Lens barrel and imaging device

Abstract

To provide a lens barrel which enables driving of heavy lenses and high-speed driving of lenses.SOLUTION: A lens barrel comprises a first lens retaining frame for retaining a first lens, a first drive unit configured to move the first lens retaining frame in an optical axis direction, and a second drive unit configured to impart a force to the first lens retaining frame in the optical axis direction, where the first and second drive units are of different types.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a lens barrel and an imaging device. [Background technology]

[0002] It is known to use, for example, a stepping motor or a voice coil motor as a drive source for moving a lens in the optical axis direction (for example, Patent Document 1). There is a demand for driving heavy lenses and for driving lenses at high speeds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-118600 A Summary of the Invention

[0004] According to a first aspect, a lens barrel includes a first lens holding frame that holds a first lens, a first drive unit that moves the first lens holding frame in the optical axis direction, and a second drive unit that applies a force to the first lens holding frame in the optical axis direction, and the first drive unit and the second drive unit are different types of drive units. The movement of the first lens holding frame in the optical axis direction by the first driving unit and the application of the force in the optical axis direction to the first lens holding frame by the second driving unit are performed in parallel. .

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

[0006] The configurations of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view showing a camera equipped with a lens barrel and a camera body according to the first embodiment. [Figure 2] 2(A) and 2(B) are a perspective view and a plan view, respectively, showing the lens holding frame, the first drive source unit, and the second drive source unit. [Figure 3] 3A and 3B are diagrams for explaining the force applied to the lens holding frame and the attitude of the lens holding frame. [Figure 4] FIG. 4A is a timing chart for explaining general control of a stepping motor, and FIG. 4B is a timing chart for explaining control in the first embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of control of the first driving source unit and the second driving source unit. [Figure 6] 6(A) and 6(B) are diagrams illustrating an example of control of the first driving source unit and the second driving source unit. [Figure 7] 7(A) and 7(B) are respectively a perspective view and a plan view showing a lens holding frame, a first drive source unit, and a second drive source unit according to the second embodiment. [Figure 8] 8(A) and 8(B) are respectively a perspective view and a plan view showing a lens holding frame, a first drive source unit, and a second drive source unit according to the third embodiment. [Figure 9] FIG. 9 is a cross-sectional view illustrating a lens barrel having two lens groups as a focus lens group. DETAILED DESCRIPTION OF THE INVENTION

[0008] First Embodiment The lens barrel according to the first embodiment will be described in detail below with reference to the drawings. Note that the scale of the shape, length, thickness, etc. of each part shown in the embodiment does not necessarily correspond to the actual product, and in each drawing, some elements may be omitted for ease of understanding. Also, in cross-sectional views, hatching of some elements may be omitted.

[0009] FIG. 1 is a cross-sectional view showing a camera 1 equipped with a lens barrel 100 and a camera body 101 according to the first embodiment.

[0010] The camera 1 includes a camera body 101 and a lens barrel 100. A lens mount LM is provided at the rear (base end) of the lens barrel 100, and is detachably attached to the camera body 101 by engaging with a body mount (not shown) of the camera body 101. Note that in this embodiment, the lens barrel 100 is detachable from the camera body 101, but this is not limiting, and the lens barrel 100 and the camera body 101 may be integrated.

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

[0012] The control unit 112 is equipped with a CPU (Central Processing Unit) and the like, and controls the overall operation of the camera 1 related to photography, including focusing drive in the camera body 101 and the attached lens barrel 100, and blur correction of captured images due to camera shake, etc.

[0013] As shown in Figure 1, lens barrel 100 according to this embodiment includes multiple lens groups, including lens group L1, arranged sequentially along a common optical axis OA. Lens barrel 100 may be a so-called zoom lens, whose focal length is variable, or a fixed-focus lens, whose focal length is fixed. Each of the multiple lens groups may consist of a single lens, or may consist of multiple lenses.

[0014] The lens group L1 is a focus lens group that moves during focusing. Note that there may be multiple focus lens groups.

[0015] The lens group L1 is held by a lens holding frame F1. The lens holding frame F1 is driven by a first drive source unit 200 and a second drive source unit 300. The lens holding frame F1, the first drive source unit 200, and the second drive source unit 300 will be described in detail below.

[0016] FIG. 2(A) is an oblique view showing the lens holding frame F1, the first drive source unit 200, and the second drive source unit 300, and FIG. 2(B) is a plan view showing the lens holding frame F1, the first drive source unit 200, and the second drive source unit 300 as viewed from the camera body 101 side.

[0017] First, the configuration of the lens holding frame F1 will be described. As shown in Figures 2(A) and 2(B), the lens holding frame F1 has a cylindrical portion 11 that holds the lens group L1, and the outer periphery of the cylindrical portion 11 is provided with a first guide portion 12 for guiding the lens holding frame F1 in the direction of the optical axis OA, and a second guide portion 13 for restricting movement of the lens holding frame F1 in the rotational direction.

[0018] The first guide portion 12 engages with a guide bar 41 fixed to the fixed barrel 10 (see FIG. 1) parallel to the optical axis OA, thereby guiding the lens holding frame F1 in the direction of the optical axis OA.

[0019] The second guide portion 13 engages with the sub-guide bar 42. The sub-guide bar 42 is fixed to the fixed barrel 10 (see FIG. 1) and restricts the movement of the lens holding frame F1 in the rotational direction.

[0020] Next, a description will be given of the first driving source unit 200. The first driving source unit 200 is disposed near the guide bar 41. As shown in FIG. 2(A), the first driving source unit 200 includes a stepping motor (STM) 201, a lead screw 202, a rack 203, and an attachment member 205.

[0021] The mounting member 205 is fixed to the STM 201 and rotatably supports the lead screw 202. The mounting member 205 has a plurality of holes (not shown), and the first drive source unit 200 is fixed to the fixed barrel 10 by fastening the mounting member 205 to the fixed barrel 10 with screws or the like.

[0022] The STM 201 is a motor driven by a pulse signal output from a drive control device 110 (see FIG. 1) provided inside the lens barrel 100. The drive control device 110 controls the focusing drive of the lens group L1 under the control of a control unit 112 of the camera body 101. Specifically, the drive control device 110 converts the focus drive amount (the amount by which the lens holding frame F1 is moved) input from the control unit 112 of the camera body 101 into the number of pulses of the STM 201 (the drive amount of the STM 201), and outputs the pulse signal to the STM 201.

[0023] The lead screw 202 is directly connected to the output shaft of the STM 201 and is rotationally driven by the STM 201. The lead screw 202 extends in the direction of the optical axis OA, and has a screw groove formed on its outer periphery.

[0024] A rack 203 is engaged with the lead screw 202. A groove that engages with the thread groove of the lead screw 202 is formed on the surface of the rack 203 that comes into contact with the lead screw 202. The rack 203 is also connected to the lens holding frame F1. As a result, when the rack 203 moves in the direction of the optical axis OA as the lead screw 202 rotates, the lens holding frame F1 is guided by the guide bar 41 and moves in the direction of the optical axis OA together with the rack 203. In this way, by driving the lead screw 202 to rotate, the lens holding frame F1 can be driven in the direction of the optical axis OA. A nut may be used instead of the rack 203.

[0025] Even when the first drive source unit 200 is not supplying power to the STM 201, the lead screw 202 and the rack 203 are engaged, so it is possible to maintain the position of the lens retaining frame F1. However, because the torque of a stepping motor is relatively weak, when using a stepping motor to drive the lens retaining frame F1 in the direction of the optical axis OA, if the lens retaining frame F1 is heavy, it is difficult to move the lens retaining frame F1.

[0026] Therefore, in the first embodiment, the second drive source unit 300 applies a force in the optical axis OA direction to the lens holding frame F1, thereby assisting the first drive source unit 200 in driving the lens holding frame F1.

[0027] 2A, the second drive source unit 300 includes a voice coil motor (VCM) 310. The VCM 310 is a moving coil type VCM including a yoke 301, a magnet 302, and a coil 303.

[0028] The yoke 301 is fixed to, for example, the fixed barrel 10. The yoke 301 has a first portion 301a and a second portion 301b extending in the direction of the optical axis OA. A magnet 302 is provided between the first portion 301a and the coil 303. The magnet 302 is fixed to the first portion 301a so that the first portion 301a side is the south pole and the second portion 301b side is the north pole. Note that a further magnet may be provided between the second portion 301b and the coil 303 so that the first portion 301a side is the south pole and the second portion 301b is the north pole.

[0029] The coil 303 is attached to the coil holding portion 14 of the lens holding frame F1. A drive signal (current) is input to the coil 303 from the drive control device 110 (see FIG. 1). When a current flows through the coil 303, the magnetic force of the magnet 302 causes the coil 303 to move in the direction of the optical axis OA. More specifically, the electromagnetic interaction between the coil 303 through which the current flows and the magnet 302 causes the coil 303 to move in the direction of the optical axis OA. By changing the direction of the current flowing through the coil 303, the movement direction of the coil 303 can be switched between the subject side and the camera body 101 side (image plane side). Furthermore, by changing the current value of the current flowing through the coil 303, the drive force and movement speed of the coil 303 can be changed.

[0030] The voice coil motor cannot maintain the position of the coil when no current is supplied to the coil. Therefore, when the lens retaining frame F1 is moved in the direction of the optical axis OA using only the voice coil motor, if the power to the camera 1 is turned off and no current is supplied to the voice coil motor, the lens retaining frame F1 can move freely in the direction of the optical axis OA. Therefore, when driving the lens retaining frame F1 using only the voice coil motor, a structure is required to prevent the lens retaining frame F1 from colliding with other components, or a component (such as a cushioning material) is required to prevent damage to the lens retaining frame F1 and other components if the lens retaining frame F1 collides with them.

[0031] In the first embodiment, the lens holder frame F1 is driven in the optical axis OA direction by the first drive source unit 200, and the second drive source unit 300 assists the first drive source unit 200 in driving the lens holder frame F1. As a result, when using an STM 201 with the same output, it is possible to move a heavier lens holder frame F1 than when the lens holder frame F1 is moved in the optical axis OA direction by the first drive source unit 200 alone (when the second drive source unit 300 is not provided) without reducing the focus speed and position control accuracy. Furthermore, when using an STM 201 with the same output to move a lens holder frame F1 of the same weight, it is possible to move the lens holder frame F1 faster than when the second drive source unit 300 is not used in combination. This point will be described later. Furthermore, it is possible to move a heavier lens holder frame F1. Furthermore, since the first drive source unit 200 can maintain the position of the lens holding frame F1 even when power is not being supplied to the STM 201, there is no need for a structure to prevent the lens holding frame F1 from colliding with other components when the camera 1 is powered off.

[0032] Next, the arrangement of the first driving source unit 200 and the second driving source unit 300 in the first embodiment will be described.

[0033] In this first embodiment, as shown in FIG. 2(B), the second drive source unit 300 is arranged on the opposite side of the first drive source unit 200 in a plane perpendicular to the optical axis OA of the lens group L1, perpendicular to a first straight line LN1 connecting the first drive source unit 200 (more specifically, the central axis AX1 of the lead screw 202 provided in the first drive source unit 200) and the optical axis OA, and across a second straight line LN2 passing through the optical axis OA.

[0034] 3A and 3B are diagrams for explaining the forces acting on the lens retaining frame F1 and the attitude of the lens retaining frame F1. As shown in Fig. 3A, when the lens retaining frame F1 is driven only by the first drive source unit 200, the lens retaining frame F1 is tilted by the driving force DF1 from the first drive source unit 200, and the lens retaining frame F1 moves in the direction of the optical axis OA with the optical axis OA1 of the lens group L1 tilted with respect to the optical axes OA of the other lens groups.

[0035] On the other hand, in the first embodiment, the second drive source unit 300 is disposed on the opposite side of the second straight line LN2 to the first drive source unit 200. Therefore, as shown in Fig. 3(B), the lens retaining frame F1 can be driven in the direction of the optical axis OA by the driving force DF1 from the first drive source unit 200 and the driving force DF2 from the second drive source unit 300 in a state in which the optical axis OA1 of the lens group L1 and the optical axis OA of the other lens groups are substantially aligned, that is, in a state in which the posture of the lens retaining frame F1 is stable.

[0036] (control) Next, we will explain the control of the first driving source unit 200 and the second driving source unit 300. First, we will explain the general control of the STM 201 provided in the first driving source unit 200 using Fig. 4(A). Fig. 4(A) is a timing chart for explaining the general control of the STM 201.

[0037] In general control of the STM201, as shown in Figure 4(A), to prevent the STM201 from losing synchronization, the pulse speed of the pulse signal output to the STM201 is gradually increased from drive to a predetermined pulse speed (constant operating speed). This gradually increases the rotation speed of the STM201. The period during which the pulse speed of the pulse signal is gradually increased (the period from drive start to time t1) is called the acceleration period. After that, a pulse signal is output to the STM201 at a constant pulse speed. This causes the STM201 to rotate at a constant speed (constant speed period from time t1 to t2). Then, after the STM201 has been driven a predetermined number of times, the pulse speed of the pulse signal output to the STM201 is gradually decreased to prevent the STM201 from losing synchronization. This gradually reduces the rotation speed of the STM201. The period during which the pulse speed of the pulse signal is gradually decreased (the period from time t2 to drive stop) is called the deceleration period. The rate of increase in the pulse speed during the acceleration period and the rate of decrease in the pulse speed during the deceleration period are determined in advance based on the output of the STM 201, the weight of the lens holding frame F1, and the like.

[0038] Next, the control of the first drive source unit 200 and the second drive source unit 300 will be described using the flowchart in Fig. 5 and the timing chart in Fig. 4(B). Note that in Fig. 4(B), when the current value of the current supplied to the VCM 310 is positive, the coil 303 applies a force to the lens retaining frame F1 in the same direction as the movement direction of the lens retaining frame F1, and when the current value is negative, the coil 303 applies a force to the lens retaining frame F1 in the opposite direction to the movement direction of the lens retaining frame F1. Note that the following description will be given for a case where a lens retaining frame F1 of the same weight is moved the same distance using an STM201 with the same output as the stepping motor used in the description of Fig. 4(A).

[0039] 5 starts when the power supply to the camera 1 is turned on. In the process of Fig. 5, first, in step S11, the drive control device 110 waits until it receives a focus drive amount from the control unit 112 of the camera body 101.

[0040] When the drive control device 110 receives the focus drive amount from the control unit 112 (step S11 / YES), the process proceeds to step S12, where it converts the focus drive amount into the number of pulses of the STM 201. At this time, the drive control device 110 determines the number of pulses N1 for the acceleration period, the number of pulses N2 for the constant speed period, and the number of pulses N3 for the deceleration period according to predetermined conditions.

[0041] Next, the drive control device 110 executes the process of step S13 and the process of step S14 in parallel. In step S13, the drive control device 110 transmits a pulse signal to the STM 201. In addition, in step S14, the drive control device 110 supplies a current to the VCM 310. At this time, the drive control device 110 supplies a current to the VCM 310 so that the coil 303 moves in the same direction as the direction in which the lens holding frame F1 is driven.

[0042] As shown in FIG. 4B, when the STM 201 is driven, current is supplied to the coil 303 of the VCM 310, assisting in the drive of the lens holding frame F1. The assistance from the VCM 310 provides a margin of torque for the STM 201. Therefore, when the first drive source unit 200 and the second drive source unit 300 are used together as in the first embodiment, the rate of increase in the pulse speed (the rotation speed of the STM 201) during the acceleration period can be set to be greater than when only the first drive source unit 200 is used (as in FIG. 4A). This allows the acceleration period to be shorter than when only the first drive source unit 200 is used.

[0043] Returning to Fig. 5, in step S15, drive control device 110 determines whether pulses equal to the first number of pulses have been output. Here, the first number of pulses is the sum of the number of pulses N1 during the acceleration period and the number of pulses N2 during the constant velocity period. In other words, drive control device 110 determines whether the constant velocity period has ended.

[0044] When the first number of pulses has been output (step S15 / YES), the process proceeds to step S16, where the drive control device 110 reverses the direction of the current supplied to the VCM 310. As a result, a force is applied to the lens holding frame F1 in the direction opposite to the movement direction of the lens holding frame F1.

[0045] As shown in Fig. 4(B), by reversing the direction of the current supplied to the VCM 310, the VCM 310 assists in stopping the lens holding frame F1, thereby creating a torque margin for the STM 201. Therefore, when the first drive source unit 200 and the second drive source unit 300 are used together, the rate of decrease in the pulse speed (the rotation speed of the STM 201) during the deceleration period can be set to be greater than when only the first drive source unit 200 is used (as in Fig. 4(A)). This makes it possible to shorten the deceleration period compared to when only the first drive source unit 200 is used.

[0046] In this way, the acceleration period and deceleration period can be made shorter than when only the first drive source unit 200 is used, so the lens holding frame F1 can be moved at a higher speed than when only the first drive source unit 200 is used.

[0047] Returning to Fig. 5, in step S17, drive control device 110 determines whether pulses equal to the second number of pulses have been output. Here, the second number of pulses is the sum of the number of pulses N1 in the acceleration period, the number of pulses N2 in the constant speed period, and the number of pulses N3 in the deceleration period. In other words, drive control device 110 determines whether the deceleration period has ended.

[0048] When the second number of pulses has been output (step S17 / YES), the process proceeds to step S18, and the drive control device 110 stops supplying current to the VCM 310.

[0049] The control unit 112 of the camera body 101 determines whether the difference between the current position of the lens holding frame F1 and the focus position is within a predetermined range, and if the difference between the current position of the lens holding frame F1 and the focus position is not within the predetermined range, it again transmits the focus drive amount to the drive control device 110. Having received the focus drive amount, the drive control device 110 again executes the processing from step S11.

[0050] In this way, the drive control device 110 drives the STM 201 and the VCM 310 in parallel, so that the VCM 310 can assist the STM 201 in driving the lens holding frame F1.

[0051] In addition, the drive control device 110 starts supplying current to the VCM 310 when the STM 201 starts driving the lens holding frame F1, and stops supplying current to the VCM 310 when the STM 201 finishes driving the lens holding frame F1, thereby reducing power consumption.

[0052] As described above in detail, according to the first embodiment, the lens barrel 100 comprises the lens retaining frame F1 that retains the lens group L1, the first drive source unit 200 that includes the STM 201 and moves the lens retaining frame F1 in the direction of the optical axis OA, and the second drive source unit 300 that includes the VCM 310 and applies a force to the lens retaining frame F1 in the direction of the optical axis OA, the STM 201 and the VCM 310 being different types of motors. This makes it possible to increase the weight of the lens retaining frame F1 and to increase the speed of movement of the lens retaining frame F1 compared to when the lens retaining frame F1 is driven by only the first drive source unit 200.

[0053] Furthermore, according to the first embodiment, lens barrel 100 is provided with guide bar 41 that guides lens barrel 100 in the direction of optical axis OA, and first drive source unit 200 is disposed near guide bar 41. This allows lens retaining frame F1 to move in the direction of optical axis OA more smoothly than when first drive source unit 200 is disposed at a position farther away from guide bar 41.

[0054] Furthermore, according to the first embodiment, the second drive source unit 300 is disposed on the opposite side of the first drive source unit 200 in a plane perpendicular to the optical axis OA of the lens group L1, across a second straight line LN2 that is perpendicular to a first straight line LN1 connecting the first drive source unit 200 and the optical axis OA and passes through the optical axis OA. This makes it possible to move the lens retaining frame F1 in the direction of the optical axis OA while keeping the posture of the lens retaining frame F1 stable, as described with reference to FIG. 3(B).

[0055] Furthermore, according to the first embodiment, the first drive source unit 200 maintains the position of the lens holding frame F1 even when no current is supplied to the STM 201. This eliminates the need for a structure to prevent the lens holding frame F1 from colliding with other components when the camera 1 is powered off.

[0056] Furthermore, according to the first embodiment, the STM 201 is a motor that can calculate the amount of movement of the lens holding frame F1 from the amount of drive of the STM 201. This eliminates the need to provide a sensor or the like to detect the amount of rotation of the STM 201, thereby reducing the parts cost of the lens barrel 100.

[0057] Furthermore, in the first embodiment, VCM 310 includes magnet 302 and coil 303, and coil 303 is driven without contact with magnet 302. This makes it possible to suppress the generation of dust due to sliding, compared to, for example, using a lead screw and a rack (or nut) that contacts the lead screw instead of VCM 310.

[0058] In the first embodiment, the drive control device 110 may supply a constant amount of power to the VCM 310 while driving the STM 201, as shown in FIG. 6(A), or may vary the power supplied to the VCM 310 over time, as shown in FIG. 6(B). In the case of FIG. 6(A), the VCM 310 applies a constant force to the lens holding frame F1 while driving the STM 201. This makes it possible to drive the heavier lens holding frame F1 than when using only the STM 201.

[0059] 6(B), while the STM 201 is driving, the force that the VCM 310 applies to the lens holder frame F1 decreases over time. As a result, when the lens holder frame F1 starts to move, a large force is used to support the drive of the lens holder frame F1, and as the lens holder frame F1 approaches its stopping position and assistance is no longer necessary, the driving force of the VCM 310 can be reduced.

[0060] Furthermore, at low temperatures, motor torque decreases and the motor's internal resistance increases, which can cause the motor's rotation to be unable to keep up with the input pulse count, potentially resulting in loss of synchronization. Therefore, it is necessary to rotate the motor at a speed that will prevent loss of synchronization, but reducing the motor's rotation speed will slow down the movement speed of the lens frame F1. Therefore, by using the VCM310 to support the drive of the lens frame F1 by the STM201, it is possible to increase the speed at which loss of synchronization will not occur at low temperatures. This allows the lens frame F1 to be driven smoothly over a wide temperature range.

[0061] 6A and 6B, the driving force of the STM 201 is constant, but the driving force of the STM 201 may be variable. For example, if the motor rotation speed is reduced when the lens holding frame F1 starts to move and then gradually increased, the driving force of the STM 201 may be increased when the lens holding frame F1 starts to move and then gradually decreased.

[0062] In the first embodiment, the value of the current supplied to the VCM 310 during the constant speed period may be lower than the value of the current supplied to the VCM 310 during the acceleration period. Also, the value of the current supplied to the VCM 310 may be reduced over time during the acceleration period.

[0063] Furthermore, in the first embodiment, a sensor may be provided to detect the actual rotation speed of the STM 201, and the current supplied to the coil 303 may be changed in accordance with the actual rotation speed of the STM 201. For example, when the rotation speed of the STM 201 is low, the current value supplied to the coil 303 may be increased, and as the rotation speed of the STM 201 increases, the current value supplied to the coil 303 may be decreased.

[0064] 5 are executed in parallel, i.e., the STM 201 and the VCM 310 are driven in parallel, but this is not limiting. For example, the STM 201 may be driven first, followed by the VCM 310. That is, step S14 may be executed after step S13 is executed. Also, the VCM 310 may be driven first, followed by the STM 201. That is, step S13 may be executed after step S14 is executed.

[0065] Second Embodiment In the second embodiment, the arrangement of the first drive source unit 200 and the second drive source unit 300A is different from that of the first embodiment. Fig. 7(A) is a perspective view showing the lens retaining frame F1A, first drive source unit 200, and second drive source unit 300A according to the second embodiment, and Fig. 7(B) is a plan view of the lens retaining frame F1A, first drive source unit 200, and second drive source unit 300A as viewed from the camera body 101 side.

[0066] The second drive source unit 300A has the same structure as the second drive source unit 300. The coil 303 of the second drive source unit 300A is held by the coil holding portion 14A of the lens holding frame F1.

[0067] 7(B), in the second embodiment, the second drive source unit 300A is arranged on the first drive source unit 200 side relative to a second straight line LN2 that passes through the optical axis OA and is perpendicular to a first straight line LN1 that connects the first drive source unit 200 (more specifically, the central axis AX1 of the lead screw 202 included in the first drive source unit 200) and the optical axis OA in a plane perpendicular to the optical axis OA of the lens group L1. More specifically, as shown in FIG. 7(B), in the plane perpendicular to the optical axis OA of the lens group L1, the first drive source unit 200 and the second drive source unit 300A face each other in the circumferential direction of a circle centered on the optical axis OA, with the guide bar 41 between them.

[0068] In the second embodiment, the position where the second drive source unit 300A applies force to the lens holding frame F1 is close to the position where the first drive source unit 200 drives the lens holding frame F1, so the propulsion force of the lens holding frame F1 can be increased compared to when the first drive source unit 200 and the second drive source unit 300A are positioned on opposite sides of the second straight line LN2.

[0069] In the second embodiment, the first drive source unit 200 and the second drive source unit 300A face each other in the circumferential direction of a circle centered on the optical axis OA, with the guide bar 41 sandwiched between them, but this is not limiting. The second drive source unit 300A may be located anywhere on a plane perpendicular to the optical axis OA of the lens group L1, as long as it is located closer to the first drive source unit 200 than the second straight line LN2. For example, the second drive source unit 300A may be located at a position facing the guide bar 41 with the first drive source unit 200 sandwiched between them.

[0070] Third Embodiment The third embodiment is provided with a plurality of second drive source units. Fig. 8(A) is a perspective view showing a lens holding frame F1B, a first drive source unit 200, and second drive source units 300B1 and 300B2 according to the third embodiment, and Fig. 8(B) is a plan view showing the lens holding frame F1B, the first drive source unit 200, and the second drive source units 300B1 and 300B2 as viewed from the camera body 101 side.

[0071] The second drive source unit 300B1 has the same configuration as the second drive source unit 300, and the second drive source unit 300B2 has the same configuration as the second drive source unit 300A. The coil 303 of the second drive source unit 300B1 is attached to the coil holding portion 14B1 of the lens holding frame F1B, and the coil 303 of the second drive source unit 300B2 is attached to the coil holding portion 14B2.

[0072] 8(A) and 8(B), in the third embodiment, lens barrel 100 is equipped with two second drive source units 300B1 and 300B2. Second drive source unit 300B1 is orthogonal to a first line LN1 connecting first drive source unit 200 (more specifically, central axis AX1 of lead screw 202 included in first drive source unit 200) and the optical axis OA in a plane perpendicular to the optical axis OA of lens group L1, and is disposed on the opposite side of first drive source unit 200 across a second line LN2 that passes through the optical axis OA. Second drive source unit 300B2 is disposed closer to first drive source unit 200 than the second line LN2.

[0073] As a result, the second drive source unit 300B2 arranged near the first drive source unit 200 increases the propulsion force of the lens holding frame F1, and the second drive source unit 300B1 allows the lens holding frame F1 to move in the direction of the optical axis OA while stabilizing the posture of the lens holding frame F1.

[0074] In the first to third embodiments, the lens group L1 is a focus lens group, but the lens group L1 may be a zoom lens group.

[0075] Furthermore, in the first to third embodiments, a linear ultrasonic motor or a rod ultrasonic motor may be used instead of the STM 201. When a linear ultrasonic motor or a rod ultrasonic motor is used, a position detection sensor may be provided.

[0076] In the first to third embodiments, the VCMs 310, 310A, 310B1, and 310B2 may be moving magnet type VCMs in which the magnet 302 is attached to the lens holding frame F1 and the coil 303 is attached to the fixed barrel .

[0077] Furthermore, lens barrel 100 may include multiple focus lens groups. Figure 9 is a cross-sectional view illustrating lens barrel 100A that includes lens group L1 and lens group L2 as focus lens groups.

[0078] In FIG. 9, the lens group L1 is held by a lens holding frame F1, the lens group L2 is held by a lens holding frame F2, and the lens holding frames F1 and F2 are adjacent to each other in the direction of the optical axis OA.

[0079] The lens barrel 100A includes a second drive source unit 300D that applies a force in the optical axis OA direction to the lens retaining frame F1, and a third drive source unit 400 that applies a force in the optical axis OA direction to the lens retaining frame F2. The second drive source unit 300D includes a VCM 310D that includes a yoke 501, a magnet 502, and a coil 303. Meanwhile, the third drive source unit 400 includes a VCM 410 that includes the yoke 501, the magnet 502, and the coil 403. The VCM 310D of the second drive source unit 300D and the VCM 410 of the third drive source unit 400 share the yoke 501 and the magnet 502. This allows for a reduction in the number of parts in the second drive source unit 300D that applies a force in the optical axis OA direction to the lens retaining frame F1, and the third drive source unit 400 that applies a force in the optical axis OA direction to the lens retaining frame F2. Therefore, when a drive source unit that assists in driving the multiple focus lens groups that the lens barrel has is provided for each focus lens group, the weight of the lens barrel 100A can be reduced compared to when the yoke 501 and magnet 502 are not shared.

[0080] In the first to third embodiments, a position detection sensor may be provided to detect the position of the lens holding frame F1. For example, an optical encoder, a magnetic encoder, or a potentiometer may be used as the position detection sensor. When an optical encoder is used, for example, a photointerrupter or a photoreflector may be used.

[0081] The above-described embodiment is a preferred example of implementation, but is not limited to this, and various modifications are possible within the scope of the gist, and any constituent elements may be combined. [Explanation of symbols]

[0082] 1 camera 41 Guide bar 100, 100A lens barrel 101 Camera Body 110 Drive control device 200 First drive unit 201 Stepping motor 300, 300A, 300B1, 300B2, 300D Second drive unit 310 Voice Coil Motor 400 Third drive unit L1 and L2 lens groups F1, F2 lens holder LN1 1st straight line LN2 Second Line

Claims

1. a first lens holding frame that holds a first lens; a first drive unit that moves the first lens holding frame in the optical axis direction; a second driving unit that applies a force to the first lens holding frame in the optical axis direction; Equipped with the first driving unit and the second driving unit are different types of driving units, the movement of the first lens holding frame in the optical axis direction by the first driving unit and the application of the force in the optical axis direction to the first lens holding frame by the second driving unit are performed in parallel. Lens barrel.

2. a guide bar that guides the first lens holding frame in the optical axis direction; The first drive unit is disposed near the guide bar. The lens barrel according to claim 1 .

3. the second driving unit is disposed on the opposite side of the first driving unit across a second line that perpendicularly intersects a first line connecting the first driving unit and the optical axis and passes through the optical axis, in a plane perpendicular to the optical axis of the first lens; 3. The lens barrel according to claim 1 or 2.

4. the second driving unit is disposed on a side of the first driving unit in a plane perpendicular to the optical axis of the first lens, with respect to a second line that perpendicularly intersects a first line connecting the first driving unit and the optical axis and passes through the optical axis; 3. The lens barrel according to claim 1 or 2.

5. The second driving unit is provided in plurality, one of the plurality of second driving units is arranged on the opposite side of the first driving unit, across a second line that intersects perpendicularly with a first line connecting the first driving unit and the optical axis and passes through the optical axis, in a plane perpendicular to the optical axis of the first lens; and another of the plurality of second driving units is arranged on the first driving unit side of a second line that intersects perpendicularly with the first line connecting the first driving unit and the optical axis and passes through the optical axis, in a plane perpendicular to the optical axis of the first lens.

3. The lens barrel according to claim 1 or 2.

6. The movement amount of the first lens holding frame can be calculated from the drive amount of the first drive unit. The lens barrel according to any one of claims 1 to 5.

7. the first driving unit maintains the position of the first lens holding frame even when no current is supplied thereto; The lens barrel according to any one of claims 1 to 6.

8. The first driving unit is a stepping motor or an ultrasonic motor. The lens barrel according to any one of claims 1 to 7.

9. the second drive unit includes a stator and a mover, The mover is driven in a non-contact manner relative to the stator. The lens barrel according to any one of claims 1 to 8.

10. the second drive unit is a voice coil motor; The lens barrel according to any one of claims 1 to 9.

11. a control unit that controls the first drive unit and the second drive unit, When the control unit receives information regarding the driving of the first driving unit, the control unit drives the first driving unit and the second driving unit. The lens barrel according to any one of claims 1 to 10.

12. The control unit does not drive the second drive unit while the first drive unit is not being driven. The lens barrel according to claim 11.

13. While driving the first driving unit, the control unit reduces the driving force of the second driving unit over time.

13. The lens barrel according to claim 11 or 12.

14. a detection unit that detects a rotational position of an output shaft of the first drive unit, The control unit controls the second drive unit based on the detection result of the detection unit.

13. The lens barrel according to claim 11 or 12.

15. a direction in which the second driving unit applies the force to the first lens holding frame is the same as or opposite to a direction in which the first driving unit moves the first lens holding frame; The lens barrel according to any one of claims 1 to 14.

16. a second lens holding frame that holds the second lens; a third drive unit that applies a force in the optical axis direction to the second lens holding frame; Equipped with The second drive unit and the third drive unit share some of their components. The lens barrel according to any one of claims 1 to 15.

17. the first lens holding frame and the second lens holding frame are disposed adjacent to each other in the optical axis direction; The lens barrel according to claim 16.

18. An imaging device comprising the lens barrel according to any one of claims 1 to 17.

Images