Image blurring correcting apparatus and imaging apparatus

The present invention provides an image blurring correcting apparatus comprising: a correcting optical system which corrects image blurring; a parallel link member which is arranged in parallel with an imaging optical axis and supports the correcting optical system with free parallel movement in the direction perpendicular to the imaging optical axis; and a driving force generating device with one end being fixed to a fixed part of the parallel link member and a movable end on the other end being connected to the correcting optical system, wherein the driving force generating device is driven to move the correcting optical system parallel in the direction perpendicular to the imaging optical axis by the parallel link member so as to correct the image blurring.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image blurring correcting apparatus and an imaging apparatus, and particularly to an image blurring correcting apparatus for correcting image blurring generated by hand movement and an imaging apparatus having the image blurring correcting apparatus.

2. Description of the Related Art

An image blurring correcting apparatus is, as described in Japanese Patent Application Laid-Open No. 9-80550 for example, composed of a correcting lens for correcting image blurring, a guide member for guiding the correcting lens in the direction perpendicular to an imaging optical axis with free movement, a deflection detection sensor for detecting deflection of a camera, a voice coil motor which is an actuator of the correcting lens, or the like. This image blurring correcting apparatus drives the correcting lens by the electromagnetic force of the voice coil motor to the direction opposite to the deflection direction so as to compensate movement due to the deflection of the camera obtained by a detection output of the deflection detection sensor.

In addition, there is also known the image blurring correcting apparatus, as described in Japanese Patent Application Laid-Open No. 2002-350917, provided with a compensator lens supported movably in the direction perpendicular to an optical axis and a rocking shaft with one end supported swingably by a fixed part and the compensator lens being connected to the other end so that the rocking shaft swings to drive the compensator lens in the direction to correct the image blurring.

SUMMARY OF THE INVENTION

However, the image blurring correcting apparatus disclosed in the Japanese Patent Application Laid-Open No. 9-80550 has the problem that the voice coil motor is arranged in the side of the correcting optical system and the restrictions of the shape of the voice coil motor cause the correcting optical system and a lens barrel which accommodates the voice coil motor to be large-sized and flat shape, resulting in the lens barrel being unable to be miniaturized.

In addition, the image blurring correcting apparatus disclosed in Japanese Patent Application Laid-Open 2002-350917 has the problem that the compensator lens is inclined with respect to the imaging optical axis due to the swing of the rocking shaft, which requires to dispose a dedicated mechanism for compensating the inclination at a support part of the rocking shaft or a connection part of the rocking shaft and the compensator lens in order to solve the problem, resulting in the complexity of the mechanism and the difficulty in manufacturing.

The present invention is made in view of such a situation and an object thereof is to provide an image blurring correcting apparatus which can miniaturize the lens barrel with a simple structure and the imaging apparatus provided with the image blurring correcting apparatus.

In order to accomplish the foregoing object, an image blurring correcting apparatus according to a first aspect comprising: a correcting optical system which corrects image blurring; a parallel link member which is arranged in parallel with an imaging optical axis and supports the correcting optical system with free parallel movement in the direction perpendicular to the imaging optical axis; and a driving force generating device with one end being fixed to a fixed part of the parallel link member and a movable end on the other end being connected to the correcting optical system, wherein the driving force generating device is driven to move the correcting optical system parallel in the direction perpendicular to the imaging optical axis by the parallel link member so as to correct the image blurring.

According to the image blurring correcting apparatus of the first aspect, the correcting optical system is supported with free parallel movement in the direction perpendicular to the imaging optical axis by the parallel link member arranged in parallel with the imaging optical axis, and the driving force generating device with one end being fixed to the fixed part of the parallel link member and the movable end on the other end being connected to the correcting optical system moves the correcting optical system parallel in the direction perpendicular to the imaging optical axis by the parallel link member so as to correct the image blurring. In other words, the image blurring correcting apparatus of the present invention is able to support the correcting optical system in the direction perpendicular to the imaging optical axis with the simple structure by supporting the correcting optical system with the parallel link member, and to prevent an optical axis of the moved correcting optical system being inclined with respect to the imaging optical axis by an effect of the parallel link member. In addition, since the parallel link member and the driving force generating device are disposed in the direction of the imaging optical axis, an area of a plane in the direction perpendicular to the imaging optical axis becomes small, and thereby the lens barrel becomes small.

A second aspect of the present invention is characterized by the driving force generating device in the first aspect being a bimorph piezoelectric actuator.

According to the second aspect, the bimorph piezoelectric actuator constituted by pasting thin sheets of piezoelectric ceramics together via a metal plate of an electrode or directly is applied as the driving force generating device. A voltage is applied to the bimorph piezoelectric actuator to provide a potential, and resulting piezoelectric transversal effect is used to expand one of the two thin sheets and contract the other to obtain bending displacement, which causes the correcting optical system to move in the direction to correct the image blurring. Since the bimorph piezoelectric actuator is in a sheet form and disposed along the imaging optical axis, a disposition space in the lens barrel is reduced and can contribute to the miniaturization of the lens barrel. In addition, since the bimorph piezoelectric actuator is superior to other actuators in terms of displacement precision, generative force, and a speed of response, it is suitable as an actuator of the image blurring correcting apparatus which requires high precision and quick response.

A third aspect of the present invention provides an imaging apparatus provided with the image blurring correcting apparatus of the first or second aspects.

According to the imaging apparatus of the third aspect, which has the image blurring correcting apparatus with a simple structure and the miniaturized lens barrel, the whole imaging apparatus can be miniaturized.

According to the present invention, since the correcting optical system is supported with free parallel movement in the direction perpendicular to the imaging optical axis by the parallel link member arranged in parallel with the imaging optical axis, and the driving force generating device with one end being fixed to the fixed part of the parallel link member and the movable end on the other end being connected to the correcting optical system moves the correcting optical system parallel in the direction perpendicular to the imaging optical axis by the parallel link member so as to correct the image blurring, there can be provided the image blurring correcting apparatus which can miniaturize the lens barrel with a simple structure as well as the imaging apparatus provided with the image blurring correcting apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of an image blurring correcting apparatus and an imaging apparatus according to the present invention will be described in accordance with the drawings.

Although the following description describes an example where the imaging apparatus of the present invention is applied to a digital camera10provided with a bending optical system, the present invention is not limited thereto and can be applied to the common digital camera which has an imaging optical axis in the width direction of the body of the imaging apparatus and a camera-equipped cell phone having a camera function.

FIG. 1is a front perspective view of the digital camera10of an embodiment, andFIG. 2is a rear perspective view of the digital camera10.FIG. 3is a block diagram illustrating a whole configuration of the digital camera10.

As illustrated inFIGS. 1 and 2, a camera case12of the digital camera10assumes the thin and flat appearance of a substantially rectangular parallelepiped shape in the width direction with a horizontally long shape wherein the size of the width direction of the camera case12is longer than the height direction thereof. The bending optical system and an image sensor are accommodated in the camera case12.

As illustrated inFIG. 1, an object window14A of an optical finder14and a stroboscope luminescent section16having a xenon pipe are disposed on the upper part of the front face of the camera case12side by side, and a shooting button18is arranged on the top face of the camera case12. The shooting button18is halfway pressed and fully pressed by an index finger of a right hand of a user who grasps the camera case12. Focus adjustment is performed at the time of the half-press operation, and the full-press operation is carried out thereafter so that an image of an object is formed on the image sensor via the bending optical system which is described later. In addition, an opening22in a rectangular shape through which a lens barrel20holding the bending optical system is taken in and out is formed on the top face of the camera case12.

Meanwhile, on the rear face of the camera case12, a liquid crystal display monitor24, a power switch26, a mode selection switch28, a menu/OK key30, a cancel key32, a cross key34, and an eyepiece window14B of the optical finder14are disposed at the predetermined positions, respectively, as illustrated inFIG. 2. The power switch26is operated in order to direct start and stop of the operation of the whole digital camera10, i.e., the start and stop of supplying power from a power supply. The mode selection switch28is a switch for selecting one mode among a camera mode which shoots a still image, an animation mode which shoots an animation, and a reproduction mode which reproduces the image recorded on a recording medium, and the image based on the selected mode is displayed on the liquid crystal display monitor24. The menu/OK key30is an operation key having both a function as a menu button for instructing to display a menu on the screen of the liquid crystal display monitor24and a function as an OK button for instructing determination, execution, or the like of a selected content. The cancel key32is used, for example, when deleting a desired target such as a selected item, canceling an instructed content, or making it return to the previous operating condition. The cross key34is disposed to be tilted freely in the vertical and horizontal directions, and used as the operation key for instructing selection of various setting items in setting such as the mode, change in setting contents, or deletion of recorded images, as well as the operation key for instructing adjustment of zoom or frame advance/reverse at the time of reproduction.

The overall operation of the digital camera10is controlled by a central processing unit (CPU)36as illustrated inFIG. 3. The CPU36functions as a control device for controlling a camera system in accordance with a predetermined program, while functions as a computing device for performing various computations, such as automatic exposure (AE) computation, automatic-focusing (AF) computation, and white balance (WB) adjustment computation.

A ROM40connected with the CPU36via a bus38stores a program executed by the CPU36and various data required for the control, and an EEPROM42stores CCD pixel defect information, various constants/information regarding camera operation, or the like.

In addition, a memory (SDRAM)44is used as an expansion area of the program and a computation working area of the CPU36while being used as temporary storage of image data or voice data. A recording section (HDD)46is a temporary storage memory dedicated for the image data, and can be deleted by operating the cross key34of the digital camera10.

The shooting button18is an operation button for inputting the instruction to start shooting, and constituted of a two-step stroke type switch having an S1switch set to ON when halfway pressed and an S2switch set to ON when fully pressed.

The liquid crystal display monitor24is also used as the display screen for a user interface, and the information including menu information, selection items, and the setting contents, is displayed if needed. Moreover, the image data recorded on the recording section46is reduced in size and thumbnailed on the liquid crystal display monitor24. Although the liquid crystal display monitor24is a liquid crystal display, it can be replaced with other types of the display such as an organic electroluminescence display.

The digital camera10has a medium socket47, to which a recording medium48is mounted. The form of the recording medium is not particularly limited, but can use various media, including a semiconductor memory card represented by SmartMedia (trademark), a portable small hard disk, a magnetic disk, an optical disk, and a magneto-optic disk.

A medium controller50performs necessary signal transformation in order to deliver an input/output signal suitable for the recording medium48mounted to the medium socket47.

In addition, the digital camera10is provided with a USB interface section52as a communication device for connecting with a personal computer or other external instruments. The external instrument is connected to a connector as a communication terminal connected to the USB interface section52via a non-illustrated USB cable, allowing delivery of the data such as the image data with the external instrument. Apparently, a communication mode is not limited to the UBS and other communication modes may be applied.

Next, the shooting function of the digital camera10is described.

If the camera mode or the animation mode is selected by the mode selection switch28, the power is supplied to an imaging section containing a color CCD solid state image sensor (hereinafter, the CCD)54, so that the shooting is enabled.

The lens barrel20is an optical unit containing a taking lens group100having the bending optical system and a mechanical shutter56combined with lens diaphragms. The lens barrel20is electrically driven by a lens actuator58and a lens diaphragm actuator60which are controlled by the CPU36to perform zoom control, focus control, and iris control.

Light which passed the taking lens group100forms the image on a light-receiving surface of the CCD54. A number of photodiodes (light receiving elements) are arranged two-dimensionally on the light-receiving surface of the CCD54, and red (R), green (G), and blue (B) primary color filters are arranged with a predetermined array structure corresponding to the respective photodiodes. In addition, the CCD54has an electronic shutter function which controls charge storage time (shutter speed) of the respective photodiodes. The CPU36controls the charge storage time at the CCD54via a timing generator62. Note that other types of the image sensor, such as a MOS type, may be used instead of the CCD54.

An object image formed on the light-receiving surface of the CCD54is transferred into a signal charge of an amount corresponding to an incident light amount by the respective photodiodes. The signal charge accumulated in the respective photodiodes is read sequentially as a voltage signal (image signal) corresponding to the signal charge based on a driving pulse provided from the timing generator62in accordance with an instruction by the CPU36.

The signal output from the CCD54is sent to an analog processing section (CDS/AMP)64, in which the sample hold (correlation double sampling processing) of R, G, and B signals for every pixel is carried out and added to an A/D converter66after being amplified. The point sequential R, G, and B signals transferred into digital signals by the A/D converter66are stored in the memory44via an image input controller68.

An image signal processing circuit70processes the R, G, and B signals stored in the memory44in accordance with the instruction by the CPU36. In other words, the image signal processing circuit70functions as an image processing device including such as a synchronization circuit (processing circuit which interpolates a spatial gap of the color signal associated with the color filter array of a single-plate CCD to transfer the color signal simultaneously), a white balance correction circuit, a gamma correction circuit, an outline correction circuit, and a luminance/color-difference signal generating circuit, to perform predetermined signal processing utilizing the memory44in accordance with a command from the CPU36.

The RGB image data input into the image signal processing circuit70is transferred into the luminance signal and the color-difference signal in the image signal processing circuit70, while a predetermined processing such as gamma correction being performed. The image data processed in the image signal processing circuit70is recorded on the recording section46.

When carrying out the monitor output of the taken image to the liquid crystal display monitor24, the image data is read from the data recording section46and sent to a video encoder72via the bus38. The video encoder72transfers the input image data into the signal of a predetermined method for display (for example, an NTSC color composite video signal) and outputs the signal to the liquid crystal display monitor24.

If the shooting button18is halfway pressed and S1is set to ON, the digital camera10starts AE and AF processing. In other words, the image signal output from the CCD54is input into an AF detection circuit74and an AE/AWB detection circuit76via the image input controller68after A/D conversion.

The AE/AWB detection circuit76includes a circuit which divides one screen into a plurality of areas (for example, 16×16) and integrates the RGB signals per the divided area and provides the CPU36with the integrated value. The CPU36detects the brightness of the object (object luminance) based on the integrated value acquired from the AE/AWB detection circuit76and calculates an exposure value (imaging EV value) suitable for the imaging. A lens diaphragm value and a shutter speed are determined in accordance with the calculated exposure value and a predetermined program diagram, and the CPU36controls the electronic shutter and iris of the CCD54in accordance therewith to obtain proper light exposure.

Moreover, the AE/AWB detection circuit76calculates an average integrated value for the respective colors of the RGB signals per divided area at the time of automatic white balance adjustment and provides the CPU36with the calculated result. The CPU36acquires the integrated values of R, B, and G, respectively to acquire the ratio of R/G and B/G per divided area, determines the type of the light source based on such as distribution of these R/G and B/G values in color spaces of R/G and B/G. Based on a white valance adjustment value suitable for the determined type of the color source, the CPU36controls a gain value (white balance correction value) for R, G, and B signals of a white valance adjustment circuit, so that the respective ratio values are approximately 1 for example, to correct the signals of respective color channels. When the gain value of the white valance adjustment circuit is adjusted so that the respective ratio values are other than 1, the image in which a certain color remained can be generated.

As for the AF control in the digital camera10, contrast AF in which a focusing lens (mobile lens which contributes to focus adjustment among a lens optical system constituting the taking lens group100) is moved so that a high frequency component of the G signal of the video signal becomes the maximum, for example, is applied. In other words, the AF detection circuit74includes a high-pass filter which passes only the high frequency component of the G signal, an absolute value processing section, an AF area extraction section which clips the signal in a focal target area set up preliminarily in the screen (for example, center of the screen), and an integration section which integrates absolute value data in an AF area.

The data of the integrated value acquired by the AF detection circuit74is reported to the CPU36. The CPU36controls the lens actuator58to move the focusing lens, while computing a focal evaluation value (AF evaluation value) on a plurality of AF detection points to determine a lens position where the evaluation value becomes the maximum as a focus position. Then, the lens actuator58is controlled to move the focusing lens to the acquired focus position. The computation of the AF evaluation value is not limited to the aspect utilizing the G signal, but a luminance signal (Y signal) may be utilized.

The shooting button18is halfway pressed and S1is set to ON so that the AE/AF processing is performed, while the shooting button18is fully pressed and S2is set to ON so that the imaging operation for recording is started. The image data acquired in response to S2being set to ON is transferred into the luminance/color-difference signal (Y/C signal) in the image signal processing circuit70, and stored in the memory44after predetermined processing such as the gamma control is performed.

The Y/C signal stored in the memory44is compressed by a compressing/expanding circuit78in accordance with a predetermined format, and then recorded on the recording medium48via the medium controller50. For example, the still image is recorded in the JPEG format.

When the reproduction mode is selected by the mode selection switch28, the compressed data of the last image file recorded on the recording medium48(file recorded at the last) is read. When the file regarding the last record is a still image file, the read image compressed data is, after being expanded to the non-compressed YC signal via the compressing/expanding circuit78and transferred into the signal for display via the image signal processing circuit70and the video encoder72, output to the liquid crystal display monitor24. Thereby, the image content of the file is displayed on the screen of the liquid crystal display monitor24.

During reproduction of one frame of the still image (including during reproduction of a head frame of the animation), the file of the reproduction target can be switched by operating the right key or left key of the cross key34(forward frame advance/reverse frame advance). The image file at the position of the frame being advanced is read from the recording medium48, and the still image or the animation is reproduced on the liquid crystal display monitor24similarly as above. Note that the digital camera10is driven with the power of a battery82supplied via a power supply circuit80.

In addition, the digital camera10is provided with a connector (not illustrated) disposed on the bottom face of the camera case12for charging the battery82which is a secondary battery. Moreover, a connector (not illustrated) for transmitting the image data stored in the recording section46to other devices is also disposed on the bottom face of the camera case12. The above is the whole configuration of the camera10.

FIGS. 4 and 5are cross sectional views illustrating a configuration of the taking lens group100of the digital camera10, whereinFIG. 4is the cross sectional view where the telescopic lens barrel20is extended upward with respect to a fixed lens barrel102and an entrance window104projects outward from the top face of the camera case12to be located in a use position, whileFIG. 5is the cross sectional view where the lens barrel20is contracted downward with respect to the fixed lens barrel102and the entrance window104is completely contained in the camera case12to be located in an non-use position. Note that the entrance window104may be a transparent plate which penetrates only the light or may be the lens. The width of the extended lens barrel20, which is in the direction along the long side of the digital camera10, is substantially equal to the size in a longitudinal direction of the opening22on the top face of the camera case12so that the lens barrel20is taken in and out through the opening22. The entrance window104is provided on the lens barrel20in any of the center, the left side or the right side on the lens barrel20in the longitudinal direction of the digital camera10. Moreover, as shown inFIG. 4, the entrance window104is provided on the front face of the digital camera10.

The taking lens group100illustrated in these drawings is an imaging optical system to form the image by guiding the light from the object to the CCD54. The imaging optical system includes the entrance window104which takes in the light from the object, a bending optical system106which bends an optical path entered from the entrance window104in the substantially perpendicular direction, a front lens108, zoom optical system lenses110and112, the mechanical shutter combined with lens diaphragms56, and a relay lens114. The relay lens114is the correcting optical system which corrects the image blurring, which is supported by a parallel linkage mechanism (parallel link member) described later and driven in the direction to correct the image blurring by the bimorph piezoelectric actuator (driving force generating device).

The bending optical system106is arranged to face the entrance window104and to bend the optical path entered from the entrance window104downward by 90 degrees. Although a rectangular prism with a reflective surface107on an inclined surface is used as the bending optical system106, it is not limited to the rectangular prism but other optical elements such as a simple mirror which can bend the optical path of the light may be applied. Note that reference numeral55designates a cover glass which protects an imaging surface of the CCD54.

The zoom optical system lenses110and112are arranged between the bending optical system106and the CCD54, so that an imaging optical axis L thereof passes through the center of the reflective surface107of the bending optical system106and is angled by 45 degrees with respect to the reflective surface107while passing through the center of the CCD54and being perpendicular to the imaging surface of the CCD54. The lens barrel20is expanded and contracted along the imaging optical axis L of the zoom optical system lenses110and112.

The zoom optical system lenses110and112are constituted of a zoom lens group110for changing magnifying power of the imaging and a focal lens group112for focal control, which are, in the use position ofFIG. 4, disposed in the position to acquire a predetermined magnifying power of the imaging (for example, optical 3× zoom) by the zoom lens group110attached to the lens barrel20being spaced with respect to the focal lens group112for focal control attached to the fixed lens barrel102. AlthoughFIGS. 4 and 5do not illustrate a zoom mechanism which moves the zoom optical system lenses110and112in the direction of the optical axis L to adjust a focal length, a desired focal length can be adjusted by moving the zoom optical system lenses110and112in the use position ofFIG. 4by the zoom mechanism described above. In addition, the focal length may be changed by changing an amount of extension of the lens barrel20with a motor (not illustrated) to change the relative position of the zoom optical system lenses110and112.

The lens barrel20has a telescopic structure with respect to the fixed lens barrel102as described above, and the respective spacings among the zoom lens group110, the shutter56, and the focal lens group112are shortened when contained as illustrated inFIG. 5. At this time, the entrance window104is completely contained in the camera case12to be protected from soiling or flaw even without a dedicated barrier. Note that the lens barrel20with the telescopic structure is moved to the position ofFIG. 4or5by a rack (not illustrated) being formed on the side of the lens barrel20and a pinion (not illustrated) which mates with the rack being driven to rotate positively or negatively with a motor (not illustrated).

Next, the image blurring correcting apparatus of the embodiment is described.

An image blurring correcting apparatus120of a first embodiment illustrated inFIGS. 6 and 7includes two pairs of parallel linkage mechanisms122and124to move the relay lens114parallel and two bimorph piezoelectric actuators126and128.

The parallel linkage mechanism122is composed of a pair of resin plates130and132of the rectangular shape with the equal length, and the resin plates130and132are arranged opposite to each other via a lens frame134of the relay lens114formed in the square shape. The resin plates130and132are disposed in parallel with the imaging optical axis L in the state of non-operation.

At the lower ends of the resin plates130and132, stays136and138extending outward are formed via hinge sections131and133used as rotation joints at the fixed side of the parallel linkage mechanism122. The resin plates130and132are fixed to the fixed lens barrel102via the stays136and138by a fixture, such as a rivet. While the upper ends of the resin plates130and132are formed integrally with a middle frame135having an opening137of the size including the relay lens114being formed, hinge sections140and142are formed at the connecting points so that they become rotation joints at the free side of the parallel linkage mechanism122. By the parallel linkage mechanism122constituted in this manner, the middle frame135is supported with free parallel movement in the X direction in the plane perpendicular to the optical axis L.

The parallel linkage mechanism124is similarly composed of a pair of resin plates144and146of the rectangular shape with the length equal to the resin plates130and132, and the resin plates144and146are arranged opposite to each other via the lens frame134. The resin plates144and146are disposed in parallel with the imaging optical axis L in the state of non-operation.

On the upper ends of the resin plates144and146, stays148and150are formed via hinge sections145and147which serve as the rotation joints at the fixed side of the parallel linkage mechanism124, as illustrated inFIG. 7. The stays148and150are connected with the stays151and153formed in the middle frame135with a non-illustrated rivet. While the lower ends of the resin plates144and146are formed integrally with the lens frame134, hinge sections152and154are formed at the connecting points so that they may become the rotation joints at the free side of the parallel linkage mechanism124. By the parallel linkage mechanism124constituted in this manner, the relay lens114is supported with free parallel movement in the Y direction in the plane perpendicular to the imaging optical axis L. Therefore, since the relay lens114is moved in the X direction via the parallel linkage mechanism124by the middle frame135being moved in the X direction, the relay lens114is moved in the X and Y directions as a result.

Meanwhile, the bimorph piezoelectric actuator126illustrated inFIG. 6is constituted by pasting thin sheets of piezoelectric ceramics together via a metal plate of an electrode, and is configured so as to apply the + voltage and the − voltage to the respective electrodes. While the bimorph piezoelectric actuator126is arranged in parallel with the resin plate132of the parallel linkage mechanism122, a fixed end156of the bimorph piezoelectric actuator126is fixed to the fixed lens barrel102and a movable end158of the bimorph piezoelectric actuator126is engaged with a hook160which protrudes on the side of the middle frame135. If a potential is given to the bimorph piezoelectric actuator126via a drive circuit169from a controller (CPU)168ofFIG. 8with such a configuration, the resulting piezoelectric transversal effect expands one sheet and contracts the other so that bending displacement can be obtained. The bending displacement enables to move the relay lens114parallel in the X direction via the middle frame135as illustrated inFIGS. 9A and 9B. Since the lens frame134is held by the parallel linkage mechanism122at this time, an a amount of the parallel movement is obtained in the X direction of the plane perpendicular to the imaging optical axis L without being inclined with respect to the imaging optical axis L, as illustrated inFIG. 9B.

The bimorph type piezoelectric actuator128is similarly constituted by pasting the thin sheets of the piezoelectric ceramics together via the metal plate of the electrode. While the bimorph piezoelectric actuator128is arranged in parallel with the resin plate146of the parallel linkage mechanism124, a fixed end162of the bimorph piezoelectric actuator128is fixed to a stay163of the middle frame135with a screw165and a movable end164of the bimorph piezoelectric actuator128is engaged with a hook166which protrudes on the side of the lens frame134, as illustrated inFIG. 6. If the potential is given to the bimorph piezoelectric actuator128via the drive circuit169from the controller168ofFIG. 6with such a configuration, the resulting piezoelectric transversal effect expands one sheet and contracts the other so that the bending displacement can be obtained. The bending displacement enables to move the relay lens114parallel in the Y direction via the middle frame135as illustrated inFIGS. 10A and 10B. Since the lens frame134is held by the parallel linkage mechanism124at this time, a b amount of the parallel movement is obtained in the Y direction of the plane perpendicular to the imaging optical axis L without being inclined to the imaging optical axis L, as illustrated inFIG. 10B.

As illustrated inFIG. 8, detection sensors (for example, acceleration sensor)167A and167B which detect the deflection in the X and Y directions are built in the digital camera10. The controller168described above controls the drive circuit169so as to apply the voltage to move the relay lens114by the amount of deflection in the direction opposite to the deflection direction to the bimorph piezoelectric actuator126and128to compensate the movement due to the deflection of the digital camera10acquired by the detection output from these deflection detection sensors167A and167B.

According to the image blurring correcting apparatus120of the first embodiment illustrated inFIGS. 6 to 10, the bimorph piezoelectric actuators126and128are in the plate form and disposed along the imaging optical axis L, the space for disposition in the fixed lens barrel102can be reduced, allowing to contribute to the miniaturization of the fixed lens barrel102. Thereby, according to the digital camera10having the bending optical system, even when the image blurring correcting apparatus120is built into their imaging optical system, the camera case12can be made thinner.

In addition, since the bimorph piezoelectric actuators126and128are superior to the other actuators in terms of displacement precision, generative force, and a speed of response, they are suitable as the actuator of the image blurring correcting apparatus120which requires high precision and quick response.

Although the bimorph piezoelectric actuators126and128are explained as the driving force generating device, the driving force generating device which is able to transform electrical energy into mechanical energy can be applied. Moreover, a bimetal and a shape memory alloy may be applied.

FIG. 9illustrates an image blurring correcting apparatus170of a second embodiment.

A resin plate174of a parallel linkage mechanism172is provided integrally with the lens frame134, and is attached to the non-illustrated lens-barrel via a stay176. In addition, a movable end180of a bimorph piezoelectric actuator178is connected to the lens frame134with rivets182and182, while a stay186is fixed to a fixed end184of the bimorph piezoelectric actuator178with the non-illustrated rivet. Since the bimorph piezoelectric actuator178is arranged opposite to the resin plate174via the lens frame134and fixed to the lens barrel via the stay186as with the resin plate174, a pair of the parallel linkage mechanisms172are constituted of the resin plate174and the bimorph piezoelectric actuator178. If the potential is given to the bimorph piezoelectric actuator178with such a configuration, the movable end180of the bimorph piezoelectric actuator178is deflected as indicated by an arrow, so that the relay lens114can be moved parallel in the plane perpendicular to the imaging optical axis L. By providing a pair of the parallel linkage mechanism172in the perpendicular direction of two axes, the relay lens114can be moved in the plane perpendicular to the imaging optical axis, allowing to correct the image blurring. Reference numerals188,190,192, and194designate the rotation joints of the parallel linkage mechanism172.

Since the bimorph piezoelectric actuator is rigid in the state where the electric potential is not given, it can be utilized in an ordinary camera where the imaging optical axis coincides with the width direction of the camera case (including a lens-barrel-collapsible camera and a lens-exchangeable camera) as a device which holds the correcting optical system thereof while the power is OFF. Suitably, the potential is given to the bimorph piezoelectric actuator just before turning off the power supply of the camera, the correcting optical system is held slightly upward with respect to the imaging optical axis against gravity, and the power supply is turned off in this state. Thereby, a spring member becomes unnecessary for hanging the correcting optical system from the lens barrel to support it aside from the driving force generating device of the correcting optical system.

FIGS. 12 and 13illustrate an image blurring correcting apparatus200of the second embodiment, wherein the same reference numerals are given to the same or similar members with the image blurring correcting apparatus120illustrated inFIGS. 6 and 7and the description thereof is omitted.

The image blurring correcting apparatus200has a structure which uses eight pins202,204,206,208,210,212,214, and216as the rotation joints of the parallel linkage mechanism.

In other words, the lower ends of the resin plates130and132of the parallel linkage mechanism122are fixed rotatably to the fixed lens barrel102via the pins202and204used as the rotation joints at the fixed side of the parallel linkage mechanism122. The upper ends of the resin plates130and132are connected rotatably with the middle frame135via the pins206and208used as the rotation joints at the free side of the parallel linkage mechanism122. By the parallel linkage mechanism122constituted in this manner, the middle frame135is supported with free parallel movement in the X direction in the plane perpendicular to the optical axis L.

The parallel linkage mechanism124is similarly configured so that the upper ends of the resin plates144and146are connected rotatably with the middle frame135via the pins210and212used as the rotation joints at the fixed side of the parallel linkage mechanism124. In addition, the lower ends of the resin plates144and146are connected rotatably with the lens frame134via the pins214and216used as the rotation joints at the free side of the parallel linkage mechanism124. By the parallel linkage mechanism124constituted in this manner, the relay lens114is supported with free parallel movement in the Y direction in the plane perpendicular to the imaging optical axis L. Therefore, since the relay lens114is moved in the X direction via the parallel linkage mechanism124by the middle frame135being moved in the X direction, the relay lens114is moved parallel in the X and Y directions as a result.