JP3791057B2 - Blur correction device, photographing optical system, and camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shake correction apparatus that corrects shake due to camera shake or the like by moving part or all of a lens.
[0002]
[Prior art]
Conventionally, this type of blur correction device detects camera shake and corrects the blur on the film surface by moving a part of the lens along the shake.
[0003]
FIG. 7 is a conceptual diagram illustrating camera shake. The camera 1 has 6 degrees of freedom and performs pitching, yawing, and rolling motions that are rotational motions of 3 degrees of freedom and motions in the X, Y, and Z directions that are translational motions of 3 degrees of freedom. In general, a camera shake correction apparatus performs a camera shake correction for a motion with two degrees of freedom of pitching and yawing.
[0004]
Next, a description will be given of a shake correction method when the camera causes pitching shake. FIG. 8A is a schematic view when the camera is not shaken. The subject A forms an image at the position B on the film surface 8 through the blur correction lens 2. FIG. 8B is a schematic view when the camera causes pitching. When the camera 1 causes pitching, the image formed at the position B on the film surface 8 moves to the position B ′. This is a blur on the film surface. This blur can be corrected by driving the blur correction lens 2 in a direction perpendicular to the optical axis.
[0005]
The camera movement is monitored by an angular velocity sensor. As the angular velocity sensor, a piezoelectric vibration type sensor that detects Coriolis force generated by normal rotation is used. As this angular velocity sensor, two angular velocity meters for detecting pitching blur and for detecting yawing blur are used. Using the outputs of these angular velocity sensors, the blur correction lens is driven so as to correct camera shake.
[0006]
However, when blur correction control is performed while the camera is stationary, the image may be deteriorated as compared to the case where blur correction is not performed. This reason is due to noise, drift, etc. added to the angular velocity sensor. In such a case, the photographer performs shooting while setting a mode in which no blur correction is performed.
[0007]
When blur correction is not performed in this way, it is necessary to lock the blur correction lens so that it does not move. The same applies to the case of carrying the camera after shooting, and it is necessary to lock the camera so that the shake correction lens does not move due to vibration or impact applied from the outside.
[0008]
Japanese Patent Laid-Open No. 4-328532 has an engagement hole, a first lock member integrally coupled to the optical axis eccentric means, an inclined portion and a flat portion, and a fixed portion of the apparatus or an optical axis eccentricity. A second locking member that is movably provided in the means and that locks the optical axis eccentric means in a predetermined position by engaging the flat portion via the engaging hole and the inclined portion of the first locking member. A locking means is disclosed.
[0009]
[Problems to be solved by the invention]
However, in Japanese Patent Laid-Open No. 4-328532, since the locking means is provided on the outer periphery of the vibration reduction lens to lock the vibration reduction lens, the diameter of the lens barrel increases and the number of parts increases. There was a problem that it led to cost increase.
[0010]
It is an object of the present invention to provide a shake correction device that can reliably lock a shake correction optical system without significantly increasing the number of parts and increasing the diameter of a lens barrel.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 is directed to a blur correction optical system (2) that moves in a plane substantially orthogonal to the optical axis to correct image blur, and the blur correction optical system (2). In the shake correction device including the optical system holding member (3) for holding the optical system, the optical system holding member (3) is elastically supported in the plane substantially orthogonal to the optical axis, and the shake correction optical system (2) is supported. And an elastic support member (4) that allows movement in the plane by the optical system holding member (3) against the elastic force of the elastic support member (4). Rotation drive means (21) for rotating about the shaft center, and a latch holding member (25) for holding the optical system holding member (3) rotated against the elastic force of the elastic support member (4). It is characterized by that.
[0012]
According to a second aspect of the present invention, in the blur correction device according to the first aspect, the elastic support member (4) is at least three elastic wires. According to a third aspect of the present invention, in the blur correction device according to the first or second aspect, the elastic support member (4) is disposed substantially parallel to the optical axis. A fourth aspect of the present invention is the blur correction apparatus according to any one of the first to third aspects, wherein the rotation driving means (21) includes a coil (24), a magnet (23), and the like. It is characterized by including. The invention according to claim 5 is the shake correction apparatus according to any one of claims 1 to 4, wherein the shake correction is performed before the holding using the locking holding member (25). The optical system (2) is centered. The invention of claim 6 is the shake correction apparatus according to any one of claims 1 to 5, wherein the shake correction apparatus is activated based on the shake correction switch (7). To do. The invention according to claim 7 is the shake correction apparatus according to claim 6, wherein holding using the locking holding member (25) is performed when the shake correction switch (7) does not perform shake correction. It is characterized by performing. The invention of claim 8 is an imaging optical system, characterized in that the blur correction apparatus according to any one of claims 1 to 7 is used. The invention of claim 9 is a camera (1), wherein the photographing optical system according to claim 8 is used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a shake correction unit of the shake correction apparatus according to the present embodiment.
The blur correction lens 2 constitutes a part of the photographing optical system, moves in a direction substantially orthogonal to the optical axis, and corrects blur, and is attached to the lens chamber 3.
[0014]
The blur correction drive unit 10 is for driving the blur correction lens 2, and here, a voice coil motor (VCM) including a coil 11, a magnet 12, yokes 13 and 14, and the like is used.
The coil 11 is wound around a direction parallel to the optical axis L, and is attached to the lens chamber 3. The magnet 12 is polarized and magnetized in two poles. The yokes 13 and 14 are made of a material having high magnetic permeability such as iron. The yoke 13 is attached so as to face the magnet 12 and sandwich the coil 11. The magnet 14 is attached to the yoke 14 by its magnetic force.
[0015]
In the blur correction drive unit 10, a magnet 12 and yokes 13 and 14 form a magnetic circuit as indicated by an arrow C in the figure. According to the left-hand rule, electromagnetic force is generated in the direction perpendicular to the direction of current flow and the direction of the lines of magnetic force, and the blur correction lens 2 can be driven in the direction of arrow D in the figure.
[0016]
The lens position detection unit 15 is for monitoring the movement of the blur correction lens 2, and includes a slit 16, a light emitting element (IRED) 17, a position detection element (PSD) 18, and the like.
The slit 16 is attached to the lens chamber 3, is made of a material having a low infrared reflectance on the surface, and has a long hole in a direction perpendicular to the detection direction. The light emitting element 17 is an element that emits light for position detection, and for example, an infrared light emitting diode (IRED) or the like is used. The position detection element 18 is a one-dimensional position detection element, and for example, a PSD (Position Sensitive Device) that is a composite photodiode is used.
[0017]
In the lens position detection unit 15, since the light projected from the light emitting element 17 passes through the slit 16 and enters the position detection element 18, the movement of the slit 16, that is, the movement of the blur correction lens 2 is detected by the position detection element 18. The movement of the light incident on the lens is detected, and the movement of the blur correction lens 2 can be detected by the output thereof.
[0018]
The blur correction drive unit 10 and the lens position detection unit 15 are provided one for the X direction and one for the Y direction inside the blur correction unit.
[0019]
FIG. 2 is a cross-sectional view showing a portion rotated 45 degrees around the optical axis with respect to FIG.
The elastic support member 4 is a four-wire member having high conductivity such as beryllium copper, and supports the lens chamber 3 in a cantilever manner with respect to the annular electric substrate 5. The blur correction lens 2 is elastically supported by such a structure, thereby forming a kind of link mechanism and being able to move in a plane substantially orthogonal to the optical axis L. The elastic support member 4 plays a role of energizing the coil 11 through the electric substrate 5.
[0020]
FIG. 3 is a diagram illustrating a lock mechanism of the shake correction apparatus according to the present embodiment.
The lock mechanism 20 includes a lock plate 21, a lock VCM unit 22, a latch unit 25, and the like.
The lock plate 21 is provided on the top plate 6 and is allowed to move only in the rotational direction with respect to the optical axis (see FIGS. 1 and 2). The lock plate 21 is an annular member, and has four cutout portions 21 a having a shape like a ratchet wheel on the inner periphery at the center opening. The notch 21a is provided in correspondence with the four protrusions 3a formed on the upper surface of the lens chamber 3. When the lock plate 21 rotates, the notch 21a protrudes from its inner wall surface. Engages with part 3a.
The lock plate 21 has a coil attachment portion 21b and a latch arm portion 21c formed on the outer periphery thereof.
[0021]
FIG. 4 is a diagram showing in detail the lock VCM unit of the shake correction apparatus according to the present embodiment.
The lock VCM section 22 is for driving the lock plate 21 to rotate, and includes a lock drive magnet 23 and a lock drive coil 24.
The lock driving magnet 23 is a magnet that is polarized and magnetized in two in-plane poles, and forms a magnetic field in the direction of arrow E in the figure together with the yoke 13. The coil 24 is formed integrally with the coil mounting portion 21b of the lock plate 21. When a current is passed through the coil 24, a force in the left direction (arrow F) in the figure is generated.
[0022]
As shown in FIG. 3, the latch unit 25 includes a latch magnet portion 25a fixed to the top plate 6, an iron plate 25b fixed to the latch arm portion 21b of the lock plate 21, and the like. Latching is performed by adsorbing 25b.
The iron plate 25b is attached via a spring 25c. The spring 25c functions to relieve shock when the iron plate 25b is attracted to the magnet 25a.
[0023]
In FIG. 3A, when an electric current is passed through the coil 24, the lock plate 21 integrated with the coil 24 can generate a force in the rotational direction about the optical axis. That is, the lock plate 21 is rotated in the arrow F direction in the figure by the locking VCM unit 22.
[0024]
When the rotation angle of the lock plate 21 exceeds a certain angle, the notch 21 a comes into contact with the four protrusions 3 a provided in the lens chamber 3. Further, when the lock plate 21 rotates, the lens chamber 3 is rotated to twist the elastic support member 4 and is latched by the latch unit 25.
[0025]
In this way, the lens chamber 3 is rotated by the lock plate 21 and latches in a state where the elastic support member 4 is twisted, so that the blur correction lens 2 is locked by the urging force of the elastic support member 4. Become. The image stabilization lens 2 rotates at the time of locking, but does not move in the vertical and horizontal directions, so that the image is not moved by the locking operation, and the photographer can lock the camera without feeling unnatural. It can be carried out.
[0026]
When the lock is released, the lock driving coil 24 is energized in the opposite direction to that at the time of lock, thereby pulling the iron plate 25b away from the latch magnet 25a and releasing the lock. Usually, a large force is required to separate the iron plate attracted by the magnetic force from the magnet, but the lock can be released with a slight force because of the spring force of the twisted elastic support member 4.
[0027]
Such a latch mechanism normally requires a spring for releasing the latch, but in this embodiment, the elastic support member 4 itself supporting the blur correction lens 2 plays a role of this spring. There is no need to use a spring for releasing the latch, and the number of parts can be reduced.
[0028]
FIG. 5 is a block diagram showing a system in the yawing direction of the shake correction apparatus according to the present embodiment.
The yawing angular velocity sensor 31 is for monitoring the yawing angular velocity of the camera 1 when the camera 1 is shaken by yawing. The output signal of the angular velocity sensor 31 is connected to the filter circuit 32. .
The filter circuit 32 is a circuit that cuts high-frequency noise components and DC components, and the output signal thereof is digitized via the A / D converter 33 and then taken into the blur correction CPU 34.
The blur correction switch 7 is a switch for starting the blur correction device, and the information is input to the blur correction CPU 34.
[0029]
Based on the captured data, the lens focal length information 36 sent from the lens CPU 35, the lens data stored in the EEPROM 37, the subject distance information sent from the main CPU 41, and the like. Generate location information.
[0030]
Here, the main CPU 41 is a central processing unit that is provided on the body side and manages the basic photographing control of the camera, and is connected to an AF / AECPU 42 that controls distance measurement and photometry, and an EEPROM 43 that stores various data. ing. The main CPU 41 is supplied with a BC voltage 44 and is input with various information such as a release signal from a release switch 45. Further, based on the photographing control process, the shutter magnet 46, the spool motor 47, the charge motor 48, and the like are driven and controlled, and communicated with the lens-side blur correction CPU 34 via the lens contact 49.
[0031]
The shake correction CPU 34 generates a drive signal for driving the shake correction lens 2 based on the target position information described above, and energizes the coil 11 of the shake correction drive unit 10 via the PWM driver 38. The blur correction lens 2 is driven. Then, the position information of the driven blur correction lens 2 is monitored by the PSD 18 of the lens position detection unit 15 and taken into the blur correction CPU 34 via the A / D converter 39.
[0032]
The blur correction CPU 34 is connected to the lock VCM 22 and sends a lock drive signal in accordance with the flow of FIG. 6 in order to lock the blur correction lens 2.
[0033]
FIG. 6 is a flowchart showing a lock flow of the shake correction apparatus according to the present embodiment.
The blur correction CPU 34 detects the state of the blur correction switch 7 (Step 101), and starts unlocking if it is ON (Step 102). After unlocking, various types of shake correction information are acquired (Step 103). Here, the various blur correction information refers to focal length, subject distance, lens-specific information, and the like. After acquiring the blur correction information, the blur correction control is performed (Step 104).
[0034]
During the shake correction control, the state of the shake correction switch 7 is detected at any time (Step 105). When the shake correction switch 7 is ON, the shake correction information is reacquired (Step 103), and it is checked whether the focal length and the subject distance have changed. When the focal length and the subject distance are changed, the control is switched to the control corresponding to the information (Step 104).
[0035]
When the shake correction switch 7 is turned off, the shake correction lens 2 is locked (Step 106). Note that operations such as centering may be performed before locking. In order to confirm the lock state, the VCM 10 is energized (Step 107), and the output fluctuation of the PSD 18 is confirmed (Step 108).
If the output of the PSD 18 fluctuates more than the specified value, it is determined that the lock is insufficient and the lock operation is performed again (Step 106). When the fluctuation of the output of the PSD 18 is equal to or less than the specified value, it is determined that the locking operation is completed and the operation is terminated.
[0036]
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
In the present embodiment, a permanent magnet is used as the latch magnet 25a, but an electromagnet may be used.
The rotation of the lock plate may be in the reverse direction or may be alternately twisted in both the forward and reverse directions.
[0037]
Japanese Laid-Open Patent Publication No. 8-87046 discloses that the correction optical system is moved from the unlocked state to the locked state by an elastic member through the lock member. Since it is not supported by the elastic support member as described above but supported by the stage, it cannot be twisted, and an elastic member (coil spring 87) for moving in the lock direction when locked is required. Is different.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, since the optical system holding member is locked by rotating about the optical axis center of the shake correcting optical system, the diameter of the lens barrel is not increased. Since the elastic support member is held in a rotated state against the elastic force of the elastic support member, there is no significant increase in the number of parts, and the blur correction optical system can be reliably locked.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a shake correction unit of a shake correction apparatus according to an embodiment.
FIG. 2 is a cross-sectional view showing a portion rotated 45 degrees around the optical axis with respect to FIG.
3 is a view of the blur correction unit of FIG. 1 as viewed from the optical axis direction.
FIG. 4 is a diagram showing in detail a lock VCM unit of the shake correction apparatus according to the present embodiment.
FIG. 5 is a block diagram showing a yawing direction system of the shake correction apparatus according to the present embodiment.
FIG. 6 is a flowchart showing a lock flow of the shake correction apparatus according to the present embodiment.
FIG. 7 is a conceptual diagram illustrating camera shake.
FIG. 8 is a diagram schematically showing camera shake.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Camera 2 Shake correction lens 3 Lens chamber 3a Protrusion part 4 Elastic member 5 Electric board 6 Top plate 7 Shake correction switch 10 Shake correction drive part 15 Lens position detection part 20 Lock mechanism 21 Lock board 21a Notch part 22 Locking VCM part 23 Magnet for Lock Drive 24 Coil for Lock Drive 25 Ratchet Unit 25a Latch Magnet Part 25b Iron Plate 25c Spring 34 Blur Correction CPU

Claims (9)

In a blur correction apparatus including a blur correction optical system that moves in a plane substantially orthogonal to the optical axis to correct image blur, and an optical system holding member that holds the blur correction optical system,
An elastic support member that elastically supports the optical system holding member in the plane substantially orthogonal to the optical axis, and allows movement in the plane by the blur correction optical system;
Rotation driving means for rotating the optical system holding member about the optical axis of the blur correction optical system against the elastic force of the elastic support member ;
A blur correction device comprising: an engagement holding member that holds the optical system holding member rotated against the elastic force of the elastic support member. The blur correction device according to claim 1,
The blur correction device, wherein the elastic support member is at least three elastic wires. 3. The shake correction apparatus according to claim 1, wherein the elastic support member is disposed substantially in parallel with the optical axis. 4. The shake correction apparatus according to claim 1, wherein the rotation driving unit includes a coil and a magnet. 5. 5. The shake correction apparatus according to claim 1, wherein the shake correction optical system is centered before holding using the locking holding member. 6. Blur correction device. 6. The shake correction apparatus according to claim 1, further comprising a shake correction switch that activates the shake correction apparatus. The shake correction apparatus according to claim 6, wherein when the shake correction switch stops the shake correction apparatus, holding is performed using the locking holding member. A photographing optical system using the blur correction device according to any one of claims 1 to 7. A camera using the photographing optical system according to claim 8.

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