JP2009222995A - Lens barrel and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel capable of satisfactory camera shake correction precision, irrespective of a focal distance, even in a variable power optical system. <P>SOLUTION: This lens barrel has an imaging optical system, an actuator allowing driving amount control by an open group, a driven member moved in a plane orthogonal to an optical axis of the imaging optical system by the actuator, and laid together with an optical member or an imaging element, and a position detecting part for detecting a position of the driven member, and allows switching between the driving amount control of the actuator based on the position detection by the position detecting part and the driving amount control of the actuator by the open group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens barrel having a camera shake correction function and an imaging apparatus including the lens barrel.

  2. Description of the Related Art Conventionally, an active camera shake correction technique that obtains a clear image by correcting optical axis shift due to camera shake has been put into practical use. This camera shake correction technique is generally of a type that moves a part of the imaging optical system and a type that moves the image sensor.

As such a camera shake correction device, by using a stepping motor that is an actuator capable of driving amount control (open loop control) by inputting a predetermined driving signal, a driven member on which an image sensor is mounted is moved. A device that performs camera shake correction is known (for example, see Patent Document 1).
JP 2007-206553 A

  However, when a camera shake correction mechanism is configured using a stepping motor capable of open loop control as an actuator that performs camera shake correction, there are the following problems.

  The stepping motor can divide one rotation (360 degrees) and rotate and stop every minute, but the rotation angle for each step varies and has a minute rotation error. . Similarly, the lead screw rotated by the stepping motor also has a slight error in the feed amount of the screw thread during one rotation.

  Furthermore, since the driven member on which the lens or the image pickup device is mounted has a clearance for sliding between the guide shaft and the like, the clearance is caused only by the clearance, and the movement of the driven member is accurate. There is a risk of hindrance.

  On the other hand, when the image pickup optical system mounted on the image pickup device is a zoom lens capable of zooming, even if the amount of camera shake of the photographer is the same, driven to correct camera shake at short focus and long focus The amount by which the member is moved is different. Specifically, when the camera shake amount of the photographer is the same, the amount of movement of the driven member is small at the short focus with a wide angle of view, and the amount of movement is increased at the long focus with a narrow angle of view.

  When the imaging optical system has a short focus, the amount of movement due to camera shake correction is small, so the ratio of error due to rotation angle error of the above stepping motor, screw feed amount error, clearance play, etc. increases, and correction accuracy There is a problem that camera shake correction accuracy deteriorates on the short focus side.

  In view of the above problems, the present invention includes a lens barrel capable of obtaining good camera shake correction accuracy regardless of the focal length, even in a variable magnification optical system, and the lens barrel. The object is to obtain a possible imaging device.

  The above object is achieved by the invention described below.

  (1) An imaging optical system that guides subject light, an actuator capable of driving amount control by open loop, and an optical member or an imaging element that is moved in a plane perpendicular to the optical axis of the imaging optical system by the actuator. In a lens barrel having a driven member mounted in parallel and a position detection unit for detecting the position of the driven member, the driving amount control of the actuator based on the position detection by the position detection unit, and the open loop A lens barrel characterized by switching between driving amount control of an actuator.

  (2) The drive amount control region by the open loop of the actuator is wider than the region in which the actuator drive amount control based on the position detection by the position detection unit is performed. Lens barrel.

  (3) The imaging optical system is a variable magnification optical system, and controls the drive amount of the actuator based on position detection by the position detection unit on the short focus side of the variable magnification optical system, and opens on the long focus side. The lens barrel according to (1) or (2), wherein the driving amount of the actuator is controlled by control.

  (4) An imaging apparatus comprising the lens barrel according to any one of (1) to (3), wherein camera shake correction is performed by moving the driven member.

  (5) The imaging apparatus according to (4), including a mode in which the camera shake correction is performed during framing and shooting, and a mode in which the camera shake correction is not performed during framing and performed during shooting.

  According to the present invention, even with a variable magnification optical system, a lens barrel capable of obtaining good camera shake correction accuracy regardless of the focal length, and an imaging capable of good camera shake correction, including the lens barrel. An apparatus can be obtained.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is a diagram illustrating an example of an internal arrangement of main component units of the imaging apparatus 100 according to the present embodiment. FIG. 3 is a perspective view of the imaging apparatus 100 as viewed from the subject side.

  As shown in the figure, in the imaging apparatus 100, a lens barrel 50 including a bending imaging optical system capable of zooming is arranged as shown in the figure, and an opening 51 is arranged to take in a subject light beam. The opening 51 is provided with a lens barrier (not shown) that is in an open state that exposes the opening 51 and a closed state that covers the opening 51.

  Reference numeral 52 denotes a flash light emission window. Reference numeral 53 denotes a flash unit including a reflector, a xenon tube, other main capacitors, a circuit board, and the like disposed behind the flash light emission window. Reference numeral 54 denotes an image recording memory card. A battery 55 supplies power to each unit of the imaging apparatus. The memory card 54 and the battery 55 can be inserted and removed from a not-shown lid.

  A release button 56 is arranged on the upper surface of the imaging apparatus 100, and a shooting preparation operation, that is, a focusing operation and a photometry operation are performed by pushing the first step (hereinafter referred to as switch S1ON). The photographing exposure operation is performed by (hereinafter referred to as switch S2ON). A main switch 57 is a switch for switching the imaging apparatus between an operating state and a non-operating state. When switched to the operating state by the main switch 57, the lens barrier (not shown) is opened and the operation of each part is started. When the main switch 57 is switched to the non-operating state, the lens barrier (not shown) is closed and ends the operation of each unit.

  On the back surface of the imaging apparatus 100, an image display unit 58 that is configured by an LCD, an organic EL, or the like and displays an image, other character information, or the like is disposed. Although not shown, a zoom button for zooming up and down, a playback button for playing back a captured image, a menu button for displaying various menus on the image display unit 58, and a desired function are selected from the display. An operation member such as a selection button is arranged.

  Although not shown, each part is connected between these main constituent units and a circuit board on which various electronic components are mounted is arranged to drive and control each main constituent unit. Yes. Similarly, although not shown, an external input / output terminal, a strap attaching portion, a tripod seat, and the like are provided.

  In the present embodiment, description is made using a bending imaging optical system capable of zooming, but an imaging optical system in which the optical axis is not bent may be used.

  FIG. 2 is a block diagram illustrating an overview of the imaging apparatus 100 according to the present embodiment.

  As shown in the figure, the imaging optical system 40 in the lens barrel 50 is configured to move a predetermined lens group by the first motor 20 and the second motor 21 and is subjected to zooming and focus adjustment. . Further, in the lens barrel 50, two actuators 61 for moving the image sensor 6 in a direction to cancel the image movement in the yaw direction and the pitch direction shown in FIG. The image sensor 6 is moved by the first drive actuator 61P and the second drive actuator 61Y. Note that the independent first and second drive actuators 61P and 61Y constituting the actuator 61 do not have to match the pitch direction and the yaw direction, and the image is taken in an arbitrary direction by combining the two actuators. What is necessary is just to be able to move an element.

  In the present embodiment, the first drive actuator 61P and the second drive actuator 61Y that move the image sensor 6 are stepping motors that can control the rotation angle in an open loop by a predetermined signal input. Yes.

  Further, a sensor 62 is provided for detecting the moving position of the image sensor 6 by the actuator 61. The position in the pitch direction is determined by the pitch direction position sensor 62P, and the position in the yaw direction is determined by the yaw direction position sensor 62Y.

  The actuator 61 is driven by a driver 63 controlled by the control unit 30. The first motor 20 and the second motor 21 are also driven by drivers 22 and 23 controlled by the control unit 30, respectively.

  A shake detection sensor 64 that detects the shake detects the shake of the lens barrel 50. Specifically, the shake detection sensor 64P detects an angular velocity in the pitch direction (specifically, an inertial angular velocity (ground angular velocity)), and the shake detection sensor 64Y detects an angular velocity in the yaw direction.

  The signals from the shake detection sensors 64P and 64Y are amplified and filtered by the shake detection circuit 65, detected as a signal indicating “shake”, and input to the control unit 30 constituted by, for example, a microcomputer. It has become.

  In the control unit 30, a predetermined software program stored in the ROM 81 is executed using a RAM (not shown) as a work area, and functions of the respective units are executed. For example, the control output unit 35 obtains the current angle in the pitch direction and the yaw direction based on the signal from the shake detection circuit 65, and obtains an output value that reduces the difference between the current angle and the target angle. That is, a control command value for driving the image pickup device 6 to move in the plane is generated so as to suppress the shake detected by the shake detection circuit 65. The control output unit 35 outputs the generated control command value to the driver 63.

  The driver 63 drives the first drive actuator 61P and the second drive actuator 61Y based on the control command value. As a result, the image sensor 6 is displaced in-plane, and the camera shake is corrected. The pitch direction position sensor 62 </ b> P and the yaw direction position sensor 62 </ b> Y are sensors for detecting the position of the image sensor 6 driven in-plane by the actuator 61 and feedback-controlling the displacement drive of the image sensor 6.

  The EEPROM 82 is storage means for storing adjustment data related to control of camera shake correction in addition to individual data such as a zoom position at the time of zooming of the image pickup optical system 40 and an infinite focus position of the focus lens.

  In addition, the imaging apparatus 100 is provided with a signal processing unit 71, an A / D conversion unit 72, an image processing unit 73, and an image memory 74 as processing units that handle images obtained by the imaging element 6. The image of the analog signal acquired by the image sensor 6 is A / D converted by the A / D converter 72 via the signal processor 71 and subjected to predetermined image processing by the image processor 73, and then temporarily stored in the image memory 74. Stored. The image stored in the image memory 74 is recorded on the memory card 54 as a recording image, or displayed on the image display unit 58 as a live view display image by performing a desired process.

  An operation switch group 150 such as a cross key button, a zoom operation button, a mode selection dial, and a mode setting button group is connected to the control unit 30, and the imaging apparatus 100 is operated based on the operation by a user operation. ing.

  Hereinafter, the lens barrel 50 according to the present embodiment will be described.

  FIG. 3 is a cross-sectional view of the lens barrel 50 according to the present embodiment. This figure is a cross-sectional view of a surface including the optical axis OA before bending and the optical axis OB after bending.

  In the figure, reference numeral 1 denotes a first lens group. The first lens group 1 is a prism 11 that is a reflection member that bends the optical axis OA in a substantially right angle direction with a lens 11 that is arranged toward the subject with an optical axis of OA. 12 and a lens 13 arranged with the optical axis OB bent by the prism 12 as an optical axis. The first lens group 1 is a lens group fixed to the main body 10.

  Reference numeral 2 denotes a second lens group, which is incorporated in the second lens group frame 2k. The second lens group 2 is a lens group that moves integrally with the second lens group lens frame 2k during zooming (hereinafter also referred to as zooming).

  Reference numeral 3 denotes a third lens group, which is fixed to the main body 10. The third lens group 3 is a lens group that does not move.

  S is a unit having at least one of an aperture and a shutter. This unit S is fixed to the main body 10.

  Reference numeral 4 denotes a fourth lens group, which is incorporated in the fourth lens group frame 4k. The fourth lens group is a lens group that moves integrally with the fourth lens group lens frame 4k at the time of zooming, and also moves alone to perform focus adjustment (hereinafter also referred to as focusing).

  The second lens group 2 and the fourth lens group 4 are located far away from the third lens group 3 at a wide angle, and move in a direction approaching the third lens group 3 with zooming to the long focal point side. To do.

  Reference numeral 90 denotes an image sensor moving mechanism, which is assembled on a base plate 91 fixed to the main body 10. The image sensor moving mechanism 90 can move the image sensor in a plane orthogonal to the optical axis OB, and the movement is corrected by this movement. A CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, or the like is used as the imaging device. An infrared light cut filter is disposed in front of the image sensor.

  As shown in the figure, a flexible printed circuit board FPC that inputs and outputs power and signals is connected to the image sensor moving mechanism 90 with a slack.

  FIG. 4 is a perspective view showing the image sensor moving mechanism 90 according to the present embodiment. FIG. 5 is a plan view showing the image sensor moving mechanism according to the present embodiment. The image sensor moving mechanism 90 includes an image sensor 6, a pitch direction position sensor 62P, a yaw direction position sensor 62Y, a first drive actuator (stepping motor in this example) 61P, and a second drive actuator (this example). In this case, a stepping motor 61Y is provided.

  The imaging element moving mechanism 90 is provided with a P-direction moving plate 93 that is guided by two guide shafts 92a and 92b fixed to the base plate 91 and is movable in the direction of the arrow P shown in the drawing. The P-direction moving plate 93 is integrally formed with an arm portion 93m and a PI shielding plate 93f. The arm portion 93m is engaged with a nut that is screwed into a lead screw that is rotated by a stepping motor 61P that is a first drive actuator. Thereby, the P-direction moving plate 93 is moved in the direction of the arrow P by the rotation of the stepping motor 61P. The PI shielding plate 93f is formed so as to pass between the light projecting and receiving portions of the photo interrupter PIp, which is a position detection unit fixed to the base plate 91.

  Two guide shafts 95 a and 95 b are fixed to the P-direction moving plate 93. A Y-direction moving plate 96 is provided which is guided by the guide shafts 92a and 92b and is movable in the direction of the arrow Y shown in the figure. Similarly, although not shown in the drawings, the Y-direction moving plate 96 is integrally formed with an arm portion and a PI shielding plate. The arm portion is engaged with a nut that is screwed into a lead screw that is rotated by a stepping motor 61Y that is a second drive actuator. Thereby, the Y-direction moving plate 96 is moved in the arrow Y direction by the rotation of the stepping motor 61Y. The PI shielding plate is formed so as to pass between the light projecting and receiving portions of the photo interrupter PIy which is a position detection unit fixed to the base plate 91.

  The Y-direction moving plate 96 is provided with the image sensor 6 and an infrared light cut filter.

  Thereby, by rotating the stepping motors 61P and 61Y, the Y-direction moving plate 96, that is, the imaging element lens 6 can be moved in a plane orthogonal to the optical axis OB of the imaging optical system.

  An operation at the time of shooting of the imaging apparatus including the lens barrel 50 configured as described above will be described. At the time of shooting with the imaging apparatus according to the present embodiment, a shooting mode in which no camera shake correction is performed and a camera shake correction shooting mode in which camera shake correction is performed can be selected. The shooting mode and the second camera shake correction shooting mode can be selected.

  FIG. 6 is a flowchart showing an outline of the operation in the first camera shake correction photographing mode. Hereinafter, the operation in the first camera shake correction photographing mode will be described according to the same flow.

  First, a through image of a subject is displayed on the image display unit (step S101). Next, it waits for the first push of the release button (switch S1 is turned on) (step S102). When the switch S1 is turned on (step S102; Yes), a shooting preparation operation is performed (step S103). The shooting preparation operation is a focusing operation or a photometry operation for predetermining exposure conditions during shooting.

  Next, it is confirmed again whether the switch S1 is ON (step S104). If the switch S1 is not turned on (step S104; No), the process returns to step S102 and waits for the switch S1 to be turned on. When the switch S1 is turned on (step S104; Yes), it waits for the release button to be pushed in the second stage (switch S2 is turned on) (step S105).

  When the switch S2 is turned on (step S105; Yes), photographing is performed while correcting camera shake (step S106). Thereafter, the photographed image is recorded on the memory card (step S107), and photographing of one frame is completed.

  The above-described camera shake correction shooting in step S106 will be described in more detail.

  FIG. 7 is a flowchart showing an outline of the operation at the time of camera shake correction photographing in step S106.

  When the switch S2 is turned on in step S105, it is determined whether or not the focal length of the imaging optical system before execution of camera shake correction photographing is shorter than a predetermined focal length (step S151). When the focal length is shorter than the predetermined focal length (step S151; Yes), the P direction by the pitch direction position sensor and the yaw direction position sensor, which are position detectors, is used to suppress the shaking detected by the shaking detection circuit. Based on the detection of the positions of the moving plate and the Y-direction moving plate, the first stepping motor and the two stepping motors that are the second driving actuator are controlled to perform shooting while correcting the camera shake (step S152). ). That is, when the focal length is shorter than a predetermined value, the driving amounts of the two stepping motors as actuators are performed by feedback control while looking at the position detection value obtained from the position detection unit.

  The predetermined focal length is preferably set to a focal length in which the maximum movement amount for camera shake correction is the same as that in the feedback controllable region or the maximum movement amount for camera shake correction is smaller than in the feedback controllable region. The feedback controllable area refers to an area where the position detection value at the position detection unit changes.

  On the other hand, when the focal length of the imaging optical system before execution of the camera shake correction shooting is longer than the predetermined focal length (step S151; No), a predetermined signal input is performed so as to suppress the shaking detected by the shaking detection circuit. By performing drive control of the two stepping motors that are the first drive actuator and the second drive actuator, the image is taken while correcting the camera shake (step S162). That is, when the focal length is longer than the predetermined value, the drive amount control of the two stepping motors that are actuators is performed in an open loop.

  FIG. 8 is a diagram illustrating the driving amount of the stepping motor (the amount of movement of the driven member) and the output of the photo interrupter that is a position detection unit. This figure is the same for both the position detection of the P-direction moving plate and the position detection of the Y-direction moving plate.

  As shown in the figure, the position of the PI shielding plate at which the output of the photo interrupter, which is a position detection unit, has a substantially median value is set as the initial position. When the imaging optical system has a short focus, camera shake correction is performed by feedback control using the photointerrupter output within a region where the photointerrupter output before and after the initial position changes. In the case of the above-mentioned long focus, the camera shake correction is performed by open loop control without using the photo interrupter output. By doing this, the ratio of error due to stepping motor rotation angle error, screw feed amount error, clearance play due to clearance, etc. on the short focus side where the movement amount for camera shake correction is small can be reduced, and the degree of influence on the correction accuracy Can be suppressed.

  As shown in FIG. 8, the focal length range in which the feedback control is performed is shorter (ie, shorter) when the region moved for camera shake correction is narrower than the region where the output of the photo interrupter as the position detection unit changes. When the region to be moved for camera shake correction is wider than the region where the output of the photo interrupter changes (that is, the long focal side), open loop control is performed. For this reason, it is preferable to use a position detection unit that can be obtained in a wider range of output change.

  FIG. 9 is a flowchart showing an outline of the operation in the second camera shake correction photographing mode. Hereinafter, the operation in the second camera shake correction photographing mode will be described according to the same flow.

  First, a through image of a subject is displayed on the image display unit (step S201). Next, it waits for the release button to be pushed down (switch S1 is turned on) (step S202). When the switch S1 is turned on (step S202; Yes), a shooting preparation operation is performed (step S203). The shooting preparation operation is a focusing operation or a photometry operation for predetermining exposure conditions during shooting.

  Next, a camera shake correction operation is started (step S204). Thereafter, it is confirmed again whether the switch S1 is turned on (step S205). If the switch S1 is not turned on (step S205; No), the process returns to step S202 and waits for the switch S1 to be turned on. When the switch S1 is turned on (step S205; Yes), it waits for the second push of the release button (switch S2 is turned on) (step S206).

  When the switch S2 is turned on (step S206; Yes), photographing is performed while correcting camera shake (step S207). After shooting, the camera shake correction is stopped (step S208), the shot image is recorded on the memory card (step S209), and shooting of one frame is completed.

  The outline of the operation at the time of the camera shake correction shooting in step S207 in the second camera shake correction shooting mode is the same as the flowchart shown in FIG.

  The above is the schematic operation in the second camera shake correction shooting mode.

  That is, the second camera shake correction shooting mode is a mode in which camera shake correction is performed at the time of framing before shooting and at the time of shooting. Mode. In the first camera shake correction shooting mode, power can be saved compared to the second camera shake correction shooting mode.

  In the above-described embodiment, the description has been made using the four-group zoom imaging optical system, but the present invention is not limited to this. Moreover, although the example which moves an image pick-up element within the surface orthogonal to an optical axis was demonstrated, it is also applicable to the lens which comprises an image pick-up optical system. Further, although an example in which a photo interrupter is used for the position detection unit has been described, it is needless to say that a Hall element or the like may be used.

It is a figure which shows an example of the internal arrangement | positioning of the main structural unit of the imaging device which concerns on this Embodiment. It is a block diagram which shows the outline | summary of the imaging device which concerns on this Embodiment. It is sectional drawing of the lens barrel which concerns on this Embodiment. It is a perspective view which shows the image pick-up element moving mechanism which concerns on this Embodiment. It is a top view which shows the image pick-up element moving mechanism which concerns on this Embodiment. It is a flowchart which shows the operation | movement outline | summary at the time of the 1st camera shake correction imaging mode. It is a flowchart which shows the operation | movement outline | summary at the time of camera-shake correction imaging | photography in step S106 of FIG. It is a figure which shows the output of the drive amount (driven member movement amount) of a stepping motor, and the photo interrupter which is a position detection part. It is a flowchart which shows the operation | movement outline | summary at the time of 2nd camera shake correction imaging | photography mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 2k 2nd lens group frame 3 3rd lens group 4 4th lens group 4k 4th lens group frame 6 Imaging element 10 Main trunk 15, 16 Guide shaft 20 1st motor 21 Second motor 61P First drive actuator (stepping motor)
62Y Second drive actuator (stepping motor)
91 Base plate 92a, 92b Guide shaft 93 P direction moving plate 95a, 95b Guide shaft 96 Y direction moving plate PIp, PIy Position detection unit 90 Image sensor moving mechanism 50 Lens barrel 100 Imaging device

Claims (5)

An imaging optical system that guides the subject light, an actuator that can control the drive amount by open loop, and an optical member or an imaging device that is moved by the actuator in a plane perpendicular to the optical axis of the imaging optical system are mounted together. In a lens barrel having a driven member and a position detection unit for detecting the position of the driven member,
A lens barrel that switches between driving amount control of the actuator based on position detection by the position detection unit and driving amount control of the actuator by open loop. 2. The lens barrel according to claim 1, wherein a drive amount control region by an open loop of the actuator is wider than a region in which the actuator drive amount is controlled based on position detection by the position detection unit. . The imaging optical system is a variable magnification optical system, and performs a drive amount control of the actuator based on position detection by the position detection unit on the short focal side of the variable magnification optical system, and the open-loop control on the long focal side. 3. The lens barrel according to claim 1, wherein the driving amount of the actuator is controlled. An image pickup apparatus comprising the lens barrel according to claim 1, wherein camera shake correction is performed by moving the driven member. The imaging apparatus according to claim 4, further comprising: a mode in which the camera shake correction is performed during framing and shooting, and a mode in which the camera shake correction is not performed during framing and performed during shooting.

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