JP2012225947A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel achieving a small image magnification change, a low driving sound and a reduced power consumption even during a wobbling operation.SOLUTION: The lens barrel includes a plurality of focus lens groups for changing an imaging distance by individually moving in an optical axis direction, and a plurality of focus actuators for driving the respective focus lens groups. The lens barrel further includes a control unit having a wobbling mode for controlling only one of the plurality of focus lens groups to reciprocate back and forth in the optical axis direction.

Description

  The present invention relates to a lens barrel having a plurality of focus lens groups and a diaphragm for changing a diaphragm aperture of a photographing lens, and a camera system using the lens barrel.

  In recent years, digital cameras capable of converting an optical image of a subject into an electrical image signal and outputting the same have rapidly spread. The lens barrel described in Patent Document 1 has a plurality of focus lens groups, and a plurality of focus lens groups are driven by a single motor using a cam mechanism. Further, the movement of the focus lens group and the movement of the aperture are linked to change the aperture diameter according to the shooting distance.

JP 2006-154473 A

  However, in a conventional lens barrel, when a wobbling operation is performed for moving image shooting or the like, a plurality of focus lens groups are moved simultaneously by a cam mechanism. There is a first problem that driving sound and power consumption increase. Further, the conventional lens barrel has a second problem that the aperture of the diaphragm linked with the focus lens group changes due to the wobbling operation, and the luminance of the optical image also changes.

  The technique disclosed herein solves the first of the two problems described above, and an object thereof is to provide a lens barrel that has a small image magnification change, driving sound, and low power consumption even during a wobbling operation.

The lens barrel disclosed here is
A plurality of focus lens groups that change the shooting distance by moving in the direction of the optical axis,
A plurality of focus actuators each driving the focus lens group;
A control unit having a wobbling mode for controlling only one focus lens group to reciprocate back and forth in the optical axis direction among the plurality of focus lens groups.

  According to the technique disclosed herein, it is possible to provide a lens barrel that can reduce image magnification change, drive sound, and power consumption even during a wobbling operation.

Schematic configuration diagram of digital camera Block diagram showing the configuration of the camera body Schematic perspective view of digital camera (A) Top view of camera body, (B) Rear view of camera body Cross section of interchangeable lens unit (focused at infinity) Cross section of interchangeable lens unit (focused at infinity) Exploded perspective view of second lens group unit Exploded perspective view of the fourth lens group unit Exploded perspective view of fifth lens group unit (A) Configuration diagram of optical system in infinite focus state, (B) Configuration diagram of optical system in latest focused state Diagram showing the position of each lens group during focusing

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
<Overview of digital camera>
The digital camera 1 will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of a digital camera 1. As shown in FIG. 1, a digital camera 1 (an example of an imaging apparatus) is an interchangeable lens type digital camera, and mainly includes a camera body 3 and an interchangeable lens unit 2 (removably attached to the camera body 3). An example of a lens barrel). The interchangeable lens unit 2 is attached to a body mount 4 provided on the front surface of the camera body 3 via a lens mount 95.

  FIG. 2 is a block diagram showing the configuration of the camera body 3. FIG. 3 is a schematic perspective view of the digital camera 1. 4A is a top view of the camera body 3, and FIG. 4B is a rear view of the camera body 3. FIG. 5 to 6 are schematic sectional views of the interchangeable lens unit 2 in different planes. FIG. 7 is an exploded perspective view of the first focus adjustment unit 72. FIG. 8 is an exploded perspective view of the second focus adjustment unit 73. FIG. 9 is an exploded perspective view of the third focus adjustment unit 74. 10A and 10B are configuration diagrams of the optical system L. FIG. FIG. 10A shows a focused state at infinity, and FIG. 10B shows a closest focused state. FIG. 11 shows the distance from the image sensor 11 of each lens group during focusing.

  In the present embodiment, a three-dimensional orthogonal coordinate system is set for the digital camera 1. The optical axis AZ of the optical system L (described later) coincides with the Z-axis direction (an example of the optical axis direction). The X axis direction coincides with the horizontal direction in the vertical shooting posture of the digital camera 1. The Y-axis direction coincides with the vertical direction in the horizontal shooting posture of the digital camera 1. In the following description, “front” refers to the subject side (Z axis direction positive side) of the digital camera 1, and “rear” refers to the opposite side of the subject side of the digital camera 1 (user side, Z axis direction). Means negative side).

<Interchangeable lens unit>
A schematic configuration of the interchangeable lens unit 2 will be described with reference to FIGS. As shown in FIG. 1, the interchangeable lens unit 2 includes an optical system L, a lens support mechanism 71 that supports the optical system L, a first focus adjustment unit 72, a second focus adjustment unit 73, and a third focus adjustment. A unit 74, an aperture adjustment unit 75, a shake correction unit 76, and a lens microcomputer 40 are provided.

(1) Optical system The optical system L forms an optical image of a subject. The optical system L is mainly composed of six lens groups. Specifically, as shown in FIGS. 10A and 10B, the optical system L includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. The third lens group G3 having a positive refractive power, the fourth lens group G4 having a positive refractive power, the fifth lens group G5 having a negative refractive power, and a sixth lens having a positive refractive power It has group G6.

  The first lens group G1 includes a first lens L1, a second lens L2, and a third lens L3. The second lens group G2 is a focus lens group, and includes a fourth lens L4, a fifth lens L5, and a sixth lens L6. The third lens group G3 is a blur correction lens group, and includes a seventh lens L7. The fourth lens group G4 is a focus lens group, and includes an eighth lens L8, a ninth lens L9, and a tenth lens L10. The fifth lens group G5 is a focus lens group and includes an eleventh lens L11. The sixth lens group G6 includes a twelfth lens L12 and a thirteenth lens L13. The optical system L has a plurality of focus lens groups G2, G4, G5. The plurality of focus lens groups G2, G4, and G5 move in the optical axis direction to change the shooting distance (object distance).

  As shown in FIGS. 10A, 10B, and 11, the second lens group G2 moves along the optical axis AZ on the side of the image sensor 11 during focusing from the infinitely focused state to the most recently joined focused state. The fourth lens group G4 and the fifth lens group G5 move to the subject side along the optical axis AZ.

  Furthermore, in order to suppress the shake of the optical image due to the movement of the digital camera 1, the seventh lens L7 moves in two directions orthogonal to the optical axis AZ.

  As shown in FIG. 11, when the focus lens groups move from the infinitely focused state to the recently joined focus state, the moving direction is constant. Therefore, since it is not necessary to invert the focus lens group at the time of detecting contrast AF, it is possible to improve the AF accuracy without being affected by the hysteresis of the motor and the drive mechanism.

(2) Lens Support Mechanism The lens support mechanism 71 is a mechanism for supporting the lens groups G1 to G6 of the optical system L so as to be fixed or movable, and includes a lens mount 95, a fixed frame 50, and a guide pole support frame. 51, a first lens group support frame 52, a second lens group support frame 53, a third lens group support frame 54, an aperture unit 62 (an example of an aperture), a fourth lens group support frame 55, a fifth A lens group support frame 56, a sixth lens group support frame 57, and a focus ring unit 88 are provided.

  The lens mount 95 is a portion to be attached to the body mount 4 of the camera body 3 and has a lens side contact 91.

  The fixed frame 50 supports a front frame 61, a first lens group support frame 52, a diaphragm unit 62, a first focus motor 63 (an example of a focus actuator), and a second focus motor 64 (an example of a focus actuator). At the same time, the front end portions of the four guide poles 63b, 63c, 64b, 64c extending in the Z-axis direction are supported and fixed to the guide pole support frame 51. The first focus motor 63 and the second focus motor 64 are stepping motors, for example.

  The guide pole support frame 51 supports the sixth lens group support frame 57, guide poles 65c and 65b, and a third focus motor 65 (an example of a focus actuator), and four guide poles 63b, 63c, 64b, and 64c. The rear side end portion is supported and fixed to the lens mount 95. The third focus motor 65 is a stepping motor, for example.

  The front frame 61 is fixed to the fixed frame 50, and a female thread portion 61a for attaching an optical filter such as a polarizing filter or a protective filter and a conversion lens is formed at the tip.

  The first lens group support frame 52 is fixed to the fixed frame 50 and supports the first lens group G1.

  The second lens group support frame 53 supports the second lens group G2, and includes a bearing portion 53a, a rotation stop portion 53b, a rack support portion 53c, and a protrusion 53d. A guide pole 63b is inserted into the bearing portion 53a, and a guide pole 63c is inserted into the anti-rotation portion 53b. With the rotation around the optical axis AZ restricted, the second lens group support frame 53 moves in the Z-axis direction. Is supported so as to be movable. The rack support portion 53c supports the first rack 58 so as to be movable and rotatable integrally in the Z-axis direction. The protrusion 53d is a portion for detecting the origin of the second lens group G2, and is provided at a position where it can pass through the detection region of the first photosensor 66. The first rack 58 has a plurality of teeth (not shown), and the teeth mesh with the lead screw 63 a of the first focus motor 63.

  The third lens group support frame 54 supports the third lens group G3. The third lens group support frame 54 is supported so as to be movable in two directions orthogonal to the optical axis AZ.

  The fourth lens group support frame 55 supports the fourth lens group G4, and includes a bearing portion 55a, a detent portion 55b, a rack support portion 55c, and a protrusion 55d. A guide pole 64b is inserted into the bearing portion 55a, and a guide pole 64c is inserted into the anti-rotation portion 55b so that the rotation around the optical axis AZ is restricted, and the fourth lens group support frame 55 is in the Z-axis direction. Is supported so as to be movable. The rack support portion 55c supports the second rack 59 so as to be integrally movable and rotatable in the Z-axis direction. The protrusion 55d is a portion for detecting the origin of the fourth lens group G4, and is provided at a position where it can pass through the detection region of the second photosensor 67. The second rack 59 has a plurality of teeth (not shown), and the teeth mesh with the lead screw 64 a of the second focus motor 64.

  The fifth lens group support frame 56 supports the fifth lens group G5, and includes a bearing portion 56a, a detent portion 56b, a rack support portion 56c, and a protrusion 56d. The guide pole 65b is inserted into the bearing portion 56a, the guide pole 65c is inserted into the anti-rotation portion 56b, and the fifth lens group support frame 56 is in the Z-axis direction with the rotation around the optical axis AZ restricted. Is supported so as to be movable. The rack support part 56c supports the third rack 60 so as to be movable and rotatable integrally in the Z-axis direction. The protrusion 56d is a portion for detecting the origin of the fifth lens group G5, and is provided at a position where it can pass through the detection region of the third photosensor 68.

  The third rack 60 has a plurality of teeth (not shown), and the teeth mesh with the lead screw 65 a of the third focus motor 65.

  The sixth lens group support frame 57 supports the sixth lens group G6 and is fixed to the guide pole support frame 51.

  The focus ring unit 88 includes a focus ring 89 and a focus ring angle detection unit 90 that detects the rotation angle of the focus ring 89. The focus ring 89 has a cylindrical shape, and is supported by the fixed frame 50 and the front frame 61 so as to be rotatable around the optical axis AZ in a state where movement in the Z-axis direction is restricted. The focus ring angle detection unit 90 can detect the rotation angle and the rotation direction of the focus ring 89. For example, the focus ring angle detection unit 90 includes two photo sensors (not shown). The focus ring 89 has a plurality of protrusions 89a that are arranged at equal intervals in the rotation direction and protrude in the Z-axis direction. Each photosensor has a light emitting part (not shown) and a light receiving part (not shown), and a plurality of protrusions 89a pass between the light emitting part and the light receiving part, whereby the rotation angle of the focus ring 89 And the direction of rotation can be detected. The focus ring 89 may have another structure such as a movable lever.

(3) Focus Adjustment Unit The first focus adjustment unit 72 includes a first focus motor 63, a focus lens drive control unit 41, and a first photo sensor 66 (an example of a position sensor). The first focus motor 63 is closer to the imaging surface than the aperture unit 62, is fixed to the fixed frame 50, and drives the second lens group support frame 53 in the Z-axis direction. The lead screw 63 a of the first focus motor 63 rotates based on the drive signal input from the focus lens drive control unit 41. The rotational movement generated by the first focus motor 63 is converted into a straight movement in the Z-axis direction of the second lens group support frame 53 by the lead screw 63a and the first rack 58, and the second lens group support frame 53 is moved in the Z-axis direction. It becomes possible to move to.

  The second focus adjustment unit 73 includes a second focus motor 64, a focus lens drive control unit 41, and a second photo sensor 67 (an example of a position sensor). The second focus motor 64 is closer to the imaging surface than the aperture unit 62, is fixed to the fixed frame 50, and drives the fourth lens group support frame 55 in the Z-axis direction. The lead screw 64 a of the second focus motor 64 rotates based on the drive signal input from the focus lens drive control unit 41. The rotational movement generated by the second focus motor 64 is converted into a straight movement in the Z-axis direction of the fourth lens group support frame 55 by the lead screw 64a and the second rack 59, and the fourth lens group support frame 55 is moved in the Z-axis direction. It becomes possible to move to.

  The third focus adjustment unit 74 includes a third focus motor 65, a focus lens drive control unit 41, and a third photo sensor 68 (an example of a position sensor). The third focus motor 65 is closer to the imaging surface than the aperture unit 62, is fixed to the guide pole support frame 51, and drives the fifth lens group support frame 56 in the Z-axis direction. The lead screw 65 a of the third focus motor 65 rotates based on the drive signal input from the focus lens drive control unit 41. The rotational movement generated by the third focus motor 65 is converted into a straight movement in the Z-axis direction of the fifth lens group support frame 56 by the lead screw 65a and the third rack 60, and the fifth lens group support frame 56 is moved in the Z-axis direction. It becomes possible to move to.

  A focus lens drive control unit 41 (an example of a control unit) can control all three focus motors 63, 64, and 65 at different driving speeds at the same time. It is also possible to drive only the focus motor. When the focus lens groups G2, G4, G5 are driven to the in-focus position, the AF operation can be speeded up by driving the three focus motors 63, 64, 65 simultaneously. In addition, the focus lens drive control unit 41 moves the shooting distance back and forth within a very small range in order to confirm the in-focus position in moving image shooting or the like. For example, by driving only the fifth lens group G5, which is the lightest focus lens group, it is possible to reduce image magnification change, driving sound, and power consumption. Specifically, the focus lens drive control unit 41 controls the third focus motor 65 so as to drive only the fifth lens group G5 back and forth in the optical axis AZ direction during the wobbling operation.

  Further, since the three focus motors 63, 64, 65 are all on the imaging surface side with respect to the aperture unit 62, the focus motors are used for the third lens group support frame 54 and the shake correction unit 76 (an example of the shake correction device). Since there is no need to provide notches to avoid, the lens barrel can be downsized.

(4) Aperture Adjustment Unit The aperture adjustment unit 75 includes an aperture unit 62, an aperture drive motor (an example of an aperture actuator, not shown) that drives the aperture unit 62, and an aperture drive control unit (control) that controls the aperture drive motor. Part) 42). The aperture drive motor is, for example, a stepping motor. The aperture drive motor is driven based on a drive signal input from the aperture drive control unit 42. The aperture blade 62a is driven in the opening direction and the closing direction by the driving force generated by the aperture driving motor, and the aperture shape changes. The aperture value of the optical system L can be changed by driving the aperture blade 62a. The aperture drive control unit 42 controls to change the aperture diameter according to the shooting distance. Since the aperture drive motor and the aperture drive control unit 42 are provided independently of the focus adjustment unit, the aperture drive motor can be stopped when it is not desired to change the aperture diameter, such as a wobbling operation during movie shooting. It is possible to obtain an image having no luminance change during the wobbling operation.

(5) Shake Correction Unit The shake correction unit 76 is a unit for suppressing the shake of the optical image caused by the movement of the interchangeable lens unit 2 and the camera body 3, and includes the electromagnetic actuator 46, the position detection sensor 47, the shake. And a correction microcomputer 48.

  The electromagnetic actuator 46 drives the third lens group support frame 54 in a direction orthogonal to the optical axis AZ. That is, the electromagnetic actuator 46 drives the third lens group G3 (an example of a shake correction lens group) in a direction orthogonal to the optical axis AZ. The position detection sensor 47 is a sensor for detecting the position of the third lens group support frame 54 with respect to the aperture unit 62. The interchangeable lens unit 2 is equipped with a motion detection sensor (not shown) such as a gyro sensor. The shake correction microcomputer 48 controls the electromagnetic actuator 46 based on the detection result of the position detection sensor 47 and the detection result of the motion detection sensor. Thereby, the shake of the subject image due to the movement of the digital camera 1 can be suppressed.

  Note that electronic shake correction that corrects shake appearing in an image based on image data output from the image sensor 11 may be applied as a method for suppressing shake of the subject image. Further, as a method for suppressing the shake of the optical image, a sensor shift method in which the imaging sensor 11 is driven in two directions orthogonal to the optical axis AZ may be applied.

(6) Lens microcomputer 40 The lens microcomputer 40 has a CPU (not shown), a ROM (not shown), and a memory 40a, and various functions are realized by reading a program stored in the ROM into the CPU. Can be realized. For example, the lens microcomputer 40 can recognize from the detection signal of the first photosensor 66 that the second lens group support frame 53 is at the origin position.

  The memory 40a is a non-volatile memory and can hold stored information even when power supply is stopped. The memory 40a stores, for example, information about the interchangeable lens unit 2 (lens information), focus group position information according to the subject distance, and the like (FIG. 11). The lens microcomputer 40 controls the focus motors 63, 64, 65 based on the position information of the focus group according to the subject distance, and each focus lens group is driven in the Z-axis direction. The lens microcomputer 40 can grasp the positions of the focus lens groups G2, G4, and G5 in the optical axis AZ direction. That is, the lens microcomputer 40 can grasp the subject distance. The subject distance is the distance to the subject on which the optical image is focused by the optical system L. Specifically, the lens microcomputer 40 recognizes that the second lens group support frame 53 is at the origin position based on the detection signal of the first photosensor 66, and then drives the first focus motor 63 (for example, step). The position of the second lens group G2 in the optical axis AZ direction is grasped by counting (number). Further, the lens microcomputer 40 recognizes that the fourth lens group support frame 55 is at the origin position based on the detection signal of the second photosensor 67, and then determines the drive amount (for example, the number of steps) of the second focus motor 64. By counting, the position of the fourth lens group G4 in the optical axis AZ direction is grasped. Further, the lens microcomputer 40 recognizes that the fifth lens group support frame 56 is at the origin position based on the detection signal of the third photosensor 68, and then determines the drive amount (for example, the number of steps) of the third focus motor 65. By counting, the position of the fifth lens group G5 in the optical axis AZ direction is grasped.

<Camera body>
A schematic configuration of the camera body 3 will be described with reference to FIGS. As shown in FIGS. 1 to 4, the camera body 3 includes a housing 3 a, a body mount 4, an operation unit 39, an image acquisition unit 35, an image display unit 36, a finder unit 38, and a body microcomputer 10. (An example of a drive control unit, an example of a preliminary operation detection unit) and a battery 22 (an example of a main power source).

(1) Case The case 3 a constitutes the exterior part of the camera body 3. As shown in FIGS. 4A and 4B, a body mount 4 is provided on the front surface of the housing 3a, and an operation unit 39 is provided on the back and top surfaces of the housing 3a. Yes. Specifically, on the rear surface of the housing 3a, the display unit 20, the power switch 25, the mode switching dial 26, the cross operation key 27, the menu setting button 28, the setting button 29, and the mode switching button 34 are displayed. In addition, a moving image shooting operation button 24 is provided. A shutter button 30 is provided on the upper surface of the housing 3a.

(2) Body Mount The body mount 4 is a portion to which the lens mount 95 of the interchangeable lens unit 2 is attached, and has a body side contact (not shown) that can be electrically connected to the lens side contact 91. . The camera body 3 can transmit and receive data to and from the interchangeable lens unit 2 via the body mount 4 and the lens mount 95. For example, the body microcomputer 10 (described later) transmits a control signal such as an exposure synchronization signal to the lens microcomputer 40 via the body mount 4 and the lens mount 95.

(3) Operation Unit As shown in FIGS. 4A and 4B, the operation unit 39 has various operation members for the user to input operation information. For example, the power switch 25 is a switch for turning on / off the power of the digital camera 1 or the camera body 3. When the power is turned on by the power switch 25, power is supplied to each part of the camera body 3 and the interchangeable lens unit 2.

  The mode switching dial 26 is a dial for switching operation modes such as a still image shooting mode, a moving image shooting mode, and a reproduction mode, and the user can switch the operation mode by rotating the mode switching dial 26. When the still image shooting mode is selected with the mode switching dial 26, the operation mode can be switched to the still image shooting mode. When the moving image shooting mode is selected with the mode switching dial 26, the operation mode is switched to the moving image shooting mode. be able to. In the movie shooting mode, movie shooting is basically possible. Furthermore, when the playback mode is selected by the mode switching dial 26, the operation mode can be switched to the playback mode, and the captured image can be displayed on the display unit 20.

  The cross operation key 27 is a button that allows the user to select the vertical and horizontal directions. For example, a desired menu can be selected from various menu screens displayed on the display unit 20 by using the cross operation key 27.

  The menu setting button 28 is a button for setting various operations of the digital camera 1. The setting button 29 is a button for confirming execution of various menus.

  The moving image shooting operation button 24 is a button for instructing start and stop of moving image shooting. Even if the operation mode selected with the mode switching dial 26 is the still image shooting mode or the playback mode, pressing the moving image shooting operation button 24 forces the operation regardless of the setting content with the mode switching dial 26. The mode shifts to the movie shooting mode, and movie shooting is started. Further, when the moving image shooting operation button 24 is pressed during moving image shooting, the moving image shooting is terminated, and the operation mode selected by the mode switching dial 26, that is, the operation mode before starting moving image shooting is shifted to. For example, when the still image shooting mode is selected by the mode switching dial 26 when the moving image shooting operation button 24 is pressed, the operation mode is automatically set to the still image shooting mode after the moving image shooting operation button 24 is pressed again. Migrate to

  The shutter button 30 is operated by the user during shooting. When the shutter button 30 is operated, a timing signal is output to the body microcomputer 10. The shutter button 30 is a two-stage switch that can be pressed halfway and fully. When the user performs a half-press operation, photometry processing and distance measurement processing are started. When the user fully presses the shutter button 30 while the shutter button 30 is half-pressed, a timing signal is output, and the image acquisition unit 35 acquires image data.

  Further, as shown in FIG. 2, a lens removal button 99 (an example of a lens removal operation unit and an example of a preliminary operation detection unit) for removing the interchangeable lens unit 2 from the camera body 3 is provided on the front surface of the camera body 3. It has been. The lens removal button 99 has, for example, a contact (not shown) that is turned on when pressed by the user, and is electrically connected to the body microcomputer 10. When the lens removal button 99 is pressed, the built-in contact is turned on, and the body microcomputer 10 can recognize that the lens removal button 99 has been pressed.

(4) Image Acquisition Unit The image acquisition unit 35 mainly includes an image sensor 11 (an example of an image sensor) such as a CCD (Charge Coupled Device) that performs photoelectric conversion, and a shutter unit 33 that adjusts the exposure state of the image sensor 11. The shutter control unit 31 controls the drive of the shutter unit 33 based on the control signal from the body microcomputer 10, and the image sensor drive control unit 12 controls the operation of the image sensor 11.

  The imaging sensor 11 is, for example, a CCD (Charge Coupled Device) sensor that converts an optical image formed by the optical system L into an electrical signal. The image sensor 11 is driven and controlled by a timing signal generated by the image sensor drive control unit 12. The imaging sensor 11 may be a CMOS (Complementary Metal Oxide Semiconductor) sensor.

  The shutter control unit 31 drives the shutter drive actuator 32 and operates the shutter unit 33 according to the control signal output from the body microcomputer 10 that has received the timing signal.

  In the present embodiment, a contrast detection method using image data generated by the image sensor 11 is employed as the autofocus method. By using the contrast detection method, highly accurate focus adjustment can be realized.

(5) Body Microcomputer The body microcomputer 10 is a control device that controls the center of the camera body 3 and controls each part of the digital camera 1 according to the operation information input to the operation unit 39. Specifically, the body microcomputer 10 is equipped with a CPU, a ROM, and a RAM, and the body microcomputer 10 can realize various functions by reading a program stored in the ROM into the CPU. For example, the body microcomputer 10 acquires a function for detecting that the interchangeable lens unit 2 is attached to the camera body 3 or information necessary for controlling the digital camera 1 such as focal length information from the interchangeable lens unit 2. It has a function.

  The body microcomputer 10 can receive signals from the power switch 25, the shutter button 30, the mode switching dial 26, the cross operation key 27, the menu setting button 28, and the setting button 29, respectively. Various information regarding the camera body 3 is stored in the memory 10 a in the body microcomputer 10. The memory 10a is a non-volatile memory and can hold stored information even when power supply is stopped.

  The body microcomputer 10 periodically generates a vertical synchronization signal, and generates an exposure synchronization signal based on the vertical synchronization signal in parallel with the generation of the vertical synchronization signal. Since the body microcomputer 10 knows in advance the exposure start timing and exposure end timing based on the vertical synchronization signal, the body microcomputer 10 can generate the exposure synchronization signal. The body microcomputer 10 outputs a vertical synchronization signal to a timing generator (not shown), and outputs an exposure synchronization signal to the lens microcomputer 40 via the body mount 4 and the lens mount 95 at a constant cycle. The lens microcomputer 40 acquires positional information of the second lens group support frame 53, the fourth lens group support frame 55, and the fifth lens group support frame 56 in synchronization with the exposure synchronization signal.

  The image sensor drive control unit 12 generates a read signal of the image sensor 11 and an electronic shutter drive signal at a constant period based on the vertical synchronization signal. The image sensor drive control unit 12 drives the image sensor 11 based on the readout signal and the electronic shutter drive signal. That is, the imaging sensor 11 reads out pixel data generated by a large number of photoelectric conversion elements (not shown) in the imaging sensor 11 to a vertical transfer unit (not shown) in accordance with the readout signal.

  Further, the body microcomputer 10 controls the focus adjustment units 72, 73 and 74 via the lens microcomputer 40.

  The image signal output from the image sensor 11 is sequentially sent from the analog signal processing unit 13 to the A / D conversion unit 14, the digital signal processing unit 15, the buffer memory 16, and the image compression unit 17 for processing. The analog signal processing unit 13 performs analog signal processing such as gamma processing on the image signal output from the imaging sensor 11. The A / D conversion unit 14 converts the analog signal output from the analog signal processing unit 13 into a digital signal. The digital signal processing unit 15 performs digital signal processing such as noise removal and edge enhancement on the image signal converted into a digital signal by the A / D conversion unit 14. The buffer memory 16 is a RAM (Random Access Memory) and temporarily stores an image signal. The image signals stored in the buffer memory 16 are sequentially sent from the image compression unit 17 to the image recording unit 18 for processing. The image signal stored in the buffer memory 16 is read by an instruction of the image recording control unit 19 and transmitted to the image compression unit 17. The image signal data transmitted to the image compression unit 17 is compressed into an image signal in accordance with an instruction from the image recording control unit 19. The image signal has a smaller data size than the original data by this compression processing. As a method for compressing an image signal, for example, a JPEG (Joint Photographic Experts Group) method for compressing each frame image signal is used. Thereafter, the compressed image signal is recorded in the image recording unit 18 by the image recording control unit 19. Here, when a moving image is recorded, a JPEG method in which a plurality of image signals are compressed for each image signal of one frame can be used. H.264 / AVC format can also be used.

  The image recording unit 18 creates a still image file or a moving image file by associating an image signal with predetermined information to be recorded based on an instruction from the image recording control unit 19. Then, the image recording unit 18 records a still image file or a moving image file based on a command from the image recording control unit 19. The image recording unit 18 is, for example, an internal memory and / or a detachable removable memory. Note that the predetermined information to be recorded together with the image signal includes date and time when the image was captured, focal length information, shutter speed information, aperture value information, and shooting mode information. The still image file has a format similar to, for example, the Exif (registered trademark) format or the Exif (registered trademark) format. The moving image file is, for example, H.264. H.264 / AVC format and H.264 format. This format is similar to the H.264 / AVC format.

(6) Image Display Unit The image display unit 36 includes a display unit 20 and an image display control unit 21. The display unit 20 is a liquid crystal monitor, for example. The display unit 20 displays the image signal recorded in the image recording unit 18 or the buffer memory 16 as a visible image based on a command from the image display control unit 21. As a display form on the display unit 20, a display form in which only an image signal is displayed as a visible image and a display form in which the image signal and information at the time of photographing are displayed as a visible image are conceivable.

(7) Finder Unit The finder unit 38 includes a liquid crystal finder 8 that displays an image acquired by the imaging sensor 11, and a finder eyepiece window 9 provided on the back surface of the housing 3a. The user can view the image displayed on the liquid crystal finder 8 by looking through the finder eyepiece window 9.

(8) Battery The battery 22 supplies power to each part of the camera body 3 and further supplies power to the interchangeable lens unit 2 via the lens mount 95. In the present embodiment, the battery 22 is a rechargeable battery. The battery 22 may be a dry cell or an external power source that is externally powered by a power cord.

<Operation of digital camera>
The operation of the digital camera 1 will be described.

(1) Shooting mode The digital camera 1 has two shooting modes. Specifically, the digital camera 1 has a finder photographing mode in which the user observes the subject through the finder eyepiece window 9 and a monitor photographing mode in which the user observes the subject through the display unit 20.

  In the finder shooting mode, for example, the image display control unit 21 drives the liquid crystal finder 8. As a result, an image of the subject (so-called through image) acquired by the image sensor 11 is displayed on the liquid crystal finder 8.

  In the monitor photographing mode, for example, the display unit 20 is driven by the image display control unit 21, and a real-time image of the subject is displayed on the display unit 20. Switching between the two shooting modes can be performed by a shooting mode switching button 34.

(2) Still Image Shooting The body microcomputer 10 sets the aperture value of the optical system L to the aperture value calculated based on the photometric output of the image sensor 11 when the shutter button 30 is fully pressed by the user. A command is transmitted to the lens microcomputer 40. Then, the aperture driving control unit 42 is controlled by the lens microcomputer 40, and the aperture unit 62 is narrowed down to the instructed aperture value. Simultaneously with the aperture value instruction, a drive command is transmitted from the image sensor drive control unit 12 to the image sensor 11, and a drive command for the shutter unit 33 is transmitted. The image sensor 11 is exposed by the shutter unit 33 for the time of the shutter speed calculated based on the photometric output of the image sensor 11.

  When the operation mode of the shake correction unit 76 is ON, the shake correction unit 76 performs a shake correction operation to be described later at least while the image sensor 11 is exposed.

  The body microcomputer 10 executes a photographing process and transmits a control signal to the image recording control unit 19 when the photographing is completed. The image recording unit 18 records the image signal in the internal memory and / or the removable memory based on a command from the image recording control unit 19. The image recording unit 18 records information on the shooting mode (autofocus shooting mode or manual focus shooting mode) in the internal memory and / or the removable memory together with the image signal based on a command from the image recording control unit 19.

  Further, after the exposure is completed, the imaging sensor drive control unit 12 reads out image data from the imaging sensor 11, and after predetermined image processing, the image data is output to the image display control unit 21 via the body microcomputer 10. As a result, the captured image is displayed on the display unit 20.

  Further, after the exposure is completed, the shutter unit 33 is reset to the initial position by the body microcomputer 10. Further, a command is issued from the body microcomputer 10 to the lens microcomputer 40 to the diaphragm drive control unit 42 to reset the diaphragm unit 62 to the open position, and a reset command is issued from the lens microcomputer 40 to each unit. After the reset is completed, the lens microcomputer 40 notifies the reset to the body microcomputer 10. The body microcomputer 10 confirms that the shutter button 30 has not been pressed after receiving the reset completion information from the lens microcomputer 40 and completing a series of processes after exposure, and ends the photographing sequence. To do.

(4) Movie shooting The digital camera 1 also has a function of shooting a movie. In the moving image shooting mode, image data is generated by the imaging sensor 11 at a constant cycle, and autofocus by a contrast detection method is continuously performed using the generated image data. In the movie shooting mode, when the shutter button 30 or the movie shooting operation button 24 is pressed, a movie is recorded in the image recording unit 18, and when the shutter button 30 or the movie shooting operation button 24 is pressed again, the image is recorded. Recording of the moving image in the recording unit 18 stops.

  When the operation mode of the shake correction unit 76 is ON, the shake correction unit 76 performs a shake correction operation to be described later at least while a moving image is recorded.

(5) Shake Correction Operation Shake applied to the digital camera 1 is detected by the shake detection unit. The shake detection unit includes a first angular velocity sensor that detects shake in the pitching direction (Y direction) and a second angular velocity sensor that detects shake in the yawing direction (X direction). The shake correction microcomputer 48 integrates the output signals obtained by the first angular velocity sensor and the second angular velocity sensor with respect to time and converts them into shake angle information of the digital camera 1 in the pitching direction and yawing direction. The shake correction microcomputer 48 calculates target position information of the third lens group G3 for returning the movement of the optical image on the imaging surface caused by the shake of the digital camera 1 based on the shake angle information. In order to move the third lens group G3 in accordance with the target position information, the shake correction microcomputer 48 determines the difference between the target position information and the current position information of the third lens group G3 detected by the position detection sensor 47. And a signal is transmitted to a pitch actuator (not shown) and / or a yaw actuator (not shown).

  The pitch actuator and / or the yaw actuator drives the third lens group G3 based on this signal. Thus, the shake of the subject image caused by the shake of the digital camera 1 is corrected.

[Other Embodiments]
Embodiments of the present invention are not limited to the above-described embodiments, and various modifications and changes can be made without departing from the spirit of the present invention. The above-described embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

(1)
In the above-described embodiment, the digital camera can shoot still images and moving images. However, the digital camera may only shoot still images or only moving images.

(2)
In the above-described embodiment, the digital camera may be, for example, a digital still camera, a digital video camera, a camera phone, and a camera PDA.

(3)
The digital camera 1 described above does not have a quick return mirror, but a quick return mirror may be mounted like a conventional single-lens reflex camera.

(4)
The configuration of the optical system L is not limited to the above-described embodiment. For example, the third lens group G3 may be composed of a plurality of lenses, or the sixth lens group G6 may not be provided.

(5)
In the above-described embodiment, the exposure time to the image sensor 11 is controlled by operating the shutter unit 33. However, the exposure time of the image sensor 11 may be controlled by an electronic shutter.

(6)
In the above-described embodiment, there are three focus adjustment units. However, any number of focus adjustment units may be used as long as the number is two or more.

(7)
The interchangeable lens unit 2 described above (an example of a lens barrel) is a single focus optical system, but may be a zoom optical system in which the focal length can be changed.

(8)
The first focus motor 63, the second focus motor 64, and the third focus motor 65 may be other actuators than the stepping motor. For example, the actuator is an electromagnetic motor, a voice coil motor, a vibration type actuator using a piezoelectric element, or the like.

(9)
The focus lens drive control unit 41 may control the first focus motor 63 so as to drive only the second lens group G2 back and forth in the optical axis AZ direction during the wobbling operation. Further, the focus lens drive control unit 41 may control the second focus motor 64 so as to drive only the fourth lens group G4 back and forth in the optical axis AZ direction during the wobbling operation. Preferably, the focus lens drive control unit 41 controls the third focus motor 65 so as to drive only the fifth lens group G5 back and forth in the optical axis AZ direction during the wobbling operation. This is because the fifth lens group G5 is the lightest of the plurality of focus lens groups G2, G4, G5.

(10)
The aperture drive motor may not be a stepping motor but may be another actuator. For example, the actuator is an electromagnetic motor, a voice coil motor, a vibration type actuator using a piezoelectric element, or the like.

[Features of the embodiment]
The features of the embodiment are listed below. The invention included in the embodiment is not limited to the following. In addition, what was described in parentheses after each configuration is a specific example of each configuration described to help understanding of the features. Each configuration is not limited to these specific examples. In addition, in order to obtain the effects described for each feature, configurations other than the described features may be modified or deleted.

(F1)
A plurality of focus lens groups (G2, G4, G5) that change the shooting distance by moving in the optical axis direction;
A lens barrel (2) comprising a plurality of focus actuators (63, 64, 65) for respectively driving the focus lens groups;
An aperture (62);
An aperture actuator that drives the aperture to change the aperture shape; and
And a control unit (42) for controlling to change the aperture shape according to the shooting distance.

  Accordingly, it is possible to provide a lens barrel that can stop the aperture driving during wobbling and that does not change in luminance during the wobbling operation.

(F2)
A plurality of focus lens groups (G2, G4, G5) that change the shooting distance by moving in the optical axis direction;
A lens barrel (2) comprising a plurality of focus actuators (63, 64, 65) for respectively driving the focus lens groups;
And a control unit (41) having a wobbling mode for controlling only one focus lens group to reciprocate back and forth in the optical axis direction among the plurality of focus lens groups.

  Accordingly, it is possible to provide a lens barrel suitable for the wobbling operation, in which the image magnification change due to the wobbling operation, the driving sound, and the power consumption are small.

(F3)
A plurality of focus lens groups (G2, G4, G5) that change the shooting distance by moving in the optical axis direction;
A lens barrel (2) comprising a plurality of focus actuators (63, 64, 65) for respectively driving the focus lens groups;
Each of the plurality of focus lens groups has a constant moving direction when the shooting distance is changed from infinity to the closest distance.

  As a result, when driving the focus lens group to the in-focus position, it is not necessary to reverse the drive direction of the focus lens group, so that it is not affected by the hysteresis of the focus actuator or drive mechanism, and the AF accuracy can be improved. It becomes.

(F4)
A plurality of focus lens groups (G2, G4, G5) that change the shooting distance by moving in the optical axis direction;
A lens barrel (2) comprising a plurality of focus actuators (63, 64, 65) for respectively driving the focus lens groups;
An aperture (62);
A shake correction lens group (G3) that is disposed closer to the subject than the stop and is movable in a direction perpendicular to the optical axis;
The plurality of focus actuators are disposed closer to the imaging surface than the diaphragm.

  As a result, it is not necessary to dispose the mechanism unit for driving the shake correction lens group away from the focus actuator, so that the lens barrel can be reduced in size.

  The present invention is suitable for a lens barrel such as an imaging device.

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Interchangeable lens unit 3 Camera main body 3a Case 4 Body mount 10 Body microcomputer 11 Image sensor (an example of an image sensor)
12 Image sensor drive control unit 20 Display unit 21 Image display control unit 22 Battery (an example of a main power source)
40 lens microcomputer 41 focus lens drive control unit 42 aperture drive control unit 46 electromagnetic actuator 47 position detection sensor 48 shake correction microcomputer 50 fixed frame 51 guide pole support frame 52 first lens group support frame 53 second lens group support frame 54 first 3 lens group support frame 55 4th lens group support frame 56 5th lens group support frame 57 6th lens group support frame 58 1st rack 59 2nd rack 60 3rd rack 61 front frame 62 aperture unit (an example of aperture)
63 First focus motor (an example of a focus actuator)
64 Second focus motor (an example of a focus actuator)
65 Third focus motor (an example of a focus actuator)
66 First photo sensor (an example of a position sensor)
67 Second photosensor (an example of a position sensor)
68 Third photosensor (an example of a position sensor)
71 Lens support mechanism 72 First focus adjustment unit 73 Second focus adjustment unit 74 Third focus adjustment unit 75 Aperture adjustment unit 76 Shake correction unit (an example of shake correction device)
88 Focus ring unit 89 Focus ring 90 Focus ring angle detector 91 Lens side contact 95 Lens mount 99 Lens removal button L Optical system G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth Lens group G6 6th lens group

Claims (4)

A plurality of focus lens groups that change the shooting distance by moving in the direction of the optical axis,
A plurality of focus actuators each driving the focus lens group;
A control unit having a wobbling mode for controlling only one focus lens group to reciprocate back and forth in the optical axis direction among the plurality of focus lens groups.
Lens barrel. An aperture actuator that drives the aperture to change the aperture and aperture shape;
And a control unit that controls to change the aperture shape according to the shooting distance,
The lens barrel according to claim 1. Each of the plurality of focus lens groups has a constant direction of movement when the shooting distance is changed from infinity to the closest distance.
The lens barrel according to claim 1 or 2. Aperture,
A shake correction lens group that is disposed closer to the subject than the stop and is movable in a direction perpendicular to the optical axis,
The plurality of focus actuators are disposed closer to the imaging surface than the diaphragm.
The lens barrel according to claim 1.

Images