JP6124509B2 - DRIVE DEVICE, AUTOFOCUS DEVICE, IMAGE DEVICE, AND LENS DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a driving device that vibrates an optical member in a direction of an optical axis with respect to a fixed member, and an autofocus device, an imaging device, and a lens device using the driving device.

  In recent years, digital cameras capable of shooting not only still images but also moving images have been commercialized. And almost all such cameras are equipped with an autofocus device. In this autofocus device, optical members that vary depending on the image pickup device are obtained by performing so-called wobbling that vibrates and drives optical members such as some lenses and image pickup devices constituting the image pickup lens in the optical axis direction of the image pickup lens. An in-focus position is detected from the contrast of the image captured at the upper position, and the focus lens is driven to focus. In this case, the vibrational driving of the optical member is required to be driven at high speed and precisely in order to accurately capture the photographing opportunity. On the other hand, there is a problem that vibration or sound is generated by the vibration drive of the optical member, which may cause discomfort to the photographer or record the sound during movie shooting. Even in such a case, it is required to reduce or eliminate vibration and sound.

  In a camera autofocus device, Japanese Patent Application Laid-Open No. 2004-228688 discloses a mechanism that evaluates a focus position from an image captured while wobbling a focus lens and drives the focus lens to a focus position. Specifically, the focus lens is wobbling driven by a stepping motor.

  On the other hand, Patent Document 2 discloses a bimorph piezoelectric element that drives a focus lens in the direction of the optical axis.

JP 2010-170051 A JP 2006-209029 A

  If auto-focusing is not performed at high speed and precision in a camera, it is necessary to drive the focus lens at high speed and precision because it may miss a photographing opportunity or deteriorate image quality. On the other hand, in order to increase the speed of autofocus, a focus position is detected by so-called wobbling, in which a part of a photographing lens and an optical member such as an image sensor are vibrated at a high speed with a predetermined amplitude. However, if high-speed and high-speed wobbling operation control is performed, the control is lost, the operation of the optical member becomes unstable, and precise position and speed control cannot be performed. In addition, even if wobbling control is stable, there is a sliding part, so vibration is generated by high-speed wobbling and is transmitted to the camera or lens, causing discomfort to the user or shooting movies. In addition, problems such as recording audible sounds generated by vibrations have occurred. Therefore, when the optical member is driven with a large amplitude and at a high speed, stable drive control is possible, and it is required to eliminate or reduce unnecessary vibration.

  For example, in the imaging apparatus disclosed in Patent Document 1, the focus lens is vibrated in the optical axis direction and the focus position is detected from images captured at different focus lens positions to bring the focus lens into the in-focus position. I have control. A stepping motor is used for so-called wobbling that vibrates the focus lens in the optical axis direction. When trying to perform high-speed wobbling with a stepping motor, the stepping motor naturally operates at a high speed. However, when the speed exceeds a predetermined level, step-out occurs and drive control becomes impossible. In addition, since the stepping motor has a sliding portion, unnecessary vibration and sound are generated when driven at high speed. Similarly, other electromagnetic actuators such as a voice coil motor, when driven at high speed, oscillate the control system on the same principle as the step-out and slide and generate vibrations and sounds.

  On the other hand, in the imaging apparatus disclosed in Patent Document 2, the lens unit is displaced in the optical axis direction by applying a predetermined voltage to the bimorph piezoelectric element, thereby focusing. Since the displacement of the piezoelectric element is originally very small, a long bimorph type piezoelectric element is used to increase the amount of displacement. Then, since the rigidity of the bimorph type piezoelectric element supporting the lens unit is lowered, the lens unit is displaced by an external force such as gravity applied to the lens unit, and the displacement is corrected to accurately position the optical axis of the lens unit. Is controlling. Therefore, the control is very complicated. In addition, since the bimorph piezoelectric element is long, the imaging device becomes large. Furthermore, the engaging portion between the bimorph tip and the lens frame for moving the bimorph type piezoelectric element in the optical axis direction is a sliding mechanism, which generates unnecessary vibrations and audible sounds. There were also problems such as.

  The above-described problems are not limited to the camera, and the same applies to image equipment including an autofocus device such as a telescope, binoculars, a projector, and a microscope.

  The present invention has been made in view of the above points, and can drive an optical member with a large amplitude at high speed and with high precision, and can reduce vibration and sound generated by the movement of the movable frame even when driven by vibration. An object of the present invention is to provide an autofocus device, an image device, and a lens device equipped with such a drive device.

One aspect of the drive device of the present invention is a drive device that oscillates and drives an optical member in the direction of the optical axis with respect to a fixed member, and the optical member is fixed to one end and the other end to the fixed member. A plurality of actuators that are supported and bent and displaced at least in the optical axis direction in response to voltage application; and an actuator control circuit that drives the plurality of actuators, the actuator control circuit comprising the optical member and the plurality of actuators. By driving the plurality of actuators so as to vibrate a bending vibrator constituted by the actuators at a frequency near the bending vibration resonance, the optical member is vibrated and displaced in the optical axis direction, and the bending vibrator frequency of the bending vibration resonance is characterized frequencies der Rukoto of the optical axis direction of the vibration displacement of the optical member.
Further, an aspect of the autofocus device of the present invention is the one aspect of the drive device of the present invention described above, and detects the in-focus position based on the image data acquired by the image sensor from the optical image formed by the photographing lens, An autofocus processing unit that outputs focus control information based on the detected in-focus position, and a focus that drives a focus lens among a plurality of lenses that constitute the photographing lens according to the focus control information from the autofocus processing unit Drive means, and timing control means for controlling the drive timing of the actuator by the actuator control circuit so as to synchronize with a predetermined phase difference with respect to the image data acquisition operation of the image sensor. The optical member is one of a plurality of lenses constituting the photographing lens or the imaging element. And characterized in that.
According to another aspect of the imaging apparatus of the present invention, the imaging apparatus includes a photographic lens including a plurality of lenses and an imaging element. The imaging apparatus includes the one aspect of the driving device of the present invention. An autofocus processing unit that detects a focal point position based on image data acquired from the optical image by the image sensor and outputs focus control information based on the detected focal point position, and focus control from the autofocus processing unit In accordance with the information, the focus driving means for driving the focus lens among the plurality of lenses constituting the photographing lens is synchronized with the image data acquisition operation of the image sensor with a predetermined phase difference. Timing control means for controlling the drive timing of the actuator by the actuator control circuit, and the optical member comprises: One of the plurality of lenses constituting the serial photographing lens, or, characterized in that the above-mentioned image pickup element.
According to another aspect of the imaging apparatus of the present invention, the imaging apparatus includes an imaging element, and the in-focus position is detected based on one aspect of the driving apparatus of the present invention and the image data acquired by the imaging element. And an autofocus processing unit that outputs focus control information based on the detected in-focus position and the actuator control so as to be synchronized with a predetermined phase difference with respect to the image data acquisition operation of the image sensor. Timing control means for controlling the drive timing of the actuator by a circuit, and the optical member is the image sensor.
One aspect of the lens apparatus of the present invention is a lens apparatus including a photographing lens including a plurality of lenses, and is detected from one aspect of the driving apparatus of the present invention and an optical image formed by the photographing lens. A focus drive unit that receives focus control information based on a focus position, and drives a focus lens among a plurality of lenses that constitute the photographing lens according to the focus control information. It is one of a plurality of lenses constituting the photographing lens.

  According to the present invention, when the optical member is driven to vibrate, the bending vibrator composed of the optical member and the plurality of actuators is vibrated at a frequency in the vicinity of the bending vibration resonance. To provide a driving device that can be precisely controlled and that generates less vibration and sound even when an optical member is driven to vibrate, and an autofocus device, an imaging device, and a lens device equipped with such a driving device. it can.

FIG. 1 shows a camera as an imaging device according to a first embodiment of the present invention, including an interchangeable lens as a lens device according to the first embodiment of the present invention using the drive device according to the first embodiment of the present invention. It is a block diagram for demonstrating the structure of a system.

2A is a front view illustrating the configuration of the wobbling mechanism of the interchangeable lens, and FIG. 2B is a cross-sectional side view taken along the line AA of the wobbling mechanism of FIG. ) Is a cross-sectional view of the wobbling mechanism of FIG.

FIG. 3 is a diagram showing the relationship between the arm length of the actuator and the vibration amplitude of the movable lens near the resonance frequency due to the mass change of the movable lens.

FIG. 4 is a diagram showing the relationship between the input voltage to the actuator and the vibration amplitude of the movable lens.

FIG. 5 is an exploded perspective view illustrating the configuration of the actuator.

FIG. 6 is a partially enlarged perspective view for explaining details of the structure of the actuator.

FIG. 7 is a diagram illustrating the configuration of the actuator and the actuator control circuit.

FIG. 8 is a diagram for explaining the phase difference between the input signal to the actuator and the position of the movable lens, and the phase difference between the input signal to the actuator and the imaging operation.

FIG. 9 is a diagram showing the phase difference between the input voltage to the actuator and the vibration of the movable lens.

FIG. 10 is a block diagram showing the configuration of the actuator control circuit.

FIG. 11 is a diagram illustrating a time chart for explaining the operation by signals output from the respective components of the actuator control circuit of FIG.

FIG. 12 is a flowchart for explaining the operation of the camera system.

FIG. 13 is a flowchart for explaining the autofocus operation.

FIG. 14A is a front view illustrating the configuration of the wobbling mechanism of the image sensor in the drive device according to the second embodiment of the present invention, and FIG. 14B is the front view of the wobbling mechanism of FIG. FIG. 14C is a sectional view taken along the line AA, FIG. 14C is a sectional view taken along the line BB of the wobbling mechanism of FIG. 14A, and FIG. 14D is a CC line of the wobbling mechanism of FIG. It is a sectional side view.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
In each drawing used for the following description, the scale is different for each component in order to make each component large enough to be recognized on the drawing. It is not limited only to the quantity of the component described in the drawing, the shape of the component, the ratio of the size of the component, and the relative positional relationship of each component.
In the following description, the direction from the camera body 200 toward the subject is referred to as the front, and the opposite is referred to as the rear. Further, an axis that coincides with the optical axis O1 of the optical system that the interchangeable lens 100 constitutes is defined as a Z axis, and two axes that are orthogonal to each other on a plane orthogonal to the Z axis are defined as an X axis and a Y axis.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration example of a camera system 10 as an imaging device according to the first embodiment of the present invention, in which the drive device according to the first embodiment of the present invention is mounted.

  A camera system 10 shown in FIG. 1 includes an interchangeable lens 100 as a lens apparatus according to a first embodiment of the present invention and a camera body 200, which are connected to be communicable via an I / F 219. .

  The interchangeable lens 100 drives and controls the focus lens 101, the variable power lens 102, the movable lens 103, the diaphragm 104, and the focus lens 101, which constitute the photographing lens 113 that forms a subject image, in the direction of the optical axis O1 for focusing. A driver 105 for controlling the driving of the diaphragm that constitutes the diaphragm 104, a driver 107 for controlling the driving of the variable power lens 102 in the optical axis direction, and a body control microcomputer (hereinafter, “ A lens control microcomputer (hereinafter referred to as “Lucom”) 108 which controls each driver and control circuit in the interchangeable lens 100 by communicating with 214 via the I / F 219 and control of the control circuit A flash memory 109 storing information necessary for the movable lens 1 and the movable lens 1 It includes a position sensor 110 for detecting a third position, a plurality of actuators 111 for driving the movable lens 103, an actuator control circuit 112 for generating an electric signal for driving the actuator 111, a.

  The camera body 200 includes a shutter 201 that controls exposure by controlling shutter shutters by a shutter drive mechanism 220 during imaging, a dustproof filter 221 that ultrasonically vibrates by a dustproof filter control circuit 222, and a photographing lens 113 that removes dust appearing in an image. An optical low-pass filter 223 that removes a high spatial frequency component of the optical image to be created, an image sensor 202 that converts an optical image created by the photographing lens 113 into an electrical signal, and an analog process that performs analog processing such as noise removal of the electrical signal of the image sensor 202 Unit 203, an analog / digital conversion unit (hereinafter referred to as "A / D conversion unit") 204 that converts an analog output of analog processing unit 203 into a digital image signal, and exposure of an image at the time of photographing by measuring light from a subject AE processing unit 205 that outputs information for controlling image processing, and performs image processing on the captured image An image processing unit 206 that outputs image information that is finally output, an AF processing unit 207 that outputs focus control information for controlling the focus by detecting the in-focus position of the optical image formed by the photographing lens, and the captured image An image compression / decompression unit 208 that compresses the information of the image or restores the compressed information to the original information, an LCD driver 209 that controls the LCD 210 that displays the captured image, information at the time of shooting, and the like. And a memory interface (hereinafter referred to as “memory I / F”) 211 for recording and recalling information at the time of shooting on the recording medium 212, an SDRAM 213 for temporarily storing information such as a shot image, a camera Bucom 214 for controlling the electric circuit of the system through the bus 217, etc., Flash memory 215 for storing information for control, etc. Operation unit 216 for operating Leeds and dial, the camera body 200 such as buttons and includes a battery 224, a power supply circuit 218.

  The camera body 200 is equipped with a camera shake prevention mechanism, and holds an X-axis gyro 225 that detects an angular velocity around the X axis, a Y-axis gyro 226 that detects an angular velocity around the Y axis, and an image sensor 202. A position detection sensor 227 for detecting the position of the holder 228 in the X-axis and Y-axis directions, an anti-vibration control circuit 229 for controlling the actuator in accordance with detection values from the respective gyros and position information of the position detection sensor 227, anti-vibration An actuator drive circuit 232 that drives the X-axis actuator 230 and the Y-axis actuator 231 in accordance with a control value from the control circuit 229, an image that is driven in the X-axis direction by the X-axis actuator 230, and driven in the Y-axis direction by the Y-axis actuator 231 A camera body by holding the holder 228 holding the element 202 and the holder 228 movably in the X-axis direction and the Y-axis direction. 00 includes a frame 233 to be fixed. Further, the camera body 200 includes a built-in strobe 234 and a strobe control circuit 235 that controls the light emission of the strobe 234 in accordance with instructions from the Bucom 214.

  Note that the Lucom 108 and / or Bucom 214 is an example of a control unit, and may have a different circuit configuration.

  In FIG. 1, the focus lens 101, the variable power lens 102, and the movable lens 103 are each represented by a single lens. However, a plurality of lens configurations may be used, and an optical filter such as an optical filter may be used. Of course, an element may be included.

  Of the above-described configurations, detailed descriptions of configurations that are similar to known digital cameras and that are not related to the present invention are omitted.

  The focus lens 101 condenses the optical image of the subject on the light receiving surface of the image sensor 202. The variable power lens 102 changes the magnification of the optical image of the subject by changing the focal length of the photographing lens 113. Of course, the focus lens 101 may be the interchangeable lens 100 configured to be operated when the optical image is scaled. The movable lens 103 oscillatingly displaced in order to oscillate the focal position of the photographic lens 113 may be the focus lens 101, the variable power lens 102, or one of the lenses constituting these lenses.

  The Lucom 108 is connected to the drivers 105, 106, 107, the I / F 219, the flash memory 109, the position sensor 110, and the actuator control circuit 112. The Lucom 108 reads / writes information stored in the flash memory 109 and controls the drivers 105, 106, 107 and the actuator control circuit 112. The Lucom 108 can also communicate with the Bucom 214 via the I / F 219, send various information to the Bucom 214, and receive various information from the Bucom 214. For example, the Lucom 108 provides information corresponding to the state of the lens operation member (not shown), the output signal (detection signal) of the position sensor 110, and information corresponding to the position and state signals of the focus lens, the variable power lens, and the aperture. Send to Bucom 214. For example, the Lucom 108 receives control information of the actuator control circuit 112 from the Bucom 214. The Lucom 108 further controls the actuator control circuit 112 based on the control information received from the Bucom 214.

  The driver 105 receives the instruction from the Lucom 108 and drives the focus lens 101 to change the focal position. The driver 106 receives the instruction from the Lucom 108 and drives the variable power lens 102 to change the focal length. The driver 107 drives the diaphragm 104 according to the instruction from the Lucom 108 to adjust the amount of light of the subject. More specifically, the focus lens 101 is driven by an unillustrated stepping motor, an VCM, an ultrasonic motor, or other actuator provided in the driver 105. The variable magnification lens 102 is driven by an actuator (not shown) such as a stepping motor, a VCM, or an ultrasonic motor provided in the driver 106. Further, the diaphragm 104 is driven by a stepping motor or the like (not shown) in the driver 107.

  The actuator control circuit 112 drives the actuator 111 under the control of the Lucom 108. The actuator 111 receives a control signal from the actuator control circuit 112, drives the actuator 111, controls the movement of the movable lens 103 attached to one end of the actuator 111, and detects the focal position of the photographing lens 113. Wobbling is a vibration operation in the direction of a minute optical axis. That is, the actuator 111 is controlled by the Lucom 108 via the actuator control circuit 112. As will be described in detail later, the actuator 111 is composed of, for example, stacked piezoelectric bodies, and is a bimorph that bends in the optical axis direction when a voltage is applied.

  The position sensor 110 detects the position of the movable lens 103 and outputs a detection signal to the Lucom 108. The position sensor 110 has a detection range, accuracy, and configuration required for the movable lens 103. As will be described in detail later, for example, it is configured by a Hall element provided in a fixed frame so as to face a magnet provided in a frame constituting the movable lens 103. Of course, for detecting the position of the movable lens 103, a GMR (giant magnetoresistive element), an optical element, or an electrostatic element may be used. Although not shown, movable mechanisms are used for the focus lens 101, the variable power lens 102, and the diaphragm 104, and each has a position detection mechanism for detecting the position of the movable member.

  The shutter 201 is driven in response to an instruction from the Bucom 214, and controls the time for exposing the subject to the image sensor 202. For example, the shutter 201 has two shutter curtains, a front curtain and a rear curtain, and performs exposure by running a slit formed by the two curtains toward the short side or the long side of the image sensor 202. Here, the shutter 201 is a mechanical type, but may be an electronic type. For example, a so-called global shutter that reads the electrical signals of all the pixels of the image sensor at the same time after exposure to the image sensor for a predetermined time may be used, or a method of reading each horizontal line of the pixel may be used.

  The image sensor 202 is an image sensor in which a Bayer array color filter is arranged in front of a photodiode constituting each pixel. The Bayer array has a line in which R pixels and G (Gr) pixels are alternately arranged in a horizontal direction, and a line in which G (Gb) pixels and B pixels are alternately arranged, and the two lines are further divided. It is configured by alternately arranging in the vertical direction. This image sensor 202 receives the light collected by the focus lens 101, the variable magnification lens 102, and the movable lens 103 by a photodiode that constitutes a pixel and performs photoelectric conversion, thereby converting the amount of light into an analog charge amount. The data is output to the processing unit 203. Note that the image sensor 202 may be a CMOS type or a CCD type.

  The analog processing unit 203 performs waveform shaping on the electrical signal (analog image signal) read from the image sensor 202 while reducing reset noise and the like, and further increases the gain so that the target brightness is obtained. . The A / D converter 204 converts the analog image signal output from the analog processor 203 into a digital image signal (hereinafter referred to as image data).

  The bus 217 is a transfer path for transferring various data generated in the camera body 200 to each unit in the camera body 200. The bus 217 is connected to the AE processing unit 205, the image processing unit 206, the AF processing unit 207, the image compression / decompression unit 208, the LCD driver 209, the memory I / F 211, the SDRAM 213, and the Bucom 214. The image data output from the A / D conversion unit 204 is temporarily stored in the SDRAM 213 via the bus 217.

  The AF processing unit 207 extracts a high-frequency component signal from the image data, and acquires a focus evaluation value such as the contrast of the image by AF (Auto Focus) integration processing. At this time, the movable lens 103 is oscillatingly driven in the optical axis direction, and this AF processing is performed using an image photographed at a position where the focal position is close to the subject and an image photographed near the distant position. By comparing the focus evaluation values, it is possible to determine the direction of the focal position. By knowing the direction in which the focal position is, AF driving can be performed at a higher speed.

  The Bucom 214 comprehensively controls various sequences of the camera body 200. An operation unit 216 and a flash memory 215 are connected to the Bucom 214.

  The operation unit 216 is an operation member such as a power button, a release button, a playback button, a menu button, a moving image button, and various input keys. When one of the operation members of the operation unit 216 is operated by the user, the Bucom 214 executes various sequences according to the user's operation. The release button has a two-stage switch of a first release switch and a second release switch. When the release button is pressed halfway and the first release switch is turned on, the Bucom 214 performs a shooting preparation sequence such as AE processing and AF processing. In addition, when the release button is fully pressed and the second release switch is turned on, the Bucom 214 performs shooting by executing a shooting sequence.

  The flash memory 215 also stores various programs executed by the Bucom 214. The Bucom 214 reads parameters necessary for various sequences from the flash memory 215 in accordance with a program stored in the flash memory 215, and executes each process.

  The camera system 10 including the interchangeable lens 100 and the camera body 200 according to the present embodiment performs wobbling that causes the movable lens 103 to vibrate in the optical axis direction in order to detect a focal position by AF operation. The wobbling frequency is generally set to a frequency at which the camera system 10 captures images per second. A camera system capable of shooting a moving image has 30 frames / second, and wobbling at 30 Hz. However, at 30 Hz, it takes about 33 ms at least for one detection, and unless this frequency is increased, the AF operation cannot be accelerated. Therefore, it is necessary to increase the imaging frequency and the wobbling frequency.

During the wobbling operation, the AF processing unit 207 detects the focal position of the taking lens 113 based on the contrast of the taken image. However, with the digital camera, the taken image is displayed on the LCD 210 so that the photographer can display the viewfinder image. Will observe. Accordingly, if the wobbling operation amount is excessively increased, blurring increases and the level becomes unacceptable. Now, assuming that the permissible circle of confusion δ, the aperture value (effective F number) F of the photographic lens 113, and the focal depth d,
d = F · δ (1)
Since the wobbling drive amount dw is generally said to be 1/4 to 3/4 of the focal depth d,
F · δ / 4 ≦ dw ≦ 3 · F · δ / 4 (2)
The permissible circle of confusion δ has no resolution below the pixel pitch of the image sensor 202, so it is generally said that it is at least the pixel pitch and the upper limit is 4 pixels or less. That is, if the pixel pitch is p,
p ≦ δ ≦ 4 · p (3)
It becomes.

More specifically, when the pixel pitch p = 5 μm and the aperture value F = 8, the wobbling drive amount dw is
10 μm ≦ dw ≦ 120 μm
Thus, it can be seen that it is sufficient if the maximum drive amount is about 120 μm. If the amount is less than this driving amount, the photographer cannot determine the image change due to the wobbling even when wobbling.

  On the other hand, it is necessary to increase the length of the piezoelectric body in order that the actuator 111 is composed of a bimorph type plate-shaped piezoelectric body and a displacement of about 120 μm is applied by applying a DC voltage. For example, when the movable lens 103 is driven at 120 Hz with a mass of 5 g, the force required to control the movable lens 103 is 0.1 N (Newton) to 0.2 N. In order to obtain a displacement width of 120 μm, even if a soft piezoelectric material with a large displacement is used and three actuators 111 are used as in this embodiment described below, the shape of the piezoelectric bimorph is A width of 3 mm, a thickness of 1 mm, and a length of 60 mm (not including the length of supporting and fixing) are the minimum required sizes, and even at this size, only a force of about 0.1 N can be generated.

  Next, details of the drive mechanism of the movable lens 103 provided in the interchangeable lens 100 will be described with reference to FIG. Here, FIG. 2A is a front view showing an outline of a main part of the driving mechanism of the movable lens 103 as viewed from the subject side, and FIG. 2B is a sectional view taken along the line AA in FIG. FIG. 2C is a cross-sectional view taken along the line BB in FIG. It should be noted that the hatching attached to each member is merely attached so that each member can be easily identified, and does not represent a cross section, a material, or the like (the same applies to other drawings).

  The driving mechanism of the movable lens 103 includes a fixed frame 301, a plurality of rectangular plate-like actuators 111 (actuators 111a, 111b, and 111c) each supported at one end by the fixed frame 301, and the actuators 111a, 111b, and 111c. And a movable frame 302 having an outer peripheral portion fixed to the end.

  The movable lens 103 includes a movable frame 302 and a lens 303 held by the movable frame 302. The ends of the actuators 111a, 111b, and 111c are fixed to the movable frame 302 by bonding or the like. In addition, the movable lens 103 may be configured by only the lens 303 without the movable frame 302, and the lens 303 may be directly fixed to the ends of the actuators 111a, 111b, and 111c by bonding or the like. Furthermore, although the lens 303 is configured as a convex lens in the drawing, an optical element such as a concave lens or a diffraction grating may be used as long as the focal position of the photographing lens 113 can be changed by its operation.

  The actuators 111a, 111b, and 111c are arranged at an equal angle around the optical axis O1 so that the longitudinal direction thereof is along the outer periphery of the movable frame 302, and both ends in the longitudinal direction are attached to the fixed frame 301 and the movable frame 302, respectively. Yes. The shape of the actuator is shown by a rectangular plate in the figure, but may be another shape such as an arc. Further, the actuators 111a, 111b, 111c and the fixed frame 301 have the end portions of the actuators 111a, 111b, 111c fitted into the cutout portions of the fixed frame 301, and pressers 305a, 305b, 305c of a plate-like elastic body such as metal. Are fixed to the fixed frame 301 with screws 306a, 306b, and 306c, whereby the actuators 111a, 111b, and 111c are pressed against and supported by the fixed frame 301. Here, by arranging insulating sheets 307a, 307b, 307c between the actuators 111a, 111b, 111c and the pressers 305a, 305b, 305c, the actuators 111a, 111b, 111c are moved to the pressers 305a, 305b, 305c. The leakage current is prevented from flowing.

  For fixing and supporting the actuators 111a, 111b, and 111c, for example, caulking or welding other than adhesion or pressing may be used.

  In the drive mechanism of the movable lens 103 configured as described above, when the movable lens 103 is driven by the actuators 111a, 111b, and 111c, in order to detect the position of the movable lens 103 in the optical axis direction, Scales 308 a, 308 b, and 308 c made of magnets are fixed to the outer periphery, and position sensors 309 a, 309 b, and 309 c made of Hall elements that detect magnetism are arranged on the fixed frame 301 so as to face each scale. Three sets of scales and position sensors are used, but one set may be used, or control in an open loop may be performed without using them. In the present embodiment, the scales 308a, 308b, and 308c and the position sensors 309a, 309b, and 309c are arranged near the maximum displacement portions of the actuators 111a, 111b, and 111c, so that the position of the movable lens 103 can be detected more precisely. It is. If the actuators are driven independently one by one, correction including the inclination of the movable lens 103 with respect to the optical axis O1 can be performed, and wobbling can be performed with extremely high accuracy. That is, in the movable lens 103 that performs wobbling, the lens driving amount is extremely small, so that a lens having a large power is used as the lens 303. Therefore, if the lens 303 is tilted, the angle of the imaging light beam is greatly changed, so that it is necessary to incorporate the lens 303 with high accuracy so that there is no tilt. However, in this embodiment, since it is possible to correct the inclination of the lens 303 of the movable lens 103, the incorporation accuracy is not so required.

  The actuators 111a, 111b, and 111c and the position sensors 309a, 309b, and 309c are connected to an electric circuit in the interchangeable lens 100 by a flex 310 made of a flexible printed board.

  Further, even when wobbling is not performed, it is possible to correct the inclination of the optical axis and the lens interval between the movable lens 103 and other lenses with extremely high accuracy by applying different DC voltages to the actuators. In addition, when wobbling control is performed by adding a correction voltage that gives this correction displacement as an offset value to the wobbling drive signal in the case of wobbling, the wobbling control becomes simpler.

FIG. 3 shows the drive frequency f and the vibration amplitude Z of the movable lens 103 measured by actually driving this mechanism. The actuators 111a, 111b, and 111c have a width of 3 mm, a thickness of 1 mm, and lengths of 23 mm and 28 mm. The actuator length here is the actuator length L in FIG. 2A and does not include the support length. On the other hand, the mass of the movable lens 103 is 6 g, 12 g, and 25 g. A bending vibrator composed of actuators 111a, 111b, 111c with an actuator length L = 28 mm and a movable lens 103 with a mass of 6 g, an actuator 111a, 111b, 111c with an actuator length L = 23 mm, and a movable lens 103 with a mass of 12 g. In the bending vibrator constituted by the above, resonance bending vibration is generated at 120 Hz, and the vibration amplitude is maximized. In the vicinity of this resonance, the vibration amplitude exceeds 100 μm, and a displacement exceeding 200 μm is realized as the displacement. Accordingly, the vibration amplitude necessary for wobbling can be realized by setting the wobbling frequency 120 Hz in the vicinity of the resonance frequency of the bending vibrator constituted by the actuators 111a, 111b, 111c and the movable lens 103 in this way. In this case, if the resonance frequency fr of the bending vibrator composed of the actuators 111a, 111b, 111c and the movable lens 103 is the bending rigidity Kb of the actuators 111a, 111b, 111c and the mass M of the movable lens 103,
fr∝ (Kb / M) ^1/2 (4)
It becomes. FIG. 3 shows a graph of the bending vibrator with the actuator length L = 23 mm and the mass of the movable lens 103 of 12 g and 25 g. The result is as shown in the above equation (4). In other words, the bending vibrator with the mass of the movable lens 103 having a mass of 12 g has a resonance frequency of 120 Hz, whereas the bending vibrator with a mass of 25 g is around 80 Hz. From this, it can be understood that the rigidity of the actuators 111a, 111b, and 111c and the mass of the movable lens 103 may be adjusted in order to resonate the bending vibrator at the target frequency of wobbling. More specifically, the actuator length L can be adjusted by changing the fixed position to the movable frame 302 or the fixed position to the fixed frame 301. FIG. 4 shows the relationship between the applied voltage to the actuators 111a, 111b, and 111c and the vibration amplitude Z in the case of a bending vibrator having an actuator length L = 28 mm and a movable lens mass of 5 g. As described above, since the voltage linearly changes, the actuator control circuit 112 can calculate and output a drive voltage corresponding to the vibration amplitude if only the proportionality constant is stored as a parameter. It is.

  Next, the structure of the actuators 111a, 111b, and 111c used in this embodiment will be described. FIG. 5 is an exploded perspective view showing details of the actuator 111 (111a, 111b, 111c) having the same structure.

  The actuator 111 is composed of a laminated piezoelectric material configured by stacking a large number of piezoelectric plates made of piezoelectric ceramics such as lead zirconate titanate. The actuator 111 includes a first piezoelectric body 413, a second piezoelectric body 416, and a third piezoelectric body 414 that perform three different operations.

  As a basic configuration, the first piezoelectric body 413 includes a rectangular plate-shaped piezoelectric body plate 401 in which an internal electrode 401a is formed on one surface, and a rectangular plate-shaped piezoelectric body plate in which an internal electrode 402a is formed on one surface. 402 is paired to form a stacked body M412, and a plurality of stacked bodies M412 are stacked. Each internal electrode 401a, 402a is drawn out to a different side surface position (a different position in the X direction in the figure). An internal electrode is connected to every other piezoelectric plate by an external electrode Sp419 and an external electrode Gm421 formed on the side surface of the piezoelectric plate laminated and baked. Further, the external electrode Sp419 and the external electrode Gm421 are also formed on the side surface of the upper plate 411 on the uppermost surface, and the end portions are routed to the upper surface side of the upper plate 411.

  Since the second piezoelectric body 416 has the same configuration as that of the first piezoelectric body 413, only different portions will be described here. One is a side lead position of the internal electrodes 403a and 404a. The lead position of the internal electrode 403a is provided between the lead positions of the internal electrodes 401a and 402a. The lead position of the internal electrode 404a is the lead position of the internal electrode 402a. It is provided on the left side of the drawer position. Another difference is that the lower layer lower plate 417 is a single piezoelectric plate that does not form a pair, and the same internal electrode as the internal electrode 403a of the uppermost piezoelectric plate 403 of the second piezoelectric body 416 is formed. Has been. The external electrode Sm420 and the external electrode Gp422 formed corresponding to the internal electrode extraction position have the same configuration as the first piezoelectric body 413.

  The third piezoelectric body 414 is located substantially at the center of the actuator 111, and is composed of an upper center layer 414u and a lower center layer 414d. The internal electrodes 414ua and 414da have different internal electrode lead positions. That is, the internal electrode 414ua is the same as the uppermost internal electrode 401a of the first piezoelectric body 413, and the internal electrode 414da is drawn to the leftmost position. Here, the third piezoelectric body 414 is constituted by two piezoelectric plates, but may be constituted by one or three or more, and the arrangement position may not be the central position in the stacking direction. good. The third piezoelectric body 414 is provided for detecting the vibration state of the actuator 111 as a voltage signal.

  The lowermost layer of the actuator 111 is provided with a reinforcing plate 418 made of a thin metal plate. The reinforcing plate 418 prevents cracking of the actuator 111 made of ceramic against an external force. If the ceramic itself has sufficient strength, the reinforcing plate 418 need not be provided.

  The laminated piezoelectric body formed in this manner is configured such that a contact voltage connected to a high voltage source is brought into contact with the external electrode Sp419 and the external electrode Gm421, and a high voltage is applied between the two electrodes, thereby the first piezoelectric body 413. Is polarized in a polarization direction 424 indicated by an arrow in FIG. Here, “S” means a signal, “G” means ground, “p” means plus, “m” means minus, and the applied high voltage is plus on the external electrode Sp419 side and minus on the external electrode Gm421 side. It is applied so that However, this plus and minus are relative, and the plus side is usually ground. Next, by applying a high voltage between the external electrode Sm420 and the external electrode Gp422, the second piezoelectric body 416 is polarized in a polarization direction 424 indicated by an arrow in FIG. Furthermore, by applying a high voltage between the external electrode Sp419, the external electrode Sm420, and the external electrode Vp423, the third piezoelectric body 416 is polarized in the polarization direction 424 indicated by the arrow in FIG. After that, the patterns 405a, 405b, 405c, 405d, and 405e of the flex 310 corresponding to the external electrodes 419, 420, 421, 422, and 423 of the actuator 111 are electrically connected. As shown in FIG. 5, the pattern Sp405a and the pattern Sm405b, and the pattern Gm405c and the pattern Gp405d are electrically connected on the flexible board 310.

  FIG. 6 is a partially enlarged view for illustrating the polarization state of the actuator 111. The actuator 111 does not have the reinforcing plate 418 shown in FIG. The polarization directions 424 of the piezoelectric plates 401 and 402 constituting the pair of the first piezoelectric bodies 413 (laminated body M412) are polarized toward the contact surface of the pair, and the pair of the second piezoelectric bodies 416 (laminated body N415) The polarization directions 424 of the piezoelectric plates 403 and 404 that are formed are polarized toward the non-contact surface. Further, the two piezoelectric plates (upper center layer 414u and lower center layer 414d) constituting the third piezoelectric body 414 are arranged with the neutral plane of the bending of the actuator 111 interposed therebetween, and the polarization direction 424 is the same direction. It has become. As described above, the third piezoelectric body 414 is disposed with the neutral surface interposed therebetween, and when the actuator 111 is bent, one generates a tensile strain and the other generates a compressive strain. Therefore, if the polarization directions 424 are opposite to each other, the charges generated by the distortion are positive and negative at the neutral plane and cancel each other out so that no signal is output. Therefore, the polarization directions are the same.

Next, driving of the actuator 111 will be described with reference to FIG.
When one of the pattern Sp405a and the pattern Gm405c of the flex 310 is connected to the ground of the actuator control circuit 112 and the other is connected to the signal output terminal of the actuator control circuit 112, a signal voltage is applied to the actuator 111 from the actuator control circuit 112. Thus, since the pattern Sp405a and the pattern Sm405b are connected and the pattern Gm405c and the pattern Gp405d are connected, one of the first piezoelectric body 413 and the second piezoelectric body 416 extends in the longitudinal direction (X direction) and the other contracts. . Here, since the first piezoelectric body 413, the second piezoelectric body 416, and the third piezoelectric body 414 are integrally fired in the actuator 111, the actuator 111 bends in the plate thickness direction (Z direction).

  On the other hand, due to the bending of the actuator 111, the third piezoelectric body 414 is also bent to generate distortion. Due to this distortion, an electric charge is generated in the electrode 414da of the third piezoelectric body 414, and the bending state of the actuator 111 is output as a voltage signal. This voltage signal is input to the actuator control circuit 112 through the pattern Vp405e of the flex 310 and used as a signal for controlling the operation of the actuator 111.

  Here, in order to bend the actuator 111, a bimorph using the first piezoelectric body 413 and the second piezoelectric body 416 is used. However, a monomorph having only the first piezoelectric body 413 is formed on the lower side of the first piezoelectric body 413. Even if a rectangular plate-like elastic body made of a material such as ceramics or metal is fixed, a bending actuator can be formed. In this case, when the first piezoelectric body 413 extends in the X direction, the elastic body itself hardly stretches, so that the first piezoelectric body 413 side is bent so as to be convex, and conversely, the first piezoelectric body 413 is in the X direction. When contracted, the elastic body is hardly contracted, so that the first piezoelectric body 413 is bent so as to be concave. In the case of this configuration, the elastic body itself reinforces the piezoelectric body, so that the reinforcing plate 418 is not necessary.

Next, the relationship between the drive signal when wobbling the movable lens 103, the operation of the movable lens 103, and the imaging operation at the time of detecting the focal position will be described with reference to FIG.
FIG. 8 (1) shows a drive signal applied to the actuator 111. As for the frequency of this drive signal, when one end of the actuator 111 is fixed to the movable lens 103 and the other end is supported by the fixed frame 301, the bending resonance of the bending vibrator constituted by the actuator 111 and the movable lens 103 is achieved. In addition, a frequency that becomes the imaging frequency is selected. This drive signal is a sine wave, and bending resonance can be generated efficiently. Even a waveform such as a rectangular wave, a triangular wave, or a trapezoidal wave other than a sine wave can be driven. The bending resonance will be described in detail later.

  FIG. 8 (2) shows the position of the movable lens 103 at the time when the movable lens 103 vibrates in the optical axis direction due to bending resonance that occurs when the drive signal of FIG. 8 (1) is applied to the actuator 111. FIG. Due to the bending resonance, the operation of the movable lens 103 is shifted in phase by the phase difference Δθp with respect to the drive voltage. Furthermore, unless image capturing is performed at a predetermined position of the movable lens 103, sufficient image contrast cannot be obtained, and the AF processing unit 207 cannot correctly determine the focus evaluation value. Therefore, it is necessary to capture an image in a range of an allowable contrast range for determination.

Specifically, FIG. 9 shows the frequency f of the drive signal near the bending resonance frequency of the bending vibrator constituted by the actuator 111 and the movable lens 103, the vibration amplitude of the movable lens 103, and the above-described phase difference Δθp. .
At a resonance frequency of 120 Hz, the vibration amplitude is maximum and the phase difference Δθp is around 90 °. In the non-resonant state below the resonance frequency, the phase difference Δθp is around 0 °, and in the case of non-resonance above the resonance frequency, the phase difference Δθp is around 180 °. In the case of ideal resonance, the phase difference Δθ smoothly changes from 0 ° before resonance to 90 ° toward the resonance point, 90 ° at the resonance point, and smoothly to 180 ° after resonance. Change. Actually, it does not become an ideal state as shown in FIG. 9, and changes depending on variations in the material and shape of parts and in assembly. Therefore, in the case of precise control, this phase difference Δθp is controlled. It is necessary to correct with.

  FIG. 8 (3) is a diagram showing the imaging operation, and imaging is performed at timings corresponding to the allowable contrast range of FIG. 8 (2). The photographing is performed alternately between a front position imaging period in which the movable lens 103 is in the front position and a rear position imaging period in which the movable lens 103 is in the rear position. At this time, the difference between the drive signal of the actuator 111 and the imaging timing becomes the phase difference Δθ. This phase difference Δθ includes the phase difference Δθp, and varies depending on variations in parts related to the wobbling mechanism and assembly variations. Therefore, the phase difference Δθ is measured in advance when the interchangeable lens 100 is manufactured, and the flash memory of the interchangeable lens 100 is thus measured. 109 and the like, and when wobbling, the value is called to correct the phase of the drive signal of the actuator control circuit 112.

FIG. 10 is a diagram showing an outline of the actuator control circuit 112, and FIG. 11 is a timing chart showing signals from the main components of the circuit corresponding to FIG.
From the Lucom 108, a signal Sig 1 obtained by correcting the phase difference Δθ with reference to the imaging synchronization signal received from the Bucom 214 is input to the D / A converter control circuit 432. In the D / A converter control circuit 432, + A is output as DATA when the signal Sig1 is High, and -A is output as DATA when the signal Sig1 is Low, and is input to the D / A converter 433. Here, A is the amplitude value of the drive signal, but is instructed by the Lucom 108 via the bus 431. The output signal Sig2 of the D / A converter 433 is input to the amplifier 435 and amplified, and then input to the low-pass filter 436, where the high frequency component is removed and output as a pseudo sine wave. The signal output from the low-pass filter 436 is amplified by the amplifier 437 and added to the first piezoelectric body 413 and the second piezoelectric body 416 of the actuator 111 as the drive signal Sig3.

  On the other hand, a voltage signal corresponding to the vibration state of the bending vibrator from the third piezoelectric body 414 of the actuator 111 is input to the low pass filter 438, and the high frequency component is removed to become the detection signal Sig4. This detection signal Sig4 is converted into digital data by the A / D converter 439, and then the phase difference Δθ with respect to the signal Sig1 is detected by the phase difference detection circuit 440 and input to the Lucom 108 as digital data. Correction of the phase with the synchronizing signal is performed.

  By adopting such a configuration of the actuator control circuit 112, even when driving near the resonance of the bending vibrator constituted by the movable lens 103 and the actuator 111, the phase difference of the vibration of the movable lens 103 with respect to the drive signal is corrected. Drive is possible, and high-speed and high-precision position control is possible.

  In the actuator control circuit 112, the D / A converter control circuit 432 is provided. However, the D / A converter 433 may be directly controlled from the Lucom 108, and the amplifiers 435 and 437 are not essential and are necessary. It may be provided accordingly. Further, the signal from the third piezoelectric body 414 of the actuator 111 is used to detect the vibration state, but the phase difference is detected using the signal from the position sensor 110 that detects the position of the movable lens 103. May be.

  Next, the operation of the camera system 10 in this embodiment will be described using the flowchart shown in FIG. When the power button is operated and the power is turned on, the Bucom 214 starts the operation of the main flow shown in FIG.

  When the operation is started, first, the Bucom 214 performs initialization at the time of system startup, and initializes the recording flag to OFF (step S1). This recording flag is a flag indicating whether or not a moving image is being recorded. When it is ON, it indicates that a moving image is being recorded. When it is OFF, it indicates that no moving image is being recorded.

  When the initialization at the time of system startup is completed, the Bucom 214 detects accessories such as the interchangeable lens 100 connected to the camera body 200 (step S2), and detects operation switches such as a playback button ( Step S3), live view display is performed (step S4). Here, an image signal is acquired by the image sensor 202, image processing is performed for live view display, and live view display is performed on the LCD 210. Next, it is determined whether or not the playback button has been pressed (step S5). If the result of this determination is that the playback button has been pressed, playback is performed (step S11). Here, image data is read from the recording medium 212 and displayed on the LCD 210.

  After the reproduction is executed in step S11 or when the reproduction button is not pressed in step S5, it is next determined whether or not the moving image button is pressed (step S6). In this step, the operation state of the moving image button is detected by the operation unit 216, and a determination is made based on the detection result. If the moving image button is pressed as a result of this determination, the recording flag is reversed (step S12). As described above, every time the movie button is pressed, the movie shooting start and end are alternately repeated. Therefore, in this step, if the recording flag is OFF, it is ON, and if it is ON, Is turned OFF and the recording flag is inverted.

  After inverting the recording flag in step S12 or if the result of determination in step S6 is that the movie button has not been pressed, it is next determined whether or not movie recording is in progress (step S7). ). If the recording flag is ON, the moving image is being recorded. Here, the determination is made based on whether the recording flag is ON.

  If the result of determination in step S7 is that video recording is not in progress, it is next determined whether or not the first release has been pressed, in other words, whether or not the first release switch has been turned from OFF to ON. (Step S8). This determination is performed based on the detection result of the operation of the first release switch that is linked to the release button. In this step, it is determined whether the first release switch has changed from OFF to ON. If the ON state is maintained, the determination result is NO.

  If the result of determination in step S8 is that the first release has been pressed, an image is taken when the first release is pressed, and AE is performed (step S9). In this image shooting, an image signal is acquired by the image sensor 202, image processing is performed, and image data used for AE is acquired. The image data is not recorded on the recording medium 212.

  In this AE, an AE processing unit 205 measures subject brightness from image data, determines an exposure control value such as an aperture value and a shutter speed, and controls values for performing live view display on the LCD 210 with appropriate exposure. Decide.

  If AE is performed in this way, then AF is performed (step S10). Here, the movable lens 103 is wobbled, the AF processing unit 207 evaluates the contrast of the image data acquired by the image sensor 202 and detects the direction of the focal position, and the Lucom 108 moves the focus lens 101 in the detection direction. The focus lens 101 is driven and controlled so that the image has the highest contrast. Details will be described later with reference to FIG.

  If the result of determination in step S8 is that the release button has not been pressed and the first release switch has not changed from OFF to ON, it is next determined whether or not the second release has been pressed. Is fully pressed, and it is determined whether or not the second release switch is turned from OFF to ON (step S13). In this step, the state of the second release switch linked to the release button is detected by the operation unit 216, and a determination is made based on the detection result.

  If the result of determination in step S13 is that the second release has been pressed, still image shooting is performed (step S14). Here, the image sensor 202 performs exposure, acquires an image signal corresponding to the subject image, and temporarily stores it in the SDRAM 213. When still image shooting is performed in this manner, the image processing unit 206 reads out an image signal from the SDRAM 213, performs image processing on still image data based on the image signal (step S15), and further performs an image compression / decompression unit. After performing the image compression processing by 208, the image is recorded on the recording medium 212 (step S16).

  If the result of determination in step S7 is that moving image recording is in progress, next, the AE processing unit 205 performs AE operation as in step S9 (step S17). Subsequently, an AF operation is performed by the AF processing unit 207 (step S18), and then moving image shooting is performed (step S19). Here, an image signal of a moving image is acquired by the image sensor 202, the image processing unit 206 performs image processing on the image data (step S20), the image compression / decompression unit 208 performs image compression of the moving image, and then the moving image Image data is recorded on the recording medium 212 (step S21).

  When the AF operation is completed in step S10, or when the release button is not fully pressed as a result of the determination in step S13, or in step S16, the image data recording medium 212 of the still image is displayed. When recording to the recording medium 212 is completed, or when recording of moving image data to the recording medium 212 is completed in step S21, it is determined whether or not the power switch of the operation unit 216 is turned off (step S22). ). If the result of this determination is that the power supply is not OFF, processing returns to step S5. On the other hand, if the result of determination is that the power supply is OFF, the main flow is ended after performing the main flow end operation.

Next, the operation of AF with wobbling related to the present invention will be described using the flowchart shown in FIG.
When the AF operation is called in step S10, the Bucom 214 first determines whether or not the AF mode setting state of the camera system 10 is set to the mode for operating wobbling by the operation unit 216 (step S101). When the determination is not a mode for operating wobbling, an operation for controlling the focus lens 101 at a position where the contrast is maximized by determining the contrast of a general captured image is omitted although details are omitted.

  On the other hand, if the determination in step S101 is the AF mode in which wobbling is performed, the wobbling frequency, the voltage value A (see DATA in FIG. 11) corresponding to the wobbling amplitude, and the phase difference θ are obtained from the flash memory 109. The data is read and set in the Lucom 108 via the I / F 219 (step S102).

  In accordance with the wobbling setting in step S102, the Lucom 108 drives the actuator 111 by the actuator control circuit 112 to wobble the movable lens 103 in the optical axis direction (step S103). Since the wobbling operation is synchronized with the shooting synchronization signal with a phase difference θ, the movable lens 103 is shot at a position close to the subject (front position), and the movable lens 103 is far from the subject (rear side). The state of shooting at the side position is alternately repeated (step S104).

  The contrast of the image data of the front side position and the image data of the rear side position thus captured is compared by the AF processing unit 207, and the direction of the focal position is sequentially detected (step S106). Next, the Bucom 214 determines whether or not the contrast detected from the captured image data is within the in-focus tolerance (step S107). If it is not within the tolerance, the focus is set to the Lucom 108 via the I / F 219. An instruction is given to drive the lens 101 by a predetermined amount in the direction of the detected focal position (step S108), and the process returns to step S103.

  On the other hand, if the determination is within the tolerance, the Lucom 108 is instructed to stop the wobbling of the movable lens 103 and the driving of the focus lens 101 via the I / F 219 (step S109), and the main flow is entered. Return.

  Whether or not the contrast is acceptable in step S107 is determined by comparing the contrast of the image data captured at the front position and the image data captured at the rear position. If the contrast difference is zero, In this state, the movable lens 103 is in a substantially intermediate position between the front side position and the rear side position. Therefore, when the wobbling is stopped in that state, the movable lens 103 stops at a focused position.

  As described above, according to the first embodiment, in the drive device that drives the movable lens 103 that is an optical member in a vibration manner in the optical axis direction with respect to the fixed frame 301 that is a fixed member, the movable lens 103 is A plurality of actuators 111 that are fixed to one end and supported by the fixed frame 301 at the other end and that bend and displace at least in the optical axis direction in response to voltage application, the movable lens 103, and the plurality of actuators 111. An actuator control circuit 112 that vibrates and displaces the movable lens 103 in the optical axis direction by driving the plurality of actuators 111 so as to vibrate the bending vibrator to be oscillated at a frequency near the bending vibration resonance. Thus, the movable lens 103 can be moved at high speed by vibrating the bending vibrator at a frequency near the bending vibration resonance. A precise drive controllable, even if vibration driving the movable lens 103 can provide a driving device generate less vibration and sound.

  Here, the actuator 111 has a plate shape, and when a voltage is applied in the plate thickness direction, the first piezoelectric body 413 that expands and contracts in a direction orthogonal to the plate thickness direction and an elastic body fixed to the first piezoelectric body 413. The first piezoelectric body 413 and the first piezoelectric body 413 have a plate shape, and are fixed to the first piezoelectric body 413 with the longitudinal direction and the plate pressure direction aligned, and voltage is applied in the plate thickness direction. In addition, it may be a bimorph composed of a second piezoelectric body 416 that expands and contracts in a direction orthogonal to the plate thickness direction and in a direction opposite to the first piezoelectric body 413.

  In addition, the actuator 111 further includes a third piezoelectric body 414 that has a plate shape and generates electric charge according to at least the expansion and contraction state of the first piezoelectric body, so that an output signal of the third piezoelectric body 414 is obtained. Can be used as a signal for controlling the operation of the actuator 111.

  The movable lens 103 may be one of a plurality of lenses constituting the photographing lens 113 and may be incorporated in the focus lens 101 or the variable power lens 102.

  Further, according to the first embodiment, the in-focus position is detected based on the image data acquired by the image sensor 202 from the optical device formed by the driving device according to the first embodiment and the photographing lens 113, and the An AF processing unit 207 that outputs focus control information based on the detected in-focus position, and the focus lens 101 of the plurality of lenses constituting the photographing lens 113 are driven according to the focus control information from the AF processing unit 207. The drive timing of the actuator 111 by the actuator control circuit 112 so as to synchronize with a predetermined phase difference with respect to the Lucom 108 and the driver 105 as focusing drive means and the image data acquisition operation of the image sensor 202. And Bucom 214 as a timing control means for controlling the Thus, by vibrating the bending vibrator at a frequency near the bending vibration resonance, the movable lens 103 can be driven and controlled with a large amount of displacement at high speed and with precision. An autofocus device that is less likely to occur can be provided.

  In addition, according to the first embodiment, in an imaging device such as the camera system 10 including the photographing lens 113 including a plurality of lenses and the image sensor 202, the driving device according to the first embodiment and the photographing described above. An AF processing unit 207 that detects a focal point position based on image data acquired by the imaging element 202 from an optical image formed by the lens 113 and outputs focus control information based on the detected focal point position; Acquisition of the image data of the imaging device 202 and the Lucom 108 and the driver 105 as focusing drive means for driving the focus lens 101 of the plurality of lenses constituting the photographing lens 113 according to the focus control information from the unit 207 The actuator control circuit 112 is synchronized with the operation with a predetermined phase difference. And Bucom 214 as a timing control means for controlling the drive timing of the actuator 111 according to the above, by causing the bending vibrator to vibrate at a frequency near the bending vibration resonance, the movable lens 103 can be moved at a high speed with a large displacement. In addition, it is possible to provide an imaging device that can be precisely driven and controlled so that even when the movable lens 103 is driven to vibrate, vibration and sound are less generated.

  In addition, according to the first embodiment, in a lens device including the photographing lens 113 including a plurality of lenses, a combination of the driving device according to the first embodiment and an optical image formed by the photographing lens 113 is detected. Lucom 108 and a driver 105 as focus drive means for receiving the focus control information based on the focal position and driving the focus lens 101 of the plurality of lenses constituting the photographing lens 113 according to the focus control information. Thus, by vibrating the bending vibrator at a frequency near the bending vibration resonance, the movable lens 103 can be driven and controlled with a large amount of displacement at high speed and with precision. It is possible to provide a lens device that is less likely to occur.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In the first embodiment, the movable lens 103 that is an optical member is wobbled with respect to the fixed frame 301 that is a fixed member. However, in the second embodiment, the movable lens 103 is an optical member with respect to the holder 228 that is a fixed member. The image sensor 202 is wobbling. Since the operation and the like are the same as those in the first embodiment, the mechanism will be described here, and the description of the operation and the like will be omitted.

  FIG. 14A is a front view for explaining the configuration of the wobbling mechanism of the image sensor in the driving apparatus according to the second embodiment, and FIG. 14B is the AA line side of the wobbling mechanism of FIG. 14C is a cross-sectional view taken along the line BB of the wobbling mechanism of FIG. 14A, and FIG. 14D is a cross-sectional view taken along the line CC of the wobbling mechanism of FIG. 14C. It is.

  The image sensor 202 includes a light receiving element 501, a case 502, and a protective glass 503. A light receiving element 501 such as a CCD or a CMOS is arranged on the bottom surface of a case 502 having a rectangular parallelepiped box shape, and an electrical terminal drawn from the light receiving element 501 to the rear side of the case 502 is a circuit arranged behind the case 502. It is electrically connected to the substrate 504. On the other hand, a rectangular plate-shaped protective glass 503 made of transparent glass, resin, or the like is fixed to the front side of the case 502 so as to seal the light receiving element 501. The rear surface of the case 502 is fixed to the front surface formed near the center of the holding plate 505 made of a metal plate such as aluminum or stainless steel by bonding or the like.

  In addition, strip-shaped actuators 111 a, 111 b, and 111 c are arranged on the rear side of the holding plate 505 along the long side direction (X direction) of the image sensor 202, and one end portion is a rear side surface from the holding plate 505. It is fixed by adhesive etc. to the part protruding to the surface. Two fixing positions are provided at the Y-direction end on one short side of the holding plate 505, and one is provided near the center of the short side on the other short side. Furthermore, the other ends of the actuators 111a, 111b, and 111c are pressed by screws 306a, 306b, and 306c so as to be sandwiched by the pressers 305a, 305b, and 305c with respect to the surface partially protruding forward from the holder 228. By fixing 305c to the holder 228, the actuators 111a, 111b, and 111c are pressed against and supported by the holder 228.

  With such a configuration, the actuators 111a, 111b, and 111c extending in the XY plane can be arranged in a small space. In addition, when the actuators 111a, 111b, 111c support the holding plate 505 at a position close to an equilateral triangle, the generated force of the actuators 111a, 111b, 111c can be applied to the holding plate 505 in a well-balanced manner and resonated. Unnecessary vibration does not occur and a large amplitude can be obtained. In this case, the same effect can be obtained even if the isosceles triangle is arranged or the non-isosceles triangle is arranged so that the acting force and moment are symmetrical.

  In the second embodiment, since the image sensor 202 is wobbling, the focal position information can be detected by wobbling even when the interchangeable lens 100 does not have a wobbling mechanism. In this case, the Bucom 214 controls the actuator control circuit 112 that drives the actuator 111.

  In addition, by individually applying DC voltage values to the actuators 111a, 111b, and 111c, it is possible to precisely adjust the tilt of the image sensor 202 and the position in the optical axis direction (Z direction). In addition, the position adjustment of the image sensor 202 that has been adjusted by a screw feed mechanism or the like can be performed very easily. In this adjustment, the adjustment value is stored in a storage element such as a flash memory. Therefore, if the position of the image sensor 202 is measured with the interchangeable lens 100 removed, the adjustment in the camera state is also possible. Conventionally, since adjustment was possible only during the assembly of the camera, the adjustment sometimes changed due to the assembly work after the adjustment. Further, even when the member expands and contracts depending on the use environment of the camera and the position of the image sensor 202 changes, the change in the position of the image sensor 202 due to the temperature change is measured in advance, and the data is used as the image sensor correction data. In other words, the position of the image sensor 202 can be adjusted in accordance with the measured temperature of the temperature sensor of the camera.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed within a scope not departing from the gist or concept of the invention that can be read from the claims and the entire specification. Cameras and camera systems are also included in the technical scope of the present invention.

  As described above, according to the second embodiment, in the driving device that drives the imaging element 202 that is an optical member in a vibrational manner in the optical axis direction with respect to the holder 228 that is a fixing member, the imaging element 202 is one end. A plurality of actuators 111 that are fixed to the other end and supported by the holder 228 at the other end and bent and displaced at least in the optical axis direction in response to voltage application, the imaging element 202, and the plurality of actuators 111. An actuator control circuit 112 that vibrates and displaces the imaging element 202 in the optical axis direction by driving the plurality of actuators 111 so as to vibrate the bending vibrator at a frequency near the bending vibration resonance; By vibrating the bending vibrator at a frequency in the vicinity of bending vibration resonance, the image pickup device 202 is driven at high speed and with high precision. Controllable, even if vibration driving the imaging device 202 can provide a driving device generate less vibration and sound.

  Here, the actuator 111 has a plate shape, and when a voltage is applied in the plate thickness direction, the first piezoelectric body 413 that expands and contracts in a direction orthogonal to the plate thickness direction and an elastic body fixed to the first piezoelectric body 413. The first piezo-electric body 413 has a plate shape and is fixed to the first piezo-electric body 413 with the longitudinal direction and the plate pressure direction aligned, and a voltage is applied in the plate thickness direction. And a bimorph composed of a second piezoelectric body 416 that expands and contracts in a direction orthogonal to the plate thickness direction and in a direction opposite to the first piezoelectric body 413.

  In addition, the actuator 111 further includes a third piezoelectric body 414 that has a plate shape and generates electric charge according to at least the expansion and contraction state of the first piezoelectric body, so that an output signal of the third piezoelectric body 414 is obtained. Can be used as a signal for controlling the operation of the actuator 111.

  Further, according to the second embodiment, the in-focus position is detected based on the image data acquired by the imaging device 202 from the optical device formed by the driving device according to the second embodiment and the photographing lens 113, and the An AF processing unit 207 that outputs focus control information based on the detected in-focus position, and the focus lens 101 of the plurality of lenses constituting the photographing lens 113 are driven according to the focus control information from the AF processing unit 207. The drive timing of the actuator 111 by the actuator control circuit 112 so as to synchronize with a predetermined phase difference with respect to the Lucom 108 and the driver 105 as focusing drive means and the image data acquisition operation of the image sensor 202. And Bucom 214 as a timing control means for controlling the Thus, by vibrating the bending vibrator at a frequency in the vicinity of the bending vibration resonance, the image pickup element 202 can be driven and controlled with a large amount of displacement at high speed and with precision. An autofocus device that is less likely to occur can be provided.

  In addition, according to the second embodiment, in an imaging device such as the camera system 10 including the photographing lens 113 including a plurality of lenses and the image sensor 202, the driving device according to the second embodiment and the photographing described above. An AF processing unit 207 that detects a focal point position based on image data acquired by the imaging element 202 from an optical image formed by the lens 113 and outputs focus control information based on the detected focal point position; Acquisition of the image data of the imaging device 202 and the Lucom 108 and the driver 105 as focusing drive means for driving the focus lens 101 of the plurality of lenses constituting the photographing lens 113 according to the focus control information from the unit 207 The actuator control circuit 112 is synchronized with the operation with a predetermined phase difference. And Bucom 214 as a timing control means for controlling the drive timing of the actuator 111, the image sensor 202 can be driven at a high speed with a large amount of displacement by vibrating the bending vibrator at a frequency near the bending vibration resonance. In addition, it is possible to provide an imaging device that can be precisely driven and controlled so that even when the imaging element 202 is driven to vibrate, vibration and sound are less generated.

  In addition, according to the second embodiment, in an imaging device such as the camera body 100 including the image sensor 202, the focus is based on the drive device according to the second embodiment and the image data acquired by the image sensor 202. An AF processing unit 207 that detects a position and outputs focus control information based on the detected in-focus position, and synchronizes with an acquisition operation of the image data of the image sensor 202 with a predetermined phase difference. And Bucom 214 as a timing control means for controlling the drive timing of the actuator 111 by the actuator control circuit 112, so that the bending vibrator can be vibrated at a frequency in the vicinity of the bending vibration resonance with a large amount of displacement. Therefore, the image sensor 202 can be driven and controlled at high speed and precisely, and the image sensor 202 can be driven by vibration. It is possible to provide an image device generate less vibration and sound.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. is there.

  For example, in the embodiment, the camera system 10 capable of exchanging the interchangeable lens 100 with respect to the camera body 200 has been described as an example. However, a camera in which the lens cannot be replaced may be used.

  The present invention is not limited to the form of the lens of the digital camera described in the above-described embodiment, but is a recording device, a mobile phone, a PDA, a personal computer, a game machine, a digital media player, a television, a GPS, It can also be applied to electronic devices such as watches.

  Further, the present invention can be similarly applied to an imaging apparatus having an imaging function and having an autofocus device such as a telescope, binoculars, a projector, and a microscope.

    DESCRIPTION OF SYMBOLS 10 ... Camera system, 100 ... Interchangeable lens, 101 ... Focus lens, 102 ... Variable magnification lens, 103 ... Movable lens, 105, 106, 107 ... Driver, 108 ... Microcomputer (Lucom) for lens control, 109 ... Flash memory, DESCRIPTION OF SYMBOLS 110 ... Position sensor 111, 111a, 111b, 111c ... Actuator, 112 ... Actuator control circuit, 113 ... Shooting lens, 200 ... Camera body, 202 ... Image sensor, 207 ... AF processing part, 214 ... Microcomputer for body control ( Bucom), 228 ... holder, 301 ... fixed frame, 302 ... movable frame, 303 ... lens, 306a, 306b, 306c ... screw, 307a, 307b, 307c ... insulating sheet, 308a, 308b, 308c ... Kale, 309a, 309b, 309c ... position sensor, 310 ... flexible, 412 ... laminate M, 419 ... external electrode Sp, 421 ... external electrode Gm, 420 ... external electrode Sm, 422 ... external electrode Gp, 423 ... external electrode Vp 401a, 402a, 403a, 404a, 414ua, 414da ... internal electrodes, 401, 402, 403, 404 ... piezoelectric plate, 405a ... pattern Sp, 405b ... pattern Sm, 405c ... pattern Gm, 405d ... pattern Gp, 405e ... Pattern Vp, 411 ... upper plate, 413 ... first piezoelectric body, 414 ... third piezoelectric body, 414u ... upper center layer, 414d ... lower center layer, 416 ... second piezoelectric body, 417 ... lower plate, 418 ... reinforcing plate 424: Polarization direction, 431: Bus, 432: D / A converter Control circuit, 433 ... D / A converter, 435,437 ... Amplifier, 436,438 ... Low pass filter, 439 ... A / D converter, 440 ... Phase difference detection circuit, 501 ... Light receiving element, 502 ... Case, 503 ... Protective glass 504 ... Circuit board, 505 ... Holding plate.

Claims (10)

A driving device for oscillatingly driving the optical member in the optical axis direction with respect to the fixed member,
A plurality of actuators that are fixed at one end and supported by the fixing member at the other end, and are bent and displaced at least in the optical axis direction in response to voltage application;
An actuator control circuit for driving the plurality of actuators;
Comprising
The actuator control circuit drives the plurality of actuators to vibrate a bending vibrator constituted by the optical member and the plurality of actuators at a frequency in the vicinity of bending vibration resonance, thereby causing the optical member to move to the optical member. Displace the vibration in the axial direction ,
The frequency of the bending vibration resonance of the bending vibrator driving apparatus according to claim frequency der Rukoto of the optical axis direction of the vibration displacement of the optical member. The frequency fr of the bending vibration resonance of the bending vibrator is as follows. If the rigidity of the plurality of actuators is kb and the mass of the optical member is M,
fr∝ (Kb / M) ^1/2
And
2. The driving device according to claim 1, wherein the plurality of actuators and the optical member have rigidity kb and mass M adjusted based on a frequency of vibration displacement of the optical member in the optical axis direction. The actuator is
It consists of a first piezoelectric body that has a plate shape and expands and contracts in a direction orthogonal to the plate thickness direction when a voltage is applied in the plate thickness direction, or
The first piezoelectric body has a plate shape, and is fixed to the first piezoelectric body with the longitudinal direction and the plate pressure direction aligned, and when a voltage is applied in the plate thickness direction, the direction orthogonal to the plate thickness direction in and expands and contracts in the first piezoelectric body and the opposite direction, a second piezoelectric body consisting of a drive device according to claim 1 or 2, characterized in that. The drive device according to claim 3 , wherein the actuator further includes a third piezoelectric body that has a plate shape and generates an electric charge corresponding to at least the expansion and contraction state of the first piezoelectric body. The optical member driving device according to any one of claims 1 to 4, characterized in that at least one of the plurality of lenses constituting the imaging lens. The optical member driving device according to any one of claims 1 to 4, characterized in that an image pickup element. A driving device according to any one of claims 1 to 4 ,
An autofocus processing unit that detects a focal point position based on image data acquired by an imaging element from an optical image formed by the photographing lens and outputs focus control information based on the detected focal point position;
In accordance with focus control information from the autofocus processing unit, focusing drive means for driving a focus lens among a plurality of lenses constituting the photographing lens,
Timing control means for controlling the drive timing of the actuator by the actuator control circuit so as to be synchronized with a predetermined phase difference with respect to the image data acquisition operation of the image sensor;
Comprising
The autofocus device, wherein the optical member is one of a plurality of lenses constituting the photographing lens or the imaging element. An imaging device comprising a photographic lens including a plurality of lenses and an image sensor,
A driving device according to any one of claims 1 to 4 ,
An autofocus processing unit that detects a focal position based on image data acquired by the imaging element from an optical image formed by the photographing lens, and outputs focus control information based on the detected focal position;
In accordance with focus control information from the autofocus processing unit, focusing drive means for driving a focus lens among a plurality of lenses constituting the photographing lens,
Timing control means for controlling the drive timing of the actuator by the actuator control circuit so as to be synchronized with a predetermined phase difference with respect to the image data acquisition operation of the image sensor;
Comprising
The image device, wherein the optical member is one of a plurality of lenses constituting the photographing lens or the imaging element. An imaging device including an image sensor,
A driving device according to any one of claims 1 to 4 ,
An autofocus processing unit that detects a focal position based on image data acquired by the imaging element and outputs focus control information based on the detected focal position;
Timing control means for controlling the drive timing of the actuator by the actuator control circuit so as to be synchronized with a predetermined phase difference with respect to the image data acquisition operation of the image sensor;
Comprising
The image device, wherein the optical member is the imaging device. A lens apparatus including a photographing lens including a plurality of lenses,
A driving device according to any one of claims 1 to 4 ,
Focus drive means for receiving focus control information based on a focus position detected from an optical image formed by the photographing lens, and driving a focus lens among a plurality of lenses constituting the photographing lens according to the focus control information When,
Comprising
The lens device according to claim 1, wherein the optical member is one of a plurality of lenses constituting the photographing lens.

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