. Positioned in the plane. As described above, in this conventional example, the positioning in the orthogonal plane of the lens holder 301 is performed by only the lead screw 302 and one guide bar 305.

  Reference numeral 303 denotes a nut member, and one end face is a slope inclined in the radial direction. The nut member 303 is attached to the lens holder 301 with the inclined surface in contact with the inclined surface of the nut mounting portion 301e. A key portion 301d is formed at the root portion of the nut attachment portion 301e, and the nut member 303 is key-fitted with the key portion 301d, whereby the rotation of the nut member 303 is restricted.

  A spring 304 is disposed between the other end surface of the nut member 303 and the sleeve portion 301b. The nut member 303 is pressed against the nut mounting portion 301e in the optical axis direction by the biasing force of the spring 304, so that the nut member 303 is prevented from falling off from the nut mounting portion 301e (thrust rattling biasing).

  Further, when the nut member 303 is pressed against the slope of the nut mounting portion 301e by the biasing force of the spring 304, a pressing force in the arrow A direction acts on the nut member 303. As a result, the nut member 303 and the male screw portion 302c can be engaged with each other without any play (engagement play urging). Further, since the pressing force in the direction opposite to the A direction acts on the lens holder 301 as a reaction of the pressing force of the nut member 303 in the A direction, backlash between the sleeve portions 301a and 301b and the lead screw 302 is also suppressed. (Energization to the guide bar).

JP 2004-94172 A (page 6, FIG. 2, FIG. 3, FIG. 5) Japanese Patent Laid-Open No. 7-151947 (page 4, FIG. 1) Japanese Patent Laid-Open No. 10-20177 (page 6, FIG. 1)

  However, in the system using a rack as the engaging member of the lead screw as in the conventional lens driving device shown in FIGS. 10 to 12, there is a problem that so-called tooth jump is likely to occur due to external force or vibration. In particular, in order to cope with the recent reduction in size and diameter of the lens barrel, it is also necessary to reduce the diameter and pitch of the lead screw. For example, if a lead screw having an outer diameter of φ0.8 mm and a pitch of about 0.2 mm is used, this tooth jump occurs frequently, and there is a problem that feed accuracy in the optical axis direction is remarkably lowered.

  Further, for the purpose of reducing the thickness, the length of the shaft portion 110a of the rack 110 in the optical axis direction is shortened as in the example of FIG. Then, when the lead screw rotates and the driving force is transmitted, the rack 110 is easily tilted in the optical axis direction, and there is a problem that the feeding accuracy in the optical axis direction is deteriorated.

  On the other hand, in the method using a nut as a meshing member of the lead screw as in the conventional lens driving device shown in FIG. For this reason, tooth skipping as in the system using the rack shown in FIG. 10 does not occur. However, there is a drawback that the repulsive force of the coil spring 209 increases as the lens holder 202 moves rightward in the drawing. For this reason, there is a problem that the repulsive force of the coil spring 209 changes depending on the position of the lens, and the tilt amount of the lens holder 202 changes.

  Further, unlike the system using the rack of FIG. 11, there is no function of generating an urging force (the urging of the lens holder with respect to the guide bar) that pulls the second group lens holder 105 in the F direction. For this reason, the sliding position of the guide bar and the lens holder 105 cannot be stably maintained, and there is a problem that image shaking is likely to occur during photographing.

  In assembly, the nut 207 is inserted into the corresponding groove 202 b of the lens holder 202, and then the lead screw 205 is inserted into the corresponding hole 202 d and the nut 207 of the lens holder 202. For this reason, there is also a problem that the assemblability is inferior to the method using the rack shown in FIG. Furthermore, there is no structure for preventing the backlash of the rotation stop dowel 202f of the lens holder 202 and the notch 207a that restricts the rotation of the nut 207 around the optical axis, and this backlash reduces the optical axis feed accuracy. There is also a problem.

  On the other hand, in the conventional lens driving device shown in FIG. 14, the inclined surface in which the end surface of the nut member 303 is inclined in the radial direction is brought into contact with the inclined surface of the nut mounting portion 301e. Thereby, it is possible to urge the lens holder with respect to the guide bar, which has not been realized in the conventional lens driving device shown in FIG. However, in this conventional example, the lead screw 302 that transmits the driving force is also used as a guide bar that holds the lens holder 301.

  That is, the lens holder is not supported by the guide bar that is firmly fixed to the barrel main body and has a smooth surface as in the conventional example shown in FIGS. That is, the lens holder is supported by a lead screw that rotates during driving and has an uneven surface. Thereby, it moves, rubbing on the unevenness | corrugation of the tooth | gear of a lead screw. Such as undulation in a plane perpendicular to the optical axis of the lead screw itself caused by vibration and rotation, these are directly transmitted to the lens holder.

  For this reason, the support structure of the lens holder shown in FIG. 14 has a problem that image shaking and image quality deterioration are likely to occur due to vibration and decentering of the lens holder, as compared with the structure shown in FIGS. is there. Similarly to the conventional example shown in FIG. 13, there is no structure for preventing the backlash between the nut member 303 and the key portion 301d that restricts the rotation of the nut member 303 around the optical axis. There is also a problem that the axis feed accuracy deteriorates.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to solve the problems of tooth skipping and feeding accuracy that occur during downsizing with respect to a system using a conventional rack. In addition, the lens drive that solves the problems of not being urged against the guide bar of the lens holder, the problem of assembling and feeding accuracy, and the problem of vibration and eccentricity during driving compared to the conventional method using nuts. An object is to provide an apparatus.

  In order to achieve the above object, the invention of claim 1 according to the present invention is based on a lens holder for holding a lens, a guide bar for slidably supporting the lens holder in the optical axis direction, and an output from a drive source. A rotating lead screw, a meshing member that is screwed with the lead screw and moves in the optical axis direction as the lead screw rotates, an elastic member that can move in the optical axis direction integrally with the lens holder, and the lens holder And a drive unit including a biasing member that generates a biasing force by the elastic force of the elastic body, and the biasing member has a direction substantially parallel to the optical axis and the optical axis. It is characterized in that it is biased in two directions substantially perpendicular to the direction.

  According to a second aspect of the present invention, the engagement member includes a receiving portion (a notch portion in the embodiment) that receives an urging force from the urging member, and the receiving portion is provided on the engagement member. It is used in common with a rotation restricting portion (notch portion in the embodiment) that restricts rotation around the optical axis.

  According to a third aspect of the present invention, the biasing member includes a biasing portion (a biasing dowel in the embodiment) for transmitting a biasing force to the meshing member, and the lens holder The receiving part is urged by the urging part by being supported by an axis parallel to the optical axis and rotating around the axis.

  According to a fourth aspect of the present invention, the urging portion has a dowel shape that engages with the rotation restricting portion.

  According to a fifth aspect of the present invention, the direction of the urging force in a plane perpendicular to the optical axis of the urging member is parallel to a center line passing through the center of the rotation restricting portion and the lead screw. It is not, It is a lens drive device of Claims 1-4 characterized by the above-mentioned.

  According to the present invention, in a lens driving device including a lead screw and a meshing member, an elastic member that is movable in the optical axis direction integrally with the lens holder, and an attachment that generates a biasing force by the elastic force of the elastic body supported by the lens holder. A biasing member. The urging member urges the engaging member simultaneously in two directions, a direction substantially parallel to the optical axis and a direction substantially perpendicular to the optical axis. As a result, the lens holder can be biased with respect to a guide member such as a guide bar, which has not been realized in a lens driving device provided with a nut as a meshing member, and there is an effect of improving the positional accuracy of the lens.

  In addition, it is possible to bias the rotation stopper dowel to the notch portion, which has not been realized in a lens driving device including a nut as a meshing member, and there is an effect of improving the accuracy in the optical axis feeding direction. In addition to such biasing, two types of backlashing of thrust backlash and engagement backlash can be performed simultaneously. That is, it is possible to perform the biasing in a total of four directions with one elastic member. In addition to improving the feeding accuracy in the direction of the optical axis and the positional accuracy of the lens, there are effects of cost reduction and compactness by reducing the number of parts.

  Further, the receiving portion of the meshing member that receives the biasing force in the direction perpendicular to the optical axis from the biasing member is shared with the notch portion that is provided in advance in the meshing member. For this reason, it is not necessary to provide a new space as a receiving part, and it is not necessary to change the shape of the part significantly, so that it can be mounted with a small space and low cost.

In addition, since the spring moves in the optical axis direction together with the lens holder, the meshing member, and the biasing member, the repulsive force of the spring is constant regardless of the position of the lens, and the effect of preventing the problem that the amount of tilt of the lens holder changes is prevented. is there.
Further, when the drive component is incorporated into the lens holder, it is only necessary to insert the meshing member at a predetermined position between the lens holder and the urging member, which has an effect of improving assemblability.

In addition, it absorbs the relative displacement in the plane perpendicular to the optical axis between the connecting portion and the lead screw, which is caused by vibrations and tilts generated in the meshing member, manufacturing errors, assembly errors, etc., and has the effect of improving the positional accuracy of the lens. is there. This is because the meshing member has a notch and is fitted to a rotation stopper dowel integrated with the lens holder.
Furthermore, since a female screw is used as the meshing portion of the meshing member, tooth skipping does not occur when a small diameter and small pitch lead screw is used, and accurate driving in the optical axis feeding direction is possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a rear perspective view of a lens driving apparatus showing an embodiment of the present invention, FIG. 3 is a side view, and FIG. 4 is a rear view. 1, 3 and 4, reference numerals 4a, 4b and 4c denote guide bars which are arranged in parallel with the optical axis. Reference numeral 1 denotes a lens holder for holding a photographing lens, 1a, 1b, and 1c are support portions that engage with the guide bars 4a, 4b, and 4c, and the lens holder 1 is slidably supported in the optical axis direction. The support of the lens holder is not limited to the support structure as shown in FIGS. 1, 3, and 4, and any form can be used as long as the lens holder 1 is slidably supported in the optical axis direction. . For example, a support structure using a sleeve portion and a U-shaped groove as already shown in FIGS.

  2 is a meshing member that transmits a driving force from a lead screw to be described later to the lens holder 1, 3 is a biasing member that biases the meshing member 2, and 6 is meshed with the meshing member 3, and is driven by a motor (not shown). The lead screw 5 is a biasing spring.

  Here, FIG. 6 is an enlarged rear perspective view in the vicinity of the drive unit, and FIG. 7 is an enlarged front perspective view in the vicinity of the drive unit. As shown in FIGS. 6 and 7, the meshing member 2 is provided with a female screw portion 2 a that is screwed with the lead screw 6, and a notch portion 2 b that is engaged with a rotation stopper dowel 1 d provided on the lens holder 1. Yes. In FIG. 7, the rotation stopper dowel 1d is shown in a broken state (shaded portion).

  The urging member 3 includes a support shaft 3 a that is supported at a predetermined position of the lens holder 1. Further, as shown in FIG. 3, a contact portion 3c for urging the engaging member 2 in the direction parallel to the optical axis, and a urging portion 2 for urging the engaging member 2 in the direction perpendicular to the optical axis as shown in FIG. An urging dowel 3b is provided. The biasing dowel 3b engages with the notch 2b of the meshing member 2 together with the rotation stop dowel 1d of the lens holder.

  As shown in FIG. 6, the spring 5 has a torsion portion 5a that generates an elastic force (arrow T in the figure) in a direction substantially parallel to the plane perpendicular to the optical axis, and an elastic force (in the figure, in the direction parallel to the optical axis). And a coil portion 5b that emits an arrow C), and can generate elastic force in two directions. The entire spring 5 is supported on the support shaft 3a of the biasing member 3 by the coil portion 5b. The movable part 5c of the torsion part 5a of the spring 5 is supported by the engagement member 2 receiving part 2c, and the fixed part 5d of the torsion part 5a is supported by the spring receiving part 1e of the lens holder 1, respectively.

  FIG. 2 is a view showing a state in which the meshing member 2 and the lead screw 6 are disassembled. At the time of assembly, as shown in FIG. 2, the contact member 1f of the lens holder 1 and the contact portion 3c of the urging member 3 are formed with the engagement member 2 screwed to the lead screw 6 and integrated. The gap is inserted from the direction of arrow K in FIG.

  In this case, as shown in FIG. 7, the notch 2b of the engagement member 2 is engaged with the urging dowel 3b of the urging member 3, and then the rotation stopping dowel 1d of the lens holder 1 is engaged. insert. Further, as shown in FIG. 2, the tip of the engaging member 2, the tip of the contact portion 1f of the lens holder 1, and the end of the contact portion 3c of the biasing member 3 are all tapered surfaces. It can be installed smoothly.

  With the above configuration, when the drive component is incorporated into the lens holder 1, the engagement member 2 and the lead screw 6 are placed in the gap formed by the contact portion 1 f of the lens holder 1 and the contact portion 3 c of the biasing member 3. It only needs to be inserted as one. Therefore, better assemblability can be obtained as compared with the lens driving device using the conventional nut shown in FIGS.

Next, the urging operation in the present embodiment will be described in detail with reference to FIGS.
As shown by an arrow H in FIG. 3, due to the elastic force generated by the coil portion 5 b of the spring 5, the abutting portion 3 c of the biasing member 3 always keeps the meshing member 2 against the abutting portion 1 f of the lens holder 1. Energize. As a result, it is possible to prevent thrust play, which is play in the direction parallel to the optical axis between the lens holder 1 and the meshing member 2.

  Further, in this structure, when driven in the optical axis direction, the spring 5 together with the lens holder 1, the engagement member 2 and the biasing member 3 moves in the optical axis direction. For this reason, the repulsive force of the spring 5 is constant regardless of the position of the lens. Therefore, there is no problem that the amount of tilt of the lens holder changes depending on the lens position as in the conventional example shown in FIG.

  Further, as described above, the meshing member 2 and the lens holder 1, and the meshing member 2 and the biasing member 3 are formed in the long groove-shaped notch portion 2b, the dowel-shaped anti-rotation dowel 1d and the biasing force in a plane perpendicular to the optical axis. It is regulated by the dowel 3b. That is, the contact portion 1f of the lens holder 1 and the contact portion 3c of the urging member 3 are always in contact with the meshing member 2 without play in the optical axis direction, but are perpendicular to the optical axis. It can be freely displaced within a limited range. As a result, it is possible to prevent vibrations and falls generated in the meshing member 2 from being transmitted to the lens holder 1. Further, while absorbing the relative displacement in the plane perpendicular to the optical axis between the contact portion 1f of the lens holder 1 and the lead screw 6 which may be caused by a manufacturing error, an assembly error, etc., in a state where no play occurs. It is possible to drive.

  FIG. 5 is an enlarged rear view in which a part of the lens holder 1 is cut. As shown by the arrow S in FIG. 5, the biasing member 3 rotates in the direction of the arrow S around the support shaft 3a by the elastic force (arrow T) generated by the torsion part 5b of the spring 5. That is, the urging dowel 3 of the urging member 3 urges the notch 2 of the engaging member 2 that is engaged in the direction of arrow S.

  At this time, rattling of each part is prevented under the following conditions (a) to (c). That is, a) the lead screw 6 is fixed to the lens barrel body c integrally with a motor (not shown), b) the rotation-stop dowel 1d is integrated with the lens holder 1, and c) the urging member 3 is a support shaft 3a. Only supported by the lens holder 1. Under these conditions, with the lead screw 6 as a fixed point, the backlash 6 of the lead screw 6 and the female thread portion 2 and the backlash g3 between the rotation stopper 1d and the cutout portion 2 are prevented by the action of the urging force S.

  Further, when the reaction of the biasing force S described above acts on the lens holder 1 from the support shaft 3a, a force that biases the entire lens holder 1 in the directions of arrows F1 and F2 in FIG. 5 works. That is, a force for urging the engaging portions 1a and 1b of the lens holder 1 to the guide bars 4a and 4b is exerted, and play between the engaging portions 1a and 1b and the guide bars 4a and 4b is prevented. The Rukoto.

In the lens driving device provided with the female thread portion as the meshing member as in the conventional example shown in FIG. 13, the improvement of the lens position accuracy has not been realized. In contrast, the biasing structure as described above allows the lens holder engaging portion to be biased to the guide bar, thereby improving the positional accuracy of the lens.
Similarly, the rotation stop dowel 1d can be biased toward the notch 2b, which has not been realized in the conventional example shown in FIGS. 13 and 14, and the accuracy in the optical axis feeding direction can be improved.

  As described above, in the configuration of the present embodiment, the urging to the guide bar, the urging of the rotation stopper, and the urging of the thrust backlash and the engagement backlash can be performed simultaneously. That is, it is possible to perform the biasing in a total of four directions with one elastic member, and it is possible to reduce the cost and reduce the size by reducing the number of parts.

Further, as described above, the receiving portion of the meshing member 2 that receives the biasing force in the direction perpendicular to the optical axis from the biasing member 3 is shared with the notch portion 2b that is provided in advance in the meshing member having the female thread portion. To do. For this reason, it is not necessary to provide a new space as a receiving portion, and it is not necessary to change the shape of the part significantly.
Further, since the female thread portion 2a is used as the meshing portion of the meshing member 2, when a small diameter / small pitch lead screw is used, it occurs in a lens driving device using a rack as shown in FIG. Tooth jumping does not occur. Therefore, it is possible to drive accurately in the optical axis feeding direction.

  As shown in FIG. 5, the urging force S in a direction substantially perpendicular to the optical axis of the urging member 3 has an angle with respect to a center line H passing through the notch 2 b and the center of the lead screw 6. Yes. Accordingly, the biasing force S by the biasing dowel 3b (biasing portion) does not escape along the long groove shape of the notch 2b (receiving portion), and the biasing can be performed more efficiently.

  Further, at the time of assembly, before the engagement member 2 is inserted into a predetermined position between the lens holder 1 and the biasing member 3, the biasing dowel 3b portion of the biasing member 3 is moved by the biasing force T in FIG. There is a possibility of jumping more than necessary in the S direction.

  A structure for preventing this will be described with reference to FIG. 8 which is a side view of the engagement member 2 before being assembled and FIG. 9 which is a bottom view of the same state. When the contact portion 1f of the lens holder 1 is viewed from below, a recess 1g is formed as shown in FIG. Further, the biasing member 3 is biased in the direction of the arrow H in the figure by the biasing force of the coil portion 5b of the spring 5, but there is no meshing member 2 before assembly. For this reason, the urging dowel 3b of the urging member 3 enters the above-described recess 1g.

  In this state, since the urging force acts on the urging member 3 in the direction of arrow S in FIG. 5, the urging member 3 is abutted against one side (upper in FIG. 9) and the position is regulated. Become. That is, even before the engagement member 2 is assembled, the urging dowel 3b portion of the urging member 3 does not jump up more than necessary, and smooth assembly is possible.

It is a back perspective view of the drive device concerning the embodiment of the present invention. It is a back perspective view at the time of the assembly of the drive device concerning the embodiment of the present invention. It is a side view of the drive device concerning the embodiment of the present invention. It is a rear view of the drive device concerning the embodiment of the present invention. It is a back surface enlarged view of the drive device concerning the embodiment of the present invention. It is a back enlarged view of the drive part of the drive device concerning the embodiment of the present invention. It is a front enlarged view of the drive part of the drive device concerning the embodiment of the present invention. It is a side view before the assembly of the drive device concerning the embodiment of the present invention. It is an assembly bottom view of the drive device concerning the embodiment of the present invention. It is a disassembled perspective view of the drive device which has a rack in a prior art example. It is an enlarged view of the lens holder of the drive device which has a rack in a prior art example. It is an enlarged view of the vicinity of a rack of a drive device having a rack in a conventional example. It is a perspective view of the drive device which has a nut in a prior art example. It is a side view of the drive device which has a nut in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens holder 1a, 1b, 1c Support part 1d Anti-rotation dowel 1e Spring receiving part 1f Contact part 1g Concave part 2 Engagement member 2a Female thread part 2b Notch part 3 Energizing member 3a Support shaft 3b Energizing dowel 3c Contact part 4a , 4b, 4c Guide bar 5 Spring 5a Torsion part 5b Coil part 5c Movable part 5d Fixed part 6 Lead screw 7 Lead screw

Claims (5)

A lens holder that holds the lens, a guide bar that supports the lens holder so as to be slidable in the optical axis direction, a lead screw that is rotated by an output from a drive source, and a screw that is screwed to the lead screw to rotate the lead screw A meshing member that moves in the optical axis direction, an elastic member that can move integrally with the lens holder in the optical axis direction, and a biasing force that generates a biasing force by the elastic force of the elastic body. A drive unit comprising a member,
The urging member urges the engagement member in two directions, a direction substantially parallel to the optical axis and a direction substantially perpendicular to the optical axis.   The engagement member includes a receiving portion that receives an urging force from the urging member, and the receiving portion is shared with a rotation restricting portion that restricts rotation of the engagement member around the optical axis. The lens driving device according to claim 1.   The biasing member has a biasing portion that transmits a biasing force to the meshing member, is supported by the lens holder on an axis parallel to the optical axis, and rotates around the axis to support the receiving portion. The lens driving device according to claim 1, wherein the lens driving device is biased by the biasing portion.   The lens driving device according to claim 2, wherein the biasing portion has a dowel shape that engages with the rotation restricting portion.   The direction of the urging force in a plane perpendicular to the optical axis of the urging member is not parallel to a center line passing through the center of the rotation restricting portion and the lead screw. The lens driving device according to claim 1.

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