JP2013188069A - Electronic camera and lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera that achieves a sure wobbling operation when taking a moving image.SOLUTION: An electronic camera 1 includes: lens barrels 20 and 220; a camera body 40 having an imaging setting section 90 to permit selection of a moving image taking mode; and a control section 100 disposed on either the lens barrels 20 and 220 or the camera body 40. The lens barrels 20 and 220 include first actuators 50 and 250 for moving first moving bodies 29 and 229 whose one end is connected to a first electromechanical conversion element 51 by being expanded and contracted upon application of a DC voltage to the first electromechanical conversion element 51, and which hold an imaging lens L1. When the moving image taking mode is selected in the imaging setting section 90 of the camera body 40, the control section 100 causes wobbling driving for the imaging lens L1 using the first actuators 50 and 250 in the lens barrels 20 and 220.

Description

  The present invention relates to an electronic camera and a lens barrel.

In recent years, some electronic cameras having an interchangeable lens equipped with a vibration wave motor have taken not only still images but also moving images (see, for example, Patent Document 1). In an electronic camera that performs such a moving image, a wobbling operation that is unique to moving image shooting is performed.
In this wobbling operation, a small wobbling amplitude is required because the focal depth is shallow when the focal length is large. Further, when the focal length is small, the depth of focus is deep, so that a large wobbling amplitude is required.

JP 2009-153286 A

  In particular, when the focal length is large, the wobbling amplitude is small, and mechanical backlash and the like exist, so that there is a problem that position accuracy and speed control become very difficult.

  An object of the present invention is to solve such problems and to provide an electronic camera and a lens barrel that can perform a reliable wobbling operation during moving image shooting.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

According to the first aspect of the present invention, by applying a DC voltage to the first electromechanical transducer (51) to expand and contract, one end is joined to the first electromechanical transducer (51) and a photographing lens ( L1) The lens barrel (20, 220) having the first actuator (50, 250) for moving the first moving body (29, 229) holding the photographing unit and the shooting setting unit (90) capable of selecting the moving image shooting mode In the electronic camera (1) comprising: a camera body (40) having a control unit (100) provided on one of the lens barrel (20, 220) and the camera body (40). When the moving image shooting mode is selected in the shooting setting unit (90) of the camera body (40), the unit (100) is configured to move the first actuator in the lens barrel (20, 220). 50, 250) to carry out the wobbling drive of the photographing lens (L1) using an electronic camera (1), characterized in.
According to a second aspect of the present invention, in the electronic camera (1) according to the first aspect, the lens barrel (20, 220) includes a second electromechanical transducer (13, 213) excited by a drive signal. An elastic body (12, 212) that is joined to the second electromechanical transducer (13, 213) and generates a traveling vibration wave on the drive surface (12a) by the excitation, and the elastic body (12, 212). A second surface that has a sliding surface (20, 220) in pressure contact with the driving surface (12a), is driven by the progressive vibration wave, and generates a driving force for the photographing lens (L1) by the driving. A movable body (15, 215), and a second actuator (10, 210) capable of driving the wobbling of the photographing lens (L1). The control unit (100) includes the first actuator (50,250) Other switches the said second actuator (10, 210), to carry out the wobbling driven by either an electronic camera (1), characterized in.
According to a third aspect of the present invention, in the electronic camera (1) according to the second aspect, the lens barrel (20, 220) has a zoom lens mechanism, and the control unit (100) has a predetermined focus. When the distance is greater than the distance, the wobbling drive is performed by the first actuator (50, 250). When the focal length is less than the predetermined focal length, the wobbling drive is performed by the second actuator (10, 210). This is an electronic camera (1).
According to a fourth aspect of the present invention, in the electronic camera (1) according to the second or third aspect, the control unit (100) is a single drive for the first actuator (50, 250). The position of the first moving body (29, 229) is controlled by changing the voltage of the signal. For the second actuator (10, 210), the phase difference value and the driving frequency of two frequency driving signals are used. The electronic camera (1) is characterized in that the speed of the second moving body (15, 215) is controlled by changing a value.
According to the fifth aspect of the present invention, by applying a DC voltage to the first electromechanical transducer (51) to expand and contract, one end is joined to the first electromechanical transducer (51) and a photographing lens ( A lens barrel (20, 220) including a first actuator (50, 250) for moving a first moving body (29, 229) holding L1).
The invention described in claim 6 is the lens barrel (20, 220) according to claim 5, wherein the lens barrel (20, 220) is a shooting setting section (90) capable of selecting a moving image shooting mode. ) Can be attached to and detached from the camera body (40), and when the moving image shooting mode is selected in the shooting setting section (90) of the camera body (40), the first actuator (50, 250) is The lens barrel (20, 220) is characterized in that wobbling driving of the used photographing lens (L1) is performed.
Note that the configuration described with reference numerals may be modified as appropriate, and at least a part of the configuration may be replaced with another component.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic camera and lens barrel which can perform a reliable wobbling operation | movement at the time of video recording can be provided.

It is a figure explaining the electronic camera of 1st embodiment. It is a figure explaining the lens-barrel of 1st embodiment. It is a perspective view of an elastic body and a mover. It is a figure explaining the 1st actuator of 1st embodiment, (a) is voltage = 0V, (b) is-to terminal A,-terminal B is set to GND, (c) is the state shrunk in the optical axis direction, The terminal A is +, the terminal B is GND, and is extended in the optical axis direction. It is a figure explaining arrangement | positioning of a 1st actuator. It is a block diagram explaining the 2nd actuator of 1st embodiment, and the drive device of a 1st actuator. It is a flowchart explaining switching of the control method with respect to the imaging | photography information and focal distance information from a lens or a camera in this embodiment. It is a figure which shows the phase difference of a 2nd actuator, the relationship between a frequency, and rotational speed. It is a figure explaining the relationship of the moving speed and position of a 2nd actuator, a 1st actuator, and a lens in time series when a moving image mode is selected and a focal distance is larger than d. It is a figure explaining the relationship of the moving speed and position of a 2nd actuator, a 1st actuator, and a lens in time series when a moving image mode is selected and a focal distance is smaller than d. It is a figure explaining the lens-barrel of 2nd embodiment of this invention. It is a figure explaining the 2nd actuator of 2nd embodiment. It is a figure explaining operation | movement of the 2nd actuator of 2nd embodiment.

Hereinafter, an embodiment of an electronic camera 1 according to the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a diagram illustrating an electronic camera 1 according to a first embodiment of the present invention.
The electronic camera 1 according to the present embodiment includes an imaging optical system (lens barrel) 20 and a camera body 40. The camera body 40 includes an imaging device 30, an AFE (Analog front end) circuit 60, an image processing unit 70, and a sound detection unit 80. Furthermore, the electronic camera 1 includes an operation member 90, a buffer memory 110, a recording interface 120, a memory 130, a monitor 140, and a CPU 100, and can be connected to a PC 150 as an external device.

  The lens barrel 20 is composed of a plurality of optical lens groups, and forms a subject image on the light receiving surface of the image sensor 30. In FIG. 1, the optical lens system is simplified and illustrated as a single lens. As will be described later, in the optical lens system, the driving unit of the optical lens L1 for AF has a structure in which the first actuator 50 is mounted on the moving element 15 of the second actuator 10.

The exposure time (shutter speed) to the image sensor 30 is determined by the operation member 90 or the state of the image.
The image sensor 30 is configured by a CMOS image sensor or the like in which light receiving elements are two-dimensionally arranged on a light receiving surface. The image sensor 30 photoelectrically converts the subject increase caused by the light beam that has passed through the imaging optical system 20 to generate an analog image signal. The analog image signal is input to the AFE circuit 60.

  The AFE circuit 60 performs gain adjustment (signal amplification according to ISO sensitivity) for the analog image signal. Specifically, the imaging sensitivity is changed within a predetermined range in accordance with a sensitivity setting instruction from the CPU 100. The AFE circuit 60 further converts the image signal after analog processing into digital data by a built-in A / D conversion circuit. The digital data is input to the image processing unit 70.

The image processing unit 70 performs various types of image processing on the digital image data.
The buffer memory 110 temporarily records image data in the pre-process and post-process of image processing by the image processing unit 70.

  The sound detection unit 80 includes a microphone and a signal amplification unit, detects and captures sound from the subject direction mainly during moving image shooting, and transmits the data to the CPU 100. The voice detection unit 80 may be a built-in microphone of the electronic camera 1 or an external microphone attached to the contact point of the electronic camera 1. When an external microphone is attached, it can be detected.

The operation member 90 indicates a mode dial, a cross key, an enter button, and a release button, and sends an operation signal corresponding to each operation to the CPU 100.
Selection of still image shooting or moving image shooting is also performed by the operation member 90, and an operation signal corresponding to the selection operation is sent to the CPU 100.

The CPU 100 comprehensively controls operations performed by the electronic camera 1 by executing a program stored in a ROM (not shown). For example, AF (autofocus) operation control, AE (automatic exposure) operation control, auto white balance control, and the like are performed.
Here, the AF (autofocus) operation control is performed based on the operation signal sent from the operation member 90 or the focal distance, and the second actuator 10 or the first actuator 50 is applied to the driving device 160 of the lens barrel 20 described later. It is assumed that the operation control of whether or not to drive is included.

  The recording interface 120 has a connector (not shown), and a recording medium is connected to the connector, and data is written to and read from the connected recording medium.

The memory 130 records a series of image data subjected to image processing.
In the electronic camera 1 having such a configuration, the present invention captures an image corresponding to a moving image.
The monitor 140 is composed of a liquid crystal panel, and displays an image, an operation menu, and the like according to an instruction from the CPU 100.

  FIG. 2 is a diagram illustrating the lens barrel 20 according to the first embodiment of the present invention, and is a view showing a state in which the second actuator 10 and the first actuator 50 are incorporated in the lens barrel 20.

First, the configuration of the second actuator 10 will be described.
The vibrator 11 includes an electromechanical conversion element (hereinafter, referred to as a piezoelectric body) 13 such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and an elastic body 12 to which the piezoelectric body 13 is bonded. It is configured. Although a traveling wave is generated in the vibrator 11, this embodiment will be described as a traveling wave of 9 waves as an example.

  The elastic body 12 is made of a metal material having a high resonance sharpness, has an annular shape as shown in FIG. 3, and has a groove cut on the opposite surface to which the piezoelectric body 13 is joined. The tip end surface of the protruding portion (the portion where there is no groove) becomes the driving surface 12a and is brought into pressure contact with the sliding surface 15a of the moving element 15. The reason for cutting the groove is to make the neutral surface of the traveling wave as close to the piezoelectric body 13 as possible, thereby amplifying the amplitude of the traveling wave on the drive surface 12a. The surface of the drive surface 12a of the elastic body 12 is provided with a lubricating coating film for ensuring drive performance and improving durability.

  The piezoelectric body 13 is divided into two phases (A phase and B phase) along the circumferential direction. In each phase, elements in which polarization is alternated are arranged every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.

  The piezoelectric body 13 is generally made of a material such as lead zirconate titanate, commonly called PZT. In recent years, lead-free materials such as potassium sodium niobate, potassium niobate, and sodium niobate are used because of environmental problems. , Barium titanate, bismuth sodium titanate, potassium bismuth titanate and the like.

A non-woven fabric 16, a pressure plate 17, and a pressure member 18 are disposed on the opposite side of the piezoelectric body 13 from the side where the mover 15 is disposed.
The nonwoven fabric 16 is an example of felt, and is disposed adjacent to the piezoelectric body 13 to prevent the vibration of the vibrating body from being transmitted to the pressure plate 17 and the pressure member 18.

The pressure plate 17 is pressurized by the pressure member 18.
The pressure member 18 is disposed below the pressure plate 17 and generates pressure. In this embodiment, the pressure member 18 is a disc spring, but it may be a coil spring or a wave spring instead of a disc spring. The pressure member 18 is held by being fixed to the fixing member 21 via the pressing ring 19.

The mover 15 is made of a light metal such as aluminum, and a sliding material for improving wear resistance is provided on the surface of the sliding surface 15a (see FIG. 3).
A vibration absorbing member 22 made of rubber or the like is disposed on the opposite side of the moving element 15 from the vibrator side, and an output transmission member 23 is further disposed to absorb vibrations in the vertical direction of the moving element 15.

The output transmission member 23 regulates the pressurization direction and the radial direction by a bearing 24 provided on the fixed member 21, thereby regulating the pressurization direction and the radial direction of the moving element 15. .
The output transmission member 23 has a protrusion 25, and a fork 27 connected to the cam ring 26 is engaged with the protrusion 25, and the cam ring 26 is rotated as the output transmission member 23 rotates. .

  A key groove 26a is obliquely cut in the cam ring 26, and a fixing pin 28a provided in the AF ring 28 is engaged with the key groove 26a. The AF ring 28 is driven in the straight direction in the axial direction and can be stopped at a desired position. A first actuator 50 is mounted on the AF ring 28.

  The holding ring 19 is attached to the fixing member 21 with a screw, and by attaching this, the components from the output transmission member 23 to the moving element 15, the vibrator 11, and the spring can be configured as one motor unit.

Next, the first actuator 50 mounted on the AF ring 28 will be described.
The first actuator 50 is provided between the AF ring 28 and the AF lens holding unit 29. The first actuator 50, the AF ring 28, and the AF lens holding portion 29 are driven in the optical axis direction while rotating together.
Note that the lens barrel 20 of the present embodiment is a zoom lens and also includes a zoom lens group L2.

FIG. 4 is a diagram illustrating the first actuator 50 of the present embodiment.
Four layers of rectangular piezoelectric plates 51 whose polarization directions are processed in the thickness direction are stacked, and a voltage is applied between the thicknesses to expand and contract in the thickness direction.
FIG. 4A shows a state where the voltage = 0V. FIG. 4B shows a state in which the terminal A is − and the terminal B is GND, and is contracted in the optical axis direction. (C) is a state in which the terminal A is + and the terminal B is GND, and is extended in the optical axis direction. Since the voltage and the expansion / contraction amount are substantially proportional, the expansion / contraction amount is controlled by the voltage value.

FIG. 5 is a diagram for explaining the arrangement of the first actuators 50.
Joined between the end face of the AF ring 28 and the end face of the AF lens holding portion 29, four places are provided.
In the present embodiment, the first actuator 50 has four layers, but the same effect can be achieved with dozens of layers such as six layers, eight layers,. If there are many layers and the thickness is small, a large amount of expansion and contraction can be obtained at a low voltage.

FIG. 6 is a block diagram illustrating the driving device 160 for the second actuator 10 and the first actuator 50 according to the first embodiment.
First, driving / control of the second actuator 10 will be described.

The second oscillating unit 112 generates a drive signal having a desired frequency according to a command from the control unit 111.
The phase shift unit 113 divides the drive signal generated by the second oscillation unit 112 into two drive signals having different phases.
The second amplifying unit 114 boosts the two drive signals divided by the phase shift unit 113 to desired voltages, respectively.
The drive signal from the second amplifying unit 114 is transmitted to the second actuator 10, and a traveling wave is generated in the vibrator 11 by the application of the drive signal, so that the moving element 15 is driven.

  The detection unit 115 is configured by an optical encoder, a magnetic encoder, and the like, detects the position and speed of a driven object driven by driving the moving element 15, and transmits the detected value to the control unit 111 as an electric signal. Further, contrast information is also detected during moving image shooting and transmitted to the control unit 111.

The control unit 111 receives shooting information (still image mode / moving image mode, etc.) and a drive command from a lens or a camera, and controls driving of the second actuator 10 and driving of the first actuator 50.
The control unit 111 performs frequency control for the second oscillation unit 112, phase difference control for the phase shift unit 113, and voltage control for the second amplification unit 114 for the second actuator 10.
For the first actuator 50, voltage control to the first oscillation unit 152 is performed.
Further, the drive switching of the first actuator 50 and the second actuator 10 is also performed based on the focal length information from the lens and the camera.

  According to the configuration of the present embodiment, the driving device 160 for the second actuator 10 and the first actuator 50 operates as follows.

  First, photographing information and focal length information from a lens and a camera are transmitted.

(1) When the focal length is larger than a predetermined value in the moving image mode It is set so that both the first actuator 50 and the second actuator 10 are driven. The first actuator 50 is repeatedly given voltages 0, + V, and −V for wobbling driving.

  The voltage value is determined according to the focal length. That is, the greater the focal length, the smaller the wobbling amplitude, so the V value is set smaller. The V value is set according to the focal length as the control unit 111 of the driving device 160 has a V value corresponding to the focal length in advance.

  As for the second actuator 10, the set frequency is transmitted from the control unit 111 to the second oscillation unit 112 based on the contrast information from the lens, camera, or detection unit 115. A driving signal is generated from the second oscillating unit 112, and the signal is divided into two driving signals having a phase difference of 90 degrees by the phase unit, and is amplified to a desired voltage by the second amplifying unit 114.

  The drive signal is applied to the piezoelectric body 13 of the second actuator 10, and the piezoelectric body 13 is excited, and the excitation causes the ninth-order bending vibration to occur in the elastic body 12. The piezoelectric body 13 is divided into an A phase and a B phase, and drive signals are applied to the A phase and the B phase, respectively.

  The positional difference between the 9th order bending vibration generated from the A phase and the 9th order bending vibration generated from the B phase is ¼ wavelength, and the A phase drive signal and the B phase drive signal are different from each other. Since the phase is shifted by 90 degrees, the two bending vibrations are combined into nine traveling waves.

  Elliptic motion occurs at the front of the traveling wave. Therefore, the moving element 15 brought into pressure contact with the driving surface 12a is frictionally driven by this elliptical motion. An optical encoder is disposed in the driving body driven by driving the moving element 15, and an electric pulse is generated therefrom and transmitted to the control unit 111.

  The control unit 111 can obtain the current position and the current speed based on this signal, and the drive frequency of the second oscillation unit 112 is controlled based on the position information, the speed information, and the target position information. Is done.

  In the case of driving in the forward direction, the phase difference between the two drive signals (frequency voltage signals) in the phase shift unit 113 is set to a positive value, for example, +90 degrees, and in the case of driving in the reverse direction, the phase shift unit. The phase difference between the two drive signals (frequency voltage signal) at 113 may be a negative value, for example, -90 degrees.

(2) When the focal length is smaller than a predetermined value in the moving image mode The first actuator 50 is not driven, and only the second actuator 10 is driven.
First, the control unit 111 instructs a drive frequency to the second oscillation unit 112, and a drive signal is generated from the second oscillation unit 112. Further, the control unit 111 instructs the phase shift unit 113 to indicate a phase difference and controls the phase difference of the drive signal to generate wobbling drive.

On the other hand, based on the contrast information from the lens, camera, or detection unit 115, the control unit 111 also controls coarse movement of the second actuator 10.
The control unit 111 instructs the second oscillation unit 112 to specify a drive frequency, and a drive signal is generated from the second oscillation unit 112. The signal is divided into two drive signals having different predetermined phases by the phase unit. The phase difference is controlled by the control unit 111. The two drive signals are amplified to a desired voltage by the second amplifying unit 114.
The voltage value is controlled by the control unit 111. The drive signal is applied to the piezoelectric body 13 of the second actuator 10, and the piezoelectric body 13 is excited, and a traveling wave is generated in the elastic body 12 by the excitation.

(3) In the case of the still image shooting mode The first actuator 50 is not driven, and switching is performed so that only the second actuator 10 is driven.
Based on information from the lens, camera, or detection unit 115, the control unit 111 instructs the second oscillation unit 112 on the drive frequency, and a drive signal is generated from the second oscillation unit 112. The signal is predetermined by the phase unit. It is divided into two drive signals having different phases. The phase difference is controlled by the control unit 111.

  The two drive signals are amplified to a desired voltage by the second amplifying unit 114. The voltage value is controlled by the control unit 111. The drive signal is applied to the piezoelectric body 13 of the second actuator 10, and the piezoelectric body 13 is excited, and a traveling wave is generated in the elastic body 12 by the excitation.

  FIG. 7 is a flowchart illustrating switching of control methods for shooting information and focal length information from lenses and cameras in the present embodiment.

  When the still image mode is selected in step 1 (S1) (S1, NO), still image shooting is driven. That is, only the second actuator 10 is driven and the speed is controlled by the frequency of the drive signal. Switching between normal rotation and inversion switches the phase difference between the two drive signals to +90 degrees / -90 degrees.

When the moving image mode is selected (S1, YES), the process proceeds to S2.
In S2, when the focal length is larger than the desired value d (S2, YES), the first actuator 50 performs the wobbling drive. In the wobbling drive, a drive signal input to the first actuator 50 is controlled by voltage control. The second actuator 10 performs coarse movement, and the coarse movement is controlled by the frequency and voltage of the drive signal and the phase difference between the two drive signals.
When the focal length is smaller than the desired value d (S2, NO), the second actuator 10 performs wobbling driving and coarse movement. The drive control is performed by the frequency and voltage of the drive signal and the phase difference between the two drive signals.

FIG. 8 is a diagram showing the relationship between the phase difference and frequency of the second actuator 10 and the rotational speed.
When the phase difference is +90 degrees, the maximum speed of forward rotation is obtained, and when the phase difference is -90 degrees, the maximum speed of reverse rotation is obtained, and an intermediate phase difference indicates an intermediate speed value.
Further, when the drive frequency is decreased, the rotation speed is increased, and when the frequency is increased, the rotation speed is decreased and becomes zero.
For example, when the phase difference is set to +90 degrees, the rotation speed is higher when the drive frequency is smaller.
In the second actuator 10, the speed control can be performed using both the driving frequency and the phase difference individually or in combination.

  FIG. 9 shows the driving frequency / driving voltage / phase difference of the second actuator 10, the voltage of the first actuator 50, and the moving speed / position of the lens when the moving image mode is selected in this embodiment and the focal length is larger than d. It is a figure explaining the relationship of chronologically.

First, the drive frequency is set to f0 (maximum frequency) and the drive voltage is set to V0 (minimum voltage).
The phase difference of the second actuator 10 is set to 0 degree, and the drive signal is turned ON. : T0
The drive voltage of the second actuator 10 is increased. : T1
The drive voltage of the second actuator 10 is set to V1. : T2

Application start of driving voltage of the first actuator 50 from 0: t4
The wobbling drive starts and the movement of the lens starts.

The driving voltage of the first actuator 50 is + V: t5
The lens stops at the + position and detects contrast (Wbe position).

Application of negative voltage to drive voltage of first actuator 50: t6
The lens starts moving in the negative direction.

The drive voltage of the first actuator 50 is −V: t7
The lens stops at the-position and detects contrast (Waf position).

Application of positive voltage to drive voltage of first actuator 50: t8
The lens starts moving in the positive direction.

The drive voltage of the first actuator 50 is 0: t9
The lens stops at the 0 position and detects contrast (W0 position).

  The wobbling drive of the first actuator 50 is repeated, and one cycle is about 50 msec.

Between t9 and t10, the position of the subject is calculated based on the contrast detection results of the Wbe position, the Waf position, and the W0 position, and driving of the second actuator 10 is determined.
As a result of the contrast between t9 and t10, since the subject position is in the depth of focus, the second actuator 10 is not driven.

  In the subject detection result in FIG. 9, the better contrast is indicated by a smaller value (contrast is better = in focus = 1, and the numerical value decreases as the subject is out of focus). It is shown in.)

The coarse movement of the second actuator 10 will be described. For example, when the result of contrast detection in one cycle of the wobbling operation between t17 and t22 is determined that the subject is in the + direction from the current lens position,
The drive frequency f1 of the second actuator 10 is gradually changed. At the same time, the phase difference is gradually changed to +90 degrees: t22
The lens is driven and the lens position moves in the positive direction.

Phase difference is gradually changed to 0 degrees: t23
The lens stops at a predetermined position.

When the contrast detection result in one cycle of the wobbling operation between t40 and t45 determines that the subject is significantly in the + direction, the driving frequency f2 of the second actuator 10 is further reduced to increase the lens moving speed. Then, the driving amount of the lens is increased.
In the present embodiment, an example is shown in which the lens is coarsely moved in the positive direction. However, when the lens is coarsely moved in the negative direction, the phase difference may be set to −90.

  When the focal length is large, the depth of focus becomes shallow. The wobbling amplitude at the time of moving image may be substantially coincident with the depth of focus. When the focal length is large, the wobbling amplitude becomes small.

  If the wobbling amplitude is very small, for example, if the rotational drive amount of the second actuator 10 is less than the number of angles, speed control and position control become difficult due to the influence of mechanical coupling back up to the AF lens ring. Becomes complicated. Therefore, it is possible to drive with high accuracy by performing the wobbling drive with the first actuator 50 provided in the vicinity of the AF lens.

  Further, by using the first actuator 50, the wobbling drive which is a repetitive repetitive repetitive movement can be easily controlled in voltage, such as giving + voltage, 0 voltage, and -voltage in time series. There are also benefits.

  FIG. 10 shows the driving frequency / driving voltage / phase difference of the second actuator 10, the voltage of the first actuator 50, and the moving speed / position of the lens when the moving image mode is selected in this embodiment and the focal length is smaller than d. It is a figure explaining the relationship of chronologically.

First, the drive frequency is set to f0 (maximum frequency), the drive voltage is set to V0 (minimum voltage), the phase difference is set to +90 degrees, and the drive signal is turned ON. : T0
Increase drive voltage. : T1
The drive voltage is set to V1. : T2
Starting to drive the drive frequency from the maximum frequency f0: t3
The second actuator 10 starts driving while the drive frequency is being pulled.

Set to frequency f1: t4 '
From t4 to t5, the phase difference is +90 degrees, the rotation is positive, and the speed is V.
From t5 to t6, the phase is 0 degree, and the contrast is detected at the Wbe position.
t6 to t7 have a phase difference of −90 degrees, are driven in reverse rotation at a frequency f2, and have a speed of −2 V (twice V). The frequency for increasing the speed is set to f2 smaller than f1.

  The speed at the time of reverse of the wobbling operation is twice that of the normal rotation because the moving amount of the lens position is twice.

From t7 to t8, the phase is 0 degree, and the contrast is detected at the Waf position.
From t8 to t9, the phase difference is +90 degrees, the frequency is f1, the speed is V in the forward rotation drive.
From t9 to t10, the phase is 0 degree, and the contrast is detected at the W0 position.

  Thereafter, the wobbling operation by the second actuator 10 is repeatedly performed. One cycle (between t4 and t10) is a 20 Hz interval (= about 50 msec).

  Between t9 and t10, the position of the subject is calculated based on the detection results of the contrast at the Wbe position, the Waf position, and the W0 position, and the next wobbling operation is determined.

The parameters to determine are
Frequency fs between t10 and t11
Frequency fb between t12 and t13
The frequency fs2 between t14 and t15.

For example, if it is determined that the subject is between wobbling amplitudes (+1 to -1) as a result of contrast detection in one cycle of the wobbling operation between t4 and t10, wobbling is also performed in one cycle of the next wobbling operation. The amplitude is +1 to −1, and the frequency fs = f1, the frequency fb = f2, and the frequency fs2 = f1.
In this case, since the first actuator 50 is not driven, the applied voltage remains zero.

  Also, for example, if the contrast detection result in one cycle of the wobbling operation from t17 to t22 determines that the subject is in the + direction from the current lens position, the speed of the next wobbling operation, t22 to t23 is It is determined that the movement of the lens is 3 times the wobbling amplitude as 3V. In that case, frequency fs = f3 (a frequency smaller than f2), frequency fb = f2, and frequency fs2 = f1.

Furthermore, as another case, when the result of contrast detection in one cycle of the wobbling operation from t34 to t40 is determined that the subject is largely in the + direction from the current lens position, the next wobbling operation is performed at t40 to t41. Is determined to be the movement of the lens 3 times the wobbling amplitude. In that case, the frequency fs = f4 (a frequency smaller than f3), the frequency fb = f2, and the frequency fs2 = f1.
In this way, it is possible to simultaneously perform wobbling driving and coarse movement using a vibration motor.

When the focal length is small, the depth of focus is deep, so the wobbling amplitude is large. When the wobbling amplitude is large, for example, if several tens of μm are required, the driving voltage of the first actuator 50 increases and the power consumption increases.
In some cases, the limit displacement of the first actuator 50 may be exceeded, so it is more efficient to perform both the wobbling drive and the coarse movement by the second actuator 10.

When the wobbling amplitude is large, the influence of the mechanical coupling back up to the AF lens ring can be ignored with respect to the required amplitude amount, so that the second actuator 10 can be implemented.
As described above, the second actuator 10 and the piezoelectric voltage actuator are provided, and the driving method is switched according to the focal length, so that appropriate and efficient wobbling driving can be performed.

(Second embodiment)
FIG. 11 is a diagram illustrating the lens barrel 220 according to the second embodiment of the present invention, and is a diagram showing a state in which the linear second actuator 210 is incorporated in the lens barrel 220.
As illustrated in FIGS. 12 and 13, the vibrator 211 includes a piezoelectric element 213 and projecting portions 251 and 252 for extracting output. The elastic body 212 is designed so that the resonance frequencies of the longitudinal primary vibration and the bending secondary vibration match.

  When a voltage (drive signal) of this frequency is applied to the piezoelectric element 213 and the phases of both vibrations are shifted by 90 °, elliptical motion is generated in the protrusions 251 and 252 by the combination of the excited longitudinal vibration and bending vibration. . Since the protrusions 251 and 252 are in pressure contact with the relative motion member, a driving force is generated by friction. The protrusions 251 and 252 are made of a wear-resistant material and suppress frictional wear.

  The piezoelectric element 213 is generally made of a material such as lead zirconate titanate, commonly called PZT. In recent years, lead-free materials such as potassium sodium niobate, potassium niobate, and sodium niobate are used because of environmental problems. , Barium titanate, bismuth sodium titanate, potassium bismuth titanate and the like.

Next, the configuration of the lens barrel 220 of the second embodiment will be described.
The vibrator 211 is supported in the longitudinal direction at the center of the vibrator 211 by a leaf spring 218 provided on the fixing member 221.

The leaf spring 218 is also a pressure member, and presses the vibrator 211 against the moving element 215.
The fixing member 221 is attached to the fixed cylinder 222, and by attaching, the movable member 215, the vibrator 211, and the leaf spring 218 can be configured as one motor unit.
The mover 215 is made of a light metal such as aluminum, and the surface of the sliding surface is provided with sliding plating for improving wear resistance. The moving element 215 is fixed to the linear guide 223, the linear guide 223 is fixed to the fixed cylinder 222, and the moving element 215 is movable in a linear direction with respect to the fixed cylinder 222.

The mover 215 has a protrusion 225 from which a fork 227 connected to the AF ring 228 is engaged, and the AF ring 228 is driven straight.
The AF ring 228 has a structure that is movable along a straight rail 230 provided in the fixed barrel 232. A guide portion 231 provided on the AF ring 228 is engaged with the straight rail 230, and is driven in the straight direction in the optical axis direction along with the straight drive of the moving element 215 so that it can stop at a desired position. ing.

Next, the first actuator 250 mounted on the AF ring 228 will be described.
The first actuator 250 is provided between the AF ring 228 and the AF lens holding unit 29. The first actuator 250, the AF ring 228, and the AF lens holding unit 229 are driven in the optical axis direction while rotating integrally. Is done.
Note that the lens barrel 220 of the present embodiment is a zoom lens and also has a zoom lens group.

  As in FIG. 5, the first actuator 250 is joined between the end face of the AF ring 228 and the end face of the AF lens holding portion 29 and is provided at four places. The drive circuit also has the same configuration and operation as the first embodiment.

  In the present embodiment, the linear second actuator 210 is used. However, as in the first embodiment, when the moving image mode is selected and the focal length is larger than the desired value d, the first actuator 250 is used. Perform wobbling drive. In the wobbling drive, a drive signal input to the first actuator 250 is controlled by voltage control. The second actuator 210 performs coarse movement, and the coarse movement is controlled by the frequency and voltage of the drive signal and the phase difference between the two drive signals.

When the focal length is smaller than the desired value d, the second actuator 210 performs wobbling driving and coarse movement. The drive control is performed by the frequency and voltage of the drive signal and the phase difference between the two drive signals.
By doing in this way, the effect similar to 1st embodiment is acquired.

  Further, in this embodiment, since the AF ring 228 that is linearly driven is directly driven by the linear second actuator 210, from the rotation to the straight movement as in the case where the annular ultrasonic motor of the first embodiment is mounted. Since the loss that occurs during the conversion is eliminated, the conversion efficiency is improved. Therefore, the efficiency of the entire drive system can be improved.

  1: camera, 10, 210: second actuator, 11, 211: vibrator, 12, 212: elastic body, 13, 213: piezoelectric body, 15, 215: moving element, 15a: sliding surface, 20, 220: Lens barrel, 29, 229: Lens holding part, 50, 250: First actuator, 160: Drive device

Claims (6)

A lens having a first actuator for applying a DC voltage to the first electromechanical conversion element to expand and contract to move a first moving body that has one end joined to the first electromechanical conversion element and holds a photographing lens A lens barrel,
A camera body having a shooting setting section capable of selecting a video shooting mode;
A control unit provided on one of the lens barrel and the camera body;
In an electronic camera equipped with
The control unit, when the moving image shooting mode is selected in the shooting setting unit of the camera body, to perform a wobbling drive of the shooting lens using the first actuator in the lens barrel;
An electronic camera characterized by The electronic camera according to claim 1.
The lens barrel is
A second electromechanical transducer that is excited by a drive signal;
An elastic body bonded to the second electromechanical transducer and generating a progressive vibration wave on the drive surface by the excitation;
A second moving body that has a sliding surface that is in pressure contact with a driving surface of the elastic body, is driven by the progressive vibration wave, and generates a driving force of the photographing lens by the driving;
Have
A second actuator capable of wobbling driving the photographing lens;
The control unit switches the first actuator or the second actuator, and causes the wobbling drive to be performed by either one of them,
An electronic camera characterized by The electronic camera according to claim 2,
The lens barrel has a zoom lens mechanism;
The controller is
If the focal length is greater than the predetermined focal length, the wobbling drive is performed by the first actuator,
If the predetermined focal length or less, wobbling drive by the second actuator,
An electronic camera characterized by The electronic camera according to claim 2 or 3,
The controller is
For the first actuator, the position of the first moving body is controlled by changing the voltage of a single drive signal,
For the second actuator, controlling the speed of the second moving body by changing the phase difference value and the driving frequency value of two frequency driving signals;
An electronic camera characterized by The first electromechanical conversion element is provided with a first actuator that moves a first moving body that holds a photographing lens while one end is joined to the first electromechanical conversion element by applying a DC voltage to the first electromechanical conversion element to expand and contract. ,
A lens barrel characterized by The lens barrel according to claim 5,
The lens barrel can be attached to and detached from the camera body having a shooting setting unit capable of selecting a moving image shooting mode.
When the moving image shooting mode is selected in the shooting setting unit of the camera body,
Wobbling driving of the photographing lens using the first actuator is performed,
A lens barrel characterized by

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