JP2012230323A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel having a driving control mechanism in which sufficient driving force is obtained, thinning in an optical axis direction is possible, and assembly is easy.SOLUTION: A lens barrel includes: a movable frame 43 for holding a wobbling lens; and a guide shaft for supporting the movable frame 43 to be movable in an optical axis O direction. In addition, the lens barrel includes: an adsorption plate 65 that is secured to a part of the movable frame 43 and is made from magnetic material; different pole joining magnets 61 and 62 that are attached to the adsorption plate in an adsorptive state and are magnetized in a direction orthogonal to adsorption surfaces against the adsorption plate 65; a yoke 64 that is joined to a back surface side of the adsorption surfaces of the different pole joining magnets 61 and 62; and a sending piezoelectric element 66 that is coupled to the different pole joining magnets 61 and 62 through a transmission unit 67.

Description

  The present invention relates to a focus control mechanism applicable to an imaging device of an electronic camera or a mobile phone, an optical disk device, a forward / backward drive control mechanism such as a wobbling control mechanism, a lens barrel and an imaging device provided with a shake correction mechanism, or The present invention relates to a lens barrel having a collimator lens spherical aberration correction mechanism used in an optical disc apparatus.

  An electromagnetic drive mechanism and a piezoelectric element drive mechanism are known for driving a focus lens and a wobbling lens forward and backward in the optical axis direction in a conventional imaging apparatus. For example, as an electromagnetic drive mechanism incorporated in a lens barrel that can be mounted on an imaging device disclosed in Patent Document 1, there is one that applies a movable coil fixed to a movable frame that holds a lens.

  Further, the lens module disclosed in Patent Document 2 is attracted to the magnet as a piezoelectric element driving mechanism, a laminated piezoelectric element that is an electromechanical conversion element, a magnet fixed to one end in the displacement direction of the piezoelectric element, and the magnet. A lens holder having a magnetic body and holding an optical lens. By driving the magnetic material using the vibration of the permanent magnet as a driving force, the lens holder is driven back and forth in the optical axis direction.

  In addition, in the conventional imaging apparatus, what is disclosed in Patent Document 3 as having a drive mechanism for camera shake correction is a camera-correction drive mechanism that is provided on the image sensor side of the photographic lens group when camera shake occurs. The photographic lens to be arranged is displaced and driven in the direction of correcting camera shake along the lens optical axis orthogonal plane. The blur correction drive mechanism is made of an actuator made of a shape memory alloy, and the lens frame holding the photographing lens is driven to be displaced along a guide shaft disposed on a plane orthogonal to the lens optical axis.

JP 2010-256814 A JP 2008-203583 A JP 2008-11327 A

  However, in the electromagnetic drive mechanism disclosed in Patent Document 1, when a permanent magnet joined with a different polarity is arranged on the fixed side and an oval coil is fixed to the movable frame, the coil and the permanent magnet are occupied in the optical axis direction. Space becomes longer. Therefore, the length in the optical axis direction in the retracted state of the lens barrel becomes long, it is extremely difficult to reduce the thickness, and there is a concern that the outer shape of the lens barrel becomes large.

  On the other hand, in the case of applying the piezoelectric element driving mechanism, when the lens numerical aperture of the focus lens or wobbling lens is large, the N or S pole of the magnet coupled to the piezoelectric element and the magnetic material coupled to the lens holder are attracted. Power is important. However, since a short bar magnet is applied as in the lens module disclosed in Patent Document 2, the attractive force is weak and the operation of the lens holder becomes unstable. Moreover, there is a concern that magnetic flux leaks to the outside of the bar magnet, and there is a concern about weakening the attractive force.

  The present invention has been made to solve the above-described problems. In a lens barrel provided with a drive control mechanism, a sufficient driving force can be obtained, and the optical axis direction can be thinned and assembled. It is an object of the present invention to provide a lens barrel that is easy to use and an imaging device to which the lens barrel is applied.

  In order to solve the above problems, the lens barrel of the present invention is capable of moving a lens moving frame for holding an optical lens and the lens moving frame in the optical axis direction or a plane orthogonal to the optical axis direction. In a lens barrel having a guide member to support, a first magnetic member fixed to a part of the lens moving frame, and adsorbed to the first magnetic member and adsorbed to the first magnetic member A heteropolar magnet magnetized in a direction perpendicular to the surface, a second magnetic member joined to the opposite surface of the heteropolar magnet to the attracting surface side, and a transmission member interposed in the heteropolar magnet And a feeding piezoelectric element to be coupled.

  According to the present invention, in a lens barrel provided with a drive control mechanism, it is possible to provide a lens barrel that can obtain a sufficient driving force and can be thinned, and an imaging device to which the lens barrel is applied. .

1 is a configuration diagram of a camera system to which a lens barrel of a first embodiment of the present invention is attached. Block diagram of the camera system of FIG. 1 is a longitudinal sectional view taken along the optical axis of an adapter lens device in a lens barrel applied to the camera system of FIG. A view of arrow A in FIG. BB sectional view of FIG. CC sectional view of FIG. DD sectional view of FIG. Enlarged view around the movable frame holding mechanism incorporated in the adapter lens device of FIG. GG sectional view of FIG. Flowchart of AF processing in the camera system of FIG. FIG. 8 is a view showing a modification of the guide shaft pressing mechanism in the adapter lens device of FIG. 6, and a cross-sectional view corresponding to FIG. 7. The figure which looked at the lens barrel of 2nd embodiment of this invention from the object side EE sectional view of FIG. FF sectional view of FIG.

  A camera system including the lens barrel of the first embodiment of the present invention will be described with reference to the drawings.

  A camera system 1 as an imaging apparatus to which the lens barrel of the present embodiment is applied includes a body unit 5 as a camera body having an imaging element 18 as shown in the system configuration diagram of FIG. 1 and the block configuration diagram of the system of FIG. And a lens barrel 2 that can be attached to and detached from the body unit 5. The lens barrel 2 includes a barrel portion 3 that is an interchangeable lens barrel having a master lens ML, and an adapter lens device 4 that is detachable from the barrel portion 3 and includes an adapter lens AL. The

  The optical axes of the master lens ML and the adapter lens AL are indicated by “O” in the figure. In the description of the camera system 1, the object side is the front side and the image side is the rear side.

  As shown in FIG. 1, the lens barrel 3 can be coupled to the adapter lens device 4 via a lens-side mount ring 26 disposed on the image plane side, but the lens-side mount ring 26 is directly connected to the body unit 5. It can be detachably attached to the body unit 5 by being coupled to a body side mounting ring 23 provided on the front surface of the body unit 5.

  The lens barrel 3 includes a lens frame 34, a master lens ML including a focus lens 33 held by the lens frame 34, a lens driving mechanism 37 for driving the focus lens 33 forward and backward, and a lens driving circuit 36. And a lens control microcomputer (hereinafter referred to as LCPU) 35.

  The master lens ML is a zoom lens having a two-group configuration that forms an image on the imaging surface on the imaging element 18, and includes a front group lens 31 that is a first group lens having a negative refractive power in order from the object side to the image side. And a rear group lens 32 which is a second group lens having a positive refractive power including the focus lens 33. The front group lens 31 and the rear group lens 32 are driven back and forth in the direction of the optical axis O during the zooming operation of the camera. Specifically, as described in Japanese Patent Application No. 2010-233876 filed by the present applicant, the first lens group includes three lenses and has negative refractive power. The second lens group is a lens group having a positive refracting power having a nine-lens structure, and is a single lens having a positive refracting power, and includes an object-side sub lens that is driven back and forth in the direction of the optical axis O during focusing, and a eight-lens structure. Image side auxiliary lens. A stop is disposed between the front lens group 31 and the focus lens 33. This diaphragm is driven by a stepping motor provided in a diaphragm driving mechanism (not shown) or an electromagnetically driven linear motor.

  The focus lens 33 constituting the rear lens group 32 is supported by a movable lens frame 34, and the lens frame 34 is moved in the optical axis direction by a stepping motor disposed in the lens driving mechanism 37 during the focusing operation of the camera. The focus lens 33 is driven back and forth toward the focusing position. The lens driving circuit 36 drives the lens frame 34 forward and backward as described above via the lens driving mechanism 37 in accordance with a control signal from the LCPU 35. The focusing operation of the focus lens 33 will be described in detail later.

  The LCPU 35 controls each part in the lens barrel 3 such as the lens driving circuit 36. The LCPU 35 is electrically connected to a body control microcomputer (hereinafter referred to as BCPU) 10 on the body unit 5 side via communication connectors 23a to 26a as communication units, and is controlled in accordance with a command from the BCPU 10. The

  The adapter lens device 4 can be detachably mounted on the front surface of the body unit 5. When the adapter lens device 4 is mounted between the lens barrel portion 3 and the body unit 5, the lens side mount ring is mounted. 26 and the adapter object side mount ring 25 of the adapter lens device 4, and the adapter image side mount ring 24 is connected to the body side mount ring 23. The mount rings are all bayonet type, for example.

  The adapter lens device 4 includes an adapter lens AL mainly including an object side lens group 51, a wobbling lens 53, and an image side lens group 52, and a movable frame 43 that is a lens moving frame that holds the wobbling lens 53 that is an optical lens. A wobbling drive mechanism 50 for moving the movable frame 43 back and forth, a wobbling drive circuit 39, an adapter lens control microcomputer (hereinafter referred to as ACPU) 38, and a Hall element for detecting the position of the movable frame 43 78 and a magnetic scale 79 (FIG. 3). The detailed configuration and operation of the wobbling lens 53 and the adapter lens device 4 described above will be described later.

  The wobbling driving circuit 39 drives the wobbling driving mechanism 50 in accordance with a control signal from the ACPU 38 during the focusing operation of the lens barrel 3, and causes the wobbling lens 53 held by the movable frame 43 to vibrate with a small amplitude along the optical axis direction. That is, a wobbling operation is performed. This wobbling operation is performed by moving the wobbling lens 53 with small amplitude vibration when performing focusing driving by “mountain climbing control” of the focus lens 33 of the attached lens barrel 3 during still image shooting or moving image shooting. This is an operation for detecting the direction in which the focus lens 33 should move and enabling a quick focusing operation.

  The ACPU 38 controls each part in the adapter lens device 4 such as the wobbling drive circuit 39. The ACPU 38 is electrically connected to the BCPU 10 on the body unit 5 side via a communication connector 23a as a communication unit, and is controlled according to a command from the BCPU 10.

  When the adapter lens device 4 is mounted between the body unit 5 and the lens barrel 3, the BCPU 10, the ACPU 38, and the LCPU 35 are electrically connected via the communication connectors 23a, 24a, 25a, 26a, and can communicate. Become. Communication between the LCPU 35, the ACPU 38, and the BCPU 10 may be performed by optical connection or may be performed in a non-contact manner such as wireless.

  As shown in FIGS. 1 and 2, the body unit 5 has an imaging element 18 for photoelectrically converting an object image that has passed through a photographing lens such as a focus lens 33 in the lens barrel portion 3 on the optical axis O of the photographing lens. However, unlike a normal digital single-lens reflex camera, a movable mirror device for guiding a subject light beam to the finder optical system is not disposed in front of the image sensor 18. However, the adapter lens device 4 of the present embodiment can also be applied to the camera body in which the movable mirror is arranged.

  The image sensor interface circuit 11 connected to the image sensor 18 inside the body unit 5, SDRAM 13 and FLASH ROM 14 provided as storage areas, a recording medium 15, a liquid crystal monitor 16, and image processing are performed. An image processing controller 12 is provided.

  An image sensor interface circuit 11, SDRAM 13, FLASH ROM 14, recording medium 15, and liquid crystal monitor 16 are connected to the image processing controller 12. These are configured to provide an electronic imaging display function together with an electronic imaging function.

  The recording medium 15 is an external recording medium such as various memory cards or an external hard disk drive (HDD), and is communicable with the camera body unit 5 and is exchangeably mounted.

  The BCPU 10 is connected to a communication connector 23a, an image processing controller 12, and an EEPROM 17, which is a nonvolatile memory.

  The image processing controller 12 captures image data from the image sensor 18 by controlling the image sensor interface circuit 11 in accordance with a command from the BCPU 10. This image data is converted into a video signal by the image processing controller 12 and output to the liquid crystal monitor 16 for live view display. The photographer can recognize an image such as a composition of an image to be photographed from the live view display image on the liquid crystal monitor 16. It is also possible to display the recorded image after photographing on the liquid crystal monitor 16 and confirm the image.

  The SDRAM 13 is a memory for temporarily storing image data, and is used as a work area when image data is converted. The image data is subjected to various types of image processing. For example, the image data is set to be stored in the recording medium 15 after the still image is converted into JPEG data. The BCPU 10 is connected to a camera operation switch (SW) 19 and a battery 21 via a power supply circuit 22.

  The EEPROM 17 stores, as other storage areas, predetermined control parameters required for camera control, and is accessible from the BCPU 10.

  The camera operation switch 19 includes, for example, a release switch for instructing execution of a shooting operation, a still surface shooting mode, a moving image shooting mode, a mode change switch for switching a recorded image display mode, a moving image recording start switch for starting moving image shooting, a power switch, and the like , And a switch group including operation buttons necessary for operating the camera. The release switch has a half-press operation, that is, a first release switch (1RSW) operation and a full-release operation of a second release switch (2RSW).

  The power supply circuit 22 is provided to convert and supply the output voltage of the battery 21 to a voltage required by each circuit unit constituting the device.

  Here, the detailed structure of the adapter lens apparatus 4 of this embodiment is demonstrated using FIGS.

  As shown in the longitudinal sectional view of FIG. 3, the adapter lens device 4 includes front and rear fixed frames 41 and 42, a movable frame 43, and central openings of the front fixed frame 41, the movable frame 43, and the rear fixed frame 42. As the adapter lens AL held by 41a, 43a, 42a, the object side lens group 51, the wobbling lens 53, the image side lens group 52, and the wobbling incorporated in the front fixed frame 41 and the movable frame 43 are arranged in order from the object side. The driving mechanism 50, the movable frame holding mechanism 55 for switching the holding state and the releasing state of the movable frame 43, the reflection member 74 and the photo reflector 73 for detecting the initial position of the movable frame 43 during the wobbling operation, and the movable frame 43 For detecting the moving position of the adapter, the hall element 78 and the magnetic scale 79, and the adapter object-side mount mounted on the object-side end face of the front fixed frame 41 are mounted. A grayed 25, the adapter image side mount ring 24 fixed to the image surface side end face of the rear fixed frame 42, and a ACPU38 described above.

  The front fixed frame 41 and the rear fixed frame 42 are coupled and fixed by a seal stamp fitting portion Z1 in a state where the adapter lens AL, the movable frame 43, and the wobbling drive mechanism 50 are incorporated. Note that guide shafts 44 and 45, which are guide members for slidably supporting the movable frame 43, are supported by the front fixed frame 41 and the rear fixed frame 42 in a penetrating state (FIGS. 5 and 6).

  As shown in FIG. 4, the adapter image side mount ring 24 has bayonet claws 24b, and a communication connection connector contact piece 24a is arranged at the lower part of the opening. The adapter object-side mount ring 25 has a bayonet portion 25b as shown in FIGS. 2 and 3, and a communication connection connector contact piece 25a is arranged at the lower portion of the opening.

  The movable frame 43 is accommodated inside the front fixed frame 41, and is supported so as to be movable in the optical axis O direction by a guide shaft 44 that passes through one shaft hole 43b and a guide shaft 45 that passes through the other long hole 43c. (FIGS. 5 and 6). Further, a pair of shaft pressing mechanism portions 43d and 43e are provided at the front and rear end portions of the movable frame shaft hole 43b through which the guide shaft 44 penetrates (FIGS. 6 and 7). Also, the rear end surface portion and the front end surface portion of the front fixed frame 41 and the rear fixed frame 42 are made of silicon rubber or the like as a cushioning material that can come into contact when the movable frame 43 moves to the front or rear movement limit position. A pair of protrusions 71 and 72 are arranged to face each other (FIG. 3). The pair of protrusions 71 and 72 are provided, for example, at three locations in the circumferential direction. By providing the pair of protrusions 71 and 72, it is possible to prevent damage when the movable frame 43 runs away.

  The material of the movable frame 43 and the guide shafts 44 and 45 is, for example, a metal such as a magnesium alloy, but may be a PPS (polyphenylene sulfide) resin or ABS resin containing glass fibers. As the reinforcing material of the fiber reinforced plastic material (reinforced plastic material having a surface hardness of Vickers hardness of 400 to 700 Hv), carbon fiber is suitable in addition to glass fiber. In particular, when a liquid crystalline resin containing carbon fiber is applied to the movable frame 43, it is advantageous in terms of elastic modulus, and the roundness of the bearing surface formed on the movable frame 43 can be increased. In this way, plastic engineer materials of non-ceramic materials are applied to the above materials.

  As shown in FIG. 7, the shaft pressing mechanism portion 43d formed on the movable frame 43 includes a V groove 43da and an elastically deformable pressing plate portion 43db. The front side of the guide shaft 44 penetrating the movable frame 43 is sandwiched between the V-groove 43da and the pressing plate portion 43db in a slidable state. On the other hand, the shaft pressing mechanism portion 43e has the same structure as the shaft pressing mechanism portion 43d, and the rear surface side of the guide shaft 44 penetrating the movable frame 43 is also clamped by the shaft pressing mechanism portion 43e so as to be slidable. . Therefore, the movable frame 43 is supported so as to be slidable with respect to the guide shaft 44 without rattling. Furthermore, the movable frame 43 is prevented from being easily moved by the impact force or the like from the outside due to the frictional force of the shaft pressing mechanism portion with respect to the guide shaft.

  The guide shaft 45 has the same structure as that of the shaft pressing mechanism portion but is provided with a mechanism portion without the V-groove and is pressed by the pressing plate portion in a direction perpendicular to the elongated hole direction of the elongated hole 43c. Thus, the movable frame 43 is supported in a state where the guide shaft 45 is not rattled.

  Among the adapter lenses AL incorporated in the adapter lens device 4, the object side lens group 51 has negative refractive power in which the first lens of the biconvex positive lens and the second lens of the biconcave negative lens are joined in order from the object side. It is a cemented lens. The wobbling lens 53 is composed of a single biconvex positive lens, and can advance and retract by a minute width, for example, 200 μm in the direction of the optical axis O. The image side lens group 52 is a cemented lens having negative refractive power in which a positive meniscus lens having a convex surface directed toward the image side and a biconcave negative lens are cemented in order from the object side. Further, gaps a1 and a2 are provided between the object side lens group 51, the wobbling lens 53, and the image side lens group 52 (FIG. 1).

  By adopting the adapter lens AL as described above, a positive lens necessary for wobbling is secured, an optical system is advantageous for reducing aberration fluctuations, and the optical magnification of the adapter lens AL is made substantially equal. Can do. As described above, even if the adapter lens device 4 is attached to the lens barrel portion 3 by setting the magnification to approximately the same magnification, the focal length of the lens barrel 2 does not change.

  Further, the outer diameter of the adapter lens AL of the adapter lens device 4 is larger than the outer diameter of the master lens ML of the lens barrel portion 3. Thereby, even when a bright lens barrel is mounted, the peripheral light amount is secured. The optical characteristics of the other master lens ML and adapter lens AL are described in Japanese Patent Application No. 2010-038192 by the present applicant.

  These adapter lenses AL have a double D-cut shape in which the lower part is cut to escape the communication connector and the upper part is also cut (FIG. 5), but only the lower part is cut. It may be a shape.

  As shown in FIG. 3, the wobbling drive mechanism 50 is a feed comprising a spring support plate 69 inserted into and supported by the opening 41b of the front fixed frame 41, a weight member 68, and a circular or ring-shaped laminated piezo element. Piezoelectric element 66, for example, a transmission member 67 made of a non-magnetic material such as an aluminum alloy or martensitic stainless steel, and heteropolar bonded magnets 61 and 62 made of a permanent magnet with a non-magnetic material 63 interposed therebetween, These members are integrally fixed with an adhesive from the object side to the image side. In addition, a silicon agent 66a is interposed between the side surface of the feeding piezoelectric element 66 and the inner surface of the opening 41b of the front fixed frame 41 to reduce the deflection displacement of the feeding piezoelectric element 66.

  The heteropolar magnets 61 and 62 are attracted to the suction plate 65 of the first magnetic member so as to be relatively movable in a sliding friction state. The suction plate 65 is bonded and fixed to the outer periphery of the movable frame 43. The mutually attracting surfaces of the heteropolar bonded magnets 61 and 62 and the attracting plate 65 are coated with fluorine resin or sputtered. The heteropolar magnets 61 and 62 are magnetized in a direction perpendicular to the attracting surface with the attracting plate 65. Ferritic stainless steel such as SUS430 is used for the suction plate 65.

  Further, a yoke 64, which is a second magnetic member, is bonded and fixed to the back surface side, that is, the outer peripheral side of the attracting surfaces of the heteropolar magnets 61 and 62. For the yoke 64, ferritic stainless steel such as SUS430 is used, and a magnetic circuit with low magnetic resistance is configured.

  The yoke 64 includes a constricted portion 64a serving as a restricting portion, and the constricted portion 64a is slidably engaged with a guide groove 41d along the optical axis O direction disposed inside the concave portion 41c of the front fixed frame 41. Let This engagement restricts the positions of the circumferentially and radially oriented magnets 61 and 62 in the circumferential direction and the radial direction under the condition that they can move in the optical axis O direction with respect to the front fixed frame 41 via the yoke 64. The Therefore, when the movable frame 43 is incorporated into the front fixed frame 41, the movable frame 43 can be inserted without interfering with the wobbling drive mechanism 50, particularly the heteropolar magnets 61 and 62.

  When viewed from the feeding piezoelectric element 66 side, the spring support plate 69 has a centrally symmetric spring shape from which a part has been removed by an etching method, for example, a centrally symmetric hinge-type leaf spring, or mounting screw holes on the left and right, top and bottom. Formed with different asymmetric leaf springs.

  The nonmagnetic material 63 interposed between the heteropolar bonded magnets 61 and 62 is not always necessary. If a plate member made of a nonmagnetic material is bonded to both end faces of the transmission member 67, the transmission member 67 may be formed of a magnetic material.

  During a wobbling operation, when a wobbling driving voltage having a predetermined waveform is applied to the feeding piezoelectric element 66 by the wobbling driving circuit 39, the feeding piezoelectric element 66 expands and contracts in the direction of the optical axis O. Expansion and contraction of the feeding piezoelectric element 66 is transmitted to the heteropolar bonded magnets 61 and 62 via the transmission member 67. By repeating minute displacements in the optical axis direction of the heteropolar magnets 61 and 62, the suction plate 65 on the movable frame 43 side is displaced by the friction of the suction state, and the movable frame 43 is driven by wobbling in the optical axis O direction. Oscillates with small amplitude. The direction in which the suction plate 65 is displaced is determined by the driving voltage pulse waveform applied to the feeding piezoelectric element 66. When the drive voltage pulse waveform is a triangular wave, for example, assuming that the applied voltage is a triangular wave of tens of thousands of Hz as an input voltage and the time required for one triangular wave is t1 + t2, the feeding piezoelectric element 66 and the piezoelectric element 66 at time t1 (acceleration) The heteropolar magnet 61 proceeds slowly and rapidly shrinks at time t2 (deceleration). At time t2, acceleration equal to or greater than the maximum static friction between the heteropolar magnet 61 and the suction plate 65 is obtained. As described above, the heteropolar bonded magnet 61 and the attracting plate 65 move together at time t1, and slip occurs between the heteropolar bonded magnet 61 and the attracting plate 65 at time t2. The displacement of the movable frame 43 can be controlled by repeating this continuously.

  The photo reflector 73 and the reflecting member 74 are fixedly supported in a state of facing the movable frame 43 and the front fixed frame 41, respectively, as shown in FIGS. The light from the light emitting element 73a of the photo reflector 73 is reflected by the reflecting surface 74a of the reflecting member 74, enters the two-divided light receiving element 73b of the photo reflector 73, and the relative position of the movable frame 43 with respect to the front fixed frame 41 is detected. The An initial position (operation start position) at which the wobbling lens 53 starts a wobbling operation is detected by the detection signal of the photo reflector 73.

  The initial position detection operation by the photoreflector 73 will be described in detail with reference to FIG. 9. The photoreflector 73 is divided into two parts, a light emitting element 73a such as an LED and a light receiving element 73b1, 73b2 arranged on a base material. A reflection plate 74 is joined to the end surface of the movable frame 43.

  The light beam emitted from the light emitting element 73a is reflected by the reflecting plate 74, is incident on one of the light receiving elements 73b1 divided into two, and the position of the movable frame 43 is moved by the output of the difference signal from the two divided light receiving elements 73b. Detected. Thereafter, when the movable frame 43 moves to the position of the movable frame 43 ', the reflecting plate 74 also moves to the position of the reflecting plate 74', so that the light beam is incident on the other light receiving element 73b2 and is divided into two divided light receiving elements 73b. The position of the movable frame 43 ′ after the movement is detected by the output of the difference signal from. In this way, the initial position (operation start position) of the movable frame 43 can be determined. Note that a four-divided light receiving element in which the light receiving part is further divided into two by a right triangle may be applied to the two-divided light receiving element 73b.

  A Hall element 78 is attached to the right end of the outer surface of the movable frame 43 for detecting the movable frame position. On the other hand, a magnetic scale 79 in which N poles and S poles are alternately arranged at a predetermined pitch is fixed to the inner surface of the front fixed frame 41 or the rear fixed frame 42 (FIG. 3). The Hall element 78 and the magnetic scale 79 are disposed to face each other. The amount of movement of the movable frame 43 is calculated from the output signal of the hall element 78, and the output signal of the hall element 78 is also used as a detection signal during a calibration operation described later.

  The movable frame holding mechanism 55 is a holding mechanism for preventing the movable frame 43 from being damaged due to runaway or external vibration, and as shown in FIG. 8, an element holding frame 56 fixed to the side surface of the heteropolar magnet 62, A cylinder or cuboid shaped laminated piezoelectric element 57 for controlling pressure and a movable frame of the laminated piezoelectric element 57 for suppressing pressure, which are housed inside the element holding frame 56 in a state where one side is joined and supported by the spring support member 58. It comprises a ball-shaped buffer member 59 that is held in a state where it can be pressed against the suction plate 65 via a holding member 58 on the 43 side, and also functions as a sliding member. The suppression multilayer piezoelectric element 57 is held in a state in which silicon rubber 57 a is interposed between the inner surface of the element holding frame 56. The spring support member 58 is fixed to the element holding frame 56 with screws or the like.

  The operation of the movable frame holding mechanism 55 is as follows. Immediately before the heteropolar magnets 61 and 62 start to vibrate, an applied voltage (negative potential) is applied to the cylindrical or ring-type pressure-limiting laminated piezoelectric element 57 in the direction opposite to the polarization direction of the element. Is given. The pressure suppressing multilayer piezoelectric element 57 is displaced in the contracting direction, and the suction plate 65 and the buffer member 59 are separated from each other.

  When the vibrations of the heteropolar bonded magnets 61 and 62 are stopped, the suppression multilayer piezoelectric element 57 is also stopped, and the buffer member 59 is in contact with the suction plate 65 in a state where a pressing force is applied. In this contact state, the movable frame 43 is locked by the movable frame holding mechanism 55, and the forward / backward movement in the optical axis O direction is restricted. Therefore, when the movable frame holding mechanism 55 is provided, when the vibrations of the heteropolar bonded magnets 61 and 62 are in a stopped state, the apparatus is movable when external vibration is applied to the device or when the movable frame 43 is runaway. Damage to the frame 43 can be prevented.

  The pressure suppressing multilayer piezoelectric element 57 has a cylindrical shape or a rectangular parallelepiped shape, but a ring-type pressure suppressing multilayer piezoelectric element having the optical axis O as an axis is also applicable instead. In this case, the element holding frame is fixed to and supported by the inner peripheral portion of the front or rear fixed frame, and a plurality of buffer members are arranged on the inner peripheral surface of the ring-type pressure-limiting laminated piezoelectric element, It is possible to contact the suction plate or the outer periphery of the movable frame.

  Next, AF operation control in the camera system 1 to which the lens barrel 2 including the lens barrel portion 3 and the adapter lens device 4 having the above-described configuration is applied will be described with reference to FIG.

  In the lens barrel 2, the minute driving of the wobbling lens 53 forward or backward on the optical axis O is optically equivalent to the minute driving of the focus lens 33 forward or backward on the optical axis O. The imaging optical system is configured to be an AF evaluation value (contrast value) at a position where the wobbling lens 53 is slightly vibrated forward or backward on the optical axis O. Based on this AF evaluation value, the direction in which the focus position of the focus lens 33 exists is recognized, and the focus lens 33 is moved in focus.

  First, when it is detected in step S101 that the camera system 1 is in a moving image shooting start state, the process proceeds to step S102, and calibration is performed. That is, the BCPU 10 checks the operation of the movable frame 43 by the wobbling drive of the feeding piezoelectric element 66 in the calibration process. That is, a pulse drive waveform is applied to the feeding piezoelectric element 66 to vibrate, and it is confirmed that the movable frame 43 moves forward and backward by the output signal of the Hall element 78. This calibration operation is performed only under the initial AF operation state during moving image shooting after the body unit 5 is powered on. Further, when the moving image shooting start time is shortened, it is performed when the power is turned on or off. If the output signal of the Hall element 78 is not detected, that is, if the moving frame 43 is in an abnormal state in which the forward / backward movement cannot be confirmed, the process proceeds to step S103, and the BCPU 10 displays “Wobbling operation not started on the LCD monitor 16 screen. Is displayed, and the AF process is terminated.

  When the advance / retreat movement of the movable frame 43 can be confirmed in step S102, the process proceeds to step S104 to execute the wobbling operation. In this wobbling operation, a driving voltage having a predetermined waveform is applied to the feeding piezoelectric element 66, and the wobbling lens 53 is displaced in amplitude via the movable frame 43. By this wobbling operation, the moving direction of the focus lens 33 toward the focus position is detected, and the focus lens 33 is driven in that direction. In step S105, the image data from the image sensor 18 is fetched into the memory a plurality of times, for example, only five times. In step S106, the image processing unit generates a contrast value for each image data from the captured image data. The difference between the maximum value and the minimum value of the contrast value is compared with a predetermined allowable value. The BCPU 10 determines whether or not the difference between the maximum value and the minimum value is equal to or less than an allowable value. If the difference is larger, the BCPU 10 drives the focus lens 33 toward the in-focus position based on the difference in contrast value. Thereby, the focus lens 33 can be brought close to the in-focus position.

  When the BCPU 10 repeats the processing from step S104 to step S106 and determines that the obtained contrast value difference is less than or equal to the allowable value, it determines that the focus lens 33 is at the in-focus position, and proceeds to step S108. Then, the wobbling drive is stopped, the zero amplitude state of the movable frame 43 is detected from the output signal of the Hall element, and the AF operation is finished.

  When the AF operation is completed, moving image shooting is performed. The captured moving image data is processed by the image processing controller 12 and recorded on the recording medium 15. The moving image processed by the image processing controller 12 at the same time is displayed on the liquid crystal monitor 16 via the image display control circuit.

  According to the lens barrel 2 of the present embodiment applied to the camera system 1 described above, the wobbling drive mechanism 50 to which the laminated piezo element is applied as the drive mechanism of the wobbling adapter lens device 4 that can be attached to the barrel portion 3 is provided. The adapter lens device 4 can be downsized and assembled easily by arranging the drive mechanism along the optical axis O between the front fixed frame 41 and the outer peripheral portion of the movable frame 43. .

  In the wobbling drive mechanism 50, the constricted portion 64 a of the yoke 64 that is bonded and fixed to the outer peripheral side of the heteropolar magnets 61 and 62 is engaged with the guide groove 41 d of the front fixed frame 41. Therefore, the feed piezoelectric element 66 of the wobbling drive mechanism 50 and the different polarity bonded magnets 61 and 62 are restricted in the radial direction with respect to the front fixed frame 41, and when the movable frame 43 is inserted, the different polarity bonded magnets 61 and 62 and Interference due to magnetic attraction with the suction plate 65 and deformation of the spring support plate 69 can be prevented, and assembly becomes easy.

  When the movable frame holding mechanism 55 is provided, the movable frame 43 can be locked by the braking piezoelectric element 57 when external vibration is applied or when the movable frame 43 is driven out of control. It is possible to prevent the movable frame 43 from being damaged.

  In addition, by arranging the shaft pressing mechanism portions 43d and 43e, the movable frame 43 is supported by the movable frame 43 supported so as to be slidable with respect to the guide shaft 44 without rattling with respect to the guide shaft 44. The wobbling lens 53 is supported on the plane orthogonal to the optical axis O direction so as to be able to advance and retreat without wobbling, so that accurate wobbling driving can be realized.

  The structure of the wobbling drive mechanism 50 applied to the present embodiment can also be applied as a variable power drive mechanism for the front group lens 31 and the rear group lens 32 of the lens barrel 3. Furthermore, the present invention can also be applied to a spherical aberration correction mechanism for a collimator lens in an optical disc apparatus.

  In the first embodiment described above, a modification of the shaft pressing mechanism 43d disposed on the movable frame 43 of the adapter lens device 4 will be described with reference to FIG.

  The shaft pressing mechanism portion 43Bd of this modification is disposed on the front end surface portion and the rear end surface portion of the movable frame 43B which is a lens moving frame, and includes a spherical member 75 made of brass, duralumin or beryllium copper, a pressing member 76, It consists of a spring member 77. A V-groove 44Ba is provided in a martensitic stainless steel such as SUS420 which is a guide member that slidably penetrates the movable frame 43B and a guide shaft 44B in which a surface of this stainless steel is coated with a fluororesin. An escape portion 43Bdb and an upper insertion hole 43Bdc are provided in the shaft hole 43Bda on the front and rear end surface portions on the movable frame 43B side.

  The spherical member 75 has a tip spherical portion, and includes a flange portion 75b that fits into the upper insertion hole 43Bdc of the shaft hole 43Bda, and a concave portion 75a at the upper portion. The spherical member 75 is assembled in a state where the flange portion 75b is inserted into the upper insertion hole 43Bdc and the tip spherical portion is in contact with the V groove 44Ba of the guide shaft 44B.

  The surface hardness of the fluororesin coat (specifically, the tetrafluoroethylene resin coat) applied to the surfaces of the guide shaft 44B and the V groove 44Ba is set to a Vickers hardness of 160 to 400 Hv. The material of the spherical member 75 is brass, duralumin, beryllium copper, etc., and the Vickers hardness is 100 to 240 Hv. In this way, by making the surface hardness of the spherical member 75 the same or less than that of the guide shaft 44B, indentation or the like is prevented from being generated on the guide shaft or the like. In particular, the material of the guide shaft is martensitic stainless steel such as SUS420 (surface Vickers hardness 500Hv), and the spherical member is austenitic such as SUS303 or ferritic stainless steel such as SUS430 (surface Vickers hardness 200Hv). Is desirable. Of course, the material of the guide shaft is fiber reinforced plastic (surface Vickers hardness 400 to 700 Hv), and the spherical member is martensitic stainless steel such as SUS420 (surface Vickers hardness 500 Hv) or ferritic stainless steel such as SUS430 (surface Any of Vickers hardness 200Hv) may be selected.

  The pressing member 76 has a convex portion 76b. The convex portion is fitted into the concave portion 75a of the spherical member 75 and fixed to the upper portion of the upper insertion hole 43Bdc with a screw or the like.

  The spring member 77 is inserted in a compressed state between the flange portion 75 b of the spherical member 75 and the pressing member 76. Accordingly, the tip spherical surface portion of the spherical member 75 comes into contact with the V groove 44Ba of the guide shaft 44B by the urging force of the spring member 77.

  By applying the shaft pressing mechanism 43Bd having the above-described configuration, the movable frame 43B is supported so as to be slidable with respect to the guide shaft 44B without rattling. Further, the movable frame 43B is prevented from being easily moved by the impact force or the like from the outside due to the frictional force of the shaft pressing mechanism portion with respect to the guide shaft. In the shaft pressing mechanism portion 43Bd, the biasing force of the spring member 77 can be easily set, and the movable frame 43B can be slidably supported in a preferable guide shaft biasing state.

  Next, a lens barrel applied to an imaging apparatus having a blur correction function as a second embodiment of the present invention will be described with reference to FIGS.

  The lens barrel 80 according to the present embodiment is disposed in front of an image pickup device (not shown) of the image pickup device. When camera shake is detected by the image pickup device, the lens barrel 80 is photographed when the image pickup device is exposed. By displacing the lens along a plane perpendicular to the optical axis O so as to cancel out camera shake, the camera has a camera shake correction function that obtains captured image data without camera shake from the image sensor.

  The optical axis of the photographing lens is indicated by “O” in the figure. A plane orthogonal to the optical axis O is defined as an XY plane, and directions perpendicular to each other along the XY plane are defined as an X direction (left and right) and a Y direction (up and down).

  As shown in FIGS. 12 to 14, the lens barrel 80 includes a base 82 disposed on the front surface side of the imaging element and an X frame 83 that is supported so as to be movable in the X direction relative to the base 82. A Y frame 84 that is a lens moving frame that is supported so as to be movable in the Y direction relative to the X frame 83, and two-lens lens groups 121 and 122 that are optical lenses held by the Y frame 84. X guide shafts 85 and 86 which are a pair of guide members along the X direction, Y guide shafts 87 and 88 which are a pair of guide members along the Y direction, and the X frame 83 with respect to the base 82 in the X direction. An X drive mechanism 90 for driving the displacement of the Y frame 84 and a Y drive mechanism 100 for driving the Y frame 84 to move in the Y direction relative to the X frame 83.

  The base 82 is made of a plate member along the XY plane, and includes a central opening 82a, a pair of shaft support portions 82b and 82c and a pair of shaft support portions 82d and 82e that stand in the object side direction. The imaging apparatus main body (not shown) is fixedly supported. Both end portions of the X guide shaft 85 are fixedly supported by shaft support portions 82b and 82c. Both end portions of the X guide shaft 86 are fixedly supported by shaft support portions 82d and 82e.

  The X frame 83 has a central opening 83a, a pair of shaft support portions 83b and 83c and a pair of shaft support portions 83d and 83e that stand in the object side direction, and guide shaft holes 83f and 83g at both ends of the Y direction. I have. Both end portions of the Y guide shaft 87 are fixedly supported by shaft support portions 83b and 83c. Both end portions of the Y guide shaft 88 are fixedly supported by shaft support portions 83d and 83e. X guide shafts 85 and 86 are slidably fitted in the guide shaft holes 83f and 83g, respectively. Therefore, the X frame 83 is supported so as to be slidable in the X direction on the object side of the base 82.

  The Y frame 84 holds the lens groups 121 and 122 in the central opening 84a, and is provided with guide shaft holes 84b and 84c at the projecting portions at both ends in the X direction. The Y guide shafts 87 and 88 are slidably fitted into the guide shaft holes 84b and 84c, respectively. Therefore, the Y frame 84 is supported so as to be displaceable in the Y direction relative to the X frame 83, and the lens groups 121 and 122 held by the Y frame 84 are arbitrary on the XY plane with respect to the base. Supported to be displaceable in the direction.

  The X drive mechanism 90 includes a piezoelectric element substrate 98, a feeding piezoelectric element 96 made of a laminated piezoelectric element, a transmission member 97 made of a nonmagnetic material, and a heteropolar bonded magnet 91 made of a permanent magnet with a nonmagnetic material 93 interposed therebetween. , 92, and each member is integrally fixed with an adhesive along the X direction. The piezoelectric element substrate 98 is fixedly supported by a bent portion 99b of a support base 99 that is arranged upright on the object side of the base 82.

  The heteropolar magnets 91 and 92 are attracted to the first magnetic material attracting plate 95 so as to be relatively movable in a sliding friction state. The suction plate 95 is bonded and fixed to the outer surface 83 h of the Y direction protrusion of the X frame 83. The mutually attracting surfaces of the heteropolar bonded magnets 91 and 92 and the attracting plate 95 are subjected to fluororesin coating or sputtering. The heteropolar magnets 91 and 92 are magnetized in a direction perpendicular to the attracting surface with the attracting plate 95. The adsorption plate 95 is made of ferritic stainless steel such as SUS430.

  A yoke 94, which is a second magnetic member, is bonded and fixed to the back surface side of the magnets 91 and 92 with respect to the attracting surface, that is, the anti-X frame side. Ferrite stainless steel such as SUS430 is used for the yoke 94, and a magnetic circuit with a small magnetic resistance is formed.

  The yoke 94 includes a constricted portion 94a serving as a restricting portion, and the constricted portion 94a is slidably engaged with a guide groove 99a along the X direction disposed on the support base 99. By this engagement, the positions of the heteropolar bonded magnets 91 and 92 in the Y direction orthogonal to the X direction are regulated under the condition that they can move in the X direction with respect to the support base 99 via the yoke 94. Therefore, when the X frame 83 is assembled, it can be inserted without interfering with the heteropolar magnets 91 and 92.

  In the X drive mechanism 90, when a drive voltage pulse having a predetermined waveform is applied to the feed piezoelectric element 96, the feed piezoelectric element 96 expands and contracts in the X direction. Expansion and contraction of the feeding piezoelectric element 96 is transmitted to the heteropolar bonded magnets 91 and 92 via the transmission member 97. By repeating minute displacements in the X direction of the heteropolar magnets 91 and 92, the X frame 83 is displaced in the X direction via the suction plate 95 by the frictional force in the suction state. The left and right displacement directions of the X frame 93 can be controlled by the drive voltage pulse waveform.

  The Y drive mechanism 100 includes a piezoelectric element substrate 108, a feeding piezoelectric element 106 made of a laminated piezoelectric element, a transmission member 107 made of a nonmagnetic material of aluminum alloy or martensitic stainless steel, and a nonmagnetic material 103. The above-mentioned members are integrally fixed with an adhesive along the Y direction. The piezoelectric element substrate 108 is fixedly supported by a bent portion 109 b of a support base 109 that is arranged upright on the object side of the X frame 83.

  The heteropolar magnets 101 and 102 are attracted to the first magnetic material attracting plate 105 in a state in which sliding relative movement is possible and in a state in which frictional movement is possible. The suction plate 105 is bonded and fixed to the outer surface 84 d of the X direction protrusion of the Y frame 84. The mutually attracting surfaces of the heteropolar bonded magnets 101 and 102 and the attracting plate 105 are subjected to fluororesin coating or sputtering. The heteropolar magnets 101 and 102 are magnetized in a direction orthogonal to the attracting surface with the attracting plate 105. For the adsorption plate 105, ferritic stainless steel such as SUS430 is used.

  Further, a yoke 104 as a second magnetic member is bonded and fixed to the back surface side of the attracting surface of the heteropolar magnets 101 and 102, that is, the side opposite to the Y frame. For the yoke 104, ferritic stainless steel such as SUS430 is used, and a magnetic circuit with low magnetic resistance is configured.

  The yoke 104 includes a constricted portion 104a serving as a restricting portion, and the constricted portion 104a is slidably engaged with a guide groove 109a along the Y direction disposed on the support base 109. By this engagement, the position of the heteropolar bonded magnets 101 and 102 in the X direction orthogonal to the Y direction is restricted under the condition that the magnets 101 and 102 can move in the Y direction with respect to the support base 109 via the yoke 104. Therefore, when the Y frame 84 is assembled, it can be inserted without interfering with the heteropolar bonded magnets 101 and 102.

  In the Y drive mechanism 100, when a drive voltage pulse having a predetermined waveform is applied to the feed piezoelectric element 106, the feed piezoelectric element 106 expands and contracts in the Y direction. Expansion and contraction of the feeding piezoelectric element 106 is transmitted to the heteropolar bonded magnets 101 and 102 via the transmission member 107. By repeating minute displacements in the Y direction of the heteropolar magnets 101 and 102, the Y frame 84 is displaced in the Y direction via the suction plate 105 by the frictional force in the suction state. The upper and lower displacement directions of the Y frame 84 can be controlled by the drive voltage pulse waveform.

  Hall elements 111 and 113 for position detection are disposed on the base 82 and the X frame 83, respectively, and the permanent magnets 112 and 112 are disposed on the X frame 83 and the Y frame 84 in a state of facing the Hall elements 111 and 113, respectively. 114 is arranged. The hall element 111 detects the movement position of the X frame 83 in the X direction, and the hall element 113 detects the movement position of the Y frame 84 in the Y direction.

  An operation at the time of camera shake correction processing in the imaging apparatus including the lens barrel 80 configured as described above will be described.

  In the image pickup apparatus, when camera shake is detected during exposure of the image sensor, driving for displacing the X frame 83 and the Y frame 84 in a direction in which the camera shake is corrected with respect to the piezoelectric elements 96 and 106 for feeding. A voltage pulse is applied. The feeding piezoelectric elements 96 and 106 are respectively driven to extend and contract, the X frame 83 is displaced relative to the base 82 via the X drive mechanism 90, and the Y frame 84 is X via the Y drive mechanism 100. As a result, the lens groups 121 and 122 held by the Y frame 84 are displaced in the direction of correcting camera shake on the XY plane. An imaging signal output from the imaging device due to the displacement of the lens groups 121 and 122 does not include a camera shake component.

  According to the lens barrel 80 of the present embodiment, by applying the X and Y drive mechanisms 90 and 100 to which the laminated piezo elements are applied, the drive mechanism is set to one side of the X frame 83 and the Y frame 84, respectively. The lens barrel can be downsized and assembled easily.

  Further, the constricted portion 104a of the yoke 104 that is bonded and fixed to the outside of the heteropolarly bonded magnets 91, 92 and 101, 102 by the X, Y drive mechanisms 90, 100 is provided in the guide grooves 99a, 101a of the support bases 99, 109, respectively. Engaged. Therefore, when the X frame 83 and the Y frame 84 are assembled, the positions of the heteropolar bonded magnets 91 and 92 are restricted, and the interference between the X frame 83 and the Y frame 84 can be prevented, and the assembly becomes easy.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  As described above, the lens barrel of the present invention is a lens barrel provided with a drive control mechanism, in which a sufficient driving force is obtained, the optical axis direction can be thinned, and the assembly is easy. It can be used as

2, 80 ... lens barrel 43 ... movable frame (lens moving frame)
44, 45 ... Guide shaft (guide member)
53 ... Wobbling lens (optical lens)
57 ... Suppressing laminated piezoelectric element (suppressing piezoelectric element)
59 ... Cushioning member (sliding member)
65, 95, 105 ... adsorption plate (first magnetic member)
61, 62, 91, 92, 101, 102 ... heteropolar magnets 64, 94, 104 ... yoke (second magnetic member)
64a, 94a, 104a ... Constriction part (regulation part)
66, 96, 106 ... Feeding piezoelectric element 67, 97, 107 ... Transmission member 84 ... Y frame (lens moving frame)
85, 86 ... X guide shaft (guide member)
87, 88 ... Y guide shaft (guide member)
121, 122 ... Lens group (optical lens)
O: Optical axis direction XY plane: Plane orthogonal to optical axis direction

Claims (6)

In a lens barrel that includes a lens moving frame that holds an optical lens, and a guide member that supports the lens moving frame in a direction that is movable in the optical axis direction or in a plane that is orthogonal to the optical axis direction.
A first magnetic member fixed to a part of the lens moving frame;
A heteropolar bonded magnet attached in a state of being attracted to the first magnetic member and magnetized in a direction perpendicular to the attracting surface with the first magnetic member;
A second magnetic member joined to the opposite surface of the heteropolar magnet to the attracting surface;
A feed piezoelectric element coupled to the heteropolar magnet via a transmission member;
A lens barrel comprising:   The lens movement frame is movable in the optical axis direction of the optical lens, and the guide member supports the lens movement frame so as to be slidable in the optical axis direction. The lens barrel described.   3. The second magnetic member includes a restricting portion, and the transmission member provided between the feeding piezoelectric element and the heteropolar magnet is joined with a nonmagnetic material. The lens barrel described.   The lens barrel according to claim 2, wherein the optical lens is a single positive lens and has a D-cut portion or a double D-cut portion.   The lens according to claim 3, wherein a pressure-controlling piezoelectric element and a sliding member are provided on a side surface of the heteropolar bonded magnet, and the sliding member presses the movable frame when the magnet is in a displacement stopped state. The lens barrel. 3. The imaging device including the lens barrel according to claim 2, wherein a driving voltage is applied to the feeding piezoelectric element when the power is turned on or the power is turned off to vibrate the heteropolarly bonded magnet in the optical axis direction. An image pickup apparatus that performs a calibration control operation of moving a lens moving frame in an optical axis direction and detecting and confirming a position of the lens moving frame.

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