Drive and optical device

Abstract

To provide a driving device and an optical device capable of efficiently obtaining thrust and reducing size and weight even when a movement amount in driving an optical member is large and the weight of a movable portion is large.SOLUTION: A driving device includes: a magnetic circuit unit 31 having a first magnet 45, a second magnet 46, a first yoke 47 that holds the first magnet 45 and the second magnet 46, and a second yoke 48 disposed between the first magnet 45 and the second magnet 46; a first coil 32A that is bonded to a first zoom lens 22A and corresponds to the first magnet 45; and a second coil 32B that is bonded to a second zoom lens 22B and corresponds to the second magnet 46. The magnetic circuit unit 31 drives the first coil 32A and the second coil 32B, and the thickness of the second yoke 48 is larger than the thickness of the first yoke 47.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a driving device for driving an optical system and an optical device. [Background technology]

[0002] Patent Document 1 describes a lens drive device that moves a drive coil provided in a movable lens unit of a camera in the optical axis direction using a magnetic circuit consisting of a magnet and a yoke. In this lens drive device, a cylindrical lens barrel in which the movable lens unit is disposed is formed with a notch that communicates the inside and outside, and a part of the yoke that constitutes the magnetic circuit is attached so as to be positioned inside the lens barrel, and the drive coil is arranged so as to be slidably fitted onto part of the yoke. The lens drive device has two or more movable lens units, and a yoke is provided that is common to the two or more movable lens units.

[0003] Patent Document 2 describes a lens driving device including a movable part that holds a lens, a substantially annular yoke member fixed to the movable part, a permanent magnet fixed to the inner periphery of the yoke member, a coil fixed to a base that passes through the space inside the yoke member and faces the permanent magnet, and a biasing means that biases the movable part in at least one direction along the optical axis direction of the lens. The yoke member is configured by joining a first yoke member and a second yoke member, and the joint between the first yoke member and the second yoke member is located approximately in the center of the permanent magnet in the optical axis direction of the lens. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-116352 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-76944 Summary of the Invention

[0005] One embodiment of the technology disclosed herein provides a driving device and an optical device that can efficiently obtain thrust even when the amount of movement when driving an optical system is large and the weight of the moving part is heavy, and that can be made smaller and lighter. [Means for solving the problem]

[0006] One aspect of the technique disclosed herein is a driving device for driving a first optical system and a second optical system arranged along an optical axis direction, the driving device including a first member, a first coil, and a second coil. The first member drives the first coil with an electromagnetic force generated in the first coil and drives the second coil with an electromagnetic force generated in the second coil, and the second yoke has a thickness greater than that of the first yoke. The first coil is coupled to the first optical system and corresponds to the first magnet. The second coil is coupled to the second optical system and corresponds to the second magnet. The first member includes the first magnet, a second magnet arranged along the optical axis direction with the first magnet, a first yoke that holds the first magnet and the second magnet, and a second yoke arranged between the first magnet and the second magnet.

[0007] The first yoke preferably has a split portion located between the first magnet and the second magnet in the optical axis direction, and the second yoke is preferably provided at the split portion. The second yoke is preferably sandwiched between the first yoke split at the split portion.

[0008] It is preferable that the first yoke has a side surface arranged along the optical axis direction and a groove portion located between the first magnet and the second magnet in the optical axis direction and provided on the side surface, and that the second yoke is arranged in the groove portion.

[0009] It is preferable that the optical system is provided with a position detection sensor, the first members being arranged in a pair at positions facing each other across the optical axes of the first optical system and the second optical system, and the position detection sensor being located between the pair of first members to detect the positions of the first optical system and the second optical system.

[0010] The position detection sensor has a first position detection sensor that detects the position of the first optical system and a second position detection sensor that detects the position of the second optical system, and it is preferable that the first position detection sensor and the second position detection sensor are located at different positions in the circumferential direction around the optical axis.

[0011] If the dimension of the first magnet and second magnet in the optical axis direction is defined as the length dimension, the dimension in the tangential direction of a circle centered on the optical axis of the first optical system and the second optical system is defined as the width dimension, the dimension in the radial direction intersecting the optical axis direction and the tangential direction is defined as the thickness dimension, and the force generated by passing electricity through the first coil and the second coil is defined as the thrust, it is preferable that the width dimension be set to a dimension such that, when the length dimension and thickness dimension are fixed values, the ratio of the increase in thrust to the increase in width dimension is equal to or greater than a threshold value.

[0012] The first magnet and the second magnet preferably have width dimensions such that the ratio is equal to or greater than a threshold value, and are arranged in plural numbers around the circumference of a circle.The length dimensions are preferably set in accordance with the movement amounts of the first optical system and the second optical system.

[0013] At least one of the first optical system and the second optical system preferably weighs 20 g or more and has a dimension in the optical axis direction of 15 mm or more.

[0014] The optical system preferably includes a first holding member that holds the first optical system and the first coil, and a second holding member that holds the second optical system and the second coil, the first coil and the second coil being arranged facing each other with a second yoke sandwiched between them, the first holding member having a first holding portion that holds the first coil at a position opposite the second yoke from the first coil, and the second holding member having a second holding portion that holds the second coil at a position opposite the second yoke from the second coil.

[0015] It is preferable that one of the first and second yokes has a protrusion and the other has a recess, and that the first and second yokes are joined by fitting the protrusion into the recess.

[0016] It is preferable that a support member for supporting the first yoke is provided, and that the support member has an opening for inserting the second yoke into the groove from a direction perpendicular to the side surface.

[0017] An optical device according to one aspect of the technology of the present disclosure is an optical device having the above-described driving device. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is an exploded perspective view of the digital camera. [Figure 2] FIG. 1 is a side view of a digital camera. [Figure 3] FIG. 2 is a cross-sectional view of a main part of a lens barrel. [Figure 4] FIG. [Figure 5] FIG. 2 is an exploded perspective view of a first coil, a second coil, a first holding member, and a second holding member. [Figure 6] FIG. 10 is a perspective view illustrating a process of supporting the drive device on the lens barrel body. [Figure 7] FIG. 2 is an exploded perspective view of a first yoke, a second yoke, a first magnet, and a second magnet. [Figure 8] FIG. 2 is a side view of the magnetic circuit unit. [Figure 9] 10 is a perspective view showing a process in which a first yoke is inserted into the through holes of the first holding member and the second holding member, and the first yoke sandwiches and joins the second yoke. FIG. [Figure 10] 4 is an explanatory diagram schematically showing the flow of magnetic flux from a first magnet and a second magnet. FIG. [Figure 11] FIG. 4 is an explanatory diagram illustrating the dimensions of a first magnet. [Figure 12] 10 is a graph showing the relationship of thrust change amount to the length and width of the first magnet. [Figure 13] FIG. [Figure 14] FIG. 1 is a block diagram showing a schematic configuration of a digital camera. [Figure 15]FIG. 2 is a cross-sectional view of a main part of the lens barrel when the imaging optical system is positioned on the wide-angle side. [Figure 16] FIG. 2 is a cross-sectional view of a main part of the lens barrel when the imaging optical system is positioned on the telephoto side. [Figure 17] FIG. 10 is a perspective view of a drive device according to a second embodiment. [Figure 18] FIG. 10 is an exploded perspective view of a first yoke, a second yoke, a first magnet, and a second magnet in a second embodiment. [Figure 19] FIG. 10 is a perspective view showing the configuration of a lens barrel body in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] [First embodiment] As shown in Fig. 1, a digital camera 10 includes a camera body 11 and an interchangeable lens barrel 12. A lens mount 13, a release switch 14, a power switch (not shown), and other components are provided on the front of the camera body 11. The lens mount 13 has a circular imaging opening 13A. The lens barrel 12 is detachably attached to the lens mount 13. The lens barrel 12 is an example of an optical device according to the present invention.

[0020] An imaging element 16 is built into the camera body 11. The imaging element 16 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Device) image sensor, or an organic thin-film imaging element. The lens mount 13 is provided with a body-side signal contact 17 (see FIG. 14) inside the imaging opening 13A for electrically connecting with the lens barrel 12 for communication. The camera body 11 also has a grip portion 11A.

[0021] 2, lens barrel 12 includes lens barrel main body 21, imaging optical system 22, drive unit 23, and zoom ring 24. Lens barrel main body 21 is cylindrical and holds imaging optical system 22 and drive unit 23 inside, with a lens mount 25 (see FIGS. 3 and 14) and lens-side signal contact 26 (see FIGS. 3 and 14) provided at its rear end. When lens barrel 12 is attached to camera body 11, imaging optical system 22 forms an image of subject light on image sensor 16.

[0022] 3, drive device 23 is disposed inside lens barrel 12. Drive device 23 is a voice coil motor (hereinafter referred to as VCM), and drives first zoom lens 22A and second zoom lens 22B, which are part of imaging optical system 22. Drive device 23 is attached to lens barrel main body 21 via attachment member 27 or the like.

[0023] In the lens barrel 12, the magnification is changed by changing the distance between the first zoom lens 22A and the second zoom lens 22B. The lens barrel 12 changes the focal length without changing the focus position by moving the first zoom lens 22A and the second zoom lens 22B. Specifically, when the first zoom lens 22A moves toward the subject, the second zoom lens 22B moves toward the image plane, and when the first zoom lens 22A moves toward the image plane, the second zoom lens 22B moves toward the subject. This makes it possible to change the focal length without changing the focus position. Note that the maximum amount of movement of the first zoom lens 22A and the second zoom lens 22B during a magnification change operation differs depending on the optical design.

[0024] The first zoom lens 22A is held by a first holding member 28A. The first holding member 28A is connected to a first coil 32A, which will be described later. On the other hand, the second zoom lens 22B is held by a second holding member 28B. The second holding member 28B is connected to a second coil 32B, which will be described later. The first zoom lens 22A and the second zoom lens 22B correspond to the first optical system and the second optical system, respectively, in the claims.

[0025] As shown in FIG. 4, the driving device 23 includes magnetic circuit units 31A to 31D, a first holding member 28A, a second holding member 28B, a first coil 32A, a second coil 32B, a first position detection sensor 33A, a second position detection sensor 33B, a first guide shaft 34A, a second guide shaft 34B, a lens control unit 61, and a VCM driver 62.

[0026] Hereinafter, the magnetic circuit unit 31 will be referred to as magnetic circuit unit 31, or magnetic circuit unit 31A, magnetic circuit unit 31B, magnetic circuit unit 31C, magnetic circuit unit 31D, etc. However, when simply referring to magnetic circuit unit 31, it does not specify any one of them and includes a description common to all magnetic circuit units 31, and when referring to magnetic circuit unit 31A, magnetic circuit unit 31B, magnetic circuit unit 31C, magnetic circuit unit 31D, it will describe the magnetic circuit unit 31 arranged in a specific position. Note that the magnetic circuit unit 31 corresponds to the first member in the claims.

[0027] Lens control unit 61 controls the supply of electricity to first coil 32A and second coil 32B via VCM driver 62. Furthermore, lens control unit 61 controls each part of lens barrel 12, as will be described later.

[0028] As shown in Fig. 5, the first coil 32A is wound in an octagonal shape having four sides aligned with the positions of four first magnets 45 (described later) and four sides connecting these four sides. The second coil 32B is also wound in an octagonal shape like the first coil 32A. The first coil 32A is coupled to the first holding member 28A. That is, the first coil 32A is coupled to the first zoom lens 22A via the first holding member 28A. The first holding member 28A has a cylindrical portion 41A and a flange portion 41B.

[0029] The cylindrical portion 41A holds the first zoom lens 22A. The flange portion 41B protrudes from the outer peripheral surface of the cylindrical portion 41A. The flange portion 41B has an octagonal outer shape to match the first coil 32A. The first coil 32A is fixed to the flange portion 41B. As a result, the first coil 32A is arranged around the optical axis OA. The optical axis OA is the optical axis of the first zoom lens 22A and the second zoom lens 22B. The first zoom lens 22A and the second zoom lens 22B are arranged so that the positions of their optical axes OA coincide with each other.

[0030] The flange portion 41B is integrally formed with four through holes 41C, a guide tube 41D, a guide groove 41E, and a sensor holding portion 41F. A first yoke 47A, which will be described later, is inserted through the through hole 41C. The through hole 41C is formed inside the portion where the first coil 32A is fixed to the flange portion 41B. The first guide shaft 34A is movably fitted into the inner circumferential surface of the guide tube 41D. The guide groove 41E is provided at a position that is rotationally symmetrical with the guide tube 41D by 180 degrees about the optical axis OA. The second guide shaft 34B is movably fitted into the guide groove 41E.

[0031] The sensor holder 41F is provided at a position outside the first coil 32A. The sensor holder 41F holds a position detection magnet 55 (see FIGS. 9 and 13) that constitutes the first position detection sensor 33A. The first position detection sensor 33A will be described later.

[0032] The second coil 32B is coupled to the second holding member 28B. That is, the second coil 32B is coupled to the second zoom lens 22B via the second holding member 28B. The second holding member 28B has a cylindrical portion 42A and a flange portion 42B. The flange portion 42B has an octagonal outer shape to match the second coil 32B. The flange portion 42B is integrally formed with four through holes 42C, a guide cylinder 42D, a guide groove 42E, and a sensor holding portion 42F.

[0033] A first yoke 47B, which will be described later, is inserted through the through hole 42C. The through hole 42C is formed inside the portion where the first coil 32A is fixed to the flange portion 41B. The first guide shaft 34A is movably fitted into the inner circumferential surface of the guide tube 42D. The guide groove 42E is provided at a position that is rotationally symmetrical with the guide tube 42D by 180 degrees about the optical axis OA. The second guide shaft 34B is movably fitted into the guide groove 42E.

[0034] Sensor holding portion 42F is provided at a position outside second coil 32B. Sensor holding portion 42F holds position detection magnet 55 (see FIGS. 9 and 13) that constitutes second position detection sensor 33B. Second position detection sensor 33B will be described later.

[0035] As shown in FIG. 6, first guide shaft 34A and second guide shaft 34B are fixed inside lens barrel main body 21 while fitted into guide tubes 41D, 42D and guide grooves 41E, 42E. Specifically, the base ends of first guide shaft 34A and second guide shaft 34B are fitted into fixing holes 21A, 21B provided inside lens barrel main body 21. Meanwhile, the tip ends of first guide shaft 34A and second guide shaft 34B are fitted into fixing holes 27A, 27B provided in mounting member 27. Mounting member 27 is coupled to lens barrel main body 21. That is, the tip ends of first guide shaft 34A and second guide shaft 34B are coupled to the inside of lens barrel main body 21 via mounting member 27. Note that for convenience of explanation, FIG. 6 shows the lens barrel main body 21 partially cut away and omitted.

[0036] As described above, the first guide shaft 34A and the second guide shaft 34B are fixed inside the lens barrel body 21 and arranged along the Z-axis direction (optical axis direction). As a result, the first guide shaft 34A and the second guide shaft 34B guide the first holding member 28A and the second holding member 28B, i.e., the first zoom lens 22A and the second zoom lens 22B, in the Z-axis direction. The Z-axis direction is the direction along the optical axis OA. As described above, the positions of the optical axes OA of the first zoom lens 22A and the second zoom lens 22B coincide with each other, and the first zoom lens 22A and the second zoom lens 22B are guided by the first guide shaft 34A and the second guide shaft 34B. In other words, the first zoom lens 22A and the second zoom lens 22B are provided so as to be movable within a predetermined range in the Z-axis direction.

[0037] 7, the magnetic circuit unit 31 includes a first magnet 45, a second magnet 46, a first yoke 47, and a second yoke 48. The first yoke 47 and the second yoke 48 are made of a magnetic material such as iron. The first yoke 47 is divided into two parts, a first yoke 47A and a first yoke 47B.

[0038] The first yoke 47A and the first yoke 47B are formed in a bent shape. Specifically, the first yoke 47A and the first yoke 47B are formed in a U-shape.

[0039] As shown in FIG. 8, first yoke 47A is located on the tip side (subject side) in the Z-axis direction. First yoke 47A has an outer flat plate portion 51A, an inner flat plate portion 51B, and a folded portion 51C connecting these flat plate portions 51A and 51B. The outer and inner flat plate portions 51A and 51B extend in the Z-axis direction. The inner surface (the surface facing the optical axis OA) of outer flat plate portion 51A is installation surface 51D, and first magnet 45 is fixed to this installation surface 51D. First magnet 45 is fixed to installation surface 51D by, for example, adhesive. Installation surface 51D extends in the Z-axis direction. First yokes 47A and 47B are attached to lens barrel body 21 by, for example, screwing, adhesive bonding, or press-fitting.

[0040] The first magnet 45 has an N pole magnetized on the outer flat plate portion 51A side of the first yoke 47A and an S pole magnetized on the opposite inner flat plate portion 51B side. The first magnet 45 is selected from, for example, a ferrite magnet, an alnico magnet, a samarium-cobalt magnet, a neodymium magnet, etc.

[0041] The first yoke 47A has a folded portion 51C located at the tip end and an open end 51E located at the base end. The open end 51E has a recess 51F (see FIG. 7) that is recessed from the end face toward the tip end. The open end 51E and the recess 51F correspond to a dividing portion in the claims.

[0042] On the other hand, the first yoke 47B is located closer to the base end (image plane side) in the Z-axis direction than the first yoke 47A. The first yoke 47B has an outer flat plate portion 52A, an inner flat plate portion 52B, and a folded portion 52C connecting these flat plate portions 52A and 52B. The outer and inner flat plate portions 52A and 52B extend in the Z-axis direction. The inner surface (the surface on the optical axis OA side) of the outer flat plate portion 52A is a mounting surface 52D, and the second magnet 46 is fixed to this mounting surface 52D. The second magnet 46 is fixed to the mounting surface 52D by, for example, adhesive. The mounting surface 52D extends in the Z-axis direction.

[0043] The second magnet 46 has an S pole magnetized on the outer flat plate portion 52A side of the first yoke 47B and an N pole magnetized on the opposite inner flat plate portion 52B side. The second magnet 46 is selected from, for example, a ferrite magnet, an alnico magnet, a samarium-cobalt magnet, a neodymium magnet, etc.

[0044] The first yoke 47B has a folded portion 52C located at the tip end and an open end 52E located at the base end. A protruding portion 52F (see FIG. 7) that protrudes from the end face toward the tip end is formed at the open end 52E. The open end 52E and the protruding portion 52F correspond to the dividing portion in the claims.

[0045] Second yoke 48 is disposed along the X-axis direction (the tangent direction of a circle centered on optical axis OA) and the Y-axis direction (the radial direction intersecting the Z-axis direction and the X-axis direction). Second yoke 48 is formed with convex portions 48A and 48B that convex from the inner and outer end faces in the Y-axis direction, and concave portions 48C and 48D that concave from the centers of convex portions 48A and 48B.

[0046] The second yoke 48 has protrusions 48A and 48B fitted into recess 51F of the first yoke 47A, and recesses 48C and 48D fitted into protrusion 52F of the first yoke 47B. This couples the first yokes 47A and 47B to the second yoke 48. The first yokes 47A and 47B may be coupled to the second yoke 48 only by fitting the protrusions 48A and 48B into recess 51F and the recesses 48C and 48D into protrusion 52F, or by combining these fittings with bonding using an adhesive or the like.

[0047] In the present invention, the thickness dimension t5 of the second yoke 48 is formed to be larger (thicker) than the thickness dimensions t1 to t4 of the first yoke 47. Note that the reference character t1 represents the thickness dimension of the outer flat plate portions 51A and 52A, the reference character t2 represents the thickness dimension of the inner flat plate portions 51B and 52B, the reference character t3 represents the thickness dimension of the folded portion 52C, and the reference character t4 represents the thickness dimension of the folded portion 51C.

[0048] 9, the first yoke 47A has the inner flat plate portion 51B inserted through the through hole 41C of the first holding member 28A. As described above, the first coil 32A is fixed at a position outside the through hole 41C, and therefore the first coil 32A is located inside the first yoke 47A inserted through the through hole 41C, and more specifically, is disposed at a position corresponding to the first magnet 45.

[0049] Meanwhile, the inner flat plate portion 52B of the first yoke 47B is inserted through the through hole 42C of the second holding member 28B. As described above, the second coil 32B is fixed at a position outside the through hole 42C, and therefore the second coil 32B is located inside the first yoke 47B that is inserted through the through hole 41C, and more specifically, is disposed at a position corresponding to the second magnet 46.

[0050] 9 shows a state in which the first yokes 47A and 47B are inserted into one through-hole 41C and one through-hole 42C, respectively, and the first yokes 47A and 47B sandwich and couple the second yoke 48, but in reality, the first yokes 47A and 47B are inserted into the remaining three through-holes 41C and 42C, respectively, and the first yokes 47A and 47B sandwich and couple the second yoke 48. That is, the four magnetic circuit units 31A to 31D are arranged around the first zoom lens 22A, the first coil 32A, the second zoom lens 22B, and the second coil 32B, and portions of the first coil 32A and the second coil 32B are arranged inside the magnetic circuit units 31A to 31D.

[0051] By coupling the first yokes 47A and 47B with the second yoke 48, the first magnet 45 and the second magnet 46, which are fixed to the first yokes 47A and 47B, respectively, are arranged along the Z-axis direction. The first yoke 47 has an open end 51E, a recessed portion 51F, an open end 52E, and a protruding portion 52F, i.e., a divided portion, located between the first magnet 45 and the second magnet 46 in the Z-axis direction. The second yoke 48 is provided in the divided portion. Specifically, the second yoke 48 is sandwiched between the first yokes 47A and 47B, which are divided at the positions of the open end 51E, the recessed portion 51F, the open end 52E, and the protruding portion 52F. As a result, the second yoke 48 is arranged between the first magnet 45 and the second magnet 46.

[0052] As described above, the first yokes 47A, 47B are coupled to the second yoke 48, and the first coil 32A and a portion of the second coil 32B are arranged inside the magnetic circuit unit 31, so that the first coil 32A is arranged within the magnetic field of the first magnet 45, and the second coil 32B is arranged within the magnetic field of the second magnet 46.

[0053] 10, the first coil 32A is disposed inside a magnetic circuit made up of the first magnet 45, the first yoke 47A, and the second yoke 48. Therefore, when the VCM driver 62 energizes the first coil 32A under the control of the lens control unit 61 and an electromagnetic force is generated in the first coil 32A, the first coil 32A, which is located within the magnetic field of the first magnet 45, moves in the optical axis direction along the inner flat plate portion 51B. This allows the first holding member 28A and the first zoom lens 22A, which are provided integrally with the first coil 32A, to move in the Z axis direction.

[0054] On the other hand, the second coil 32B is disposed inside a magnetic circuit made up of the second magnet 46, the first yoke 47B, and the second yoke 48. Therefore, when the VCM driver 62 energizes the second coil 32B under the control of the lens control unit 61 and an electromagnetic force is generated in the second coil 32B, the second coil 32B, which is located within the magnetic field of the second magnet 46, moves in the Z-axis direction along the inner flat plate portion 52B. This allows the second holding member 28B and the second zoom lens 22B, which are provided integrally with the second coil 32B, to move in the Z-axis direction.

[0055] When the first coil 32A and the second coil 32B are energized, an electromagnetic force is generated by the magnetic field and the current (so-called Fleming's left-hand rule). By aligning the direction in which this electromagnetic force is generated with the optical axis OA, the electromagnetic force is used as a thrust to drive the first coil 32A and the second coil 32B in the Z-axis direction.

[0056] As described above, the second yoke 48 serves both as a magnetic circuit (comprised of the first yoke 47A and the second yoke 48) for moving the first coil 32A and as a magnetic circuit (comprised of the first yoke 47B and the second yoke 48) for moving the second coil 32B. Therefore, the magnetic flux from the first magnet 45 (indicated by the dashed arrow in FIG. 10) and the magnetic flux from the second magnet 46 (indicated by the two-dot chain arrow in FIG. 10) are concentrated in the second yoke 48.

[0057] In conventional VCMs, all yokes are formed from a material of a uniform thickness. If the thickness of second yoke 48 were the same as that of first yoke 47, the magnetic flux from first magnet 45 and the magnetic flux from second magnet 46 would concentrate, increasing the magnetic flux density within second yoke 48 and causing the saturated magnetic flux to leak outside second yoke 48. In other words, the magnetic flux from first magnet 45 and second magnet 46 would not be used efficiently as thrust for first coil 32A and second coil 32B.

[0058] However, in the present invention, thickness t5 of second yoke 48 is formed to be larger than thicknesses t1 to t4 of first yoke 47, thereby suppressing an increase in magnetic flux density in second yoke 48 where the magnetic flux of first magnet 45 and second magnet 46 concentrates, thereby preventing the magnetic flux from becoming saturated. In other words, the magnetic flux of first magnet 45 and second magnet 46 can be used efficiently as thrust for first coil 32A and second coil 32B.

[0059] For example, at least one of the first zoom lens 22A and the second zoom lens 22B weighs 20 g or more and has a dimension in the Z-axis direction (optical axis direction) of 15 mm or more. In this way, in order to move the relatively heavy and large first zoom lens 22A and the second zoom lens 22B using the VCM, the dimensions of each part of the first magnet 45 and the second magnet 46 are determined so as to efficiently generate thrust (electromagnetic force).

[0060] As shown in FIG. 11, if the dimension of the first magnet 45 in the Z-axis direction is the length dimension H1, the dimension in the X-axis direction is the width dimension W1, and the dimension in the Y-axis direction is the thickness dimension T1, and the force generated by passing current through the first coil 32A is the thrust F1 (thrust for each first magnet 45), it is preferable to set the width dimension W1 so that the thrust change amount dF1 / dW1, which is the ratio of the increase dF1 in thrust F1 to the increase dW1 in width dimension W1, is a large value.

[0061] Fig. 12 is a graph showing the relationship of thrust change amount dF1 / dW1 to length dimension H1 and width dimension W1 of first magnet 45. Note that thickness dimension T1 of first magnet 45 is constant regardless of length dimension H1 and width dimension W1. In Fig. 10, the smaller the hatched mesh, the larger the thrust change amount dF1 / dW1, and vice versa.

[0062] The length H1 of the first magnet 45 is determined by the amount of movement of the first coil 32A, i.e., the first zoom lens 22A, and the thickness T1 is determined by the space inside the lens barrel 12. Therefore, in order to efficiently generate thrust to move the first zoom lens 22A, it is preferable to set the width W1 to a value that efficiently generates thrust relative to the predetermined (fixed) length H1 and thickness T1. That is, in FIG. 12, it is preferable to select the width W1 from a region where the thrust change amount dF1 / dW1 is large (a region with small hatching lines) when the length H1 and thickness T1 are fixed. Furthermore, it is preferable to set a threshold value for the thrust change amount dF1 / dW1, and to set the width W1 to a dimension where the thrust change amount dF1 / dW1 is equal to or greater than the threshold value when the length H1 and thickness T1 are fixed.

[0063] The dimensions of the second magnet 46 are set in the same manner as for the first magnet 45. That is, if the dimension of the second magnet 46 in the Z-axis direction is defined as length H2, the dimension in the X-axis direction is defined as width W2, and the dimension in the Y-axis direction is defined as thickness T2, and the force generated by energizing the first coil 32A is defined as thrust F2 (thrust for each second magnet 46), it is preferable to select the width W2 from a region (region with small hatched lines) where the thrust change amount dF2 / dW2, which is the ratio of the increase dF2 in thrust F2 to the increase dW2 in width W2, is large when the length H2 and thickness T2 are fixed. Furthermore, it is preferable to set a threshold value for the thrust change amount dF2 / dW2, and to set the width W2 to a dimension where the thrust change amount dF2 / dW2 is equal to or greater than the threshold value when the length H2 and thickness T2 are fixed.

[0064] As described above, the first magnet 45 and the second magnet 46 preferably have width dimensions W1, W2 such that the thrust change amounts dF1 / dW1, dF2 / dW2 are equal to or greater than threshold values, and a plurality of magnetic circuit units 31 including the first magnet 45 and the second magnet 46 are arranged in the circumferential direction centered on the optical axis OA. This allows a plurality of first magnets 45 and second magnets 46 having dimensions that allow thrust to be obtained efficiently, and therefore the thrust of the first coil 32A and the second coil 32B increases as the number of first magnets 45 and second magnets 46 increases. In this embodiment, four magnetic circuit units 31A to 31D are arranged in the circumferential direction centered on the optical axis OA.

[0065] As described above, first holding member 28A holds first zoom lens 22A and first coil 32A, and second holding member 28B holds second zoom lens 22B and second coil 32B. First coil 32A and second coil 32B are disposed facing each other with second yoke 48 sandwiched therebetween. As shown in Fig. 10, first holding member 28A has flange portion 41B (first holding portion) that holds first coil 32A at a position opposite second yoke 48 with respect to first coil 32A, and second holding member 28B has flange portion 42B (second holding portion) that holds second coil 32B at a position opposite second yoke 48 with respect to second coil 32B. This means that when the angle of view of the imaging optical system 22 is changed, the first holding member 28A and the second holding member 28B do not interfere with each other, and the first coil 32A and the second coil 32B can be positioned closer to each other, thereby improving design freedom.

[0066] 13, the magnetic circuit units 31 are arranged in pairs at positions facing each other across the optical axis OA. That is, the magnetic circuit units 31A and 31C are arranged in pairs at positions facing each other across the optical axis OA, and the magnetic circuit units 31B and 31D are arranged in pairs at positions facing each other across the optical axis OA.

[0067] The first position detection sensor 33A is located between the magnetic circuit unit 31A and the magnetic circuit unit 31B. The first position detection sensor 33A detects the position of the first holding member 28A, i.e., the first zoom lens 22A. The first position detection sensor 33A is composed of a position detection magnet 55 and a magnetic sensor 56. For example, a multi-pole magnetized magnet is used as the position detection magnet 55, and an MR sensor (Magnetoresistive sensor) is used as the magnetic sensor 56.

[0068] Position-detecting magnet 55 is attached to sensor holding portion 41F of first holding member 28A (see FIG. 9). Magnetic sensor 56 is attached to lens barrel body 21 so as to face position-detecting magnet 55 (see FIG. 8). Position-detecting magnet 55 is magnetized in a pattern in which north and south poles are alternately arranged along the Z-axis direction. The magnetization pattern width is, for example, approximately 100 μm. Magnetic sensor 56 is configured using, for example, various magnetoresistive (MR) elements whose electrical resistance value changes depending on the strength of a magnetic field.

[0069] The magnetic sensor 56 outputs a pulse signal or a periodically changing electrical signal corresponding to the alternating north-south pole arrangement pattern of the position-detecting magnet 55 to the lens control unit 61. Based on this output, the lens control unit 61 can detect the position of the first holding member 28A, i.e., the first zoom lens 22A. Note that the first position detection sensor 33A is not limited to this, and may be configured, for example, by a hall sensor using a hall element and a magnet.

[0070] Meanwhile, second position detection sensor 33B is located between magnetic circuit unit 31C and magnetic circuit unit 31D and detects the position of second zoom lens 22B. Thus, first position detection sensor 33A and second position detection sensor 33B are located at different positions in the circumferential direction about optical axis OA. Therefore, first position detection sensor 33A and second position detection sensor 33B do not interfere with each other, and the space inside barrel body 21 can be used effectively, allowing for efficient component placement.

[0071] Like the first position detection sensor 33A, the second position detection sensor 33B is composed of a position-detecting magnet 55 and a magnetic sensor 56. The position-detecting magnet 55 is attached to the sensor holder 42F of the second holding member 28B (see FIG. 9). As with the first position detection sensor 33A, the magnetic sensor 56 of the second position detection sensor 33B outputs a pulse signal or a periodically changing electrical signal corresponding to the alternating north-south pole arrangement pattern of the position-detecting magnet 55 to the lens control unit 61. Based on this output, the lens control unit 61 can detect the position of the second holding member 28B, i.e., the second zoom lens 22B. Note that the second position detection sensor 33B is not limited to this, and may be composed of, for example, a Hall sensor using a Hall element and a magnet.

[0072] As shown in FIG. 14, the lens barrel 12 includes an imaging optical system 22, a first coil 32A, a second coil 32B, a first position detection sensor 33A, a second position detection sensor 33B, a lens control unit 61, a VCM driver 62, a motor driver 63, a motor 64, etc.

[0073] Lens control unit 61 is made up of a microcomputer equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores programs and parameters used by the CPU, and a RAM (Random Access Memory) (none of which are shown) used as a work memory for the CPU, and controls each part of lens barrel 12. Lens control unit 61 is connected to a VCM driver 62, a motor driver 63, a first position detection sensor 33A, and a second position detection sensor 33B.

[0074] The lens control unit 61 controls the driving of the aperture unit 65, the first zoom lens 22A, and the second zoom lens 22B based on control signals from the camera body control unit 71, which will be described later. The lens control unit 61 detects the rotation position of the zoom ring 24 using a sensor (not shown), and moves the first zoom lens 22A and the second zoom lens 22B based on information on the rotation direction and amount. Note that the lens control unit 61 may also move the first zoom lens 22A and the second zoom lens 22B based on control signals from the camera body 11.

[0075] The imaging optical system 22 includes multiple lenses including a first zoom lens 22A and a second zoom lens 22B, an aperture unit 65, and the like. The first zoom lens 22A and the second zoom lens 22B move in the Z-axis direction when current is applied to the first coil 32A and the second coil 32B, thereby varying the angle of view of the imaging optical system 22. The lens control unit 61 transmits control signals to the VCM driver 62 to move the first zoom lens 22A and the second zoom lens 22B in accordance with information about the direction and amount of rotation of the zoom ring 24 or in accordance with a control signal from the camera body 11. The VCM driver 62 applies current to the first coil 32A and the second coil 32B based on the control signal.

[0076] The diaphragm unit 65 moves a plurality of diaphragm blades 65A by driving a motor 64, thereby changing the amount of light incident on the image sensor 16. The motor driver 63 controls the driving of the motor 64 based on the control of the lens control unit 61.

[0077] The camera body control unit 71 includes a CPU, a ROM that stores programs and parameters used by the CPU, and a RAM (none of which are shown) that is used as work memory for the CPU. The camera body control unit 71 controls the camera body 11 and various parts of the lens barrel 12 connected to the camera body 11. A release signal is input to the camera body control unit 71 from the release switch 14. A body-side signal contact 17 is also connected to the camera body control unit 71.

[0078] The lens side signal contact 26 comes into contact with the body side signal contact 17 when the lens mount 25 of the lens barrel 12 is attached to the lens mount 13 of the camera body 11, electrically connecting the lens barrel 12 and the camera body 11.

[0079] The shutter unit 72 is a so-called focal plane shutter, and is disposed between the lens mount 13 and the image sensor 16. The shutter unit 72 is provided so as to be able to block the optical path between the image sensor 16 and the image sensor 22, and is variable between an open state and a closed state. The shutter unit 72 is in the open state when capturing live view images and moving images. The shutter unit 72 temporarily switches from the open state to a closed state when capturing still images. The shutter unit 72 is driven by a shutter motor 73. A motor driver 74 controls the driving of the shutter motor 73.

[0080] The imaging element 16 is driven and controlled by the camera body control unit 71. The imaging element 16 has a light receiving surface made up of a plurality of pixels (not shown) arranged in a two-dimensional matrix. Each pixel includes a photoelectric conversion element, and performs photoelectric conversion on the subject image formed on the light receiving surface by the imaging optical system 22 to generate an imaging signal.

[0081] The image sensor 16 also includes signal processing circuits (none of which are shown), such as a noise reduction circuit, an auto-gain controller, and an A / D conversion circuit. The noise reduction circuit performs noise reduction processing on the image signal. The auto-gain controller amplifies the level of the image signal to an optimal value. The A / D conversion circuit converts the image signal into a digital signal and outputs it from the image sensor 16 to the bus line 76. The output signal from the image sensor 16 is image data (so-called RAW data) with one color signal for each pixel.

[0082] The image memory 75 stores one frame of image data output to the bus line 76. The image data processing unit 77 reads one frame of image data from the image memory 75 and performs known image processing such as matrix calculation, demosaic processing, gamma correction, luminance / color difference conversion, and resizing.

[0083] The LCD driver 78 sequentially inputs one frame's worth of image data that has been image-processed by the image data processing unit 77 to the image display unit 79. The image display unit 79 is provided, for example, on the rear surface of the camera body 11, and sequentially displays live view images at a regular interval. A card I / F (Interface) 81 is incorporated in a card slot (not shown) provided in the camera body 11, and is electrically connected to a memory card 82 inserted into the card slot. The card I / F 81 stores the image data that has been image-processed by the image data processing unit 77 in the memory card 82. When playing back and displaying the image data stored in the memory card 82, the card I / F 81 reads the image data from the memory card 82.

[0084] The camera body control unit 71 operates the aperture unit 65 in accordance with exposure information calculated by an AE (Automatic Exposure) processing unit 84 (described later), and sends a control signal for changing the aperture diameter to the lens control unit 61. The lens control unit 61 controls the motor driver 74 based on the control signal, and controls the aperture diameter of the aperture unit 65 so as to obtain the aperture value calculated by the AE processing unit 84.

[0085] The AE processing unit 84 calculates the integrated value of each color signal from one frame of image data. The camera body control unit 71 calculates the appropriate exposure value based on the integrated value calculated for each frame of image, and determines the aperture value so that the appropriate exposure value calculated for a preset shutter speed is achieved. The camera body control unit 71 sends a control signal to the lens control unit 61. The lens control unit 61 controls the motor driver 63 based on the control signal, and operates the aperture unit 65 to an aperture diameter that achieves the determined aperture value.

[0086] The operation of lens barrel 12 of this embodiment will be described. When lens barrel 12 is attached to camera body 11 and a power switch (not shown) is operated by a user who is taking the picture, power is supplied to each part of digital camera 10.

[0087] When the digital camera 10 is powered on, the image sensor 16, the camera body control unit 71, the lens control unit 61, etc. are activated. As described above, in response to information on the direction and amount of rotation of the zoom ring 24, or when a control signal is received from the camera body control unit 71, the lens control unit 61 moves the first zoom lens 22A and the second zoom lens 22B.

[0088] 15 and 16 , an operation of moving the first zoom lens 22A and the second zoom lens 22B in the Z-axis direction by energizing the first coil 32A and the second coil 32B will be described. Note that the examples shown in FIGS. 15 and 16 illustrate the first zoom lens 22A and the second zoom lens 22B constituting a four-group imaging optical system 22. That is, the imaging optical system 22 is configured, in order from the subject side, with the first optical system 22C, the first zoom lens 22A, the second zoom lens 22B, and the fourth optical system 22D. The first zoom lens 22A and the second zoom lens 22B correspond to the second and third optical systems. The first optical system 22C and the fourth optical system 22D are optical systems whose positions are restricted relative to the lens barrel body 21 and do not move in the Z-axis direction. Note that the optical system having a zoom lens described in this embodiment is merely an example, and the present invention is also applicable to optical systems having a focus lens, etc.

[0089] As shown in Fig. 15, when the imaging optical system 22 of the lens barrel 12 is on the wide-angle side, the first zoom lens 22A and the second zoom lens 22B are spaced apart from each other. On the other hand, as shown in Fig. 16, when the imaging optical system 22 of the lens barrel 12 is on the telephoto side, the first zoom lens 22A and the second zoom lens 22B are close to each other.

[0090] When the angle of view of the imaging optical system 22 is changed from the wide-angle side shown in Fig. 15 to the telephoto side shown in Fig. 16, current is applied to the first coil 32A and the second coil 32B, and the directions of the currents flowing through the first coil 32A and the second coil 32B are reversed. As a result, the first coil 32A located within the magnetic field of the first magnet 45 moves toward the base end in the Z-axis direction, and the second coil 32B located within the magnetic field of the second magnet 46 moves toward the tip end in the Z-axis direction. In other words, the first holding member 28A and the first zoom lens 22A, which are provided integrally with the first coil 32A, move toward the base end, and the second holding member 28B and the second zoom lens 22B, which are provided integrally with the second coil 32B, move toward the tip end.

[0091] When current is applied to the first coil 32A and the second coil 32B, the first holding member 28A and the first zoom lens 22A move toward the base end and the second holding member 28B and the second zoom lens 22B move toward the tip end, and as shown in Figure 16, the imaging optical system 22 moves to the telephoto side, i.e., the first zoom lens 22A and the second zoom lens 22B are positioned close to each other.

[0092] On the other hand, when changing the angle of view of the imaging optical system 22 from the telephoto side shown in Fig. 16 to the wide-angle side shown in Fig. 15, the direction of the current flowing through the first coil 32A and the second coil 32B is reversed from that in the above case. As a result, the first holding member 28A and the first zoom lens 22A, which are integral with the first coil 32A, move toward the distal end, and the second holding member 28B and the second zoom lens 22B, which are integral with the second coil 32B, move toward the proximal end. In other words, the first zoom lens 22A and the second zoom lens 22B are positioned apart from each other.

[0093] As described above, the drive unit 23 includes the first yoke 47 that holds the first magnet 45 and the second magnet 46, and the shared second yoke 48 disposed between the first magnet 45 and the second magnet 46. This allows for efficient thrust when driving the first coil 32A and the second coil 32B, thereby reducing the weight and size of the drive unit 23 and, ultimately, the lens barrel 12. While conventional drive units use magnetic circuits consisting of separate components for the first and second coils to drive the first and second coils, the present invention uses the shared components, i.e., the first yoke 47 and the second yoke 48, to drive the first coil 32A and the second coil 32B. This allows for reduced weight and size by the amount of component sharing. Furthermore, the thickness t5 of the second yoke 48 is greater than the thicknesses t1 to t4 of the first yoke 47, preventing magnetic flux saturation as described above. Therefore, the magnetic flux of first magnet 45 and second magnet 46 can be used efficiently as thrust for first coil 32A and second coil 32B. In other words, there is no need to use magnets or yokes that are larger than necessary, and drive device 23, and therefore lens barrel 12, can be made even lighter and more compact.

[0094] [Second embodiment] In the first embodiment described above, the first yoke 47 has a split portion at a position between the first magnet 45 and the second magnet 46 in the optical axis direction, and the second yoke 48 is provided in the split portion, but the present invention is not limited to this, and the second embodiment described below illustrates a configuration in which a groove portion is provided on the side surface of the first yoke and the second yoke 48 is arranged in this groove portion.

[0095] As shown in Fig. 17, the drive device 90 in this embodiment includes four magnetic circuit units 91. Like the drive device 23 in the first embodiment, the drive device 90 is disposed inside the lens barrel 12 and drives the first zoom lens 22A and the second zoom lens 22B, which are part of the imaging optical system 22. The magnetic circuit units 91 correspond to the "first member" in the claims. The configuration other than the magnetic circuit units 91 is similar to that of the drive device 23 in the first embodiment, and the same components are designated by the same reference numerals and will not be described again.

[0096] 18, the magnetic circuit unit 91 includes a first magnet 45, a second magnet 46, a first yoke 92, and a second yoke 93. The first yoke 92 and the second yoke 93 are made of a magnetic material such as iron. The first yoke 92 is made up of a first yoke 92A and a first yoke 92B.

[0097] The first yoke 92A is formed in a bent shape. Specifically, the first yoke 92A is formed in a U-shape. The first yoke 92A has an outer flat plate portion 94A, an inner flat plate portion 94B, and a folded portion 94C connecting these flat plate portions 94A, 94B. The outer and inner flat plate portions 94A, 94B extend in the optical axis direction. The inner surface of the outer flat plate portion 94A (the surface on the optical axis OA side) is an installation surface 94D, and the first magnet 45 and the second magnet are fixed to this installation surface 94D.

[0098] The first magnet 45 and the second magnet 46 fixed to the first yoke 92A are arranged along the Z-axis direction. The first magnet 45 and the second magnet are fixed to the installation surface 94D by, for example, adhesive. The installation surface 94D extends in the Z-axis direction. The first yoke 92A is attached to the inside of the lens barrel body 21 by, for example, screwing, adhesive bonding, or press-fitting.

[0099] The first yoke 92A has a folded portion 94C located on the base end side and an open end 94E located on the base end side. One end of the open end 94E (one end of the outer flat plate portion 94A) is formed with a recess 94F that is recessed from the end face toward the base end side. The other end of the open end 94E (one end of the inner flat plate portion 94B) is formed with a protrusion 94G that is protruded from the end face toward the tip end side.

[0100] The first yoke 92A has a side surface 94H and a groove 94I. The side surface 94H is a surface that is arranged along the Z-axis direction. Specifically, the side surface 94H is one of the end surfaces in the X-axis direction of the flat plate portions 94A, 94B and the folded portion 94C. The groove 94I is provided on the side surface 94H, is located between the first magnet 45 and the second magnet 46 in the Z-axis direction, and is a groove that is arranged along the Y-axis direction.

[0101] The first yoke 92A has an inner flat plate portion 94B inserted through the through hole 41C of the first holding member 28A and the through hole 42C of the second holding member 28B. As a result, the first coil 32A is disposed at a position corresponding to the first magnet 45, and the second coil 32B is disposed at a position corresponding to the second magnet 46, similar to the first embodiment.

[0102] The first yoke 92B is disposed at the tip of the first yoke 92A in the Z-axis direction. The first yoke 92B is disposed along the Y-axis direction and the X-axis direction. The first yoke 92B has a recessed portion 95A recessed from the inner end face in the Y-axis direction and a protruding portion 95B protruding from the outer end face. The protruding portion 95B of the first yoke 92B fits into the recessed portion 94F of the first yoke 92A, and the recessed portion 95A fits into the protruding portion 94G of the first yoke 47B. This couples the first yoke 92A and the first yoke 92B together.

[0103] The second yoke 93 is disposed along the Y-axis direction and the X-axis direction. That is, the second yoke 93 is disposed parallel to the first yoke 92B. The second yoke 93 is formed in a T-shape with protrusions 93A and 93B that protrude from the inner and outer end faces in the Y-axis direction. The second yoke 93 is inserted into the first yoke 92A with the protrusions 93A and 93B fitting into the groove 94I of the first yoke 92A. That is, the second yoke 93 is disposed in the groove 94I. This couples the first yoke 92A and the second yoke 93.

[0104] Similar to the first embodiment, the thickness of the second yoke 93 is greater than the thickness of the first yoke 92. Note that the first yoke 92A may be coupled to the first yoke 92B and the second yoke 93 only by fitting the convex portion 95B to the concave portion 94F, the concave portion 95A to the convex portion 94G, and the convex portions 93A and 93B to the groove portion 94I, or by combining these fittings with bonding using an adhesive or the like.

[0105] As described above, the driving device 90, like the driving device 23 of the first embodiment, includes a first yoke 92 that holds the first magnet 45 and the second magnet 46, and a common second yoke 93 disposed between the first magnet 45 and the second magnet 46. This allows for efficient thrust when driving the first coil 32A and the second coil 32B, thereby reducing the weight and size of the driving device 90 and, ultimately, the lens barrel 12. Furthermore, the thickness of the second yoke 93 is greater than the thickness of the first yoke 92, preventing magnetic flux saturation. Therefore, the magnetic flux of the first magnet 45 and the second magnet 46 can be efficiently used as thrust for the first coil 32A and the second coil 32B. This allows for further weight and size reductions of the driving device 90 and the lens barrel 12.

[0106] As a modification of the second embodiment, as shown in FIG. 19 , an opening 21C for inserting a second yoke 93 may be formed in the lens barrel main body 21. As described above, the first yoke 92A is attached inside the lens barrel main body 21. That is, the lens barrel main body 21 is a support member that supports the first yoke 92A. In the assembly process, the first yoke 92A is attached to the lens barrel main body 21 before the second yoke 93. In the example shown in FIG. 19 , the first zoom lens 22A, the second zoom lens 22B, the first holding member 28A, the second holding member 28B, the first coil 32A, the second coil 32B, the first magnet 45, the second magnet 46, and the like are also arranged inside the lens barrel main body 21, similar to the first embodiment.

[0107] Opening 21C is a through-hole that penetrates from the outside to the inside of lens barrel body 21 along a direction (X-axis direction) perpendicular to side surface 94H of first yoke 92A, and is formed to match the position of groove 94I of first yoke 92A. In other words, opening 21C allows second yoke 93 to be inserted into groove 94I from the X-axis direction.

[0108] As described above, first yoke 47A is inserted through through-hole 41C of first holding member 28A and through-hole 42C of second holding member 28B, and first coil 32A and second coil 32B are disposed at positions corresponding to first magnet 45 and second magnet 46. The assembly work for all of these involves moving parts along the Z-axis direction, so it is efficient to perform this work in a process beyond second yoke 93. Also, because lens barrel body 21 has a cylindrical shape that is aligned with the Z-axis direction, it is easier to move parts along the Z-axis direction.

[0109] Then, with first zoom lens 22A, second zoom lens 22B, first yoke 47A, first yoke 47B, first magnet 45, second magnet 46, first holding member 28A, second holding member 28B, first coil 32A, second coil 32B, etc. arranged inside lens barrel body 21, second yoke 93 can be inserted into groove 94I from the X-axis direction through opening 21C. As described above, the efficiency of the assembly work can be improved, and the productivity of lens barrel 12 is improved.

[0110] In each of the above embodiments, the hardware structure of processing units that execute various processes, such as the lens control unit 61 and the camera body control unit 71, is the following various processors: The various processors include a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) and functions as various processing units, a GPU (Graphical Processing Unit), a PLD (Programmable Logic Device), which is a processor whose circuit configuration can be changed after manufacture, such as an FPGA (Field Programmable Gate Array), and a dedicated electrical circuit, which is a processor with a circuit configuration designed specifically for executing various processes.

[0111] A single processing unit may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, multiple FPGAs, a combination of a CPU and an FPGA, or a combination of a CPU and a GPU). Also, multiple processing units may be configured with a single processor. Examples of multiple processing units configured with a single processor include, first, a configuration in which one processor is configured with a combination of one or more CPUs and software, as typified by client or server computers, and this processor functions as multiple processing units. Second, a configuration in which a processor is used that realizes the functions of an entire system including multiple processing units on a single IC (Integrated Circuit) chip, as typified by SoCs (System On Chips). In this way, the various processing units are configured with one or more of the above-mentioned various processors as a hardware structure.

[0112] Furthermore, the hardware structure of these various processors is, more specifically, an electric circuit in the form of a combination of circuit elements such as semiconductor elements.

[0113] In the above-described embodiments, the first zoom lens 22A and the second zoom lens 22B are exemplified as optical systems driven by a driving device, but the present invention is not limited to this and may be applied to driving devices that drive other optical systems. Furthermore, the optical device according to the present invention can be applied to lens barrels of smartphones, video cameras, etc. in addition to lens barrels of digital cameras. [Explanation of symbols]

[0114] 10. Digital Camera 11 Camera body 11A Grip 12 Lens barrel 13 Lens mount 13A Imaging aperture 14 Release switch 16 image sensor 17 Body side signal contact 21 Lens barrel body 21A, 21B fixing hole 21C opening 22 Imaging optical system 22A 1st zoom lens 22B 2nd zoom lens 22C First group optical system 22D 4th group optical system 23 Drive unit 24 Zoom ring 25 lens mount 26 Lens side signal contact 27 Mounting material 27A, 27B fixing hole 28A First holding member 28B Second holding member 31 Magnetic circuit unit 31A~31D Magnetic circuit unit 32A 1st coil 32B Second coil 33A First position detection sensor 33B Second position detection sensor 34A First guide shaft 34B Second guide shaft 41A Cylindrical part 41B flange 41C through hole 41D Guide tube 41E Guide groove 41F Sensor holder 42A Cylindrical part 42B flange 42C through hole 42D Guide tube 42E Guide groove 42F Sensor holder 45 First Magnet 46 Second magnet 47 First York 47A, 47B 1st York 48 Second York 48A, 48B convex part 48C, 48D recess 51A, 52A Outer flat plate part 51B, 52B Inner flat plate part 51C Folded section 51D Installation surface 51E Open end 51F Recess 52C Folded section 52D installation surface 52E open end 52F convex part 55 Position detection magnet 56 Magnetic Sensor 61 Lens control unit 62 VCM driver 63 Motor Driver 64 motor 65 Aperture unit 65A aperture blades 71 Camera body control unit 72 Shutter unit 73 Shutter motor 74 Motor Driver 75 Image Memory 76 Bus Line 77 Image data processing section 78 LCD Driver 79 Image display unit 81 Card I / F (Interface) 82 Memory Card 84 AE (Automatic Exposure) processing section 90 Drive Unit 91 Magnetic circuit unit 92 First York 92A 1st York 92B 1st York 93 Second York 93A, 93B convex parts 94A Outer flat plate part 94B Inner flat plate part 94C Folded section 94D Installation surface 94E open end 94F Recess 94G convex part 94H side 94I Groove 95A Recess 95B convex part H1 length dimension OA optical axis T1 thickness dimension t1~t4 Thickness dimensions t5 thickness dimension W1 width dimension

Claims

1. A driving device that drives a first optical system and a second optical system that are arranged along an optical axis direction, a first member including a first magnet, a second magnet arranged along the optical axis direction with respect to the first magnet, a first yoke that holds the first magnet and the second magnet, and a second yoke arranged between the first magnet and the second magnet; a first coil coupled to the first optical system and corresponding to the first magnet; a second coil coupled to the second optical system and corresponding to the second magnet; the first member drives the first coil by an electromagnetic force generated in the first coil, and drives the second coil by an electromagnetic force generated in the second coil; The second yoke has a thickness greater than that of the first yoke.

2. the first yoke has a dividing portion at a position between the first magnet and the second magnet in the optical axis direction, The drive device according to claim 1 , wherein the second yoke is provided in the dividing portion.

3. The drive device according to claim 2 , wherein the second yoke is sandwiched between the first yokes that are divided at the dividing portion.

4. The first yoke is a side surface disposed along the optical axis direction; a groove portion provided on the side surface and located between the first magnet and the second magnet in the optical axis direction, The drive device according to claim 1 , wherein the second yoke is disposed in the groove.

5. A position detection sensor is provided, the first members are arranged in a pair at positions facing each other across the optical axes of the first optical system and the second optical system, The driving device according to claim 1 , wherein the position detection sensor is located between the first members arranged in a pair and detects the positions of the first optical system and the second optical system.

6. The position detection sensor a first position detection sensor that detects the position of the first optical system; a second position detection sensor that detects the position of the second optical system; The driving device according to claim 5 , wherein the first position detection sensor and the second position detection sensor are located at different positions in a circumferential direction about the optical axis.

7. When the dimension of the first magnet and the second magnet in the optical axis direction is defined as a length dimension, the dimension of the first optical system and the second optical system in a tangential direction of a circle centered on the optical axis is defined as a width dimension, the dimension in a radial direction intersecting the optical axis direction and the tangential direction is defined as a thickness dimension, and a force generated by energizing the first coil and the second coil is defined as a thrust force, The drive device according to any one of claims 1 to 6, wherein the width dimension is set to a dimension such that, when the length dimension and the thickness dimension are fixed, a ratio of an increase in the thrust force to an increase in the width dimension is equal to or greater than a threshold value.

8. The drive device according to claim 7 , wherein the first magnet and the second magnet have the width dimension such that the ratio is equal to or greater than a threshold value, and a plurality of the first magnets and a plurality of the second magnets are arranged in the circumferential direction of the circle.

9. 9. The driving device according to claim 7, wherein the length is set in accordance with the amount of movement of the first optical system and the amount of movement of the second optical system.

10. 10. The driving device according to claim 1, wherein at least one of the first optical system and the second optical system has a weight of 20 g or more and a dimension in the optical axis direction of 15 mm or more.

11. a first holding member that holds the first optical system and the first coil, and a second holding member that holds the second optical system and the second coil, the first coil and the second coil are disposed facing each other with the second yoke interposed therebetween, the first holding member has a first holding portion that holds the first coil at a position opposite to the second yoke with respect to the first coil, The drive device according to claim 1 , wherein the second holding member has a second holding portion that holds the second coil at a position opposite to the second yoke with respect to the second coil.

12. 12. The drive device according to claim 1, wherein one of the first yoke and the second yoke has a convex portion and the other has a concave portion, and the first yoke and the second yoke are coupled together by fitting the convex portion into the concave portion.

13. a support member on which the first yoke is supported, 13. The drive device according to claim 4, or any one of claims 5 to 12 that cites claim 4, wherein the support member has an opening that allows the second yoke to be inserted into the groove from a direction perpendicular to the side surface.

14. An optical device comprising a drive device according to any one of claims 1 to 13.

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