Image blur correction unit, image blur compensation device, and optical apparatus

An image blur compensation unit and image blur compensation device that can be made smaller in size. Wedge prisms, which refract light that is guided to an imaging element after passing through a lens group, are disposed on the same plane perpendicular to a central axis, and are supported by rotatable prism support portions. In order for the wedge prisms to be spaced by a predetermined distance and face each other along the central axis in a space that is formed when being placed adjacent to each other, the prism support portion supports the wedge prism on one end side along the central axis, and the prism support portion supports the wedge prism on one end side along the central axis. In this manner, the prism support portions supporting the wedge prisms, which need to be disposed along the central axis so as to be spaced by a predetermined distance and face each other, are disposed on the same plane. Therefore, the central axis-direction thickness can be made thinner, and the device can be made smaller in size.

TECHNICAL FIELD

The present invention relates to an image blur compensation unit, an image blur compensation device, and an optical device, and, for example, is preferably applied to a case where camera shake, such as those of digital cameras, is compensated for.

BACKGROUND ART

Currently, a common camera shake compensation function of cameras is of an optical type that physically adjusts an optical axis. Among the optical-type camera shake compensation functions are those of a lens-shift type and an imaging element-shift type.

The lens-shift type camera shake compensation function is designed to move, with respect to an imaging element, part of a group of lenses where a subject image is formed, or all the lenses, in a direction that offsets camera shake by using a dedicated drive mechanism to correct an optical axis, thereby guiding the subject image to the imaging element (See Patent Document 1, for example).

However, in the case of the lens-shift type camera shake compensation function, for a group of lenses that is formed for each camera, the shape of a compensation lens or a drive mechanism that satisfies optical specifications need to be designed each time.

Meanwhile, the imaging element-shift type camera shake compensation function is designed to use a dedicated drive mechanism to move an imaging element in accordance with camera shake, thereby keeping the imaging element at a certain position relative to an optical axis of a group of lens (See Patent Document 2, for example).

However, even in the case of the imaging element-shift type camera shake compensation function, a dedicated drive mechanism needs to be designed each time to be suitable for an imaging element that is different for each camera.

Accordingly, what is proposed is one in which a compensation attachment is attached onto an optical axis of an optical lens (See Patent Document 3, for example): the compensation attachment has a power transmission mechanism including a movable prism, which refracts light entering an optical lens, a motor, which drives the movable prism, and a shaft, which transmits power of the motor to the movable prism.

As a result, there is no need to design the shape of a compensation lens and a drive mechanism for each camera, resulting in simplified design.

PRIOR ART DOCUMENTS

Patent Documents

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, in the case of the conventional camera shake compensation mechanisms, if a plurality of refractive elements are arranged along an optical axis, each refractive element is supported in a circumferential direction. Therefore, the problem is that the mechanisms become large in size.

The present invention has been made in view of the above points, and is intended to propose an image blur compensation unit, image blur compensation device, and optical device that can be made smaller in size.

To solve the above problem, according to the present invention, an image blur compensation unit includes: a first and a second refractive element that are disposed along an optical axis of light that is guided to an imaging element after passing through an optical lens, and which rotate with respect to a central axis that goes along the optical axis to refract the light to correct a blur of an image that is guided to the imaging element; a first support portion that is provided in one region of 180 degrees or less out of two divided regions with respect to the central axis on a plane perpendicular to the central axis, and which supports the first refractive element on an outer periphery side; a second support portion that is provided in the other region of 180 degrees or less out of the two divided regions, and which supports the second refractive element on an outer periphery side; a base section that supports the first and second support portions at three or more points on a plane perpendicular to the central axis in such a way that the first and second support portions can rotate around the central axis; and a first and a second drive mechanism that are respectively placed in regions where the first and second support portions are provided, and which drive the first and second support portions in such a way that the first and second support portions rotate around the central axis only within the regions to rotate the first and second refractive elements, wherein the first and second drive mechanisms include a first and a second magnet that are placed on one of the base section or first and second support portions, a first and a second coil that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use an electromagnetic force that is generated between the first and second magnets and the first and second coils as current is applied to rotate the first and second support portions, and a first and a second yoke that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use a magnetic force that is generated between the first and second magnets and the first and second yokes to push the first and second support portions against the base section, the center of the first magnet is located inside a polygon connecting points where the first support portion is supported, and the center of the second magnet is located inside a polygon connecting points where the second support portion is supported.

Moreover, according to the present invention, an image blur compensation device that detects and compensates for camera shake includes: a shake detection unit that detects shake of the camera; a first and a second refractive element that are disposed along an optical axis of light that is guided to an imaging element after passing through an optical lens provided in the camera, and which rotate with respect to a central axis that goes along the optical axis to refract the light to correct a blur of an image that is guided to the imaging element; a first support portion that is provided in one region of 180 degrees or less out of two divided regions with respect to the central axis on a plane perpendicular to the central axis, and which supports the first refractive element on an outer periphery side; a second support portion that is provided in the other region of 180 degrees or less out of the two divided regions, and which supports the second refractive element on an outer periphery side; a base section that supports the first and second support portions at three or more points on a plane perpendicular to the central axis in such a way that the first and second support portions can rotate around the central axis; and a first and a second drive mechanism that are respectively placed in regions where the first and second support portions are provided, and which drive the first and second support portions in such a way that the first and second support portions rotate around the central axis only within the regions to rotate the first and second refractive elements, wherein the first and second drive mechanisms include a first and a second magnet that are placed on one of the base section or first and second support portions, a first and a second coil that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use an electromagnetic force that is generated between the first and second magnets and the first and second coils as current is applied to rotate the first and second support portions, and a first and a second yoke that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use a magnetic force that is generated between the first and second magnets and the first and second yokes to push the first and second support portions against the base section, the center of the first magnet is located inside a polygon connecting points where the first support portion is supported, and the center of the second magnet is located inside a polygon connecting points where the second support portion is supported.

According to the present invention, an optical device includes: a first and a second refractive element that are disposed along an optical axis of light, and which rotate with respect to a central axis that goes along the optical axis to refract the light; a first support portion that is provided in one region of 180 degrees or less out of two divided regions with respect to the central axis on a plane perpendicular to the central axis, and which supports the first refractive element on an outer periphery side; a second support portion that is provided in the other region of 180 degrees or less out of the two divided regions, and which supports the second refractive element on an outer periphery side; a base section that supports the first and second support portions at three or more points on a plane perpendicular to the central axis in such a way that the first and second support portions can rotate around the central axis; and a first and a second drive mechanism that are respectively placed in regions where the first and second support portions are provided, and which drive the first and second support portions in such a way that the first and second support portions rotate around the central axis only within the regions to rotate the first and second refractive elements, wherein the first and second drive mechanisms include a first and a second magnet that are placed on one of the base section or first and second support portions, a first and a second coil that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use an electromagnetic force that is generated between the first and second magnets and the first and second coils as current is applied to rotate the first and second support portions, and a first and a second yoke that are placed on the other one of the base section or first and second support portions so as to face the first and second magnets, and use a magnetic force that is generated between the first and second magnets and the first and second yokes to push the first and second support portions against the base section, the center of the first magnet is located inside a polygon connecting points where the first support portion is supported, and the center of the second magnet is located inside a polygon connecting points where the second support portion is supported.

Therefore, the first and second support portions, which are provided on the outer periphery sides of the first and second refractive elements and respectively rotate in the two divided regions of 180 degrees or less, are pushed against the base section and kept by a magnetic force generated between the yokes and the magnets that are located in the polygons connecting the points where the first and second support portions are supported. Accordingly, the first and second support portions do not enter the other regions, there is no need to provide separately, and the first and second support portions can be kept at the base section.

As described above, according to the present invention, the first and second support portions, which are provided on the outer periphery sides of the first and second refractive elements and respectively rotate in the two divided regions of 180 degrees or less, are pushed against the base section and kept by a magnetic force generated between the yokes and the magnets that are located in the polygons connecting the points where the first and second support portions are supported. Accordingly, the first and second support portions do not enter the other regions, there is no need to provide separately, and the first and second support portions can be kept at the base section. As a result, the device can be made smaller in size.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

[1. Configuration of Camera]

FIG. 1shows a camera1according to one embodiment of the present invention. The camera1includes a camera body unit2, and a lens barrel unit3, which is mounted on the camera body unit2so as to be able to be attached thereto and detached therefrom. In the camera body unit2, an imaging element4on which a subject image is formed, such as CCD (Charge Coupled Device Image Sensor) or CMOS (Complementary Metal Oxide Semiconductor), is provided.

In the lens barrel unit3, the following components are provided: a lens group5, which includes a plurality of lenses5A to5E; and an image blur compensation mechanism6, which is designed to move a subject image in a horizontal direction (X-axis direction) and a vertical direction (Y-axis direction) with respect to an optical axis L1of the lens group5. The image blur compensation mechanism6is for example disposed in a space between the lenses5D and5E where a light beam passing through the lens group5becomes narrow on the optical axis L1.

The lens group5is moved in the direction of the optical axis L1to adjust zooming and focus. The imaging element4converts a subject image, which is formed after passing through the lens group5and the image blur compensation mechanism6, into electrical signals. In the camera1, A/D conversion is carried out on the electrical signals to obtain image data.

According to the present embodiment, a direction that goes along the optical axis L1of the lens group5is referred to as Z-axis direction; a horizontal direction that is perpendicular to the Z-axis direction as X-axis direction; and a vertical direction that is perpendicular to the Z-axis direction as Y-axis direction.

As shown inFIGS. 2 to 4, the image blur compensation mechanism6is formed substantially into a flat cylindrical shape, for example, with a diameter of 30 mm and a thickness of 5 mm. The image blur compensation mechanism6is disposed in the lens barrel unit3in such a way that a central axis L2thereof is aligned with the optical axis L1of the lens group5. Incidentally, the central axis L2is the center of rotation of wedge prisms42and52, which will be described later, and is not necessarily aligned with the optical axis L1.

In the image blur compensation mechanism6, a base section10, which is made of resin or the like and is substantially formed into a circular flat plate, is covered with a cup-shaped cover section20, which is made of resin or the like, to create a space where a substrate section30and rotor units40and50are disposed.

In the base section10, a base plate11, a circular portion12, screw hole support portions13, and protruding portions14are made of resin or the like, and are formed integrally.

The base plate11is substantially in the shape of a circular flat plate, and is provided with an opening11A, whose center is the central axis L2and which is larger than the light beam of a subject image passing through the lens group5.

The circular portion12extends from an outer edge on a cover section20's side surface of the base plate11to an inner side by an amount equivalent to the thickness of the cover section20; is slightly longer in width than the width of ball grooves12A to12F in which balls17A to17F, which will be detailed later, roll; and is formed into a ring shape that is higher than the thickness of a printed board31.

The screw hole support portions13each are formed into a cylindrical shape, with screw grooves13A and13B provided inside. The screw hole support portions13are provided at predetermined positions inside the circular portion12on the cover section20's side surface of the base plate11so as to be symmetrical with respect to the central axis L2.

On the base plate11, inside the circular portion12on the cover section20's side surface, voice coils15and16, which are thinner than the height of the circular portion12, and yokes18and19are provided. The centers of the voice coils15and16each are located on a vertical line (Y-axis) that is perpendicular to the central axis L2. The voice coils15and16are so disposed as to be symmetrical with respect to the central axis L2. The voice coils15and16are formed substantially into a fan shape, with electric wires wound around so as to be substantially parallel to a surface of the base plate11. The yokes18and19are formed substantially into the same shape as the voice coils15and16.

On the base plate11, inside the circular portion12on the cover section20's side surface, protruding portions14A and14B are provided: the protruding portions14A and14B are smaller in height than the height of the yokes18and19and voice coils15and16put together, and the outer peripheral shape thereof is substantially the same as the inner peripheral shape of the voice coils15and16and yokes18and19. The protruding portions14A and14B are so placed as to be symmetrical with respect to the central axis L2.

As for the ball grooves12A to12F formed on the circular portion12, the ball grooves12A and12D are so provided as to be symmetrical with respect to the center of the base plate11, and the ball grooves12B and12E, and the ball grooves12C and12F, too, are so provided as to be symmetrical with respect to the center of the base plate11.

The ball grooves12A and12D are provided on a central line (Y-axis) that passes through the centers of the voice coils15and16. The ball grooves12B and12C are provided at line-symmetry positions that are closer to the ball groove12A (Y-axis negative direction side) than the central axis L2on the circular portion12with respect to the Y-axis in such a way that the center of the voice coil15is placed inside a triangle connecting the centers of the ball grooves12A,12B, and12C. Similarly, the ball grooves12E and12F are provided at line-symmetry positions that are closer to the ball groove12D (Y-axis positive direction side) than the central axis L2on the circular portion12with respect to the Y-axis in such a way that the winding center of the voice coil16is placed inside a triangle connecting the centers of the ball grooves12D,12E, and12F.

On the cover section20, a circular opening20A that is larger than the light beam of a subject image that passes through the lens group5is provided in such a way that the center thereof is on the central axis L2. In the cover section20, holes20B and20C, into which screws21and22are inserted, are provided at positions that face the screw hole support portions13of the base section10.

The substrate section30includes a printed board31and hall elements32and33. The printed board31is formed substantially into a flat circular shape whose diameter is almost equal to the inner diameter of the circular portion12, with the portions corresponding to the voice coils15and16removed, in such a way that the printed board31is in close contact with the inner part of the circular portion12on the base plate11.

On the printed board31, an opening31A that is slightly larger than the opening11A is provided at a position corresponding to the opening11A of the base plate11. On the printed board31, holes31B and31C are provided: Into the holes31B and31C, the two screw hole support portions13of the base section10are respectively inserted.

The hall elements32and33are provided adjacent to the voice coils15and16so as to be symmetrical with respect to the central axis L2.

The rotor unit40includes a prism support portion41, wedge prism42, magnet43, yoke44, magnet45, and yoke46, which are integrally formed with a transparent acrylic resin, for example.

The prism support portion41is formed into a flat fan plane shape which is provided around the central axis L2with the central angle thereof less than 180 degrees, and whose outer periphery radius is equal to the outer periphery radius of the circular portion12of the base section10, and whose portion corresponding to the wedge prism42is cut (or dented) around the central axis L2.

In the prism support portion41, a hole41A is provided on a center line bisecting the central angle and at a position facing the voice coil15so as to be in the shape of an outer periphery shape of the magnet43and yoke44, thereby allowing the magnet43and the yoke44to fit therein.

The plane-direction outer shape of the magnet43is slightly smaller than that of the yoke44. Therefore, since the hole41A is formed in the outer periphery shape of the magnet43and yoke44, a step41A1is so formed as to make the hole smaller along the Z-axis direction.

In the prism support portion41, a hole41B is provided in an outer periphery shape of the magnet45and yoke46, thereby allowing the magnet45and the yoke46to fit therein at a position facing the hall element32.

The plane-direction outer shape of the magnet45is slightly smaller than that of the yoke46. Therefore, since the hole41B is formed in the outer periphery shape of the magnet45and yoke46, a step41B1is so formed as to make the hole smaller along the Z-axis direction.

In the prism support portion41, a hole41C is provided at a position facing a screw hole support portion13in which a screw groove13A is provided. The hole41C is formed large enough that, when the prism support portion41rotates around the central axis L2, the screw hole support portion13in which the screw groove13A is provided comes in contact with the prism support portion41, thereby keeping the rotor units40and50from coming in contact with both ends of the prism support portions41and51even as the rotor units40and50rotate in a direction in which the rotor units40and50approaches both ends of the prism support portions41and51.

On the prism support portion41, ball grooves41D,41E, and41F are provided at positions facing the ball grooves12A,12B, and12C of the base section10on a surface facing the base section10: the cross sections of the ball grooves41D,41E, and41F are substantially in a triangular shape. That is, the prism support portion41rotates and moves in a range of 180 degrees or less around the central axis L2on the plane.

The wedge prism42is molded integrally with the prism support portion41in such a way that the wedge prism42is thinner than half the thickness of a thick portion41G, which is part of the prism support portion41that is designed to be thick and support the wedge prism42, and that the entire wedge prism42is placed closer to the base section10(Z-axis positive direction side) than the center of the thickness direction of the thick portion41G.

The wedge prism42is formed substantially into a circular flat plate shape whose center is the central axis L2. Both surfaces of the wedge prism42are tilted in such a way as to come closer to each other toward the Y-axis positive direction with respect to an XY plane (or a plane perpendicular to the central axis L2). That is, both surfaces of the wedge prism42are tilted with respect to the XY plane in such a way as to be thick on the side of the prism support portion41(Y-axis negative direction side), and thin on the opposite side (Y-axis positive direction side).

The rotor unit50include a prism support portion51, wedge prism52, magnet53, yoke54, magnet55, and yoke56, which are integrally formed with a transparent acrylic resin, for example.

The prism support portion51is formed into a flat fan plane shape which is provided around the central axis L2with the central angle thereof less than 180 degrees, and whose outer periphery radius is equal to the outer periphery radius of the circular portion12of the base section10, and whose portion corresponding to the wedge prism52is cut (or dented) around the central axis L2.

In the prism support portion51, a hole51A is provided on a center line bisecting the central angle and at a position facing the voice coil16so as to be in an outer periphery shape of the magnet53and yoke54, thereby allowing the magnet53and the yoke54to fit therein.

The plane-direction outer shape of the magnet53is slightly smaller than that of the yoke54. Therefore, since the hole51A is formed in the outer periphery shape of the magnet53and yoke54, a step51A1is so formed as to make the hole smaller along the Z-axis direction.

In the prism support portion51, a hole51B is provided in an outer periphery shape of the magnet55and yoke56, thereby allowing the magnet55and the yoke56to fit therein at a position facing the hall element33.

The plane-direction outer shape of the magnet53is slightly smaller than that of the yoke54. Therefore, since the hole51B is formed in the outer periphery shape of the magnet55and yoke56, a step51B1is so formed as to make the hole smaller along the Z-axis direction.

In the prism support portion51, a hole51C is provided at a position facing a screw hole support portion13in which a screw groove13B is provided. The hole51C is formed large enough that, when the prism support portion51rotates around the central axis L2, the screw hole support portion13in which the screw groove13B is provided comes in contact with the prism support portion51, thereby keeping the rotor units40and50from coming in contact with both ends of the prism support portions41and51even as the rotor units40and50rotate in a direction in which the rotor units40and50approaches both ends of the prism support portions41and51.

On the prism support portion51, ball grooves51D,51E, and51F are provided at positions facing the ball grooves12D,12E, and12F of the base section10on a surface facing the base section10: the cross sections of the ball grooves51D,51E, and51F are substantially in a triangular shape.

The wedge prism52is molded integrally with the prism support portion51in such a way that the wedge prism52is thinner than half the thickness of a thick portion51G, which is part of the prism support portion51that is designed to be thick and support the wedge prism52, and that the entire wedge prism52is placed closer to the cover section20(Z-axis negative direction side) than the center of the thickness direction of the thick portion51G. Incidentally, the thick portion51G is so formed as to have the same Z-axis direction thickness as the thick portion41G. The thick portions41G and51G may be equal in thickness to other portions as long as the wedge prisms42and52can be supported within the Z-axis direction thickness of the prism support portions41and51.

The wedge prism52is formed substantially into a circular flat plate shape whose center is the central axis L2. Both surfaces of the wedge prism52are tilted in such a way as to come closer to each other toward the X-axis negative direction with respect to an XY plane (or a plane perpendicular to the central axis L2). That is, both surfaces of the wedge prism52are tilted with respect to the XY plane in such a way as to be thick on the X-axis positive direction side, and thin on the opposite side (X-axis negative direction side).

When the image blur compensation mechanism6that includes the above-described components is assembled, the substrate section30is fitted into the inner side of the circular portion12of the base plate11of the base section10before being bonded together, for example; the voice coils15and16and the yokes18and19are fitted into the outer side of the protruding portions14of the base plate11before being bonded together, for example.

As for the rotor unit40, the magnet43and the yoke44are disposed in the hole41A of the prism support portion41, and the magnet45and the yoke46in the hole41B of the prism support portion41.

The rotor unit40is supported by the base section10with a predetermined gap therebetween in such a way that balls17A to17C are held between the ball grooves41D to41F of the prism support portion41, and the ball grooves12A to12C of the base section10. As for the rotor unit40, a position where a center line bisecting the central angle of the prism support portion41is aligned with the vertical direction (Y-axis) that is perpendicular to the central axis L2is set as a reference position.

At this time, in the rotor unit40, the ball grooves41D to41F only come in contact with the balls17A to17C, and the rotor unit40is three-point supported by the balls17A to17C. Therefore, the rotor unit40can rotate around the central axis L2only at a predetermined angle in a left-right direction with respect to the Y-axis.

As the rotor unit40is rotated, the wedge prism42refracts the light that enters after passing through the lens group5in accordance with the angle of the rotation, and is moved substantially along the Y-axis.

The sizes of the ball grooves12A to12C and ball grooves41D to41F are so determined that, when the prism support portion41is rotated to the leftmost or rightmost and when the screw hole support portion13in which the screw groove13A is provided comes in contact with the hole41C of the prism support portion41, the balls17A to17C do not come in contact with both ends of the ball grooves.

The rotor unit40is continuously attracted in a direction of the base section10(Z-axis positive direction) by an attractive force of the yoke18that attracts the magnet43. As a result, the rotor unit40is not separated from the base section10, and is supported by the base section10.

At this time, in the prism support portion41, the magnet43is in close contact with the yoke44because of a magnetic force. An outer periphery portion of the yoke44hangs on the step41A1, thereby keeping the magnet43and the yoke44from coming off from the prism support portion41.

Similarly, in the prism support portion41, the magnet45is in close contact with the yoke46because of a magnetic force. An outer periphery portion of the yoke46hangs on the step41B1, thereby preventing the magnet45and the yoke46from coming off from the prism support portion41and keeping the magnet45and the yoke46at a position facing the hall element32.

As for the rotor unit50, the magnet53and the yoke54are disposed in the hole51A of the prism support portion51, and the magnet55and the yoke56in the hole51B of the prism support portion51.

The rotor unit50is supported by the base section10with a predetermined gap therebetween in such a way that balls17D to17F are held between the ball grooves51D to51F of the prism support portion51, and the ball grooves12D to12F of the base section10. As for the rotor unit50, a position where a center line bisecting the central angle of the prism support portion51is aligned with the vertical direction (Y-axis) that is perpendicular to the central axis L2is set as a reference position.

At this time, in the rotor unit50, the ball grooves51D to51F only come in contact with the balls17D to17F, and the rotor unit50is three-point supported by the balls17D to17F. Therefore, the rotor unit50can rotate around the central axis L2only at a predetermined angle in a left-right direction with respect to the Y-axis. Accordingly, the prism support portions41and51each are supported by the base section10and are rotated on the same XY plane that is perpendicular to the central axis L2.

As the rotor unit50is rotated, the wedge prism52refracts the light that enters after passing through the lens group5in accordance with the angle of the rotation, and is moved substantially along the X-axis.

The sizes of the ball grooves12D to12F and ball grooves51D to51F are so determined that, when the prism support portion51is rotated to the leftmost or rightmost and when the screw hole support portion13in which the screw groove13B is provided comes in contact with the hole51C of the prism support portion51, the balls17D to17F do not come in contact with both ends of the ball grooves.

The rotor unit50is continuously attracted in a direction of the base section10(Z-axis positive direction) by an attractive force of the yoke19that attracts the magnet53. As a result, the rotor unit50is not separated from the base section10, and is supported by the base section10.

At this time, in the prism support portion51, the magnet53is in close contact with the yoke54because of a magnetic force. An outer periphery portion of the yoke54hangs on the step51A1, thereby keeping the magnet53and the yoke54from coming off from the prism support portion51.

Similarly, in the prism support portion51, the magnet55is in close contact with the yoke56because of a magnetic force. An outer periphery portion of the yoke56hangs on the step51B1, thereby preventing the magnet55and, the yoke56from coming off from the prism support portion51and keeping the magnet55and the yoke56at a position facing the hall element33.

After the substrate section30and the rotor units40and50are disposed on the base section10, the cover section20is fixed in such a way as to cover the above components as screws21and22are screwed into the screw grooves13A and13B of the screw hole support portions13.

As described above, the wedge prism42is molded in such a way that the wedge prism42is thinner than half the thickness of the thick portion41G and that the entire wedge prism42is placed closer to the Z-axis positive direction side than the center of the thickness direction of the thick portion41G. The wedge prism52is molded in such a way that the wedge prism52is thinner than half the thickness of the thick portion51G and that the entire wedge prism52is placed closer to the Z-axis negative direction side than the center of the thickness direction of the thick portion51G.

Therefore, when the rotor units40and50are supported with respect to the base section10, the wedge prisms42and52are so supported as to face a space that is formed as the prism support portions41and51are placed adjacent to each other; the wedge prisms42and52can rotate around the central axis L2(optical axis L1) without coming in contact with each other.

[3. Circuit Configuration of Camera]

The following describes the circuit configuration of the camera1with the use ofFIG. 5. Incidentally, for ease of explanation, inFIG. 5, only circuits that are used to control image blur are shown; the other portions are omitted.

The camera1includes a microcomputer61, which takes overall control; a shake detection unit62, which detects the shake of the camera1; a drive unit63, which rotates and drives the rotor units40and50; and a position detection unit64, which detects the positions of the rotor units40and50.

More specifically, in the camera body unit2, the microcomputer61, an X-axis direction gyro sensor71, a Y-axis direction gyro sensor72, gyro amplifiers73and74, power drivers75and76, and hall element drivers77and78are provided.

In the image blur compensation mechanism6, the voice coils15and16and the hall elements32and33are provided.

The microcomputer61takes the form of a computer, including CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access memory). The microcomputer61loads a basic program, which is stored in the ROM, into the RAM to execute, thereby taking overall control. The microcomputer61also loads various programs, which are stored in the ROM, into the RAM to execute, thereby carrying out various processes.

The X-axis direction gyro sensor71detects an X-axis direction angular velocity of the camera1, i.e. the X-axis direction shake, as an angular velocity signal. The Y-axis direction gyro sensor72detects a Y-axis direction angular velocity of the camera1, i.e. the Y-axis direction shake, as an angular velocity signal.

The gyro amplifiers73and74amplify the angular velocity signals detected by the X-axis direction gyro sensor71and the Y-axis direction gyro sensor72before transmitting to the microcomputer61.

The power drivers75and76applies current to the voice coils15and16under the control of the microcomputer61.

The hall elements32and33are so disposed as to face the magnets45and55, which are disposed on the prism support portions41and51, respectively. The hall elements32and33detect, as a magnetic field signal, a change in the magnetic fields that are generated by the magnets45and55and are changed by the rotational movements of the rotor units40and50.

The hall element drivers77and78amplify the magnetic field signals detected by the hall elements32and33before transmitting to the microcomputer61.

The microcomputer61calculates the amounts of X-axis and Y-axis direction shakes of the camera1on the basis of the angular velocity signals that are detected by the X-axis direction gyro sensor71and Y-axis direction gyro sensor72and are supplied via the gyro amplifiers73and74.

Then, the microcomputer61calculates the amounts of movement by which an image to be formed on the imaging element4is moved in the X-axis and Y-axis directions in order to correct the amounts of X-axis and Y-axis direction shakes of the camera1calculated.

The microcomputer61calculates an angle by which the rotor units40and50are rotated in order to move the image by the calculated amounts of movement. The microcomputer61controls the power drivers75and76to allow the rotor units40and50to rotate by the angle, and applies current to the voice coils15and16.

More specifically, after detecting the amounts of X-axis and Y-axis direction shakes of the camera1, the microcomputer61rotates and moves the rotor unit40in accordance with the amount of Y-axis direction shake, and also rotates and moves the rotor unit50in accordance with the amount of X-axis direction shake. In this manner, the microcomputer61moves the light passing through the lens group5in accordance with the amounts of camera shakes.

The microcomputer61acquires, at regular intervals, the magnetic field signals that are detected by the hall elements32and33and are supplied via the hall element drivers77and78; and calculates the rotation speed and rotation angle of the rotor units40and50on the basis of the magnetic field signals.

The microcomputer61performs a feedback control process until the rotation angles of the rotor units40and50, which are calculated at predetermined intervals, reach an angle by which the rotor units40and50need to be moved to correct the amounts of camera shakes.

As a result, the camera1can compensate for the shake of the camera1by controlling the rotation of the rotor units40and50of the image blur compensation mechanism6.

[4. Operation and Effects]

According to the above configuration, in the image blur compensation mechanism6, the wedge prisms42and52, which refract the light that is guided to the imaging element4after passing through the lens group5, are respectively supported by the prism support portions41and51, which are rotatable and are disposed on the same plane that is perpendicular to the central axis L2(optical axis L1).

At that time, the wedge prisms42and52are separated along the central axis L2with a predetermined gap therebetween so as to face a space that is created at a time when the prism support portions41and51are disposed adjacent to each other. In this manner, the prism support portion41supports the wedge prism42on the side of one end (Z-axis positive direction side) along the central axis L2; the prism support portion51supports the wedge prism52on the side of one end (Z-axis negative direction side) along the central axis L2.

Therefore, in the image blur compensation mechanism6, when the wedge prisms42and52, which need to be disposed along the central axis L2so as to face each other with a predetermined gap therebetween, are supported, the prism support portions41and51are disposed on the same plane. As a result, the thickness of the direction of the central axis L2can be made thinner than when the prism support portions41and51are disposed along the central axis L2with a predetermined distance therebetween. Therefore, the image blur compensation mechanism6can be made smaller in size.

In the image blur compensation mechanism6, on a surface of the base section10that is perpendicular to the central axis L2and which supports the prism support portions41and52, the voice coils15and16and the yokes18and19are disposed. On the prism support portions41and51, at positions facing the voice coils15and16, the magnets43and53are disposed.

In the image blur compensation mechanism6, current is applied to the voice coils15and16, and the prism support portions41and51are rotated by an electromagnetic force that is generated between the magnets43and53.

Therefore, in the image blur compensation mechanism6, all that is required is to place a mechanism for rotating the wedge prisms42and52only on one side of the base section10. As a result, the image blur compensation mechanism6can be made smaller in size accordingly. At this time, in the image blur compensation mechanism6, an attractive force generated between the yoke18and the magnet43and between the yoke19and the magnet53is used to press the prism support portions41and51against the base section10. Therefore, there is no need to provide a separate device for keeping the prism support portions41and51on the base section10. As a result, the image blur compensation mechanism6can be made smaller in size accordingly.

In the image blur compensation mechanism6, the prism support portions41and51are three-point supported by the balls17A to17C and17D to17F, which are disposed on the same plane. The centers of the magnets43and53, which are disposed on the prism support portions41and51, are each located inside a triangle that connects the supporting three points. Therefore, the rotor units40and50can be supported in a stable manner even if another device is not provided. As a result, the image blur compensation mechanism6can be made smaller in size accordingly.

According to the above configuration, the wedge prisms42and52, which refract the light that is guided to the imaging element4after passing through the lens group5, are supported by the prism support portions41and51, which are rotatable and are disposed on the same plane that is perpendicular to the central axis L2. The wedge prisms42and52are separated along the central axis L2with a predetermined gap therebetween so as to face a space that is created at a time when the prism support portions41and51are disposed adjacent to each other. In this manner, the prism support portion41supports the wedge prism42on the side of one end along the central axis L2; the prism support portion51supports the wedge prism52on the side of the other end along the central axis L2. The prism support portions41and51, which support the wedge prisms42and52that need to be disposed along the central axis L2so as to face each other with a predetermined gap therebetween, are disposed on the same plane. Therefore, the optical axis-direction thickness can be made thinner, and the device can be made smaller in size.

According to the above-described embodiment, what is described is the case where, in the image blur compensation mechanism6, the cover section20is provided. However, the present invention is not limited to that configuration. The cover section20may not be provided. Even in this case, the rotor units40and50attract each other because of a magnetic force generated between the magnet43and the yoke18and between the magnet53and the yoke19. As a result, the rotor units40and50are not detached from the base section10.

According to the above-described embodiment, what is described is the case where the wedge prisms42and52having a surface tilted with respect to a plane perpendicular to the central axis L2are used to move, in the X-axis and Y-axis directions, the light that strikes the imaging element4after passing through the lens group5. However, the present invention is not limited to that configuration. For example, a diffraction grating or the like may be used as long as it is possible to move, in the X-axis and Y-axis directions, the light that strikes the imaging element4after passing through the lens group5.

According to the above-described embodiment, what is described is the case where the image blur compensation mechanism6is provided between the lenses5D and5E. However, the present invention is not limited to that configuration. The image blur compensation mechanism6may be provided in front of the lens group5(on the opposite side from the imaging element4), or right before the imaging element4; or may be provided at any location between the lenses of the lens group5. The image blur compensation mechanism6may be provided in the camera body unit2.

According to the above-described embodiment, what is described is the case where the voice coils15and16are provided on the base section10, and the magnets43and53on the prism support portions41and51. However, the present invention is not limited to that configuration. The magnets may be provided on the base section10, and the voice coils on the prism support portions41and51.

According to the above-described embodiment, what is described is the case where the wedge prisms42and52are formed integrally with the prism support portions41and51, respectively, with the use of resin or the like. However, the present invention is not limited to that configuration. Instead of either the wedge prism42or52or both, for example, a wedge prism made of glass may be bonded and fixed to one or both surfaces of a parallel prism that is formed integrally with the prism support portions41and51with the use of resin or the like. Even in this case, as in the case of the wedge prisms42and52, it is possible to move the incident light substantially in the X-axis and Y-axis directions as the rotor units are rotated.

According to the above-described embodiment, what is described is the case where the rotor units40and50are disposed on the same plane. However, the present invention is not limited to that configuration. All that is required is that a prism support portion, which supports an outer periphery side of a wedge prism, is formed into a shape whose central angle around a central axis is less than 180 degrees, and that a magnet and a yoke are provided in the prism support portion, and that the wedge prism is so supported as to be rotatable around the central axis. For example, each of rotor units (prism support portions) paired may be disposed on a different plane.

More specifically, as shown inFIG. 6in which portions corresponding to those inFIGS. 2 to 4are represented by the same reference symbols, in an image blur compensation mechanism106, rotor units140and150are provided. In the rotor units140and150, with respect to the base section10, wedge prisms142and152are so provided as to be separated in the Z-axis negative direction. Incidentally, a cover section120is formed into a shape suited for the rotor units140and150.

Prism support portions141and151are formed into a fan shape whose central angle around the central axis L2is less than 180 degrees. The prism support portions141and151are disposed on the base section10in such a way as to be able to rotate on the same plane through balls17A to17C and17D to17F.

In the case of the prism support portions141and151, compared with the above-described prism support portions41and51, thick portions141G and151G, which are designed to support the wedge prisms142and152, are made thicker toward the Z-axis negative direction sides (the opposite-direction sides from the base section10).

The prism support portions141and151support the wedge prisms142and152on the Z-axis negative direction sides of the thick portions141G and151G that are made thicker in such a way that the slopes of the wedge prisms142and152are different by 90 degrees, and that the wedge prisms142and152face each other.

In that manner, in the image blur compensation mechanism106, with respect to the plane on which the prism support portions141and151are disposed, the wedge prisms142and152are so provided as to be separated on the Z-axis negative direction sides.

In the image blur compensation mechanism106, what is formed is a space in which nothing is provided and which extends from the opening11A of the base section10to the wedge prism142.

Accordingly, the image blur compensation mechanism106is effective especially when the prism support portions141and151and the wedge prisms142and152cannot be disposed on the same plane due to placement of each component of the camera, the lens group, and the like. In the space in which nothing is provided and which extends from the opening11A of the base section10to the wedge prism142, another lens may be provided, for example. Therefore, the device as a whole can be made smaller in size.

In another example, as shown inFIG. 7in which portions corresponding to those inFIGS. 2 to 4and6are represented by the same reference symbols, in an image blur compensation mechanism206, rotor units40and150are provided.

In the image blur compensation mechanism206, wedge prisms42and152are so disposed as to face each other; the prism support portions41and151, however, are disposed on different planes.

In order to support the prism support portions41and151on different Z-axis direction planes, a base section210includes planes that are different in height in an up-down direction (Y-axis direction) with respect to the central, axis L2; on each of the planes, the prism support portions41and151are so supported as to be rotatable through the balls17A to17C and17D and17F. Incidentally, a cover section220is formed into a shape suited for the rotor units40and150.

The image blur compensation mechanism206is effective especially when the prism support portions41and151cannot be disposed on the same plane due to placement of each component of the camera, the lens group, and the like.

As for the image blur compensation mechanism206, in a space in which nothing is provided and which extends from an opening211A of the base section210to the wedge prism42, another lens may be provided, for example. Therefore; the device as a whole can be made smaller in size.

According to the above-described embodiment, what is described is the case where the rotor units40and50are three-point supported by the balls17A to17C and17D and17F, which are concentrically arranged.

The present invention is not limited to that configuration. The balls may not be concentrically arranged as long as the centers of the magnets43and52placed on the prism support portions41and51are located inside a triangle connecting the supporting three points.

For example, as shown inFIG. 8in which portions corresponding to those inFIGS. 2 to 4are represented by the same reference symbols, in an image blur compensation mechanism306, on a circular portion312that is provided near the outer periphery of a base plate311of a base section310, ball grooves312A to312D are concentrically provided around the central axis L2.

The ball grooves312A and312B are so provided as to be symmetrical about a central line (Y-axis) that passes through the center of the voice coil15, and to be spaced by a distance longer than the length of the voice coil15(X-axis direction), for example.

The ball grooves312C and312D are so provided as to be symmetrical about a central line (Y-axis) that passes through the center of the voice coil16, and to be spaced by a distance longer than the length of the voice coil16(X-axis direction), for example.

On a base section310, a circular portion311B is provided on a base plate311so as to surround an opening311A, which is provided at the center of the base plate311around the central axis L2, and to be equal in Z-axis direction thickness to the circular portion312.

On the circular portion311B, ball grooves311C and311D are provided on a central line (Y-axis) that passes through the centers of the voice coils15and16so as to be symmetrical about the central axis L2.

The base section310supports one rotor unit (not shown) via the balls17A to17C placed in the ball grooves312A,312B, and311C. The base section310supports the other rotor unit (not shown) via the balls17D to17F placed in the ball grooves312C,312D, and311D. Incidentally, on the rotor units, ball grooves are so provided as to face the ball grooves312A,312B, and311C, and the ball grooves312C,312D, and311D.

In that manner, in the image blur compensation mechanism306, a rotor unit can be supported in such a way that the centers of the voice coils15and16are inside a triangle connecting three supporting points of the rotor unit, i.e. the centers of the magnets that are so disposed as to face the voice coils15and16on the rotor unit are inside the triangle.

According to the above-described embodiment, what is described is the case where the rotor units40and50are three-point supported by the balls17A to17C and17D to17F. However, the present invention is not limited to that configuration. All that is required is to support a rotor unit at least at three points. A rotor unit may be supported at four or more points as long as the center of a magnet that is disposed on a prism support portion so as to face a voice coil is located inside a polygon that connect the supporting points.

According to the above-described embodiment, the image blur compensation mechanism6is applied to the case where an image of the light passing through the lens group5of the camera1is moved. However, the present invention is not limited to the above. The image blur compensation mechanism6may be used in other optical devices, such as a projection device and a laser device.

For example, when being used for a projection device, the image blur compensation mechanism is placed ahead of an emitting section that emits light; the light emitted from the emitting section is refracted and moved in X-axis and Y-axis directions before being emitted as projection light. When being used for a laser device, the image blur compensation mechanism is placed ahead of a laser section that emits a laser beam; the laser beam emitted from the laser section is refracted and moved in X-axis and Y-axis directions before being emitted.

INDUSTRIAL APPLICABILITY

The present invention can be used for optical devices such as digital cameras.

EXPLANATION OF REFERENCE SYMBOLS