JP2011101559A - Vibration actuator drive unit, lens barrel, and electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration actuator drive unit which reduces noise generated at the drive of a vibration actuator. <P>SOLUTION: The vibration actuator drive unit (14) is equipped with: an output part (144) which outputs a drive signal having a frequency to the vibration actuator; and a control part (141) which causes the output part (144) to perform a first operation for outputting the drive signal to the drive actuator (12) while increasing an amplitude of the drive signal to a preset second amplitude larger than a preset first amplitude from the first amplitude after outputting the drive signal having the first amplitude to the vibration actuator (12), when a signal is given for indicating the drive of the vibration actuator (12). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vibration actuator driving device that drives a vibration actuator, a lens barrel, and an electronic camera.

A vibration wave motor (vibration actuator) is known to be a progressive vibration wave (hereinafter referred to as a traveling wave) on a driving surface of an elastic body by utilizing expansion and contraction of a piezoelectric body, as known in Japanese Patent Publication No. 01-015354 (Patent Document 1). Wave). The generated traveling wave causes an elliptical motion on the drive surface, and the movable element that is in pressure contact with the wavefront of the elliptical motion is driven. Such a vibration wave motor has a feature that it has a high torque even at a low rotation, and when mounted on a drive device, the gear of the drive device can be omitted, so that the gear noise is reduced and silence is achieved. There is an advantage that the positioning accuracy can be improved.
On the other hand, the vibration wave motor has been used as an interchangeable lens for a still camera, but its use has been shifted to an interchangeable lens for an electronic camera due to the recent progress and spread of the electronic camera.

In addition to taking still pictures, electronic cameras are also demanded by the market to be able to take moving pictures and record audio.
Taking an image of a moving image in an electronic camera having an interchangeable lens equipped with a vibration wave motor is disclosed in Patent Document 2 and describes an advantage for quietness.

Japanese Patent Publication No. 01-013544 Japanese Patent Laid-Open No. 08-080073

However, simply using an interchangeable lens equipped with a vibration wave motor does not provide the quietness required when shooting a moving image with an electronic camera. It became clear in the process of developing the camera. Specifically, when driving a lens in autofocus (hereinafter referred to as AF (Auto Focus)) operation, a minute sound generated when a drive signal is applied to a vibration wave motor is detected by a microphone that detects sound. There was a problem of being.
When the inventor analyzed the cause, when driving the vibration wave motor, the moment when the amplitude (peak voltage) of the drive signal applied to the vibration wave motor was changed stepwise from 0 to a certain voltage, the vibration wave motor Therefore, it was clarified that sound (noise) of various frequencies was generated and the audible sound was detected by the microphone, so that the desired quietness could not be obtained.

  The present invention has been made in view of the above problems, and an object thereof is to provide a vibration actuator driving device that reduces noise generated when driving a vibration actuator.

In order to solve the above problem, the present invention has the following solution. 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.
[1] In the present invention, when an output unit (144) for outputting a drive signal having a frequency to the vibration actuator (12) and a signal for instructing driving of the vibration actuator (12) are input, a predetermined value is set. After outputting the drive signal having the first amplitude to the vibration actuator (12), the drive signal is increased while increasing the amplitude of the drive signal from the first amplitude to a predetermined second amplitude larger than the first amplitude. A vibration actuator driving device (14) comprising: a control unit (141) for causing the output unit (144) to perform a first operation of outputting a signal to the vibration actuator (12).

  [2] Further, the present invention is the vibration actuator driving device (14) according to the above invention, wherein the control unit (141) is configured to output the output unit (144) when the vibration actuator (12) is stopped. Reducing the amplitude of the drive signal output from the second amplitude to the first amplitude, and causing the amplification unit (144) to perform a second operation of outputting the drive signal to the vibration actuator (12). Features.

  [3] The present invention is the vibration actuator driving device (14) according to the above-described invention, further comprising an oscillation unit (142) that outputs an oscillation signal having a frequency to the output unit (144), and the output The unit (144) amplifies the oscillation signal output from the oscillation unit (142), outputs the amplified oscillation signal to the vibration actuator as the drive signal, and the control unit (141) includes the vibration actuator ( 12), when a target speed for driving the vibration actuator is selected, a signal indicating a target frequency corresponding to the target speed is output to the oscillation unit (142), and the frequency of the oscillation signal is set to the target speed. The oscillation unit (142) is pulled up to a frequency.

  [4] Further, the present invention is the vibration actuator driving device (14) according to the above invention, wherein an upper limit speed at which the vibration actuator (12) is driven in the first operation is predetermined, When the target speed is faster than the upper limit speed when driving the vibration actuator (12) by the first operation, the control section (141) outputs a frequency corresponding to the upper limit speed to the oscillation section (142). Then, the frequency of the oscillation signal is inserted into the oscillation unit (142) up to a frequency corresponding to the upper limit speed.

  [5] Further, the present invention is the vibration actuator driving device (14) according to the above invention, wherein the control unit (141) receives a signal instructing driving of the vibration actuator (12). The output unit (144) performs a third operation of outputting the drive signal having a third amplitude larger than the first amplitude to the vibration actuator (12).

  [6] Further, the present invention is a lens barrel (10, 10A) attached to an electronic camera (1) capable of recording, the vibration actuator driving device (14) according to the invention, and the vibration actuator. (12), and when the electronic camera (1) performs recording, the control unit (141) selects the first operation, and when the electronic camera (1) does not perform recording, The lens barrel (10, 10A) is characterized by selecting three operations.

  [7] Further, the present invention provides the lens barrel (10, 10A) according to the above invention, wherein the focusing optical system (L3) moves in the optical axis direction without being rotated by the vibration actuator (12). It is characterized by providing.

  [8] The present invention further includes the lens barrel (10, 10A) according to the above invention and a recording processing unit (60) capable of recording using the built-in microphone (70), The control unit (141) selects the first operation when the recording processing unit (60) performs recording, and selects the third operation when the recording processing unit (60) does not perform recording. This is an electronic camera (1).

  [9] The present invention is the electronic camera (1) described above, wherein the recording processing unit is capable of recording voice using an external microphone (210) provided outside, and the control The unit (141) selects the third drive mode when the recording processing unit (60) performs recording using the external microphone (210).

  According to the present invention, it is possible to reduce noise generated when the vibration actuator is driven.

1 is a schematic block diagram showing a configuration of an electronic camera 1 in a first embodiment. It is the schematic which shows the structure of the lens-barrel 10 in the embodiment. It is the schematic which shows the structure of the vibration wave motor 12 in the embodiment. It is a schematic block diagram which shows the structure of the vibration wave motor drive device 14 in the embodiment. It is a flowchart which shows the drive process with respect to the vibration wave motor 12 of the vibration wave motor drive device 14 in the embodiment. 4 is a waveform diagram showing the frequency and amplitude of a drive signal and the rotational speed of a vibration wave motor 12 when a moving image mode is selected in the embodiment. FIG. It is a flowchart which shows the drive process of the vibration wave motor 12 of the vibration wave motor drive device 14 in 2nd Embodiment. 4 is a waveform diagram showing the frequency and amplitude of a drive signal and the rotational speed of a vibration wave motor 12 when a moving image mode is selected in the embodiment. FIG. It is a flowchart which shows the drive process of the vibration wave motor 12 of the vibration wave motor drive device 14 in 3rd Embodiment. It is a flowchart which shows the drive process of the vibration wave motor 12 of the vibration wave motor drive device 14 in 4th Embodiment. It is the schematic which shows the structure of 10 A of lens barrels in 5th Embodiment.

The inventor of the present invention has found that noise is generated when a drive signal is applied to the vibration actuator in order to drive the lens group in the autofocus operation. As a result of the analysis, it was revealed that the noise is sound of various frequencies generated from the piezoelectric body of the vibration actuator at the moment when the voltage of the drive signal is changed stepwise from 0 to a certain voltage value. In addition, it has been discovered that the noise generated changes in accordance with a voltage value that changes the drive signal from 0 in a stepwise manner, and that the sound pressure tends to decrease when the voltage value is low.
Therefore, in this embodiment, in a camera having a recording function, in order to reduce noise generated when a drive signal is applied, a drive signal having a voltage value at which the generated noise is equal to or lower than a desired sound pressure is applied to the vibration actuator. Then, the vibration actuator is driven by gradually changing the voltage to a predetermined voltage.

  Hereinafter, a vibration actuator, a lens barrel, and a camera according to embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic block diagram showing the configuration of the electronic camera 1 in the first embodiment. As shown in the figure, the electronic camera 1 includes a lens barrel 10, an image sensor 20, an AFE (Analog Front End) circuit 30, an image processing unit 40, a buffer memory 50, a recording processing unit 60, and a built-in microphone. 70, a recording IF (Interface) unit 80, a memory 90, a host control unit 100, an operation member 110, and a display unit 120. The electronic camera 1 can be connected to a PC (Personal Computer) 220 that is an external device, and can also be connected to an external microphone 210. The external microphone 210 can be used in place of the built-in microphone 70 when recording.

  As will be described later, the lens barrel 10 has a plurality of optical lenses as an imaging optical system, and forms a subject image on the light receiving surface of the imaging device. In FIG. 1, a plurality of optical lenses are simplified and one lens is shown. The lens barrel 10 includes an optical lens group including a third lens group (focusing optical system) L3, a vibration wave motor 12 as a vibration actuator, and a vibration wave motor drive device 14 as a vibration actuator drive device. I have.

The imaging element 20 is configured by a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) in which the light receiving elements are two-dimensionally arranged on the light receiving surface. Further, the image sensor 20 photoelectrically converts a subject image via the imaging optical system of the lens barrel 10 by a light receiving element to generate an analog image signal, and outputs the analog image signal to the AFE circuit 30.
The AFE circuit 30 performs gain adjustment (signal amplification in accordance with ISO (International Organization for Standardization) sensitivity) for the analog image signal output from the image sensor 20. The AFE circuit 30 amplifies the analog image signal within a predetermined range in accordance with the ISO sensitivity setting information input from the host controller 100, and incorporates an A / D (Analog Digital) conversion. The circuit converts the amplified analog image signal into digital image data and outputs the digital image data to the image processing unit 40.

The image processing unit 40 performs various types of image processing such as noise processing on the digital image data output from the AFE circuit 30. The buffer memory 50 temporarily stores the digital image data in the pre-process and post-process of image processing on the digital image data by the image processing unit 40.
The recording processing unit 60 amplifies the audio signal detected by the built-in microphone 70 built in the electronic camera 1 or the external microphone 210 provided outside the electronic camera 1, and controls the amplified signal as digital audio data. Output to the unit 100. In addition, the recording processing unit 60 detects that the external microphone 210 is connected, and outputs a signal indicating that the external microphone 210 is connected to the upper control unit 100.

The storage IF unit 80 is connected to a recording medium such as a memory card 81 and writes and reads data to and from the connected memory card 81. The memory 90 stores captured digital image data.
The operation member 110 includes a mode dial, a cross key, a determination button, a release button, and the like, and outputs an operation signal corresponding to each operation to the upper control unit 100. Still image shooting and moving image shooting are switched by the operation of the operation member 110 by the user.
The display unit 120 is configured by a liquid crystal panel or the like, and displays data such as images and operation menus input from the host control unit 100.

  The host control unit 100 is configured by a microprocessor or the like, and is executed by the electronic camera 1 by executing a program stored in a ROM (Read Only Memory) (not shown) or an EEPROM (Electrically Erasable Programmable Read Only Memory). Centralized control of processing. The host control unit 100 performs, for example, AF operation control, AE (automatic exposure) operation control, automatic white balance control, and the like. In the AF operation control, the host control unit 100 outputs a drive command signal that causes the vibration wave motor driving device 14 of the lens barrel 10 to drive the vibration wave motor 12 and imaging information.

The host control unit 100 is connected to an external PC 120. The PC 120 is connected to the host controller 100 to read out digital image data and digital audio data stored in the memory 70 via the host controller 100.
Here, the drive command signal is a signal for instructing driving of the vibration wave motor 12, and includes information for driving the vibration wave motor 12. The shooting information includes information indicating either the still image mode or the moving image mode and information indicating whether recording is performed using the built-in microphone 70 or the external microphone 210 in the moving image mode. Here, the still image mode is a mode in which sound is not recorded during imaging, and the moving image mode is a mode in which sound is recorded during imaging.

  FIG. 2 is a schematic view showing a configuration of the lens barrel 10 in the same embodiment. The lens barrel 10 includes an outer fixed cylinder 101 that covers the outer periphery of the lens barrel 10, a first inner fixed cylinder 102 that is positioned closer to the subject on the inner peripheral side than the outer fixed cylinder 101, and the outer fixed cylinder 101. A second inner fixed cylinder 103 positioned on the image side on the inner peripheral side, and between the outer fixed cylinder 101 and the first inner fixed cylinder 102, a vibration wave motor 12, a vibration wave motor driving device 14, A gear unit module 104 that reduces and transmits the rotational speed of the vibration wave motor 12 is disposed and fixed to the first inner fixed cylinder 102. The gear unit module 104 has a reduction gear 105 that reduces and transmits the output of the vibration wave motor 12.

  Further, the first lens group L1 and the second lens group L2 are fixed to the first inner fixed cylinder 102 from the subject side, and the fourth lens group L4 is fixed to the second inner fixed cylinder 103. Between the second lens group L2 and the fourth lens group L4, a third lens group L3 which is an AF lens for focusing held by the AF ring 107 is disposed. That is, the first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4 are sequentially arranged from the subject side to the image sensor side in the optical axis direction.

A cam ring 106 is provided between the AF ring 107 and the first inner fixed cylinder 102 so as to be rotatable about the optical axis direction as a center axis. The cam ring 106 is transmitted to the vibration wave motor 12 transmitted by the reduction gear 105. It rotates by the output of. A key groove 106a is cut in a spiral shape in the circumferential direction inside the cam ring 106. A fixing pin 107 a is provided on the outer peripheral side of the AF ring 107, and the fixing pin 107 a is inserted into the key groove 106 a of the cam ring 106.
In addition, a vibration wave motor drive device 14 is disposed on the holding portion 101 a that protrudes inward from the inner peripheral side of the outer fixed cylinder 101, and the vibration wave motor drive device 14 is electrically connected to the vibration wave motor 12 to vibrate. The wave motor 12 is driven.

  Due to the configuration of the lens barrel 10 described above, the output of the vibration wave motor 12 is rotated by rotating the cam ring 106 via the reduction gear 105, whereby the fixed pin 107 a is guided and moved to the key groove 106 a, and the AF ring 107. The AF ring 107 can be stopped by moving the cam ring 106 in the optical axis direction. That is, by driving the vibration wave motor 12, the AF ring 107 is driven in the optical axis direction and the third lens group L3 is moved, so that a focused subject image can be formed on the image sensor. .

  FIG. 3 is a schematic diagram showing the configuration of the vibration wave motor 12 in the same embodiment. The vibration wave motor 12 includes a vibrator 121, a moving element 124, a fixed member 125, a bearing 126, an output shaft 127, a pressure member 128, a bearing receiving member 129, a stopper 130, a rubber member 131, and a gear member. 132 and a pressure adjusting washer 133 are provided.

  The vibrator 121 includes an electro-mechanical conversion element (hereinafter referred to as a piezoelectric body 123) such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and an elastic body 122 connected to the piezoelectric body 123. When a voltage is applied to the vibrator 121, for example, four traveling waves are generated. The elastic body 122 is made of a metal material having a high resonance sharpness, and has an annular shape. Further, the elastic body 122 is provided with a comb-shaped portion 122a having a groove formed on the opposite surface to which the piezoelectric body 123 is bonded, and a tip surface of the protruding portion (a portion having no groove) serves as a driving surface. The portion 122a is in pressure contact with the movable element 124. Here, the groove is provided in the elastic body 122 in order to amplify the amplitude of the traveling wave on the driving surface of the elastic body 122 by bringing the neutral surface of the traveling wave as close as possible to the piezoelectric body 123 side.

  In the elastic body 122, a portion where no groove is provided is referred to as a base portion 122b. The base portion 122b is joined to the piezoelectric body 123, and the driving surface of the elastic body 122 is lubricated. The piezoelectric body 123 is divided into two phases (A phase and B phase) along the circumferential direction, and in each phase, the polarization is alternately arranged every ½ wavelength, and the A phase Between the polarization and the B phase polarization, a quarter wavelength interval is provided.

The mover 124 is made of a light metal such as aluminum, and the surface of the sliding surface that is in pressure contact with the comb-shaped portion 122a is subjected to surface treatment for improving the friction resistance. The output shaft 127 is coupled to rotate together with the moving element 124 via the rubber member 131. The rubber member 131 is preferably butyl rubber or the like having a function of coupling the moving element 124 and the output shaft 127 with adhesiveness of rubber and a function of absorbing vibration so as not to transmit vibration from the moving element 124 to the output shaft 127. is there.
The pressure member 128 is disposed between the gear member 132 fixed to the output shaft 127 and the bearing receiving member 129. The bearing receiving member 129 is inserted inside the bearing 126, and the bearing 126 is inserted inside the fixing member 125. The gear member 132 is inserted so as to fit in the D cut of the output shaft 127, is fixed by a stopper 130 such as an E clip, and rotates together with the output shaft 127. A pressure adjusting washer 133 is disposed between the pressure member 128 and the bearing receiving member.

  With the above-described configuration, the moving element 124 comes into pressure contact with the vibrating body driving surface, and the moving element 124 and the comb shape are pressed by the pressure adjusting washer 133 disposed between the pressing member 128 and the bearing receiving member 129. The pressure applied to the portion 122a is an appropriate pressure.

  FIG. 4 is a schematic block diagram showing the configuration of the vibration wave motor drive device 14 in the same embodiment. The vibration wave motor drive device 14 includes a control unit 141, an oscillation unit 142, a phase shift unit 143, an amplification unit 144, and a rotation detection unit 147.

  The oscillation unit 142 outputs an oscillation signal having a frequency corresponding to the frequency instruction signal input from the control unit 141 to the phase shift unit 143. The phase shift unit 143 generates a signal having a phase difference of 90 degrees with respect to the oscillation signal input from the oscillation unit 142, and outputs the generated signal and the input oscillation signal to the amplification unit 144. Further, the phase shift unit 143 selects either +90 degrees or −90 degrees as a phase difference that the generated signal has with respect to the oscillation signal in accordance with the signal indicating the rotation direction input from the control unit 141. .

The amplifying unit 144 includes a first amplifying unit 145 and a second amplifying unit 146. The first amplification unit 144 receives an oscillation signal from the phase shift unit 143 and a signal indicating the amplitude from the control unit 141. The first amplifying unit 144 amplifies the amplitude of the input oscillation signal in accordance with the signal indicating the input amplitude, and uses the amplified oscillation signal as the drive signal Sa to the piezoelectric body 123 (see FIG. 3).
The second amplifying unit 145 receives an oscillation signal having a phase difference of 90 degrees with respect to the oscillation signal from the phase unit 143 and a signal indicating the amplitude from the control unit 141. Further, the second amplifying unit 145 amplifies the amplitude of the input oscillation signal in accordance with the signal indicating the input amplitude, and uses the amplified oscillation signal as the drive signal Sb, the piezoelectric body 123 (see FIG. 3).

The first amplifying unit 145 and the second amplifying unit 146 transmit the drive signals Sa and Sb having an amplitude of V ₀ (first amplitude) in accordance with a signal input from the control unit 141 in the moving image mode. After being applied to 12, the amplitudes of the drive signals Sa and Sb are increased to V ₁ (second amplitude). The first amplifying unit 145 and the second amplifying unit 146 apply drive signals Sa and Sb having an amplitude of V ₁ to the vibration wave motor 12 in accordance with the signal input from the control unit 141 in the still image mode. .
Here, the amplitude (peak voltage) V ₀ is a voltage value obtained by simulation and measurement by an actual machine. Even if the amplitude of the drive signals Sa and Sb is changed from 0 to V ₀ , noise is generated in the built-in microphone 70. Is an amplitude (voltage) that is not detected. The amplitude (peak voltage) V ₁ is, for example, a rated voltage of the vibration wave motor 12. In addition, the drive signals Sa and Sb output from the first amplifying unit 145 and the second amplifying unit 146 have the same frequency as the oscillation signal.
The rotation detection unit 147 includes an optical encoder, a magnetic encoder, and the like, detects the position and moving speed of the AF ring 107 driven by the vibration wave motor 12, and outputs a signal indicating the detected value to the control unit 141. .

  The control unit 141 drives the vibration wave motor 12 in accordance with a drive command signal input from the host control unit 100 provided in the electronic camera 1. Here, the drive command signal includes the target position of the AF ring 107 as an amount for driving the vibration wave motor 12. Further, when a signal indicating the position and moving speed of the AF ring 107 is input from the rotation detecting unit 147, the control unit 141 receives the target speed Vtgt when the AF ring 107 is moved and the target corresponding to the speed Vtgt. The frequency ftgt is calculated, and the vibration wave motor 12 is driven using the calculated target speed Vtgt and the target frequency ftgt, and the AF ring 107 is moved to the target position. In addition, shooting information is input from the host control unit 100 to the control unit 141. The shooting information includes information indicating whether either the still image mode or the moving image mode is selected and whether recording is performed using the external microphone 210.

Hereinafter, a basic operation when the vibration wave motor driving device 14 drives the vibration wave motor 12 will be described.
When a drive command signal is input from the host control unit 100, the control unit 141 selects whether to drive the vibration wave motor 12 in the forward direction or the reverse direction from the target position of the AF ring 107, and selects A signal indicating the rotation direction is output to the phase unit 143 and a signal for outputting an oscillation signal having a desired frequency is output to the oscillation unit 142.

  The oscillation unit 142 generates an oscillation signal having a frequency corresponding to the signal input from the control unit 141 and outputs the oscillation signal to the phase unit 143. When the oscillation signal is input from the oscillation unit 142, the phase unit 143 outputs the oscillation signal to the first amplification unit 145, and the oscillation signal and 90 in accordance with the signal indicating the rotation direction input from the control unit 141. A signal having a phase difference of degrees is generated, and the generated signal is output to the second amplifying unit 146. Each of the first amplifying unit 145 and the second amplifying unit 146 amplifies the oscillation signal input from the phase unit 143 and applies it to the vibration wave motor 12 as drive signals Sa and Sb. The piezoelectric body 123 is excited when the drive signal Sa is applied to the A-phase electrode and the drive signal Sb is applied to the B-phase electrode, and fourth-order bending vibration is generated in the elastic body 122.

  The piezoelectric body 123 generates quaternary bending vibration generated from the A phase and B phase when two drive signals Sa and Sb having a phase difference of 90 degrees are applied to the A phase and the B phase, respectively. A fourth bending vibration is generated. The two bending vibrations are shifted by a quarter wavelength and are combined to generate four traveling waves. When the elliptical motion is generated at the wavefront of the traveling wave, the moving element 124 that is in pressure contact with the driving surface of the elastic body 122 is frictionally rotated, and the rotational motion generated in the vibration wave motor 12 is output to the output shaft 127 and It is transmitted to the gear member 132 (FIG. 3), the reduction gear 105 and the cam ring 106 to move the AF ring 107 in the optical axis direction.

  The position detection unit 147 detects the position and movement speed of the AF ring 107 and outputs information indicating the detected position and movement speed to the control unit 141. The control unit 141 changes the frequency of the oscillation signal output from the oscillation unit 142 from the position and moving speed of the AF ring 107 indicated by the information input from the position detection unit 147 and the target position, thereby changing the vibration wave motor. The control is performed to move the AF ring 107 to the target position by changing the moving speed of No. 12.

FIG. 5 is a flowchart showing a driving process for the vibration wave motor 12 of the vibration wave motor drive device 14 in the embodiment.
In the vibration wave motor drive device 14, when a drive command signal is input from the host control unit 100 to the control unit 141 (step St101), the control unit 141 detects the target position included in the input drive command signal, and position detection. The target speed Vtgt is calculated according to the position detected by the unit 147 (step St102).
The control unit 141 determines whether or not the selected shooting mode is the moving image mode from the shooting information input from the host control unit 100 (step St103).

If shooting mode is the moving image mode (step ST103: Yes), the control unit 141, the driving signal Sa, and the voltage value _{V 0} to a predetermined amplitude of Sb by the amplification unit 144 (Step St104), the vibration wave motor 12 (step St105).
Subsequently, the control unit 141 increases the amplitudes of the drive signals Sa and Sb from V ₀ to V ₁ by the amplification unit 144 (step St106), and applies them to the vibration wave motor 12.

Control unit 141, the driving signal Sa amplifying unit 144 is applied to the vibration wave motor 12, after the amplitude of Sb reaches _{V 1,} the target speed the frequency of the oscillation signal oscillation unit 142 outputs, calculated in step St102 An insertion process for changing to the target frequency ftgt corresponding to Vtgt is performed (step St107), and the vibration wave motor 12 is driven to move the AF ring 107.

On the other hand, if the shooting mode is not the video mode (step ST103: No), the control unit 141, the driving signal Sa amplifying unit 144 outputs, to the voltage value _{V 1} which is defined the amplitude of Sb in advance (step ST121), amplitude to apply a drive signal Sa _{V 1,} the Sb to the vibration wave motor 12 (step St122).
Subsequently, the control unit 141 performs an insertion process for changing the frequency of the oscillation signal output from the oscillation unit 142 to the target frequency ftgt corresponding to the target speed Vtgt calculated in Step St102 (Step St123), and the vibration wave motor. 12 is driven to move the AF ring 107.

  When the AF ring 107 starts to move, the control unit 141 determines whether the AF ring 107 has reached the target position from information indicating the position and moving speed of the AF ring 107 input from the position detection unit 147. Then, when the AF ring 107 reaches the target position, the driving of the vibration wave motor 12 is stopped (step St109).

FIG. 6 is a waveform diagram showing the frequency and amplitude of the drive signal and the rotational speed of the vibration wave motor 12 when the moving image mode is selected in the embodiment. In FIG. 6, the horizontal axis represents time, and the vertical axis represents the frequency and amplitude of the drive signal and the rotational speed of the vibration wave motor 12, respectively.
When a drive command signal is input to the control unit 141 at time t10, the operations of steps St101 to St104 are performed. At time t11, the operation of step St105 is performed, and the drive signals Sa and Sb are transmitted to the vibration wave motor 12. To be applied.
From time t12 subjected to t13, the operation of step St106 is performed, the driving signals Sa, increases the amplitude of Sb to _{V 1} from _{V 0.}

At time t14, the operation of step St107 is performed, the driving signals Sa, sweeping process of changing towards the frequency of Sb from the stop frequency _{f 0} to the target frequency ftgt is started. Here, the frequency f ₀ is a frequency higher than the drive-start frequency of the vibration wave motor 12, the target frequency ftgt is a frequency corresponding to the target speed Vtgt.
When the frequency of the drive signals Sa and Sb reaches the drive start frequency of the vibration wave motor 12 at time t15, the vibration wave motor 12 starts to drive, and the vibration wave motor 12 rotates as the frequency of the drive signals Sa and Sb decreases. Increases speed. When the frequency of the drive signals Sa and Sb reaches the target frequency ftgt at time t15, the vibration wave motor 12 is stopped by the operation of step St109.

As described above, when the moving image mode is selected, the vibration wave motor drive device 14 first applies the drive signals Sa and Sb having an amplitude V ₀ to the vibration wave motor 12 when moving the AF ring 107. Te, the driving signal Sa, gradually increases towards the amplitude of Sb to _{V 1.} As a result, noise generated from the piezoelectric body 122 of the vibration wave motor 12 when a drive signal is applied to the vibration wave motor 12 is prevented from being detected by the built-in microphone 70 and is generated when the vibration wave motor 12 is driven. Noise can be reduced.

The vibration wave motor driving device 14, when the still image mode is selected, it is changed step by step driving signals Sa, the amplitude of Sb to V ₁ from 0, driving the vibration wave motor 12. Thereby, since the time for changing the amplitudes of the drive signals Sa and Sb from V ₀ to V ₁ is not required, the driving of the vibration wave motor 12 can be started in a shorter time than in the moving image mode.

When calculating the target speed Vtgt in step St101, the control unit 141 provides a table in which the target position included in the drive command signal, the position of the AF ring 107, and the target speed Vtgt are associated in advance. The target speed Vtgt may be calculated using a table.
In addition, the control unit 141 may provide a table in which the target frequency ftgt corresponding to the target speed Vtgt is previously associated, and may calculate the target frequency ftgt using the table.

Second Embodiment
Hereinafter, the drive process with respect to the vibration wave motor 12 of the vibration wave motor drive device 14 in 2nd Embodiment is demonstrated. The vibration wave motor drive device 14 of the present embodiment has the same configuration as that of the vibration wave motor drive device 14 of the first embodiment except that the drive processing for the vibration wave motor 12 is different, and thus the description thereof is omitted. .

FIG. 7 is a flowchart showing a driving process of the vibration wave motor 12 of the vibration wave motor drive device 14 in the second embodiment.
Since Steps St201 to St205, St208 to St209, St221 to St223 shown in FIG. 7 and Steps St101 to St105, St108 to St109, St121 to St123 of the first embodiment shown in FIG. Description is omitted.

In the vibration wave motor drive device 14 of the second embodiment, in step St <b> 206, the control unit 141 determines the amplitude of the drive signals Sa and Sb applied to the vibration wave motor 12 by the amplification unit 144 to a predetermined voltage value V. _An increase to ₁ is started (step St206).
Controller 141, before the drive signal Sa, the amplitude of Sb reaches V _1, sweeping processing for changing the frequency of the oscillation signal oscillation unit 142 outputs, to the frequency corresponding to the target speed Vtgt calculated in step St202 (Step St207) and the vibration wave motor 12 is driven to move the AF ring 107.

FIG. 8 is a waveform diagram showing the frequency and amplitude of the drive signal and the rotational speed of the vibration wave motor 12 when the moving image mode is selected in the embodiment. In FIG. 8, the horizontal axis represents time, and the vertical axis represents the frequency and amplitude of the drive signal and the rotational speed of the vibration wave motor 12, respectively.
When a drive command signal is input to the control unit 141 at time t20, the operations of steps St201 to St204 are performed. At time t21, the operation of step St205 is performed, and the drive signals Sa and Sb are transmitted to the vibration wave motor 12. To be applied.
Operation of step St206 is performed at the time t22, the driving signal Sa, the amplitude of Sb starts to increase from _{V 0} to _{V 1.} Driving signals Sa, at time t23 in the middle of the amplitude of Sb is increased, the operation of step St207 is performed, sweeping process of reducing the driving signal Sa, the frequency of Sb from the stop frequency _{f 0} to the target frequency ftgt Be started.

At time t24, the driving signal Sa, the amplitude of Sb reaches _{V 1,} the control unit 141, the driving signal Sa to the amplifier 144 to stop the increase in the amplitude of Sb.
When the frequency of the drive signals Sa and Sb reaches the drive start frequency of the vibration wave motor 12 at time t25, the vibration wave motor 12 starts driving and the vibration wave motor 12 is driven according to the phenomenon of the drive signals Sa and Sb. Increases rotational speed.
When the frequency of the drive signals Sa and Sb reaches the target frequency ftgt at time t26, the control unit 141 stops the insertion process that causes the oscillation unit 142 to change the frequency of the oscillation signal to the target frequency ftgt.

As described above, in the present embodiment, the control unit 141 causes the oscillation unit 142 to start the insertion of the frequencies of the drive signals Sa and Sb without waiting for the amplitudes of the drive signals Sa and Sb to reach V ₁ . . As a result, the time from when the drive signals Sa and Sb are applied to the vibration wave motor 12 to driving can be shortened compared to the first embodiment. In other words, the driving process of the second embodiment can move the AF ring 107 to a desired position earlier than the first embodiment, and can shorten the time required for autofocusing.

In FIG. 8, the first amplifying unit 145 and the second amplifying unit 146 are denoted by S1 without increasing linearly when the amplitude is increased from V ₀ to V ₁ as in the first embodiment. You may change so that an S-shaped waveform may be drawn like a broken line.

<Third Embodiment>
Hereinafter, the drive process with respect to the vibration wave motor 12 of the vibration wave motor drive device 14 in 3rd Embodiment is demonstrated. The vibration wave motor drive device 14 of the present embodiment has the same configuration as that of the vibration wave motor drive device 14 of the first embodiment except that the drive processing for the vibration wave motor 12 is different, and thus the description thereof is omitted. .
The difference between the process of the present embodiment and the process of the first embodiment is that a predetermined maximum moving speed Vd is set as the upper limit value of the moving speed of the AF ring 107. Here, the moving image maximum speed Vd is a value obtained by simulation and measurement by an actual machine, and the sliding sound generated when the AF ring 107 is moved at the speed is not detected by the built-in microphone 70. Speed.

FIG. 9 is a flowchart showing a driving process of the vibration wave motor 12 of the vibration wave motor drive device 14 according to the third embodiment.
Note that steps St301 to St304, St308 to St311 and St321 to St323 shown in FIG. 9 and steps St101 to St104, St106 to St109 and St121 to 123 of the first embodiment shown in FIG. The description is omitted.

In step St305, the vibration wave motor drive device 14 determines whether the control unit 141 determines whether the target speed Vtgt calculated in step St302 is higher than a predetermined moving image maximum speed Vd (step St305).
When the target speed Vtgt is larger than the moving image maximum speed Vd (step St305: Yes), the control unit 141 changes the target speed Vtgt to the moving image maximum speed Vd and calculates the frequency fd corresponding to the speed Vd (step). St306).
On the other hand, when the target speed Vtgt is equal to or lower than the moving image maximum speed Vd (step St305: No), the control unit 141 does not perform the operation of step St306 described above.

  As described above, when the moving image mode is selected, when the calculated target speed Vtgt is greater than the moving image maximum speed Vd, the target speed Vtgt is changed to the moving image maximum speed Vd. Thereby, it is possible to suppress the sliding sound generated in the lens barrel 10 when the AF ring 107 moves, and to reduce the noise generated from the lens barrel 10 during moving image shooting.

<Fourth embodiment>
Next, a driving process for the vibration wave motor 12 of the vibration wave motor drive device 14 according to the fourth embodiment will be described. The vibration wave motor drive device 14 of the present embodiment has the same configuration as that of the vibration wave motor drive device 14 of the first embodiment except that the drive processing for the vibration wave motor 12 is different, and thus the description thereof is omitted. .

FIG. 10 is a flowchart showing a driving process of the vibration wave motor 12 of the vibration wave motor drive device 14 according to the fourth embodiment.
Note that steps St401 to St403, St405 to St410, St421 to St423 shown in FIG. 10 and steps St101 to St103, St104 to St109, St121 to St123 of the first embodiment shown in FIG. Description is omitted.

In step St <b> 404, the vibration wave motor drive device 14 determines whether or not the control unit 141 uses the external microphone 210 connected to the electronic camera 1 to record from the shooting information input from the host control unit 100. (Step St404).
When recording is performed using the external microphone 210 (step St404: Yes), the vibration wave motor driving device 14 performs each operation of steps St421 to St423, St409, and St410, that is, the same operation as the still image mode, and the AF ring 107 Is moved to a desired position.
On the other hand, when recording is performed without using the external microphone 210, that is, when recording is performed using the internal microphone 70, the vibration wave motor drive device 14 performs each operation of steps St405 to St410, and outputs the drive signals Sa and Sb. The vibration wave motor 12 with reduced noise generated when applied to the vibration wave motor 12 is driven to move the AF ring 107 to a desired position.

  In general, the external microphone 210 is often disposed at a position away from the main body of the electronic camera 1, and noise generated when the drive signals Sa and Sb are applied to the vibration wave motor 12, when the AF ring 107 is moved. There is almost no detection of sliding noise generated in the case. Therefore, when recording using the external microphone 210, the electronic camera 1 drives the vibration wave motor 12 as in the still image mode so that the AF ring 107 is moved to a desired position earlier than in the first embodiment. As a result, the time required for autofocusing can be reduced.

<Fifth Embodiment>
Next, as a modification of the first embodiment, a configuration of a lens barrel 10A in the fifth embodiment will be described. The present embodiment is different from the lens barrel 10 (FIG. 2) of the first embodiment in the configuration of the lens barrel 10A, and the electronic camera 1 (FIG. 1) and vibration wave motor of the first embodiment. 12 (FIG. 3) and the configuration of the vibration wave motor drive device 14 (FIG. 4) are the same as those of FIG.

  FIG. 11 is a schematic diagram showing the configuration of a lens barrel 10A in the fifth embodiment. The lens barrel 10 </ b> A includes an outer fixed cylinder 101 that covers the outer periphery of the lens barrel 10 </ b> A, a first inner fixed cylinder 102 that is positioned closer to the subject on the inner peripheral side than the outer fixed cylinder 101, and the outer fixed cylinder 101. And a second inner fixed cylinder 103 located on the image side on the inner peripheral side. The lens barrel 10 </ b> A is disposed between the outer fixed tube 101 and the first inner fixed tube 102, and is fixed to the first inner fixed tube 102, and the vibration wave motor 12 and the vibration wave motor driving device. 14 and a gear unit module 104 that transmits the rotational speed of the vibration wave motor 12 at a reduced speed. The gear unit module 104 includes a reduction gear 105 that reduces and transmits the rotational movement of the output gear member 132 of the vibration wave motor 12.

  The lens barrel 10 </ b> A meshes with the linear rail 114 provided along the optical axis direction on the first inner fixed cylinder 102 and the reduction gear 105, and is rotatably held by the second inner fixed cylinder 103. A gear 111, a screw screw 112 coupled to the gear 111, a guide portion 113 that is screwed to the screw screw 112 and held movably along the linear rail 114, and an AF ring 107 coupled to the guide portion 113 And.

  Further, the first lens group L1 and the second lens group L2 are fixed to the first inner fixed cylinder 102 from the subject side, and the fourth lens group L4 is fixed to the second inner fixed cylinder 103. Between the second lens group L2 and the fourth lens group L4, a third lens group L3 which is an AF lens for focusing held by the AF ring 107 is disposed. That is, the first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4 are sequentially arranged from the subject side to the image sensor side in the optical axis direction.

  With the configuration of the lens barrel 10A described above, when the vibration wave motor 12 is driven, the gear member 132 of the vibration wave motor 12 transmits the rotational motion to the gear 111 via the reduction gear 105. As a result, the screw ring 112 coupled to the gear 111 is rotated, so that the AF ring 107 can be moved along the straight rail 114 in the optical axis direction together with the guide portion 113. That is, by driving the vibration wave motor 12, the AF ring 107 is driven in the optical axis direction and the third lens group L3 is moved, so that a focused subject image can be formed on the image sensor. .

  Further, the lens barrel 10A of the present embodiment moves without rotating along the straight rail 114 by moving the AF ring 107 with the screw screw 112, so that sliding noise can be reduced. Further, since the lens barrel 10A does not have frictional sliding between the cam ring 106 and the AF ring 107 unlike the lens barrel 10 of the first embodiment, noise generated when the AF ring 107 is moved is further reduced. can do.

In the first to fifth embodiments described above, when the vibration wave motor 12 is stopped, the processing for driving the vibration wave motor 12 described above may be performed in the reverse order. For example, the control unit 141 causes the oscillation unit 142 to perform an insertion process for changing the frequencies of the drive signals Sa and Sb to f ₀ , stops the vibration wave motor 12, and then sets the amplitudes of the drive signals Sa and Sb to V _The amplification unit 144 stops the application of the drive signals Sa and Sb to the vibration wave motor 12. As a result, as in the case of driving the vibration wave motor 12, noise generated when the vibration wave motor 12 is stopped can be reduced and can be prevented from being detected by the built-in microphone 70.

In the first to fifth embodiments described above, the amplitude of the drive signals Sa and Sb in the still image mode has been described as the same value as the amplitude V ₁ of the drive signals Sa and Sb in the moving image mode. If the motor 12 can be driven, the amplitudes of the drive signals Sa and Sb in the still image mode may be V ₂ (third amplitude) different from V ₁ . At this time, the amplitude V ₂ is a value at least larger than V ₀ .

In the first to fifth embodiments described above, when the vibration wave motor 12 is driven in the forward direction after being driven in the forward direction, the control unit 141 performs a driving process for driving in the forward direction. Alternatively, the above-described stop process may be sequentially performed, and the vibration wave motor 12 may be temporarily stopped, and then the drive process for driving in the reverse direction and the above-described stop process may be sequentially performed. Thereby, when switching from driving in the forward direction to driving in the reverse direction, it is possible to avoid applying the drive signal Sb whose phase has been changed by 180 degrees to the vibration wave motor 12 and to prevent the generation of noise. .
Further, at least two of the first to fifth embodiments described above may be used in combination.

In FIG. 6 of the first embodiment and FIG. 8 of the second embodiment, the first amplification unit 145 and the second amplification unit 146 increase linearly when the amplitude is increased from V ₀ to V _1. Instead, it may be changed so as to draw an S-shaped waveform as indicated by a broken line indicated by S1.

  The vibration wave motor drive apparatus of the first to fifth embodiments described above may have a computer system inside. In this case, the process of driving the vibration wave motor described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Become. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  DESCRIPTION OF SYMBOLS 1 ... Electronic camera 10, 10A ... Lens barrel, 60 ... Recording process part, 12 ... Vibration wave motor, 14 ... Vibration wave motor drive device, 141 ... Control part, 142 ... Oscillation part, 144 ... Amplification part, 210 ... External microphone, L3 ... Third lens group

Claims (9)

An output unit for outputting a drive signal having a frequency to the vibration actuator;
When a signal instructing driving of the vibration actuator is input, the drive signal having a predetermined first amplitude is output to the vibration actuator, and then the amplitude of the drive signal is changed from the first amplitude to the first amplitude. A vibration actuator drive apparatus comprising: a control unit that causes the output unit to perform a first operation of outputting the drive signal to the vibration actuator while increasing the amplitude to a predetermined second amplitude greater than the amplitude. The vibration actuator driving device according to claim 1,
The control unit, when stopping the vibration actuator, outputs the drive signal to the vibration actuator while decreasing the amplitude of the drive signal output from the output unit from the second amplitude to the first amplitude. A vibration actuator driving apparatus characterized by causing the amplifying unit to perform an operation. The vibration actuator driving device according to claim 1 or 2,
An oscillation unit that outputs an oscillation signal having a frequency to the output unit;
The output unit amplifies the oscillation signal output from the oscillation unit, and outputs the amplified oscillation signal to the vibration actuator as the drive signal,
When driving the vibration actuator, the control unit selects a target speed for driving the vibration actuator, outputs a signal indicating a target frequency corresponding to the target speed to the oscillation unit, and outputs the frequency of the oscillation signal. The vibration actuator driving device is characterized in that the oscillation unit is pulled up to the target frequency. The vibration actuator drive device according to any one of claims 1 to 3,
In the first operation, an upper limit speed at which the vibration actuator is driven is determined in advance,
When the target speed is faster than the upper limit speed when driving the vibration actuator by the first operation, the control unit outputs a frequency corresponding to the upper limit speed to the oscillation unit, and the frequency of the oscillation signal The vibration actuator driving device is characterized in that the oscillation unit is pulled up to a frequency corresponding to the upper limit speed. The vibration actuator drive device according to any one of claims 1 to 4,
When a signal instructing driving of the vibration actuator is input, the control unit performs a third operation on the output unit that outputs the driving signal having a third amplitude larger than the first amplitude to the vibration actuator. A vibration actuator driving device characterized in that A lens barrel attached to an electronic camera capable of recording,
A vibration actuator driving device according to claim 5;
Comprising the vibration actuator,
The control unit selects the first operation when the electronic camera performs recording, and selects the third operation when the electronic camera does not perform recording. The lens barrel according to claim 6, further comprising: a focusing optical system that moves in an optical axis direction without being rotated by the vibration actuator. The lens barrel according to claim 6 or 7,
A recording processing unit capable of recording using a built-in microphone,
The electronic camera, wherein the control unit selects the first operation when the recording processing unit performs recording, and selects the third operation when the recording processing unit does not perform recording. The electronic camera according to claim 8,
The recording processing unit is capable of recording voice using an external microphone provided outside, and the control unit is configured to perform the third drive mode when the recording processing unit performs recording using the external microphone. An electronic camera characterized by selecting.

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