Lens barrel and image capturing device

Abstract

To prevent a member driven by a voice coil motor from colliding with other members while no current is being supplied to the voice coil motor.SOLUTION: A lens barrel is provided, comprising a first barrel 10 configured to hold a lens and to be movable in an optical axis direction, a second barrel 20 different from the first barrel, at least one first magnet 11a, 11b provided in the first barrel, and at least one second magnet 21a, 21b provided in the second barrel, where a repulsive force is generated between the first magnet and the second magnet.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] It relates to a lens barrel and an imaging device.

Background Art

[0002] As a driving device for a lens, a lens barrel employing a voice coil motor has been proposed (for example, Patent Document 1). When no current is supplied to the voice coil motor, there is a risk that a member driven by the voice coil motor may collide with other members.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] According to a first aspect, the lens barrel includes a first barrel that holds a lens and is movable in the optical axis direction, a second barrel different from the first barrel, at least one first magnet provided in the first barrel, and at least one second magnet provided in the second barrel, and a repulsive force is generated between the first magnet and the second magnet.

[0005] According to a second aspect, the imaging device includes the above lens barrel.

[0006] Note that the configuration of the embodiments described below may be appropriately improved, and at least a part thereof may be replaced with other components. Furthermore, constituent elements that are not particularly limited in terms of their arrangement are not limited to the arrangements disclosed in the embodiments, and can be arranged at positions where their functions can be achieved.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] 《First Embodiment》 Hereinafter, the lens barrel 100 according to the first embodiment will be described in detail with reference to the drawings. Note that the shapes, lengths, thicknesses, and other scales of the respective parts shown in the embodiments do not necessarily match the actual objects, and in each figure, for ease of understanding, the illustration of some elements may be omitted. Also, in the cross-sectional view, the hatching of some elements is omitted.

[0009] In the following description, unless otherwise specified, the direction parallel to the optical axis OA of the photographic optical system may be referred to as the "front-rear direction". Also, the object side is referred to as the "object side", and the side opposite to the object in the direction of the optical axis OA (camera body side) is referred to as the "image side", respectively.

[0010] FIG. 1 is a view showing a camera 1 including a lens barrel 100 and a camera body 101 according to the first embodiment. In the present embodiment, the lens barrel 100 is detachable from the camera body 101, but is not limited thereto, and the lens barrel 100 and the camera body 101 may be integrated.

[0011] The camera body 101 includes an imaging device 111, a control unit 112, etc. inside. The imaging device 111 is composed of a photoelectric conversion element such as a CCD (Charge Coupled Device), and converts the subject image formed by the imaging optical system (the lens barrel 100 attached to the camera body 101) into an electrical signal.

[0012] The control unit 112 includes a CPU (Central Processing Unit), etc., and comprehensively controls the operation of the entire camera 1 related to shooting, including the focus drive in the camera body 101 and the attached lens barrel 100.

[0013] As shown in FIG. 1, the lens barrel 100 according to this embodiment includes a fixed barrel 115. In this embodiment, the fixed barrel 115 is composed of a plurality of parts, but it may also be composed of one part. As shown in FIG. 1, a lens mount LM that makes the lens barrel 100 detachable from the camera body 101 is fixed to the fixed barrel 115.

[0014] The lens barrel 100 includes a plurality of lens groups L1 to L9 sequentially arranged along the common optical axis OA. The lens group L4 is held by the first barrel 10, the lens group L6 is held by the lens holding frame F6, and the lens group L8 is held by the lens holding frame F8. The other lens groups are held by the fixed barrel 115. Note that each of the lens groups L1 to L9 may be composed of one lens or a plurality of lenses. Note that the first barrel 10 may be a lens holding frame.

[0015] The lens group L4 is a focus lens and is provided in the focus unit 102. FIG. 2 is a cross-sectional view of the focus unit 102.

[0016] As shown in FIG. 2, the focus unit 102 according to the present embodiment includes a first cylinder 10 and a second cylinder 20 disposed on the outer peripheral side of the first cylinder 10. In the present embodiment, the first cylinder 10 is composed of one part, but it may be composed of a plurality of parts. Also, in the present embodiment, the second cylinder 20 is fixed to the fixed cylinder 115 with screws. Note that in the present embodiment, the second cylinder 20 is composed of a plurality of parts, but it may be composed of one part.

[0017] In the present embodiment, the lens group L4 performs focus adjustment by moving in the direction of the optical axis OA. The lens group L4 is driven in the direction of the optical axis OA (front-rear direction) by a voice coil motor 50 provided in the focus unit 102.

[0018] FIG. 3(a) is a perspective view showing the configuration of the voice coil motor 50, and FIG. 3(b) is a view of the voice coil motor 50 as seen from the direction of arrow AR11 in FIG. 3(a).

[0019] The voice coil motor 50 includes a first side yoke 51a and a second side yoke 51b having a length in the optical axis direction, and a center yoke 52 having a length in the optical axis direction and disposed between the first side yoke 51a and the second side yoke 51b. Also, the voice coil motor 50 includes an upper yoke 56a connecting one end in the optical axis direction of the first side yoke 51a, the second side yoke 51b, and the center yoke 52, and a lower yoke 56b connecting the other end in the optical axis direction of the first side yoke 51a, the second side yoke 51b, and the center yoke 52. Thereby, a closed magnetic circuit is formed.

[0020] A first magnet 53a is disposed on the side surface of the first side yoke 51a on the center yoke 52 side, and a second magnet 53b is disposed on the side surface of the second side yoke 51b on the center yoke 52 side.

[0021] The first magnet 53a is arranged such that, for example, the center yoke 52 side is the N pole, and the second magnet 53b is also arranged such that the center yoke 52 side is the N pole. As a result, magnetic flux enters the center yoke 52 from the N poles of the first magnet 53a and the second magnet 53b, and forms a magnetic path that returns to the S poles of the first magnet 53a and the second magnet 53b via the upper yoke 56a, the lower yoke 56b, the first side yoke 51a, and the second side yoke 51b.

[0022] Also, the voice coil motor 50 includes a coil 55 that penetrates the center yoke 52. A drive signal (current) is input to the coil 55 from a driver (not shown) provided within the lens barrel 100. When current flows through the coil 55, the coil 55 moves in the optical axis direction due to the magnetic forces of the first magnet 53a and the second magnet 53b. More specifically, the coil 55 moves in the optical axis direction due to the electromagnetic interaction between the coil 55 through which current flows and the first magnet 53a and the second magnet 53b. By changing the direction of the current flowing through the coil 55, the moving direction of the coil 55 can be switched between the subject side and the camera body 101 side. Also, by changing the value of the current flowing through the coil 55, the driving force and moving speed of the coil 55 can be changed.

[0023] FIG. 4(a) and FIG. 4(b) are perspective views of the first cylinder 10, and FIG. 5 is a perspective view of the second cylinder 20. Also, FIG. 6 is a plan view of the focus unit 102 according to the first embodiment as viewed from the object side. In FIG. 6, illustration of the member that is attached to the second cylinder 20 and holds the buffer material 40 is omitted, and the buffer material 40 is illustrated.

[0024] As shown in FIGS. 4(a) and 4(b), a first cylinder 10 is connected to a coil 55 provided in a voice coil motor 50. Thus, when the coil 55 moves straight in the direction of the optical axis OA, the first cylinder 10 is driven to move straight in the direction of the optical axis OA, and the position of the lens group L4 in the direction of the optical axis OA changes. As shown in FIG. 4(a), a position detection substrate 113 equipped with an optical encoder, a magnetic encoder, or the like is attached to the first cylinder 10. The position detection substrate 113 detects the position of the lens group L4 in the optical axis direction under the control of the control unit 112 of the camera body 101. A driver (not shown) generates a drive signal for the coil 55 based on the position of the lens group L4 detected by the position detection substrate 113 and the target position information of the lens group L4 input from the control unit 112 of the camera body 101, and outputs it to the coil 55 via a flexible printed circuit board (FPC) 114.

[0025] On the other hand, as shown in FIG. 5, the first side yoke 51a, the second side yoke 51b, the center yoke 52, the upper yoke 56a, the lower yoke 56b, the first magnet 53a, and the second magnet 53b are provided on the second cylinder 20.

[0026] As shown in FIG. 6, in this embodiment, the focus unit 102 includes a plurality (two) of voice coil motors 50. In this case, it is desirable that the two voice coil motors 50 be provided at positions facing each other across the optical axis OA in a plane perpendicular to the optical axis OA so that the driving force is transmitted maximally in the direction of the optical axis OA (front-rear direction). Note that the plurality of voice coil motors 50 may be provided at other positions. Also, the number of voice coil motors 50 may be one or three or more.

[0027] Also, as shown in FIGS. 5 and 6, a guide bar 33, a guide bar fixing member 35, a sub-guide bar 34, and a sub-guide bar fixing member 36 are arranged on the second cylinder 20. The guide bar 33 and the sub-guide bar 34 guide the first cylinder 10 driven by the voice coil motor 50 in the direction of the optical axis OA.

[0028] Since the guide bar 33 and the sub-guide bar 34 regulate the moving direction of the first cylinder 10 in the direction of the optical axis OA, it is desirable to install the guide bar 33 and the sub-guide bar 34 at positions facing each other across the optical axis OA in a plane perpendicular to the optical axis OA. Note that the guide bar 33 and the sub-guide bar 34 may be provided at other positions. Also, the sub-guide bar 34 may be omitted. Further, a plurality of sub-guide bars 34 may be provided.

[0029] As described above, the camera 1 composed of the camera body 101 and the lens barrel 100 including the focus unit 102, when a shutter button (not shown) is pressed (focus operation), the control unit 112 in the camera body 101 controls the focus drive etc. of the focus unit 102 via the voice coil motor 50. Also, the imaging element 111 converts the subject image light imaged by the lens barrel 100 into an electrical signal, and the camera body 101 records (i.e., takes a picture) the image data in a memory (not shown) provided in the camera body 101.

[0030] When the drive signal of the voice coil motor 50 is OFF, that is, when no current is supplied to the voice coil motor 50, the coil 55 of the voice coil motor 50 does not have a holding force to maintain its position. Therefore, in a state where no current is supplied to the voice coil motor 50, the first cylinder 10 connected to the coil 55 can move freely along the direction of the optical axis OA. Therefore, when the subject side of the lens barrel 100 is tilted toward the ground or the sky, the first cylinder 10 may move due to the self-weight of the lens group L4 etc. and collide with the second cylinder 20, generating a collision sound. Also, due to the collision between the first cylinder 10 and the second cylinder 20, the first cylinder 10 and the second cylinder 20 may be damaged, or each member may wear out.

[0031] Therefore, in the lens barrel 100 according to the present embodiment, a buffer member 40 is attached to the second barrel 20. The buffer member 40 is provided at a position where the first barrel 10 and the second barrel 20 come into contact with each other in the optical axis OA direction. In the present embodiment, the buffer member 40 is provided on the second barrel 20, but the buffer member 40 may be provided on the first barrel 10 or on both the first barrel 10 and the second barrel 20. Thereby, the impact when the first barrel 10 and the second barrel 20 collide can be reduced, and the collision sound can be reduced. Further, it is possible to suppress the first barrel 10 and the second barrel 20 from being damaged.

[0032] In the present embodiment, in order to prevent the collision between the first barrel 10 and the second barrel 20 or to reduce the impact at the time of the collision between the first barrel 10 and the second barrel 20, the lens barrel 100 further includes first magnets 11a and 11b (see FIG. 2) and second magnets 21a and 21b (see FIG. 2). In the following description, when there is no particular need for distinction, the first magnets 11a and 11b are referred to as the first magnet 11, and the second magnets 21a and 21b are referred to as the second magnet 21.

[0033] The first magnets 11a and 11b have, for example, a rectangular parallelepiped shape or a cubic shape. As shown in FIG. 2, the first magnet 11a is provided at the image-side end of the first barrel 10, and the first magnet 11b is provided at the object-side end of the first barrel 10. Further, the second magnets 21a and 21b have, for example, a rectangular parallelepiped shape or a cubic shape. As shown in FIG. 2, the second magnet 21a is provided at a position facing the first magnet 11a in the optical axis OA direction at the image-side end of the second barrel 20. Further, the second magnet 21b is provided at a position facing the first magnet 11b in the optical axis OA direction at the object-side end of the second barrel 20.

[0034] The first magnet 11a and the second magnet 21a are respectively attached to the first cylinder 10 and the second cylinder 20 so that a repulsive force is generated between the first magnet 11a and the second magnet 21a. The first magnet 11b and the second magnet 21b are respectively attached to the first cylinder 10 and the second cylinder 20 so that a repulsive force is generated between the first magnet 11b and the second magnet 21b. For example, the first magnet 11a and the second magnet 21a are arranged such that the facing surfaces in the optical axis OA direction have the same pole, and the first magnet 11b and the second magnet 21b are arranged such that the facing surfaces in the optical axis OA direction have the same pole. More specifically, for example, when the first magnet 11a is arranged such that the second magnet 21a side is the S pole, the second magnet 21a is arranged such that the first magnet 11a side is the S pole. Similarly, when the first magnet 11b is arranged such that the second magnet 21b side is the S pole, the second magnet 21b is arranged such that the first magnet 11b side is the S pole. By arranging in this way, a repulsive force is generated between the first magnet 11a and the second magnet 21a, and between the first magnet 11b and the second magnet 21b.

[0035] Therefore, in a state where no current is supplied to the voice coil motor 50, when the lens barrel 100 is tilted upward or downward, the first cylinder 10 moves toward the second cylinder 20, but due to the repulsive force between the first magnet 11a and the second magnet 21a, or the repulsive force between the first magnet 11b and the second magnet 21b, the speed when the first cylinder 10 collides with the second cylinder 20 can be reduced. Thereby, compared with the case where only the buffer member 40 is provided, the generation of collision sound and the breakage / wear of members can be further suppressed.

[0036] Also, as a method for reducing the speed when the first cylinder 10 collides with the second cylinder 20, a method (short brake) of short - circuiting the coil 55 to reduce the moving speed of the first cylinder 10 in a state where no current is supplied to the voice - coil motor 50 can be considered. When the short - circuited coil 55 moves in the magnetic field generated by the first magnet 53a and the second magnet 53b, a current flows through the coil 55, and a magnetic field is generated by the coil 55. As a result, a force is generated in the direction opposite to the moving direction of the coil 55, and the moving speed of the first cylinder 10 connected to the coil 55 decreases. However, in the short brake, although the terminal speed of the first cylinder 10 can be reduced, the collision between the first cylinder 10 and the second cylinder 20 cannot be prevented. On the other hand, in the present embodiment, by appropriately setting the repulsive force between the first magnet 11 and the second magnet 21, the first cylinder 10 can be prevented from colliding with the second cylinder 20. For this reason, the generation of a collision sound and the breakage of members can be prevented.

[0037] In the direction of the optical axis OA, the first cylinder 10 is arranged such that the distance D1 between the image - side end of the first cylinder 10 and the object - side surface of the buffer member 40 is smaller than the distance D2 between the image - side surface of the first magnet 11a and the object - side surface of the second magnet 21a (D1 < D2). Thereby, before the first magnet 11a and the second magnet 21b come into contact, the end of the first cylinder 10 comes into contact with the buffer member 40, so that the generation of a collision sound due to the collision between the first magnet 11a and the second magnet 21b can be suppressed, and the breakage of the first magnet 11a and the second magnet 21b can be suppressed.

[0038] In order to suppress the generation of a collision sound due to the collision between the first magnet 11a and the second magnet 21b and to suppress the breakage of the first magnet 11a and the second magnet 21b, it is desirable that the first magnet 11 and the second magnet 21 be arranged so as not to come into direct contact with each other.

[0039] For example, as shown in FIGS. 2 and 4(b), the first magnet 11a is arranged in the magnet holding frame 12 formed on the outer peripheral surface of the first cylinder 10, or as shown in FIG. 2, a protrusion 22 protruding inward from the inner peripheral surface of the second cylinder 20 is provided between the first magnet 11a and the second magnet 21a, so that the first magnet 11a and the second magnet 21a can be configured not to be in direct contact with each other.

[0040] If the repulsive force between the first magnet 11 and the second magnet 21 is too large, when the end of the first cylinder 10 approaches the second cylinder 20, the driving of the first cylinder 10 by the voice coil motor 50 may be hindered by the repulsive force. Therefore, the sizes of the first magnet 11 and the second magnet 21, the types of magnets, and the installation positions are designed so that the repulsive force between the first magnet 11 and the second magnet 21 does not significantly hinder the driving of the first cylinder 10 by the voice coil motor 50.

[0041] A more specific arrangement example of the first magnet 11 and the second magnet 21 will be further described. In order to maximize the repulsive force in the direction of the optical axis OA, the first magnet 11 and the second magnet 21 having a repulsive force are preferably arranged along a straight line parallel to the optical axis OA. For example, in FIG. 2, the center of the first magnet 11a and the center of the second magnet 21a are arranged on the same straight line parallel to the optical axis OA, and the center of the first magnet 11b and the center of the second magnet 21b are arranged on the same straight line parallel to the optical axis OA. In addition, considering the arrangement balance with other members, the arrangement of the first magnet 11 and the second magnet 21 may be an arrangement other than the above.

[0042] Also, it is desirable that the first magnet 11 of the first cylinder 10 and the second magnet 21 of the second cylinder 20 be arranged at positions where their magnetic forces do not affect the driving of the voice coil motor 50. For example, in FIG. 6, if the first magnet 11 or the second magnet 21 is arranged in the region R1 indicated by hatching, since there is no yoke (such as the first side yoke 51a and the second side yoke 51b, etc.) between the coil 55 and the first magnet 11 or between the coil 55 and the second magnet 21, there is a possibility that the magnetic force of the first magnet 11 or the second magnet 21 may affect the driving of the voice coil motor 50. Therefore, it is preferable to avoid arranging the first magnet 11 and the second magnet 21 in the region R1. Thus, for example, when using the voice coil motor 50 having the structure shown in FIGS. 3(a) and 3(b), the first magnet 11 and the second magnet 21 are arranged outside the first side yoke 51a and the second side yoke 51b (including the center yoke 52 and outside the region sandwiched between the first side yoke 51a and the second side yoke 51b) in the circumferential direction of the circle centered on the optical axis OA. In other words, in the circumferential direction of the circle centered on the optical axis OA, it is desirable that the first magnet 11 and the second magnet 21 be arranged such that either the first side yoke 51a or the second side yoke 51b is located between the first magnet 11 and the coil 55 and between the second magnet 21 and the coil 55.

[0043] As described in detail above, in this embodiment, the lens barrel 100 includes a first barrel 10 that holds the lens group L4 and is movable in the direction of the optical axis OA, a voice coil motor 50 that drives the first barrel 10 in the direction of the optical axis OA, a second barrel 20 disposed outside the first barrel 10, first magnets 11a and 11b provided on the first barrel 10, and second magnets 21a and 21b provided on the second barrel 20. A repulsive force is generated between the first magnets 11a and 11b and the second magnets 21a and 21b. Thus, even when the first barrel 10 moves toward the second barrel 20 by tilting the lens barrel 100 upward or downward in a state where no current is supplied to the voice coil motor 50, the repulsive force between the first magnet 11a and the second magnet 21a, or the repulsive force between the first magnet 11b and the second magnet 21b can reduce the speed when the first barrel 10 collides with the second barrel 20. Thereby, the impact when the first barrel 10 collides with the second barrel 20 can be reduced, the collision sound can be reduced, and damage to the first barrel 10 and the second barrel 20 can be suppressed. Further, by appropriately setting the repulsive force, it is possible to prevent the first barrel 10 from colliding with the second barrel 20.

[0044] Also, in this embodiment, the second barrel 20 is provided with a buffer member 40 at a position where the first barrel 10 contacts in the direction of the optical axis OA. Thus, even when the first barrel 10 moves toward the second barrel 20 by tilting the lens barrel 100 upward or downward in a state where no current is supplied to the voice coil motor 50, the buffer member 40 can further reduce the impact.

[0045] Also, in this embodiment, the first magnets 11a and 11b and the second magnets 21a and 21b are respectively arranged along the optical axis OA. Thereby, the repulsive force between the first magnet 11a and the second magnet 21a and the repulsive force between the first magnet 11b and the second magnet 21b can be maximized in the direction of the optical axis OA.

[0046] Further, in the present embodiment, the distance in the optical axis OA direction between the end of the first cylinder 10 and the buffer member 40 is smaller than the distance in the optical axis OA direction between the first magnets 11a (11b) and the second magnets 21a (21b). Thereby, before the first magnets 11a (11b) and the second magnets 21a (21b) come into contact, the first cylinder 10 comes into contact with the buffer member 40, so that it is possible to suppress the first magnets 11a (11b) and the second magnets 21a (21b) from coming into contact and the repulsive force from becoming infinite.

[0047] Also, in the present embodiment, the voice coil motor 50 includes a coil 55, first magnets 53a and 53b, and first side yokes 51a and 51b. In a plane orthogonal to the optical axis OA, the first side yokes 51a and 51b are positioned between the first magnets 11a and 11b and the coil 55. Thereby, the influence of the first magnets 11a and 11b on the drive of the voice coil motor 50 can be reduced.

[0048] 《Second Embodiment》 In the first embodiment, the first magnets 11a and 11b are provided at both ends of the first cylinder 10. However, in the second embodiment, one first magnet 11 is provided on the first cylinder 10. FIG. 7 is a cross-sectional view of a focus unit 102A according to the second embodiment.

[0049] As shown in FIG. 7, in the second embodiment, the first magnet 11b is not provided, and the first magnet 11a is provided at the image side end of the first cylinder 10. On the other hand, the second magnet 21a is provided at the image side end of the second cylinder 20 as in the first embodiment, but the second magnet 21b is provided in a magnet holding portion 23 provided at the central portion of the second cylinder 20.

[0050] In the second embodiment, the first magnet 11a, the second magnet 21a, and the second magnet 21b are arranged such that a repulsive force is generated between the first magnet 11a and the second magnet 21a, and a repulsive force is generated between the first magnet 11a and the second magnet 21b. Specifically, for example, when the second magnet 21a is provided such that the side closer to the first magnet 11a is the N pole, the first magnet 11a is arranged such that the side closer to the second magnet 21a is the N pole. In this case, since the side of the first magnet 11a closer to the second magnet 21b is the S pole, the second magnet 21b is arranged such that the side closer to the first magnet 11a is the S pole. Thus, similar to the first embodiment, the repulsive force between the first magnet 11a and the second magnet 21a, or the repulsive force between the first magnet 11a and the second magnet 21b can reduce the speed when the first cylinder 10 collides with the second cylinder 20, so that the generation of collision sound and the breakage / wear of the members can be further reduced. Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted.

[0051] Note that the first magnet 11a may not be provided, and the first magnet 11b may be provided at the end of the first cylinder 10 on the object side. In this case, the second magnet 21b may be provided at the end of the second cylinder 20 on the object side in the same manner as in the first embodiment, and the second magnet 21a may be provided in the magnet holding portion 23 provided at the central portion of the second cylinder 20.

[0052] 《Third Embodiment》 In the second embodiment, the first magnet 11a is provided at the end of the first cylinder 10 on the image side. However, for example, the first magnet 11c may be provided at the central portion of the first cylinder 10. FIG. 8 is a cross-sectional view of the focus unit 102B according to the third embodiment.

[0053] As shown in FIG. 8, a first magnet 11c is provided at the central portion of the first cylinder 10 in the direction of the optical axis OA. On the other hand, the second magnet 21a is provided in a magnet holding portion 23a provided on the image side of the center of the second cylinder 20 in the direction of the optical axis OA, and the second magnet 21b is provided in a magnet holding portion 23b provided on the subject side of the center of the second cylinder 20.

[0054] In the third embodiment, the first magnet 11c, the second magnet 21a, and the second magnet 21b are arranged such that a repulsive force is generated between the first magnet 11c and the second magnet 21a, and a repulsive force is generated between the first magnet 11c and the second magnet 21b. Specifically, for example, when the second magnet 21a is arranged such that the side closer to the first magnet 11c is the N pole, the first magnet 11c is arranged such that the side closer to the second magnet 21a is the N pole. In this case, since the side of the first magnet 11c closer to the second magnet 21b is the S pole, the second magnet 21b is arranged such that the side closer to the first magnet 11c is the S pole. Thus, similar to the first embodiment, the repulsive force between the first magnet 11c and the second magnet 21a, or the repulsive force between the first magnet 11c and the second magnet 21b can reduce the speed when the first cylinder 10 collides with the second cylinder 20, so that the generation of collision noise and the breakage / wear of the members can be further reduced. Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted.

[0055] Note that in the above third embodiment, the first magnet 11c is provided at the central portion of the first cylinder 10, but it is not limited thereto. The position where the first magnet 11c is provided may be other than both ends of the first cylinder.

[0056] In addition to the first to third embodiments shown above, the first to third embodiments may be appropriately combined.

[0057] In the above embodiment, the first magnet 11 was provided at one location in the circumferential direction of a circle centered on the optical axis OA. However, a plurality of first magnets 11 may be provided in the circumferential direction of the circle centered on the optical axis OA. In this case, it is preferable to arrange the plurality of first magnets 11 at substantially equal intervals in the circumferential direction of the circle centered on the optical axis OA. This is to cancel out the forces applied in directions other than the optical axis OA direction (front-rear direction) by the plurality of first magnets 11. For example, when arranging two first magnets 11 in the circumferential direction of the circle centered on the optical axis OA, it is desirable that the two first magnets 11 be arranged so as to face each other across the optical axis OA in a plane perpendicular to the optical axis OA. Also, when arranging three first magnets 11, it is desirable that the three first magnets 11 be arranged in a plane perpendicular to the optical axis OA such that the center of gravity of the triangle formed by connecting the centers of gravity of the three first magnets 11 overlaps with the center (optical axis OA) of the lens group L4.

[0058] Also, in the above embodiment, for example, in a plane including the optical axis OA, below the optical axis OA, the first magnets 11a and 11b may be arranged, and above the optical axis OA, either one of the first magnets 11a and 11b may be arranged. That is, when providing the first magnet 11 at different positions in the circumferential direction of the circle centered on the optical axis OA, the number of first magnets 11 at each position may be different.

[0059] Also, in the above embodiment, the shapes of the first magnet 11 and the second magnet 21 are not limited to rectangular parallelepipeds or cubes, and may be other shapes such as circular or spherical. Also, the shape of the first magnet 11 may be sheet-like and attached to a part or all of the object side surface or the image side surface of the first cylinder 10. The same applies to the second magnet 21. Furthermore, the shapes of the first magnet 11 and the second magnet 21 may be different. For example, the first magnet 11 may be sheet-like and the second magnet 21 may be a rectangular parallelepiped, or vice versa.

[0060] In the above-described embodiment, the case where the lens group L4 driven by the voice coil motor 50 is a focus lens has been described. However, the lens group driven by the voice coil motor 50 may be another lens such as a zooming lens, for example.

[0061] Also, in the above-described embodiment, the lens group L4 is guided by the guide bar 33 and the sub-guide bar 34 and moves. However, the present invention is not limited to this, and the lens group L4 may be guided by a configuration other than the guide bar 33 and the sub-guide bar 34.

[0062] Also, in the above-described embodiment, it is desirable that the first magnets 11a and 11b provided on the first cylinder 10 are arranged so as not to generate play in the guide bar 33 and the sub-guide bar 34 due to the repulsive force between the first magnets 11a and 11b and the second magnets 21a and 21b. Specifically, when a straight line A connecting the central axis of the guide bar 33 and the optical axis OA and a straight line B passing through the optical axis OA and perpendicular to the straight line A are defined as shown in FIG. 6 in a plane perpendicular to the optical axis OA, it is preferable to provide the first magnets 11a and 11b on the side of the guide bar 33 rather than the straight line B. Note that the first magnets 11a and 11b may be installed near the sub-guide bar 34.

[0063] Also, in the above-described embodiment, the cushioning material 40 is provided, but the cushioning material 40 may be omitted.

[0064] Also, in the above-described embodiment, the second cylinder 20 is not moved in the direction of the optical axis OA. However, the second cylinder 20 may move in the direction of the optical axis OA.

[0065] The above-described embodiment is a preferred example of implementation. However, the present invention is not limited to this, and various modifications can be made without departing from the gist, and any constituent elements may be combined.

Description of Reference Numerals

[0066] 10 First cylinder 11, 11a, 11b, 11c First magnet 20 Second cylinder 21, 21a, 21b Second magnet 33 Guide bar 40 Buffer material 50 Voice coil motor 53a First magnet 53b Second magnet 55 Coil 51a First side yoke 51b Second side yoke

Claims

1. A first cylinder that holds a lens and is movable in the optical axis direction, A second cylinder different from the first cylinder, At least one first magnet provided on the first cylinder, At least one second magnet provided on the second cylinder, and A lens barrel in which a repulsive force is generated between the first magnet and the second magnet.

2. The second cylinder is provided with a buffer material at a position in contact with the first cylinder, The lens barrel according to claim 1.

3. The distance between the end of the first cylinder in the optical axis direction and the buffer material is smaller than the distance between the first magnet and the second magnet in the optical axis direction. The lens barrel according to claim 2.

4. Further provided with a guide bar for guiding the first cylinder in the optical axis direction, The first magnet intersects perpendicularly to a first straight line connecting the guide bar and the optical axis in a plane perpendicular to the optical axis, and is disposed closer to the guide bar side than a second straight line passing through the optical axis. The lens barrel according to any one of claims 1 to 3.

5. The guide bar is fixed to the second cylinder. The lens barrel according to claim 4.

6. The second cylinder is disposed outside the first cylinder, The lens barrel according to any one of claims 1 to 5.

7. A plurality of the first magnets are provided, The plurality of first magnets are disposed opposite to each other across the optical axis in a plane perpendicular to the optical axis. The lens barrel according to any one of claims 1 to 6.

8. The first magnet is disposed at one end of the first cylinder in the optical axis direction. The lens barrel according to any one of claims 1 to 7.

9. A plurality of the first magnets are provided, The plurality of first magnets are disposed at both ends of the first cylinder in the optical axis direction, A plurality of the second magnets are provided so as to face the plurality of first magnets respectively, The lens barrel according to any one of claims 1 to 7.

10. The first magnet is disposed at a position other than both ends of the first cylinder in the optical axis direction. The lens barrel according to any one of claims 1 to 7.

11. The center of the first magnet and the center of the second magnet are disposed on the same straight line parallel to the optical axis. The lens barrel according to any one of claims 1 to 10.

12. It further includes a driving unit for moving the first cylinder in the optical axis direction. The driving unit includes a coil, a magnet, and a yoke member. In the circumferential direction of a circle centered on the optical axis, the yoke member is positioned between the first magnet and the coil. The lens barrel according to any one of claims 1 to 11.

13. An imaging device including the lens barrel according to any one of claims 1 to 12.

Images