JP2021015201A - Imaging device - Google Patents

Abstract

To provide an imaging device that corrects rotation around the optical axis, with which, designed to save power consumption though, an imaging element is maintained at a horizontal position.SOLUTION: The imaging device is characterized by having: a movable frame 22, with an imaging element 6 mounted, which is held so as to be capable of rotating relatively to a fixed frame 21 around an axis perpendicular to an imaging plane; a plurality of balls 25a, b, c held between a V groove part 21a on an inner circumferential face of the fixed frame and a V group part 22a on an outer circumferential face of the movable frame; a first magnetic circuit 23 for holding a movable part at a prescribed position by magnetic suction; a second magnetic circuit 24 composed of a second magnet 31 and a coil 34; position detection means 51 for detecting the relative rotating position of the movable frame; a magnetic circuit control unit for controlling a current applied to the coil, on the basis of the detection result of the position detection means; an electricity conduction retention mode for sending electricity to the coil and holding the movable frame at approximately center; an electricity nonconduction retention mode for not sending electricity and holding the movable frame at a prescribed position; and retention mode switching means for switching between the electricity conduction retention mode and the electricity nonconduction retention mode.SELECTED DRAWING: Figure 1

Description

The present invention relates to an imaging device having a vibration isolator that corrects blurring during shooting, and more particularly to an imaging device that corrects rotational blurring around an optical axis.

In recent years, due to the high performance of image pickup devices, many image pickup devices and photographing lenses are equipped with an image stabilization mechanism. Conventionally, so-called pitch (rotation along the axis extending in the lateral direction of the imaging device) and yaw (rotation along the axis extending in the vertical direction of the imaging device), which are more influential blurs, have been corrected. As the performance of blur correction around the pitch and yaw axes has improved, the effects of roll (rotation around the optical axis) blur cannot be ignored. On the other hand, although several types of mechanisms used in the vibration isolator have been proposed, a structure for moving the image sensor is known as a mechanism for correcting rotational blurring around the optical axis.

In Patent Document 1, a movable portion is rotatably held around an optical axis, and a VCM coil for driving is arranged along an arc centered on the optical axis to reduce roll shake correction. Anti-vibration devices have been proposed.

JP-A-2015-210392

However, in the mechanism of Patent Document 1 described above, since VCM is used for the drive unit, no force is generated between the movable portion and the fixed portion when power is not supplied. That is, in the state where the electric power is not applied, the image sensor is not fixed and the rotation position is indefinite, and the image sensor cannot be kept in the horizontal position which is the center of the operating range. And it is necessary to supply electric power to keep it in the horizontal position which is the center of the operating range.

Therefore, an object of the present invention is an image pickup device that corrects rotation around an optical axis, and aims to hold the image pickup element in a horizontal position while saving power.

In order to achieve the above object, the imaging apparatus according to the present invention is
With the image sensor
Fixed frame and
A movable frame on which the image sensor is mounted and held so as to be rotatable relative to the fixed frame around an axis perpendicular to the image pickup surface of the image sensor.
A plurality of balls, which are at least three or more, sandwiched between the V-groove portion on the inner peripheral side surface of the fixed frame and the V-groove portion on the outer peripheral side surface of the movable frame.
A first magnetic circuit composed of a first magnet and a magnetic material arranged in the movable portion and the fixed portion and holding the movable portion in a predetermined position by a magnetic attraction force.
A second magnetic circuit composed of a second magnet and a coil arranged in the movable part and the fixed part, respectively.
A position detecting means for detecting the rotation position of the movable frame relative to the fixed frame, and
The magnetic circuit control unit that controls the current applied to the coil of the second magnetic circuit based on the detection result of the position detecting means, and the magnetic circuit control unit.
An energization holding mode in which the coil is energized by the magnetic circuit control unit and the movable frame is held substantially in the center of the movable range.
A non-energized holding mode in which the movable frame is held at a predetermined position without energizing the coil by the magnetic circuit control unit.
It is characterized by having a holding mode switching means for switching between the energized holding mode and the non-energized holding mode depending on the state of the imaging device.

According to the present invention, the image sensor can be held in a horizontal position while saving power in an image pickup device that corrects rotation around an optical axis.

The figure explaining the image pickup apparatus in the 1st Example The figure explaining the image pickup apparatus provided with the vibration isolation device in 1st Example. The figure explaining the 1st magnetic circuit and the 2nd magnetic circuit in 1st Example A block diagram illustrating control by the roll driving means in the first embodiment. The figure explaining the periphery of the ball urging member in the 1st Example The figure explaining the gap relationship between the ball and the V groove part in the 1st Example. The figure explaining the relative relationship between the horizontal position of a camera and an image sensor in 1st Example. A flowchart illustrating control of the roll driving means in the first embodiment. The figure explaining the image pickup apparatus in the 2nd Example Diagram explaining shooting conditions that are likely to be affected by roll blur

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

Hereinafter, the image pickup apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 8.

FIG. 2A is a central sectional view of an image pickup apparatus provided with an optical system adjusting device according to the present invention, and FIG. 2B is a block diagram showing an electrical configuration. Those having the same reference numerals in FIGS. 2 (a) and 2 (b) correspond to each other.

In FIG. 2, 1 is a camera which is an imaging device, 2 is a lens unit mounted on the camera 1, 3 is a photographing optical system composed of a plurality of lenses, 4 is an optical axis of the photographing optical system, and 5 is a camera system. A control unit, 6 is an image pickup element, 9a is a rear display device, 9b is an EVF, 11 is an electrical contact between the camera 1 and the lens unit 2, and 12 is a lens system control unit provided in the lens unit 2. 13 indicates a lens driving means, 14 indicates a roll driving means, 15 indicates a roll blur detecting means, 16 indicates a focal plane shutter (hereinafter referred to as a shutter), 17 indicates a shutter driving means, and 18 indicates a finder optical system. The roll driving means 14 corresponds to the vibration isolator of the present invention.

FIG. 2B is a block diagram showing an electrical configuration of the image pickup apparatus.

The camera system including the camera 1 and the lens 2 includes an imaging means, an image processing means, a recording / reproducing means (a portion controlling recording and reproduction including the recording means according to the claim), and a controlling means. The image pickup means includes a photographing optical system 3 and an image pickup element 6, and the image processing means includes an image processing unit 7. Further, the recording / reproducing means includes a memory means 8 and a display means 9 (the display means 9 includes the rear display device 9a and the EVF 9b), and the control means include the camera system control unit 5, the operation detection unit 10, and the lens system control. The unit 12, the lens driving means 13, the roll driving means 14, and the roll blur detecting means 15 are included. The lens driving means 13 can drive a focus lens, a blur correction lens, an aperture, and the like. The roll shake detecting means 15 can detect rotation around the optical axis, and a vibration gyro or the like can be used. The roll driving means 14 is a mechanism for rotating the image pickup device 6 around the optical axis 4, and the specific structure thereof will be described later. Reference numeral 18 denotes a finder optical system, which is for observing EVF9b and is composed of a plurality of lens groups.

The image pickup means is an optical processing system that forms an image of light from an object on the image pickup surface of the image pickup device 6 via the photographing optical system 3. Since the focus evaluation amount / appropriate exposure amount can be obtained from the image sensor 6, the photographing optical system 3 is appropriately adjusted based on this signal to expose the object light of an appropriate amount of light to the image sensor 6 and at the same time. A subject image is formed in the vicinity of the image sensor 6. The shutter 16 is arranged between the photographing optical system 3 and the image sensor 6, and shields the light flux to the image sensor 6 by traveling a shutter curtain (not shown) arranged inside by a command of the shutter driving means 17. Or let it pass.

The image processing unit 7 has an A / D converter, a white balance adjustment circuit, a gamma correction circuit, an interpolation calculation circuit, and the like inside, and can generate an image for recording. The color interpolation processing unit 7 is provided in the image processing unit 7, and performs color interpolation (demosizing) processing from the signals of the Bayer array to generate a color image. Further, the image processing unit 7 compresses an image, a moving image, a sound, or the like by using a predetermined method.

The memory means 8 includes an actual storage unit. The camera system control unit 5 outputs the output to the recording unit of the memory means 8, and displays the image to be presented to the user on the display means 9.

The camera system control unit 5 generates and outputs a timing signal or the like at the time of imaging. The imaging system, image processing system, and recording / playback system are controlled in response to external operations. For example, the operation detection unit 10 detects the pressing of the shutter release button (not shown) to control the drive of the image sensor 6, the operation of the image processing unit 7, the compression process, and the like. Further, the display means 9 controls the state of each segment of the information display device that displays information. Further, the rear display device 9a is a touch panel and is connected to the operation detection unit 10. The camera system control unit 5 also switches which of the display means 9 the rear display device 9a and the EVF 9b is to display. In the state of being displayed on the rear display device 9a, the user directly observes the rear display device 9a. On the other hand, in the state displayed on the EVF 9b, the user observes the light rays that have passed through the finder optical system 18 composed of the plurality of lenses shown in FIG. 1A from the eyepiece lens 18a side.

The adjustment operation of the optical system of the control system will be described.

An image processing unit 7 is connected to the camera system control unit 5, and an appropriate focus position and aperture position are obtained based on the signal from the image sensor 6. The camera system control unit 5 issues a command to the lens system control unit 12 via the electrical contact 11, and the lens system control circuit 12 appropriately controls the lens driving means 13.

As described above, by controlling the operation of each part of the image pickup apparatus 1 in response to the user's operation on the operation detection unit 10, it is possible to shoot a still image and a moving image.

FIG. 1 is a diagram illustrating a roll driving means 14, which is a main part of the present invention. FIG. 1A is a view of the roll driving means 14 viewed from the lens unit 2 side along the optical axis 4. FIG. 1B is an enlarged view of the vicinity of the ball in the cross-sectional view taken along the line AA of FIG. 1A. FIG. 1 (c) is an enlarged view of the vicinity of the ball in the cross-sectional view taken along the line BB of FIG. 1 (a). FIG. 1D is a view showing the CC rotation cross section of FIG. 1A and the cross section of the ball 25a at the same height. Further, FIG. 1 (e) shows an enlarged view of the second magnetic circuit, and FIG. 1 (f) shows an enlarged view of the first magnetic circuit.

As shown in FIG. 1A, an XYZ coordinate system will be described using a Z-axis in the four optical axes, a Y-axis in the upward direction of FIG. 1A, and an X-axis in the lateral direction.

In FIG. 1, 6 is an image sensor, 14 is a roll driving means, 21 is a fixed frame, 22 is a movable frame, 23 is a first magnetic circuit, 24 is a second magnetic circuit, 25a, 25b. , 25c indicate the ball, respectively. Further, 26 indicates a ball urging member, 27 indicates a ball urging spring, and 27 indicates a ball urging member holding shaft 28. The ball urging member 26 is arranged at a position facing the first magnetic circuit 23 with the optical axis 4 in between. The first magnetic circuit 23 is composed of a magnet 41 and yokes 42 and 43. The second magnetic circuit 24 is composed of a magnet 31, a yoke 33, and a coil 34. The magnet 41 of the first magnetic circuit 23 corresponds to the first magnet, and the magnet 31 of the second magnetic circuit corresponds to the second magnet.

In FIG. 1A, the image sensor 6 is fixed to the movable frame 22. Further, the movable frame 22 is held around the optical axis 4 so as to be rotatable relative to the fixed frame 21 by sandwiching a plurality of balls between the movable frame 22 and the fixed frame 21 as described later.

In FIG. 1A, the first magnetic circuit 23 is provided in the 12 o'clock phase of the clock, and the second magnetic circuit is provided in the 9 o'clock phase of the clock. These directions can be set arbitrarily, and may be set appropriately so as to avoid interference with surrounding mechanisms (for example, a shutter mechanism).

FIG. 1B is a cross section taken along the line AA of FIG. 1A.

V-groove portions 21a and 22a formed from two angled surfaces are arranged on the inner diameter portion of the fixed frame 21 and the outer diameter portion of the movable frame 22, respectively, and the balls 25b are sandwiched by these. The V-grooves of the fixed frame 21 and the movable frame 22 are intermittently arranged on the circumference centered on the optical axis, and although not shown, the ball 25a is also the fixed frame 21 and the movable frame 22 like the ball 25b, respectively. It is sandwiched by the V-groove portions 21a and 22a of the above.

FIG. 1 (c) is a cross section taken along the line BB of FIG. 1 (a).

The ball 25c is composed of four surfaces: a V-groove portion 22a formed from two surfaces of the movable frame 22, a slope portion 21b composed of one surface of the fixed frame 21, and a slope portion 26a composed of one surface of the ball urging member 26. It is sandwiched. A V-groove structure is formed by aligning the slope portion 21b of the fixed frame 21 with the slope portion 26a of the ball urging member 26.

Further, FIG. 1 (d) shows the CC rotation cross section of FIG. 1 (a) and the cross section of the ball 25a at the same height. Further, FIG. 1D shows a plane passing through the center of the ball 25a and orthogonal to the optical axis 4 as a alternate long and short dash line 30. Although only the balls 25a are clearly shown in FIG. 1 (d), the centers of the balls 25a, b, and c and the surfaces forming the V-groove portions sandwiching them and the vertices of the surfaces are on the plane 30.

As shown in FIG. 1D, a plane 30 passing through the center of the ball 25a and orthogonal to the optical axis is arranged so as to intersect the first magnetic circuit 23 and the second magnetic circuit 24. This makes it possible to realize a vibration isolator that is thin in the thickness direction. The movable frame 22 rotates relative to the fixed frame 21 about the optical axis, but the position shown in FIG. 1 is substantially the center of the operating range of the movable frame 22, and is clockwise or counterclockwise from this position. It rotates around by the same amount of rotation.

FIG. 1 (e) is a diagram illustrating a second magnetic circuit 24.

Among the parts constituting the second magnetic circuit 24 shown in FIG. 1 (e), the magnet 31 is fixed to the movable frame 22, and the U-shaped yoke 33 and the coil 34 are fixed to the fixed frame 21. There is. By applying an electric current to the coil 34 by the magnetic circuit control unit as described later, it is possible to generate a torque that rotates relatively between the fixed frame 21 and the movable frame 22. Here, the magnet 31 is arranged on the movable frame 22 (so-called moving magnet), but since it is sufficient to generate relative torque, the parts group provided on the fixed frame 21 and the parts group provided on the movable frame 22 are It can be replaced. Which configuration should be used may be determined according to the convenience of power supply wiring and the like.

FIG. 1E shows a case where a current is not applied to the coil 34, and the arrow schematically shows the flow of magnetic flux. The magnetic flux emitted from the magnet 31 flows as shown in FIG. 1 (e). That is, it goes from the north pole to the south pole while passing through the yoke 33 having a high magnetic permeability as long as possible (while not passing through the air portion). At the position shown in FIG. 1 (e), the flow of magnetic flux is vertically symmetrical and no torque is generated. However, as will be described later, the structure is such that when the displacement is performed, positive feedback is applied to accelerate the displacement. This is a so-called solenoid-like magnetic circuit that generates torque that pushes against the edge of the operating range and stops.

FIG. 1 (f) is a diagram illustrating the first magnetic circuit 23.

Among the parts constituting the first magnetic circuit 23 shown in FIG. 1 (f), the magnet 41 and the flat plate type yoke 42 are fixed to the movable frame 22, and are the U-shaped yoke 43 and the position detecting means. The detection element 51 is fixed to the fixed frame 21. As will be described later, the magnetic attraction of the magnet 41 and the yoke 43 exerts a torque for pulling the movable frame back to approximately the center within the operating range shown in FIG. 1 (f). Here, the magnet 41 is arranged on the movable frame 22 (so-called moving magnet), but since it is sufficient to generate relative torque, the parts group provided on the fixed frame 21 and the parts group provided on the movable frame 22 are It can be replaced.

FIG. 1F shows a case where the movable frame 22 is substantially in the center of the operating range, and the arrows schematically show the flow of magnetic flux. The magnet 41 is composed of a so-called two-pole magnetized magnet whose vertical direction in FIG. 1 (f) is the direction of the magnetic field at the time of magnetization and is divided into two regions and magnetized in opposite directions. The magnetic flux emitted from the magnet 41 is schematically shown in FIG. 1 (f). That is, it goes from the north pole to the south pole while passing through the yokes 42 and 43 having high magnetic permeability as long as possible (while not passing through the air portion). As is clear from FIG. 1 (f), the first magnetic circuit 23 constitutes a closed magnetic circuit, and this state is the most stable. Therefore, the structure is such that when it is displaced, negative feedback that pushes back the displacement is applied. Therefore, a torque is generated so as to stay in the substantially center of the operating range.

The torque generated when a current is applied to the coil by the magnetic circuit control unit will be described with reference to FIG.

3 (a) and 3 (b) are diagrams for explaining how clockwise and counterclockwise torques are generated in the second magnetic circuit 24, respectively. 3 (c) and 3 (d) are diagrams for explaining the torque of the first magnetic circuit 23 when the movable frame 22 is slightly displaced clockwise.

In FIGS. 3 (a), (b), (c), and (d), the same items as those in FIG. 1 are numbered the same. Further, the arrows drawn on the coil 34 schematically indicate the direction of the current of the coil (the direction in the winding portion above when viewed from the figure), and the other arrows schematically indicate the flow of magnetic flux.

In FIG. 3A, the coil 34 of the second magnetic circuit 24 is energized in the direction shown in the drawing. At this time, a magnetic field is generated according to Ampere's law, and a magnetic flux is generated in the direction shown in the figure on the yoke 33 around which the coil 34 is wound. At this time, this magnetic flux flows into the S pole of the magnet 31 provided on the movable frame 22. On the other hand, the magnetic flux emitted from the north pole of the magnet 31 is sucked into the coil 34 via the yoke 33. That is, the portion of the yoke 33 shown in FIG. 3A above the coil 34 has an S pole, and the portion below the coil 34 has an N pole. Therefore, the magnet 31 tries to close the magnetic path, and the magnet 31 tries to move upward. As a result, clockwise torque is generated in the movable frame 22.

Since FIG. 3B shows a case where the power is applied in the direction opposite to that in FIG. 3A, contrary to FIG. 3A, the portion below the coil 34 of the yoke 33 becomes the S pole, and the coil 34 of the yoke 33 The upper part is the north pole. Therefore, the magnet 31 tries to move down to close the magnetic path. As a result, the movable frame 22 receives a counterclockwise torque.

FIG. 3 (c) is a diagram for explaining the first magnetic circuit 23 when the movable frame 22 is substantially in the center of the operating range, is in the same state as in FIG. 1 (f), and the magnetic flux is simulated by an arrow. Shown. Due to the magnetic flux shown in FIG. 3C, the U-shaped tip portion of the yoke 43 and the north and south poles of the upper surface of the magnet 41 receive a force that wants to approach, that is, an upward force. However, since the movable frame 22 has a ball sandwiched between the V-grooves of the fixed frame 21 and the movable frame 22 and the position is restricted, the magnet 41 and the yoke 42 are moved above FIG. 3 (c) by this magnetic attraction force. It doesn't move. As will be described later, the state of FIG. 3C is the most stable state of the first magnetic circuit 23.

In FIG. 3D, the movable frame 22 receives a force as shown in FIG. 3A and is slightly rotationally displaced clockwise. In the first magnetic circuit 23, the magnet 41 and the yoke are slightly relative to the yoke 43. 42 has moved slightly to the right. Although the actual movement of the movable frame 22 is a rotational displacement, it is schematically shown in a state of being translated to the right. A magnetic flux similar to that shown in FIG. 3C flows through the first magnetic circuit 23 as shown by an arrow. However, the magnetic flux passing from the north pole on the left side of the magnet 42 to the left side of the yoke 33 passes through more air portions than in the state shown in FIG. 3C. That is, since the state shown in FIG. 3C is magnetically more stable than the state shown in FIG. 3D, the magnet 41 and the yoke 42 tend to move to the left. As a result, the movable frame 22 receives a counterclockwise torque. Although not shown, similarly, when the movable frame 22 receives the torque as shown in FIG. 3 (b) and the magnet 41 and the yoke 42 move to the left with respect to the yoke 43, the same applies to FIG. 3 (c). The magnetic field is more unstable than the state shown in, and clockwise torque is generated. The first magnetic circuit 23 generates a torque that keeps the movable frame 22 substantially in the center of the operating range by the force that tries to stabilize the magnetic field. Hereinafter, the force for keeping the movable frame 22 of the first magnetic circuit 23 at a position substantially in the center of the operating range will be referred to as a central holding force.

In the roll driving means 14 shown in FIGS. 1 and 3, the amount of rotation is determined by the balance between the torque generated in the second magnetic circuit 24 and the central holding force generated in the first magnetic circuit 23. The rotation amount of the movable frame 22 is detected by the detection element 51, which will be described in detail later, and the rotation control of the movable frame 22 is performed by so-called feedback control in which the current amount of the coil 34 is adjusted by the magnetic circuit control unit until the target rotation amount is reached. Do. The details of the feedback control will be described later. Further, in the second magnetic circuit 24, when the movable frame 22 moves from a substantially central position of the operating range, positive feedback is applied as described above, and a torque for rotating the movable frame 22 to the end of the operating range is generated. .. However, when the movable frame 22 is located at the end of the operating range, the magnetic circuit is such that the central holding force generated by the first magnetic circuit 23 is larger than the torque generated by the second magnetic circuit 22. To set. By doing so, the movable frame 22 can be kept substantially in the center of the operating range even when the coil 34 is not energized.

Next, the rotation amount detection of the movable frame 22 by the detection element 51 will be described with reference to FIG. 1 (f).

The detection element 51 arranged on the yoke 43 shown in FIG. 1 (f) is a Hall element that detects a change in the magnetic flux density, and is directed to react to the magnetic flux density in the direction of the double-headed arrow 52 written on the right side of FIG. 1 (f). It is arranged in. In FIG. 1 (f), the direction of the main magnetic flux is indicated by an arrow, but in reality, there is also a so-called leakage flux that does not pass from the upper surface of the magnet 41 to the tip of the U-shape of the yoke 43. The detection element 51 detects the relative position of the magnet 41 using this leakage flux. That is, in FIG. 1 (f), since the detection element is located on the boundary line of the two-pole magnetization, the magnetic flux in the magnetic flux density detection direction shown in FIG. 1 (f) becomes almost zero. On the other hand, when the movable frame 22 rotates clockwise and the N pole on the upper surface of the magnet 41 in FIG. 1 (f) moves to the right, the magnetic flux in the magnetic flux density detection direction at the position of the detection element 51 becomes positive. .. On the contrary, when the movable frame 22 rotates counterclockwise and the S pole on the upper surface of the magnet 41 moves to the left, the magnetic flux in the magnetic flux density detection direction at the position of the detection element 51 becomes negative. If this is detected, the amount of rotation of the movable frame 22 can be known. Feedback control is performed using the detection value of the detection element 51, the movable frame 22 is moved to an arbitrary position, and roll blur is corrected.

A block diagram of the feedback control of the roll driving means 14 of the present invention is shown in FIG. The signal processing unit and the controller shown in FIG. 4 are included in the camera system control unit 5. First, the roll shake amount is acquired by the roll shake detecting means 15 shown in FIG. Next, the signal processing unit determines the amount to be corrected. The processing performed by the signal processing unit includes noise removal by the roll blur detecting means 15 and reflection of the photographer's intention. The photographer's intention is a panning operation due to a composition change, and the reflection of the photographer's intention is to set the target position to zero and hold it at a substantially central position when it is determined to be a panning operation. The controller, which is a magnetic circuit control unit, is for stably performing feedback control, and a PID controller or the like can be used. After that, a current is applied to the coil 34 of the second magnetic circuit 24, which is a drive mechanism, via a driver (not shown) or the like, and the result is obtained as a control output (rotation amount of the movable frame 22). Then, the rotation amount of the movable frame 22 is acquired by the detection element 51 and fed back. That is, control is performed so that the control output and the target value match. As a result, the position is appropriately controlled and the roll blur correction is performed.

Next, the structure around the ball urging member 26 will be described in detail with reference to FIGS. 1 (a) and 5.

5 (a) is a cross-sectional view around the ball urging member 26 shown in FIG. 1 (c) with vectors such as urging forces added, and FIG. 5 (b) is shown in FIG. 1 (a). It is a figure explaining the arrangement of the ball 25 of the roll driving means 14, and FIG. 5C is a schematic view of the DD cross-sectional view of the roll driving means 14 of FIG. 5B. FIG. 5D is a cross-sectional view showing another example of the ball urging member 26.

As described with reference to FIG. 1, the roll driving means 14 of the present invention supports the movable frame 22 by sandwiching the balls 25 with V-grooves provided in the fixed frame 21 and the movable frame 22, respectively. However, if there is an error in the dimensions of each component with respect to the design value in the above structure, it is conceivable that the gap in each V-groove portion becomes smaller than that of the ball 25, the ball 25 is caught, and the movable frame 22 cannot rotate. Or, on the contrary, if the gap in each V-groove portion is larger than that of the ball 25, play occurs and the movable frame 22 not only rotates with respect to the fixed frame 21 but also has a surface substantially perpendicular to the optical axis. It will move and the image sensor 6 will not perform the desired rotation operation. Therefore, in the present invention, the ball urging member 26, which will be described later, prevents the ball from being bitten and loosened due to an error in the parts.

As shown in FIG. 5A, the rotating shaft portion 26b of the ball urging member 26 has a hollow cylindrical structure, and the ball urging member holding shaft 28 is fitted with the hollow portion and is pivotally supported. The ball urging member 26 is movable in the Z direction. The ball urging member holding shaft 28 is connected to the fixed frame 21 to regulate the position of the ball urging member 26 in the Z direction. The ball urging spring 27 has a torsional spring structure, and is passed through the coil portion using the rotating shaft portion 26b of the ball urging member 26 as a guide rod. Further, as shown in FIG. 1A, one end of the ball urging spring 27 is hung on the springing portion 26c of the ball urging member 26, and the other end is hung on the springing portion 21c of the fixing portion 21. Then, the ball urging spring 27 generates a force for urging the ball urging member 26 shown in FIG. 1A in the counterclockwise direction around the ball urging member holding shaft 28. This counterclockwise urging force shown in FIG. 1A acts as a force for urging the ball urging member 26 in the positive direction of the Y axis shown by the arrow 61 in FIG. 5A. Then, the ball 25c in contact with the slope portion 26a of the ball urging member 26 receives a force in the direction indicated by the arrow 62 on the slope portion 26a. Further, the ball 25c rolls on the contact surface with the slope portion 26a and abuts on the left side surface which is one surface forming the V groove portion 22a of the movable frame 22 shown in FIG. 5A.

On the other hand, the ball 25c receives the force of the arrow 62 and also abuts on the right side of the V-groove portion 22a of the movable frame 22 shown in FIG. 5A, and the movable frame 22 has the force of the arrow 63 from the ball 25c on the contact surface. Receive. The one-dot line 65 shown in FIG. 5B is an axis connecting the centers of the balls 25a and 25b, and in FIG. 5C, it penetrates the center of the balls 25a. As shown in FIG. 5 (c), the movable frame 22 is centered on the axis 65 connecting the centers of the balls 25a and 25b by the force of the arrow 63, and a moment like the arrow 64 is generated by the component 63a in the Z direction of the arrow 63. .. The moment indicated by the arrow 64 causes the ball 25c to come into contact with the slope portion 21b of the fixed frame 21 shown in FIG. 5C, and the position of the movable frame 22 is restricted. Since the ball urging member 26 is urged by the ball urging spring 27, even if there is mechanical play as described above, the ball 25c can be used on the slope portion 26a of the ball urging member 26 and the slope of the fixed frame 21. The portion 21b and the V-groove portion 22a of the movable frame are in contact with each other. As a result, the position of the movable frame 22 in the Z direction is restricted. Then, the movable frame 22 is urged in the positive direction of the Y axis by the component 63b in the Y-axis direction of the force 63 received from the ball 25c by the movable frame 22 shown in FIG. 5 (c). By this force, the balls 25a and 25b are also urged and sandwiched by the V-groove portion 21a of the fixed frame 21 and the V-groove portion 22a of the movable frame 22, and the position of the movable frame 22 in the Y-axis direction is also regulated.

If the spring force of the ball urging spring 27 that transmits the force of the arrow 61 to the ball urging member 26 is too large, the force of holding the balls 25a, b, and c in the V groove portion becomes large, which becomes a load when the ball rolls. Therefore, the spring force of the ball urging spring 27 is properly designed. Desirably, the force of the arrow 61 pushes the movable frame 22 in the positive direction of the Y-axis with a force that exceeds the weight obtained by multiplying the weight of the movable group that moves together with the movable frame 22 including the movable frame 22 by the safety factor. It should be. For example, it is conceivable that when the photographer shoots with the camera 1, an inertial force is applied to the movable frame 22 due to camera shake, and the movable frame 22 receives a force in a direction opposite to the urging direction relative to the fixed frame 21. Be done. As a result, there is a concern that the movable frame 22 may translate with respect to the fixed frame 21 in a plane orthogonal to the optical axis 4, so that the movable frame 22 is urged by a force exceeding the above-mentioned assumed inertial force. Just do it. The movable frame 22 may move in translation when it receives a strong impact such as dropping, but when the camera 1 is stopped after falling, it can return to the original regulated position by the spring force. Further, when the ball urging member 26 receives the impact of dropping, the ball urging member 26 rotates clockwise as shown in FIG. 5 (b), but the right end portion of the ball urging member 26 comes into contact with the stopper portion ⇒ 21d of the fixed frame 21. By the way, rotation is regulated. The stopper portion 22d is designed so that the ball 25c does not fall off even if the ball urging member 26 rotates clockwise.

In the present invention, as shown in FIG. 5B, the ball urging member 26 is arranged at a position facing the first magnetic circuit 23 with the optical axis 4 interposed therebetween. As described above, in the first magnetic circuit 23, a force that always pulls the movable frame 22 upward as shown in FIG. 5B is generated by the magnetic attraction force. Even when the ball urging member 26 is not provided by this force, the balls 25a and 25b are sandwiched by the V-groove portion 21a of the fixed frame 21 and the V-groove portion 22a of the movable frame 22 in a urged state. Therefore, it is desirable to design the urging force by the ball urging spring 27 described above in consideration of the fact that the force in the Y-axis upward direction of the movable portion is the resultant force with the magnetic attraction force of the first magnetic circuit 23.

Here, for example, a case where the ball urging member 26 is arranged so as to urge the ball 25a at an adjacent position without facing the first magnetic circuit 23 across the optical axis 4 will be described. .. At this time, the balls 25a and 25b are urged by the attractive force of the first magnetic circuit 23 by the V-groove portion of the fixed frame 21 and the movable frame 22, the slope portion of the movable frame 22, and the slope portion 26a of the ball urging member 26, respectively. To. In this case, the attractive direction of the magnetic attractive force and the vector component of the force that urges the movable frame 22 of the ball urging member 26 whose direction coincides with the attractive direction becomes large. If the force for urging the movable frame 22 of the ball urging member 26 is weaker than the force due to the magnetic attraction of the first magnetic circuit 23, the balls 25c facing the first magnetic circuit 23 across the optical axis are not sandwiched. There is a fear. As a result, the position of the movable frame 22 is not restricted, and the position of the image sensor 6 may move other than the desired rotation during imaging. Therefore, the spring force of the ball urging spring 27 must be set to be larger than the configuration shown in FIG. 5 (c) described above. However, in that case, the urging force held by the fixed frame 21, the movable frame 22, and the V-groove portion or the slope portion of the ball urging member 26 becomes large, and the rolling resistance at the time of rolling the ball increases. As a result, it is necessary to generate a larger torque in the second magnetic circuit 24, which leads to an increase in the amount of current to the coil 34, that is, an increase in power consumption. It is also conceivable that the increase in the rotational load of the movable frame 22 due to the rolling resistance during ball rolling reduces the responsiveness during roll drive and the blur correction performance. Therefore, in the present invention, as shown in FIG. 5B, the ball urging member 26 is arranged at a position facing the first magnetic circuit 23 with the optical axis 4 interposed therebetween, so that the power consumption is suppressed and the height is high. Accurate blur correction can be performed.

In this embodiment, the slope portion 26a of the ball urging member 26 is one surface that sandwiches the ball 25c, and has a V-groove shape together with the slope portion 21b of the fixed frame 21, but the following configuration is also possible. Good.

In FIG. 5D, the slope portion 21b on the fixed frame 21 side is eliminated, and instead, the portion of the ball urging member 26 that sandwiches the ball 25c is not limited to one surface of the slope, but has a V-groove shape as shown in 26d. doing. Other parts and structures are the same as in FIG. 5C, and the ball 25c is urged in the direction of arrow 66 by the ball urging spring 27. The ball 25c may be urged in such a shape.

Further, the arrangement of the three balls 25 will be described. It is desirable that the angle φ formed by the balls 25a and 25b arranged on both sides of the first magnetic circuit 23 about the optical axis 4 shown in FIG. 5B is 120 degrees or less. The V-grooves 21a and 22a of the fixed frame 21 and the movable frame 22 that sandwich the balls 25a and 25b are urged by the ball urging member 26 so that the balls 25a and 25b do not bite as described above. In the absence state, it is configured with a slight gap. Each ball 25 is urged by the ball urging member 26 so as to fill this gap, and the ball 25 can roll. However, if the gap is large, the following problems are concerned. First, the movable frame 22 moves in the positive direction of the Y axis due to urging, and if the gap is large, the amount of movement of the movable frame 22 increases, and the rotation centers of the optical axis 4 and the movable frame 22 during rotational drive are greatly displaced. There is a concern that it will end up. Further, if the gap is large, the amount of movement of the ball urging member 26 increases, and when the movable frame 22 receives a force larger than the urging force due to an impact such as dropping or vibration, the ball 25 is sandwiched from the V groove portion. There is a concern that it will drop out. In order to prevent the balls 25 from falling off, it is necessary to increase the diameter of the balls, and there is a concern that the balls will increase in size and become thicker in the thickness direction. Therefore, it is desirable to arrange the balls 25 as described above.

FIG. 6 is a diagram schematically explaining the relationship between the V-groove portion and the angle φ formed by the two balls 25a and 25b, and only the main portion is shown. FIG. 6A shows a configuration when the angle formed by the balls 25a and 25b is 120 degrees or less, and FIG. 6B shows a configuration when the angle formed by the balls 25a and 25b is 120 degrees or more. .. The same numbers as those in FIGS. 1 and 5 are assigned.

In FIGS. 6A and 6B, the dotted line 21e shows a line connecting the intersecting vertices of the two surfaces forming the V-groove portion 21a of the fixed frame 21, and the dotted line 22b forms the V-groove portion 22a of the movable frame 22. It shows a line connecting the intersecting vertices of two faces. Further, the angles formed by the balls 25a and 25b around the optical axis 4 are represented by φ1 and φ2, respectively.

In FIGS. 6A and 6B, the movable frame 22, the fixing portion 21, the balls 25a, 25b, etc., which have the same numbers in FIGS. 6A and 6B, have the same dimensions and shapes. Yes, the relationship between the ball 25 and the radius of the circle centered on the optical axis of the V-groove portion is the same. The surface on which the V-grooves 21a and 22b of the fixed frame 21 and the movable frame 22 and the ball 25a roll is different from the dotted lines 21d and 22b, but the ball 25a can move in the Y-axis direction due to the gap relationship between the dotted lines 21d and 22a and the ball 25a. The amounts are compared relative to each other in FIGS. 6 (a) and 6 (b).

The amount of movement of the ball 25a in the direction of arrow 71 parallel to the Y axis in FIG. 6A and the amount of movement of the ball 25a in the direction of arrow 72 in FIG. 6B are larger in arrow 72. Since the Y-axis direction is the direction in which the ball urging member 26 urges the ball, the angle φ1 formed by FIG. 6A can reduce the amount of urging by the ball urging member 26. That is, when three balls 25a, 25b, and 25c are arranged on an arc to support the movable frame 22, the angle formed by the balls 25a, 25b around the optical axis 4 is formed in combination with other balls. It is desirable that it be smaller than the angle. Therefore, it is desirable that the angle formed by the balls 25a and 25b is 120 degrees or less.

As described above, in the camera of the present invention, the movable frame 22 is held substantially in the center of the operating range by the magnetic attraction force of the first magnetic circuit 23 even when the coil 34 of the second magnetic circuit 24 is not energized. That is, if the holding position of the movable frame 22 by the central holding force of the first magnetic circuit 23 is adjusted to be horizontal to the camera 1 in the manufacturing process of the camera 1, the image pickup is performed even when the power of the camera 1 is turned off. The element 6 is held at the horizontal position of the camera 1. The horizontal position of the camera 1 is a state in which the lower side of the camera 1 as shown in FIG. 2A faces the ground.

However, if the magnetic flux density of the first magnetic circuit 23 changes due to temperature changes due to high or low temperature environments or changes over time, the central holding force weakens from the initial state, and the holding position of the movable part 22 shifts from the horizontal position. It is possible that it will come. Further, due to an increase in rolling resistance between the ball 25 and the V-groove portion due to aging, there is a concern that the ball 25 and the V-groove portion may not return to the initial horizontal position even if the central holding force of the first magnetic circuit 23 does not change.

FIG. 7 is a diagram schematically showing the horizontal position of the camera 1 and the image sensor 6 and the position of the image sensor 6 when the holding position deviates from the horizontal position due to a temperature change, and is an outline of the camera 1 which is a main part of the description. The image sensor 6 is shown inside.

The image sensor 6a shown by the solid line is in a state corresponding to the horizontal position of the camera 1, and the XY axes at this time are shown by 73x and 73y, respectively. On the other hand, the image sensor 6b shown by the dotted line shows a state in which the camera 1 is held at a position tilted by θ due to a temperature change from the horizontal state. The XY axes at this time are shown by 74x and 74y, respectively. The tilt angle of the holding position due to the actual temperature change is smaller than that in FIG. 7, but it is schematically shown for explanation.

In the state of the image sensor 6b, when the photographer holds the camera 1 horizontally with respect to the ground or installs it horizontally on the device, the image taken by exposing the camera 1 horizontally and the image sensor 6b actually There is a problem that the image is not what the photographer intended due to the difference between the horizontal and horizontal. However, since the roll driving means 14 has a detection element 51 that detects the amount of rotation of the movable frame 22, the current of the coil 34 of the second magnetic circuit 24 is used by using the detection value of the detection element 51 as described above. By controlling the amount, the movable frame 22 can be kept at an arbitrary rotation position. That is, by controlling the amount of current in the coil 34, the image sensor 6 and the movable frame 22 can be held in the horizontal position even if there is a temperature change or a secular change as described above. Hereinafter, holding the image sensor 6 and the movable frame 22 by energizing the coil 34 is referred to as energization holding, and holding the image sensor 6 and the movable frame 22 without energizing the coil 34 is referred to as non-energization holding. And. However, if the movable frame 22 is always held in the horizontal position by holding the power supply, the power consumption will increase.

Therefore, in the present invention, there is a holding mode switching means, and whether the holding mode switching means horizontally holds the image sensor 6 and the movable frame 22 in the energized holding mode or the non-energized holding mode according to the state of the camera 1. To switch. The holding mode switching means is included in the camera system control unit 5. Further, in the energization holding mode, as described above, the coil 34 of the second magnetic circuit 24 is energized to hold the movable frame 22 in the horizontal position, and in the non-energization holding mode, the coil 34 is not energized and the first magnetic circuit. The movable frame 22 is held only by the central holding force of 23. By controlling in this way, the power consumption is reduced as compared with the case where the image sensor is held at the horizontal position of the camera 1 and the coil 34 is always energized to hold the image sensor 6 and the movable frame 22 horizontally. It can be suppressed.

A specific control flow will be described with reference to FIG. FIG. 8 is a flowchart illustrating a control in which the camera system control unit 5 detects the state of the camera 1 and holds the horizontal position by switching between energization holding and non-energization holding of the coil 34.

First, when the power of the camera 1 is turned on, the flow starts. In step S101, the holding mode switching means first switches to the non-energized holding mode, and the non-energized holding causes the position of the image sensor 6 to be positioned only by the magnetic attraction of the magnetic circuit 23. Hold. Then, the FLAG in the camera system control unit 5 is initialized to 0.

In step S102, the detection element 51 detects the position of the movable frame 22 and calculates the amount of rotation θ from the reference position. The reference position is the position of the movable frame 22 in a state where the horizontal position of the image sensor 6 is aligned with the horizontal position of the camera 1, and the reference position is recorded in the memory means 8 in the manufacturing process of the camera 1. Further, the amount of rotation is calculated by the camera system control unit 5 using the value detected by the detection element 51, and the calculation formula is adjusted in the manufacturing process of the camera 1.

In step S103, it is determined whether the rotation amount θ detected in step S102 is the threshold value θ0 or less, and if it is θ0 or less, the process proceeds to step S109, and if it exceeds θ0, the process proceeds to step S104. This threshold value θ0 is an allowable value when the image sensor 6 is tilted about the optical axis 4 with respect to the reference position which is the horizontal position of the camera 1. When the rotation amount θ is equal to or less than the threshold value θ0, the tilt of the image sensor 6 is within the permissible range and the holding in the non-energized holding mode is continued.

On the other hand, in step S104, the holding mode switching means switches to the energization holding mode, a current is passed through the coil 34 to hold the energization, and the FLAG in the camera system control unit 5 is set to 1.

In step S105, the non-energized holding mode is switched again by the holding mode switching means, the current flow of the coil 34 is stopped, and the non-energized holding mode is performed.

In step S106, the detection element 51 detects the amount of rotation θ of the movable frame 22 from the reference position in the same manner as in step 102.

In step S107, it is determined whether the rotation amount θ detected in step S106 is the threshold value θ0 or less, and if it is θ0 or less, the process proceeds to step S109, and if it exceeds θ0, the process proceeds to step S108.

In step S108, the holding mode switching means switches to the energization holding mode again, a current is passed through the coil 34 to hold the energization, and the image sensor 6 is held at the horizontal position of the camera 1. Then, the FLAG in the camera system control unit 5 is set to 2.

The operation from step S104 to step S108 returns to the horizontal position by the central holding force of the first magnetic circuit 23 due to the rotational load of the movable frame 22 due to the rolling resistance of the ball 25 and the rolling surface of the V-groove portion. It is a flow corresponding to the case where there is no.

By switching to the non-energized holding mode once in step S104 and then switching to the non-energized holding mode in step S105, the camera 1 is tilted from the horizontal position in the non-energized state due to a decrease in magnetic flux due to temperature change or aging. It is judged whether it is held by. When the amount of rotation θ when the camera 1 is held tilted from the horizontal position of the camera 1 in the non-energized holding state due to a decrease in magnetic flux exceeds the threshold value θ0, the energized holding mode is used to move the image sensor 6 to the horizontal position of the camera 1. Switch to. Then, FLAG is set to 2 because it is necessary to hold the power supply in order to hold it in the horizontal position.

On the other hand, when the non-energized holding mode is switched in step S105, if the load on the rotational drive of the movable frame 22 due to the rolling resistance generated in the ball 25 and the V-groove portion is larger than the central holding force, S step 104 even if no power is applied. The movable frame 22 can stay at the position where the power is held. In this case, since the image sensor 6 can be held at the horizontal position of the camera 1 even if it is held without power, it is controlled to stand by in the power-free holding mode. Then, once the energization is held, FLAG is set to 1 so that it can be held in the horizontal position even if it is returned to the non-energization holding.

Next, in step S109, it is determined whether the operation detection unit 10 has detected the pressing of the release button (not shown), and if it is determined that the release button has been pressed and the shooting command has been issued, the process proceeds to step S110. Until the release button is pressed, the process returns to step S109 and waits.

In step S110, the roll driving means 14 performs the roll blur correction operation described above while performing the exposure operation on the image sensor 6. A still image is captured by this exposure operation, and the image is recorded in the memory means 8 via the image processing unit 7.

Next, in S111, the FLAG set value is determined. If FLAG is 0, it is determined that the image sensor 6 can be held in the horizontal position by holding the non-energized state, and the process proceeds to step S112 to hold the image sensor 6 in the non-energized holding mode. If FLAG is 1, it is determined that once energization is held, non-energization can be held in the substantially center of the operating range, and the process proceeds to step S113 to switch to the energization holding mode and rotationally drive the image sensor 6 to a horizontal position. Then, in step S114, the mode is switched to the non-energized holding mode. If FLAG is 2, it is determined that energization retention is always necessary, and the energization retention mode is switched to in step S115.

In step S116, it is determined whether the power of the camera 1 is turned off. The process returns to step S109 and the flow is repeated until the power of the camera 1 is turned off. When the power is detected to be OFF, the flow is terminated.

As described above, in order to keep the image sensor 6 in the horizontal position of the camera 1, it is determined whether to hold the energization or the non-energization according to the state of the camera 1. As a result, the image sensor 6 is kept in the horizontal position of the camera 1 by passing a current only when necessary without always passing a current through the coil 34. As a result, the image sensor 6 can be held in the horizontal position of the camera 1 while saving power.

The imaging apparatus according to the second embodiment of the present invention will be described with reference to FIG.

The second embodiment has a structure having a quick return mirror and allowing the image before shooting to be observed even with an optical viewfinder.

FIG. 9 shows a central sectional view of the camera 1 having the roll driving means in the second embodiment. Those having the same function as that of FIG. 2A in the first embodiment are numbered the same. In FIG. 9, the difference from FIG. 2A of the first embodiment is that the EVF9b is eliminated, and the quick return mirror unit 81 (hereinafter, mirror unit), the phase difference AF unit 82, the focus plate 83, and the pentaprism 84 are present. It is arranged. The optical viewfinder, which is an optical viewfinder unit, includes a focus plate 83, a pentaprism 84, and a finder optical system 18.

As shown in FIG. 9, the mirror unit 81 arranged between the photographing optical system 3 and the shutter 16 includes a main mirror 81a, which is partially composed of a half mirror and allows a part of light rays to pass through, and a part thereof. It is composed of a sub-mirror 81b that reflects the light rays. Then, when the camera system control unit 5 issues an evacuation command, the mirror unit 81 retracts upward so that the light rays that have passed through the photographing optical system 3 reach the image sensor 6 from the state shown in FIG. Since the operation of retracting the mirror unit 81 is a known technique, detailed explanation of the mechanism and operation will be omitted. The state of the mirror unit 81 at the position shown in FIG. 9 is referred to as a down state, and the state of the mirror unit 81 retracted upward (not shown) is referred to as an up state. When the mirror unit 81 is in the down state, some light rays that have passed through the half mirror portion of the main mirror 81a are reflected by the sub mirror 81b, guided to the phase difference AF unit 82 as shown by the dotted line, and reach the AF sensor 82a. .. The focal length state of the subject can be detected by performing signal processing using the light rays focused by the AF sensor 82a.

On the other hand, the light rays reflected by the main mirror 81a are imaged at the focus plate 83 position, and the photographer can observe the image formed by the focus plate 83 through the pentaprism 84 and the finder optical system 18. Further, when the mirror unit 81 is in the up state, the light rays that have passed through the photographing optical system 3 are focused on the image sensor 6, and the image sensor 6 can perform exposure. The camera system control unit 5 switches between the up state and the down state of the mirror unit 81. For example, when the photographer wants to observe an optical image through an optical viewfinder during aiming before the exposure operation, the mirror unit 81 is brought down. This state is called OVF (optical viewfinder) mode. The OVF mode corresponds to the optical viewfinder mode. Then, when the photographer wants to observe the image of the rear display device 9a at the time of aiming, the mirror unit 81 is set to the up state. This state is called LV (live view) mode. In the OVF mode, the operation detection unit 10 detects the pressing of the release button (not shown), and when it is determined that the photographing command has been issued, the mirror unit 81 is switched to the up state and the image sensor 6 is exposed.

In the LV mode, even when the movable frame 22 is tilted from the horizontal position of the camera 1, the image exposed by the image sensor 6 during aiming and the image displayed by the rear display device 9a match. On the other hand, the image exposed by the image sensor 6 and the optical image observed through the optical viewfinder in the OVF mode are adjusted in the manufacturing process of the camera 1 so as to substantially match. However, as described in the first embodiment, it is conceivable that the holding position of the non-energized holding of the movable frame 22 shifts from the time of adjustment due to a temperature change or a secular change. That is, the image exposed by the image sensor 6 and the optical image observed through the optical viewfinder do not always match. In order to avoid this, it is necessary to hold the movable frame 22 at the horizontal position of the camera 1 by holding the power supply. Furthermore, in the first embodiment, if the rotation amount θ of the movable frame 22 tilted from the horizontal position of the camera 1 is within the threshold value θ ₀ when the movable frame 22 is not energized, the tilt is within the allowable range. It needs to be stricter. This is because the difference between the optical image and the exposed image observed by the optical viewfinder is more remarkable for the photographer than the difference from the horizontal position of the camera 1.

Therefore, in the second embodiment, the roll driving means 14 is controlled by switching between the energized holding mode and the non-energized holding mode by the holding mode switching means as follows in the OVF mode and the LV mode.

First, when the camera 1 is set to the LV mode, the camera 1 is controlled by the same flow as in FIG. 8 of the first embodiment. On the other hand, when the camera 1 is set to the OVF mode, after the power is turned on, the image sensor 6 is switched to the energization holding mode regardless of the rotation amount of the movable frame 22 in the non-energized holding state, and the image sensor 6 is used as the camera. Keep in the horizontal position of 1. By controlling in this way, the difference between the optical image observed through the optical viewfinder in the OVF mode and the image after shooting is reduced, and the photographer's intention is reduced in both the OVF mode and the EVF mode. You can shoot with good quality.

In this embodiment, it is shown that the energization holding mode is always set from the power ON state in the OVF mode, but other methods may be used. If there is a so-called half-press operation in which the release button is not fully pressed in either the OVF mode or the EVF mode, the following control may be performed. It is assumed that the half-press operation of the release button performs the focus detection operation and the focus drive for detecting the focal state of the lens with respect to the subject, and the full-press operation of the release button gives an image pickup command for exposure by the image sensor 6. In the OVF mode, even if the image sensor 6 is tilted with respect to the horizontal position of the camera 1 until the image sensor 6 is exposed, the photographer is observing the optical image by the optical viewfinder, so that the photographer takes an image. The inclination of the element 6 is not detected. Therefore, in the OVF mode, the state in which the power is turned on may be switched to the non-energized holding mode, and the power may be switched to the energized holding mode after the release button is half-pressed. It is possible to switch to the energization holding mode after the full pressing operation of the release button is detected, but it takes time from the non-energized holding state to the stable rotation of the movable frame 22 by the energizing holding. Since the time until this stabilization becomes a release time lag, it is desirable to switch to the energization holding mode at the timing when the half-press operation is detected. By operating in this way, further power saving can be performed. Further, in the OVF mode, after setting the threshold value θ ₀ of the amount of rotation of the movable frame 22 used in the determination of steps S103 and S107 described in the first embodiment to a smaller threshold value θ1, the flow of FIG. 8 is performed. You may go. The threshold value θ1 may be set to a level at which the difference between the optical image observed from the optical viewfinder and the image exposed by the image sensor 6 can be tolerated.

As described above, in the second embodiment, a method of controlling the roll driving means 14 in the camera 1 having an optical finder and being able to switch between the OVF mode and the EVF mode has been described. By controlling the roll driving means 14 as described above, it is possible to reduce the difference between the observed image at the time of aiming and the image due to exposure while suppressing power consumption, and it is possible to perform high-quality shooting that reflects the photographer's intention. It can be carried out.

Further, switching between the energized holding mode and the non-energized holding mode by the holding mode switching means of the movable frame 22 may be changed depending on the state of the camera 1. For example, the energized holding mode and the non-energized holding mode may be switched depending on the shooting conditions in which the influence of roll blur in the optical axis direction is likely to occur. The first condition that is likely to be affected by roll blur is that the exposure time is long. Further, the influence is likely to occur at a position where the focal length of the lens 2 is short and away from the optical axis in the image sensor 6, that is, a position where the image height is high. Under such shooting conditions where the influence of roll is likely to occur, it is desirable that the movable frame 22 of the roll anti-vibration means 14 can be widely used within the operating range. For example, if the movable frame 22 is held substantially in the center of the operating range by holding the power supply, the same stroke can be rotated both clockwise and counterclockwise, so that even if the roll shake amount is large, the shake correction can be performed. Can be accommodated.

For example, if the holding position of the movable frame 22 is tilted counterclockwise from approximately the center of the operating range due to an increase in rolling resistance due to aging, the rotation stroke to the clockwise side has a margin, but to the counterclockwise side. There is a concern that the rotation stroke of the clock will be reduced and it will not be possible to correct it when a large roll blur occurs. Therefore, when it is assumed that the amount of roll shake is large, it is desirable that the movable frame 22 is held at substantially the center of the operating range.

Therefore, as shown in FIG. 10, the energization holding mode and the non-energization holding mode may be switched depending on the focal length and the exposure time. FIG. 10 is a graph showing the conditions under which the effect of roll blur is likely to occur. The horizontal axis shows the exposure time and the vertical axis shows the focal length, and the shooting conditions below the curve 91, that is, the shooting conditions within the range surrounded by the diagonal line are the effects of roll blur. This is an example of conditions that are likely to occur.

For example, when the exposure time is 1/2 second, it is considered that the influence of roll blur is likely to occur when the focal length is F [mm] or less, and the power is switched from the power ON state to the power holding mode so as to hold the power. On the other hand, when the focal length exceeds F [mm], it is controlled whether to enter the energized holding mode or the non-energized holding mode by the same flow as in FIG. 8 of the first embodiment. In the graph of FIG. 10, it is assumed that the average value of the amount of blurring on the image plane due to the roll blurring caused by the assumed camera shake is equal to or less than a certain allowable value (for example, about 10 times the pixel size of the image sensor 6). This is an example of the graph created in. Therefore, the curve 91 showing the permissible value in the graph of FIG. 10 changes depending on the setting of the permissible value and the assumed camera shake. Further, the allowable value curve 91 changes depending on the sensor size of the camera 1.

As described above, the holding mode switching means may be controlled according to the shooting conditions such as the exposure time and the focal length. By controlling in this way, it is possible to perform roll shake correction with high performance while suppressing power consumption. In addition, although the energization holding mode and the non-energized holding mode were switched based on the focal length and the exposure time with reference to the graph of FIG. 10, when the focal length is equal to or less than a predetermined value, the energizing holding mode may be switched at all times. .. Similarly, when the exposure time is longer than the predetermined time, the energization holding mode may be switched to.

When it is installed on a support device such as a tripod, it may be switched as follows by the holding mode switching means. For example, the camera 1 has a tripod installation mode corresponding to the support device installation mode, and in the case of the tripod installation mode, the control is switched by the holding mode switching means. The tripod installation mode is a mode used in a state where the camera 1 is stably installed in a horizontal posture such as a tripod. In the tripod installation mode, it is conceivable to use a spirit level installed on the tripod to set the camera 1 in the horizontal position. Therefore, it is desirable to hold the image pickup device 6 in the horizontal position of the camera 1. Therefore, by always switching to the energization holding mode in the tripod installation mode, the horizontal position of the tripod level and the horizontal position of the camera 1 can be matched with the horizontal position of the image sensor 6. The tripod installation mode may be set by the photographer operating while looking at the rear display unit 9a, or a flat device such as a tripod if the detection value of the roll blur detection means 15 does not change for a certain period of time. You may switch to the tripod installation mode by judging that it is installed in.

1 camera, 4 optical axes, 6 image sensors, 14 roll drive means,
15 Roll blur detection means, 16 Focal plane shutter,
21 fixed frame, 22 movable frame, 23 first magnetic circuit,
24 Second magnetic circuit, 25a, 25b, 25c balls,
26 ball urging member, 27 ball urging spring, 31 second magnet,
34 coil, 41 first magnet, 51 detection element

Claims (7)

With the image sensor
Fixed frame and
A movable frame on which the image sensor is mounted and held so as to be rotatable relative to the fixed frame around an axis perpendicular to the image pickup surface of the image sensor.
A plurality of balls, which are at least three or more, sandwiched between the V-groove portion on the inner peripheral side surface of the fixed frame and the V-groove portion on the outer peripheral side surface of the movable frame.
A first magnetic circuit composed of a first magnet and a magnetic material arranged in the movable portion and the fixed portion and holding the movable portion in a predetermined position by a magnetic attraction force.
A second magnetic circuit composed of a second magnet and a coil arranged in the movable part and the fixed part, respectively.
A position detecting means for detecting the rotation position of the movable frame relative to the fixed frame, and
The magnetic circuit control unit that controls the current applied to the coil of the second magnetic circuit based on the detection result of the position detecting means, and the magnetic circuit control unit.
An energization holding mode in which the coil is energized by the magnetic circuit control unit and the movable frame is held substantially in the center of the movable range.
A non-energized holding mode in which the movable frame is held at a predetermined position without energizing the coil by the magnetic circuit control unit.
An imaging device comprising: a holding mode switching means for switching between the energized holding mode and the non-energized holding mode depending on the state of the imaging device. The first aspect of the present invention is that the holding mode switching means switches to the energizing holding operation mode when the rotation amount of the movable frame calculated by the position detecting means is equal to or more than a threshold value in the non-energized holding mode. The imaging apparatus described. When the holding mode switching means switches from the non-energized holding mode to the energized holding mode and then switches back to the non-energized holding mode, the amount of rotation of the movable frame by the position detecting means is equal to or greater than the threshold value. The imaging apparatus according to claim 1 or 2, wherein is switched to the energization holding operation mode again. Claims 1 to 1, wherein the holding mode switching means is set to an energized holding mode or a non-energized holding mode according to the focal length of the photographing optical system through which a light ray passes and forms an image at the image sensor position. Item 3. The image pickup apparatus according to any one of items 3. The method according to any one of claims 1 to 4, wherein the holding mode switching means switches to the energization holding operation mode when the exposure time for still image shooting of the imaging device is longer than a predetermined time. Imaging device. Focus on a mirror unit arranged between the photographing optical system and the imaging element to reflect light rays from the photographing optical system to change the optical path, and a light beam whose optical path is changed by the mirror unit to form an image to generate a diffused image. It has a plate, an optical finder for observing the focus plate, and an optical finder mode for observing the optical finder, and the holding mode switching means is the magnetic circuit control unit in the case of the optical finder mode. The imaging device according to any one of claims 1 to 5, wherein the mode is switched to the energization holding operation mode. A first aspect of the present invention, wherein the imaging device has a support device installation mode in which the image pickup device is installed on the support device, and the holding mode switching means switches to energization holding in the case of the support device installation mode. The imaging device according to any one of claims 6.