JPH0646314A - Two-dimensional driving device - Google Patents

Abstract

PURPOSE:To obtain a compact and low power consumption two-dimensional driving device which drives the CCD of a video camera directly and corrects the shaking of a screen in a moving table displacing a small light-weight object slightly and two-dimensionally. CONSTITUTION:The two moving axes of a first driving mechanism 4 and a second driving mechanism 10 are arranged orthogonally and each moving axis is driven by electromagnetic force of first and second rectangular coils 9, 15 and first and second magnetic circuit 8, 14. A CCD 3 flexibly moves on a driving surface and holds a stable moving table surface by the rigidity of a parallel leaf spring and a contact type supporting means capable of sliding on the driving surface in a direction perpendicular to the driving surface. Thus, a low power consumption two-dimensional driving device which is compact and is possible to perform a stable operation is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and lightweight object.
In particular, the present invention relates to a two-dimensional driving device that directly drives a CCD of a video camera in a moving table that is minutely displaced in two dimensions to correct camera shake on a screen.

[0002]

2. Description of the Related Art When hand-held shooting is performed with a video camera, a screen shake occurs due to camera shake, and when reproduced on a TV (Tejon set), a feeling similar to sea sickness due to a shift in the relative relationship between the viewer and the TV screen is produced. I have experience. To correct such screen shake, the motion vector of the shake is detected by observing the captured screen in time series, and
A method for obtaining a stable image without blurring by cutting out and displaying a part has been devised, and it is widely used as a product. (For example, Masaaki Nakayama, video movie, The Electrophotographic Society of Japan, 3rd
Volume 0, No. 1 (1991) P73-81) Regarding the technology for image stabilization by a mechanical system that does not cut out an image, a gimbal mechanism with a lens, an autofocus mechanism system, an automatic diaphragm mechanism system, and a CCD as an integrated optical system. There is an example in which camera shake correction is performed by driving with two actuators (for example, Toshio Inaji, Development of image blur prevention technology for video cameras, Technical Report of TV Society, No. 11).
Vol. 28 (1987) P19-24).

A conventional example of correcting a camera shake using a mechanical system will be described with reference to FIG. The main body 25 of the video camera faces the optical axis 26 and shoots. Shaking of the video camera body 25 due to camera shake is yawing 27 (left and right camera shake) and pitching (up and down camera shake).
The acceleration sensor (1) (2) 29, 30 is detected as 28. The optical system 31 including the CCD 3 has a gimbal mechanism 3
It is rotatably supported by the yawing direction 27 and the pitching direction 28. Then, in order to drive the optical system 31 in the respective rotating directions, the planar facing type actuators (1) (2) 3 composed of coils and magnets.
3, 34 are provided on the respective rotary shafts, and the optical system 31 is directly driven by the actuators (1) (2) 33, 34. By inputting the detection signal 35 from the acceleration sensor (1) (2) 29, 30 to the servo circuit 36 to control the power supply to the actuator (1) (2) 33, 34, a stable image with less shaking can be obtained. To shoot.

Although its application is different from that of image shake correction, the most popular apparatus for driving a small and lightweight object two-dimensionally by a minute distance is an optical pickup actuator for an optical disk, for example. As the optical pickup actuator, a movable coil type actuator is most often used in which a current is passed through a coil attached to the optical pickup and the optical pickup is driven by an electromagnetic force with a fixed magnet.

The optical pickup is supported on the fixed portion by four thin piano wires or an elastic support such as a plastic link mechanism.

A conventional optical pickup actuator is shown in, for example, Masami Shishikura, Motor for Compact Disc, Mechanical Design, Volume 32, No. 6 (1988) P28-38, which will be described below with reference to FIG. Note that FIG.
7A is a perspective view of an optical pickup actuator, FIG.
(B) is an exploded perspective view of the same.

The optical pickup actuator 37 is
Objective part 38, movable part 41 on which coils 39 and 40 are mounted, link 42 supporting movable part 41, magnetic circuit 43
It is composed of a fixing portion 44 on which is mounted. The coil 39 is energized to rotate the objective lens 38 about the rotation center 45 for tracking 46, and the coil 39 is energized to move the objective lens 38 up and down in parallel by the link 42 to perform focusing 47.

The magnetic circuit 43 of this conventional example is composed of two circuits, and the coils 39 and 40 are symmetrically arranged with the link 42 interposed therebetween.

In the coil 39, two rectangular coils form a pair, the directions of the currents I on the sides of adjacent coils are the same, and the direction of the force F generated in the magnetic field of the magnetic flux density B is set. Match. Of the 1 to 8 sides of the coil 39, two sides contribute to generating the force F1.

The coil 40 is also formed in a rectangular shape,
One side is inserted into the magnetic circuit and generates force F2 in the same magnetic field as coil 39. Force F of the four sides of coil 40
It is one side that contributes to generating 2.

[0011]

However, the above conventional configuration has the following problems. 1) When clipping from an image with camera shake by image processing, even if the number of pixels on the entire screen is 360,000,
The number of pixels after correction of camera shake is reduced to about 300,000 pixels, which is contrary to the demand of the times when high image quality is required. 2) In the system in which the entire optical system is supported by the gimbal mechanism using the mechanical system and is driven by two actuators, it is necessary to have a margin of the size of the main body 25 of the video camera according to the rotation angle of the optical system. Yes, it cannot be miniaturized. If the rotation angle for camera shake correction is ± 6 degrees, a gap of ± 10 mm is required between the optical system and the main body even if the length from the rotation center of the optical system is 100 mm. 3) The coil 39 of the optical pickup actuator is
Two rectangular coils form a pair, the directions of the currents I on the sides of the adjacent coils are the same, and the directions of the force F generated in the magnetic field of the magnetic flux density B are the same. Of 1
Of the eight sides, the two sides contribute to the generation of the force F1, and the utilization efficiency of the coil is as small as 25%.

The generated force F is F = B · I · L · sin θ (1), where L is the length of the line through which the current I flows in the magnetic field and θ is the angle at which the magnetic flux intersects the current. Since the wire length L is proportional to the product of the coil side length and the number of turns, the utilization efficiency of the coil side greatly affects the efficiency of the actuator.

The present invention solves the above-mentioned problems of the prior art by directly driving a CCD of a video camera with a small two-dimensional driving device and performing a camera shake correction without causing a reduction in pixels with a small optical system. Further, it is an object of the present invention to provide a two-dimensional driving device that raises the utilization efficiency of the coil and realizes this with low power consumption.

[0014]

In order to achieve this object, a two-dimensional drive device of the present invention comprises a first drive mechanism supported by a first parallel leaf spring in a fixed housing, and a first drive mechanism. Has a second driving mechanism supported by a second parallel leaf spring on a moving piece of the driving mechanism, the moving axes of the two moving sides are arranged at right angles, and the first and the second moving sides respectively have the moving axes. Two rectangular coils are mounted, the first magnetic circuit configured to sandwich the rectangular coil is fixed to the housing, and the second magnetic circuit is fixed to the first moving piece. Is.

Further, the first and second rectangular coils are composed of at least three or more n multi-turn coils, and n
The first and the first coils are arranged so that the current directions on the sides of adjacent coils of the individual coils are made coincident with each other, and the magnetic fluxes are orthogonalized at the adjacent (n-1) positions on the sides of the coils so that the directions of the generated forces coincide. The second magnetic circuit has a (n-1) magnetic circuit configuration such that the direction of the magnetic flux of the magnetic circuit is opposite to the side magnetic flux direction.

The first and second parallel leaf springs are
With a thin metal piece of 0.1 mm or less and a width of about 3 to 4 mm,
The moving piece is displaced in the plate thickness direction of the parallel leaf spring with a spring constant of about 10 g / mm or less, and has rigidity in the width direction of the parallel leaf spring (perpendicular to the two-dimensional drive plane). Furthermore, it has a slidable support means for increasing load bearing in a direction perpendicular to the two-dimensional drive plane.

In addition, when the moving plane of the object attached to the second moving piece is used as the vertical, a load equal to the weight of the object is applied to the moving side moving vertically and the stress of the parallel leaf spring is applied. It has a construction in which it is made to work against gravity by using a bending or bias spring.

[0018]

With this configuration, the object attached to the second moving piece supported by the parallel leaf springs that are doubled is two-dimensionally driven.

When at least three rectangular coils of the driving mechanism are constructed and the magnetic circuit is an (n-1) magnetic circuit, for example, when n is 4, four rectangular coils of 16 sides are provided. The six sides contribute to the electromagnetic action, and the output with respect to the input power can be 1.5 times that of the conventional one.

The parallel leaf spring is a thin metal piece of 0.1 mm or less and has a width of about 3 to 4 mm. The parallel leaf spring realizes a thin two-dimensional drive device by being doubled. By setting the spring constant to about 10 g / mm or less, driving with low power consumption can be easily performed, and the supporting means has a rigidity with respect to an axis orthogonal to the two-dimensional driving plane and is slidable. By using the combination of the above, it is possible to maintain a stable posture of the table surface.

When the moving plane of the object is used as a vertical plane, the parallel leaf springs bend due to the weight of the object and the moving side, but the same load as the own weight is generated in the direction opposite to the gravity. It is possible to achieve a well-balanced configuration, which facilitates driving with low power consumption.

[0022]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

1A and 1B show a two-dimensional driving device according to a first embodiment of the present invention. FIG. 1A is a three-dimensional view, and FIG. 1B is a three-dimensional view. A CCD 3 is mounted on a moving table 2 of the two-dimensional driving device 1. It shows a state where is mounted.

The two-dimensional driving device 1 is composed of the first driving mechanism 4 and the second driving mechanism 10, and the two driving mechanisms are doubled. Therefore, the thickness of the two-dimensional driving device 1 is a casing. Body 5
It became possible to reduce the thickness to 6.5 mm.

The first drive mechanism 4 includes a first moving side 7 supported by a first parallel leaf spring 6 on the housing 5, a first magnetic circuit 8 fixed on the housing 5, and a first magnetic circuit 8. It is composed of a first rectangular coil 9 fixed to the moving side 7.

The second drive mechanism 10 includes a fixed side 11 fixed to the first moving side 7 and a second moving side 13 supported by a second parallel leaf spring 12 and a first moving side 7. It is composed of a fixed second magnetic circuit 14 and a second rectangular coil 15 fixed to the second moving side 13.

The mounted CCD 3 has a size of 1/3 inch, and the size of the two-dimensional driving device 1 is limited by the size of the object, but ± 500 μm necessary for performing the image stabilization 20% of the entire screen. The size of the two-dimensional driving device 1 in the present embodiment for performing the two-dimensional driving is 30 × 29 mm.

FIG. 2 is an exploded view of the second drive mechanism 10 which is a main part of the two-dimensional drive device 1. The magnetic circuit 14 will be described in detail with reference to this figure.

The fixed side 11 and the magnetic circuit 14 are fixed to the moving side of the first drive mechanism 4 not shown. Therefore, the second drive mechanism 10 is the moving shaft 1 of the first drive mechanism 4.
It can move in 6 directions.

The moving side 13 is a parallel plate spring 12 and is a fixed side 1.
It is supported by 1 and can be displaced in the moving direction 17 by a load calculated by the spring constant of the parallel leaf spring 12. In this embodiment, the parallel leaf spring 13 has a thickness of 0.1 mm or less and a width of 3.5.
mm thin plate of phosphor bronze or stainless steel was used. As the spring constant, a spring constant of 2 to 10 g / mm was manufactured. Therefore, the force required for two-dimensional driving of ± 500 μm without load is about 1 to 5 g. Further, since it has a high rigidity with respect to the axis orthogonal to the two-dimensional drive plane, it does not bend. The amount of deflection can be suppressed within a maximum of 1 μm even when a load of 10 g is generated.

Further, in order to have load resistance, it has a supporting means slidable on a driving plane for preventing the object from being displaced vertically to the moving surface by the load. FIG. 3 shows an embodiment of the slidable supporting means, which is a housing 5
3 small balls 22 are sandwiched between the CCD 3 and the CCD 3. C
The surface of CD3 is formed of smooth optical glass and has a much larger area than the actual image plane. Therefore, a portion that is not optically used can be used as the sliding surface of the small ball 22. By having this slidable support means, it is possible to realize a drive mechanism having excellent load resistance without changing the size of the two-dimensional drive device 1.

A groove is formed on the moving side 13 so that the rectangular coil 15 can be easily mounted at a regular position.

The rectangular coil 15 is composed of n = 4 multi-turn coils, and the side 18 adjacent to each coil is the magnetic circuit 14.
The generated force F calculated by the equation (1) is obtained by being installed in the magnetic field of (1) and applying a current to the side (18).

When a current is applied to one coil, the directions of the currents are reversed on the opposite sides. Therefore, the direction of the current flowing through the coil is set to be the same in the side 18 at one location and alternate in the sides 18 at three locations.

That is, as shown in the rectangular coil connection diagram of FIG. 4, when four coils are connected in series, the winding directions are reversed between adjacent coils (FIG. 4 (a)), or In any of the three cases of connecting in parallel (FIG. 4 (b)) or using coils in series and parallel (FIG. 4 (c)), the side 1 where two coils are adjacent to each other 1
In 8, the electric current is applied so that the directions are the same.

The magnetic circuit 14 has a (n-1) = 3 magnetic circuit configuration, and since the directions of the currents flowing through the sides 18 of the rectangular coil 15 are alternated, the central magnet 19 is provided.
The polarities of the magnets 20 at both ends are opposite, and the directions of the magnetic fields with the yoke 21 are alternate. Then, the yoke 21 is inserted into the elongated hole provided on the moving side 13, and the magnetic circuit 14 is installed so that the rectangular coil 15 is sandwiched in the magnetic field.

In this embodiment, the magnetic circuit 14 is replaced by the magnet 1.
Although 9 and 20 and the yoke 21 are used, a magnet may be used instead of the yoke 21. According to the experiment, the magnetic circuit 1
The generated force when 4 is composed of only a magnet is 1.3 times that when the yoke 21 is used.

(Embodiment 2) FIG. 5 shows another embodiment of the structure of the drive mechanism when the two-dimensional drive device 1 is used in a vertically standing state, in which the magnetic circuit is omitted. The same reference numerals are given to the elements in FIG.

In this embodiment, the two-dimensional driving device 1 is standing vertically, the first driving mechanism 4 is suspended in the housing 5, and the second driving mechanism 10 has a moving direction 17 in the direction of gravity 2.
It agrees with 3. Therefore, the moving table 2 and the CCD
3. The parallel leaf spring 12 bends due to the weight of the second moving side 13, and the CCD 3 cannot be maintained at a predetermined position. Therefore, the influence of gravity is offset by applying a load equal to its own weight in the direction opposite to gravity. In this embodiment, as a means for this, the bias spring 24 is provided on the second moving side 1.
It is inserted between 3 and the first moving side 7.

Here, if the weight of the element that is affected by gravity is 4 g, the bias spring 24 having a spring constant of 1 g / mm will be used to balance the compressed 4 mm. Therefore, if the CCD 3 is designed to be in a predetermined position with the bias spring 24 contracted by 4 mm, the influence of gravity can be eliminated.

In this embodiment, the bias spring 24 is used as an example. However, the parallel leaf spring 12 is stress-bent upward and lifted up without load, and the CCD 3 is loaded under load. By designing to be in a predetermined position, the influence of gravity can be eliminated as in the case of using the bias spring 24.

[0042]

As described above, the two-dimensional driving device of the present invention as described in the embodiments has the following advantages. 1) The structure of the drive mechanism is one in which the moving side is supported by parallel leaf springs, and a thin two-dimensional drive device can be realized by forming two orthogonal axes in double. 2) Since the number of pixels does not decrease due to camera shake correction by the mechanical system, and since the CCD is driven directly, the drive displacement can be made smaller (±) compared to the case where the entire optical system is driven.
The size of the video camera can be reduced. 3) At least three rectangular coils are used, and the current directions at the adjacent (n-1) sides are matched, and a magnetic circuit is formed at these (n-1) sides, and electromagnetic force is applied. The (n-1) magnetic circuits have alternating magnetic flux directions in order to match the directions of the forces generated by. As a result, for example, the utilization efficiency of the rectangular coil with n = 4 can be 1.5 times that of the conventional one, and the power consumption can be reduced. 4) By setting the spring constant of the parallel leaf spring to 10 g / mm or less, the CCD can be driven with a small force. Further, since the parallel leaf spring has rigidity in the axial direction perpendicular to the drive shaft, the displacement is small even when receiving a load. 5) By having the contact-type supporting means slidable with respect to the driving plane, the load bearing property in the axial direction perpendicular to the driving shaft can be further provided, and the stable posture of the moving table surface can be maintained. . 6) When the two-dimensional drive device is used vertically, it can be driven without being influenced by gravity by adding stress bending of the bias spring or the parallel leaf spring so as to cancel the gravity.

As described above, the two-dimensional driving device of the present invention has many advantages, and in addition to the camera-shake correction of the video camera shown in the embodiments, it has many advantages as a small two-dimensional driving device. It can be applied.

[Brief description of drawings]

FIG. 1A is a three-dimensional view of a two-dimensional drive device according to a first embodiment of the present invention, and FIG.

FIG. 2 is an exploded view of a second drive mechanism that is a main part of the two-dimensional drive device according to the first embodiment of the present invention.

FIG. 3 is a three-sided view of a slidable support means which is a main part of the two-dimensional drive device according to the first embodiment of the present invention.

FIG. 4 is a connection diagram of a rectangular coil which is a main part of a two-dimensional driving device according to the first embodiment of the present invention.

FIG. 5 is a plan view of a driving mechanism when the two-dimensional driving device according to the second embodiment of the present invention is used while standing vertically.

FIG. 6 is a transparent perspective view of a conventional image stabilization apparatus using a mechanical system.

FIG. 7A is a perspective view of a conventional optical pickup actuator. FIG. 7B is an exploded perspective view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Two-dimensional drive device 2 Moving table 3 CCD 4 1st drive mechanism 5 Housing 6 1st parallel leaf spring 7 1st moving side 8 1st magnetic circuit 9 1st rectangular coil 10 2nd drive mechanism 11 fixed side 12 second parallel leaf spring 13 second moving side 14 second magnetic circuit 15 second rectangular coil 16 moving axis of first drive mechanism 17 moving direction 18 side 19 central magnet 20 magnets at both ends 21 yoke 22 small ball 23 gravity direction 24 bias spring 25 video camera body 26 optical axis 27 yawing (left and right camera shake) 28 pitching (upper and lower camera shake) 29 acceleration sensor (1) 30 acceleration sensor (2) 31 optical system 32 gimbal mechanism 33 actuator (1) 34 actuator (2) 35 detection signal 36 servo circuit 37 optical pick-up Actuator 38 Objective lens 39 Coil 40 Coil 41 Movable part 42 Link 43 Magnetic circuit 44 Fixed part 45 Rotation center 46 Tracking 47 Focus

Front page continued (72) Inventor Kunihiko Nakamura 3-10-1 Higashisanda, Tama-ku, Kawasaki-shi, Kanagawa Matsushita Giken Co., Ltd. No. Matsushita Giken Co., Ltd.

Claims (7)

[Claims] 1. A first moving piece supported by a first parallel leaf spring in a fixed housing, a first rectangular coil, and the housing configured to sandwich the first rectangular coil. A first drive mechanism which is fixed to the body and which comprises a first magnetic circuit; a second moving piece which is supported by a second parallel leaf spring on the fixed piece;
And a second drive mechanism composed of the second magnetic circuit configured to sandwich the second rectangular coil, and a fixed piece of the second drive mechanism and the second drive mechanism. Is mounted on the first moving piece, and by arranging the moving axes of the first driving mechanism and the second driving mechanism at a right angle, the object attached to the second moving piece is moved. Two
A two-dimensional drive device that drives in two dimensions. 2. The first and second rectangular coils are composed of at least three or more n multi-winding coils, the current directions of adjacent coils of the n coils are made to coincide with each other, and the coil sides are The magnetic fluxes are orthogonal to each other at (n-1) points adjacent to each other, and the first and second magnetic circuits are aligned with the magnetic flux directions on the side where the magnetic flux directions of the magnetic circuits are adjacent to each other. The two-dimensional driving device according to claim 1, wherein the magnetic circuit has an inverted (n-1) magnetic circuit configuration. 3. The first and second parallel leaf springs are 0.1
The width of the thin metal piece is 3 mm to 4 mm, and the moving piece is displaced in the plate thickness direction of the parallel leaf spring with a spring constant of 10 g / mm or less. The two-dimensional drive device according to claim 1, wherein the two-dimensional drive device has rigidity in a vertical direction. 4. When a load perpendicular to a two-dimensional drive plane is applied, the object has a contact type support means that is slidable so as not to cause a vertical displacement of the object with respect to the moving surface. Item 2. A two-dimensional drive device according to item 1. 5. When a two-dimensional drive plane is used as a vertical, a load equal to the weight of the object with respect to a moving side moving vertically is opposed to gravity using a stress bending of a parallel leaf spring or a bias spring. The two-dimensional drive device according to claim 1, wherein the two-dimensional drive device is operated in the direction. 6. The object mounted on the second moving piece is used as an image pickup device of a video camera, and the image pickup device is directly driven two-dimensionally in order to correct image shake due to camera shake. The two-dimensional drive device according to item 5. 7. The object attached to the second moving piece is used as an image pickup device of a video camera, and the image pickup device is directly driven two-dimensionally in order to correct image shake due to camera shake. The two-dimensional drive device according to 1.