JP5882585B2 - Image blur correction apparatus, optical apparatus, and control method thereof - Google Patents

Description

  The present invention relates to an image blur correction device arranged in a camera or the like, an optical device, and a control method thereof for correcting image blur caused by shake applied to an optical device in which the image blur correction device is mounted.

  A system for correcting image blur due to camera shake applied to the camera has been studied for the current camera, and the cause of the photographer's shooting mistake has almost disappeared.

  As a method for improving the image blur correction performance, Patent Document 1 discloses a method of generating a minute vibration by superimposing a minute amplitude signal on a driving lens on a correction lens.

JP 2002-350918 A

  However, in the conventional technique disclosed in Patent Document 1 described above, a signal that causes a predetermined amount of minute vibrations is always superimposed when the correction lens is driven, so that current consumption increases. Furthermore, noise is generated by minute vibration of the correction lens.

(Object of invention)
An object of the present invention is to provide an image blur correction apparatus, an optical apparatus, and a control method thereof that can increase current consumption and reduce noise by performing minute amplitude driving.

In order to achieve the above object, an image blur correction apparatus according to the present invention includes a shake detection unit that detects a shake of a device, and a shake correction that is driven in a direction orthogonal to the optical axis based on a detection result of the shake detection unit. The device has a predetermined angle in the tilt direction by means of an alternating drive unit that alternately drives the shake correction unit independently of the detection result of the shake detection unit, and an inclination detection unit that detects the tilt of the tilt direction of the device. An image blur correction apparatus having control means for controlling the driving condition of the alternating drive means based on the tilt when it is detected that the tilt is more than
The inclination detection means detects a drive current value of the shake correction means;
The control means treats the difference between the drive current value detected by the inclination detection means and the drive current value at the inclination of the initial position of the device as the inclination, and drives the alternating drive means based on the inclination. A condition is set .

  According to the present invention, it is possible to increase current consumption and reduce noise due to minute amplitude driving while performing minute amplitude driving.

1 is a schematic diagram illustrating an image blur correction apparatus that is Embodiment 1 of the present invention. FIG. It is a figure which shows the relationship between the inclination which concerns on Example 1, and an alternating drive signal. 3 is a flowchart illustrating an example of an operation according to the first exemplary embodiment. 6 is a flowchart illustrating another example of the operation of the first embodiment. FIG. 6 is an exploded development view illustrating an image blur correction apparatus that is Embodiment 2 of the present invention. 6 is a front view of Example 2. FIG. 6 is a cross-sectional view of Example 2. FIG.

  The mode for carrying out the invention is as described in Examples 1 and 2 below.

  Hereinafter, an image blur correction apparatus that is Embodiment 1 of the present invention will be described with reference to FIGS.

  The image blur correction device includes a shake detection sensor 4 (4a, 4b) as a shake detection unit, a holder 1 that holds a correction lens 1a as a shake correction unit, and a base member 2 that slidably supports the holder 1. Have The shake detection sensor 4 detects shake of a device in which the image blur correction device is mounted, and the correction lens 1a is driven in a direction orthogonal to the optical axis based on the detection result of the shake detection sensor 4. In addition, the permanent magnet 1b (1b-1, 1b-2) integrally attached to the holder 1, the coil 3 (3a, 3b) fixed to the base member 2, and a drive unit for controlling energization to the coil 3 7 (7a, 7b). Furthermore, it has the position detection means 10 (10a, 10b) which detects the position of the holder 1, the alternating drive signal production | generation part 8, and the load detection part 5 (tilt detection means) which detects the load of a shake correction means.

  The permanent magnet 1 b, the coil 3, the drive unit 7, and the alternating drive signal generation unit 8 constitute an alternating drive unit that alternately drives the correction lens 1 a independently of the detection result of the shake detection sensor 4. However, the permanent magnet 1b, the coil 3, and the drive unit 7 are shared with shake correction drive means. And it has the control part 6 which is a control means which sets an alternating drive condition from the information of the load detection part 5, and inputs it to the alternating drive signal generation part 8, and the shake correction drive signal generation part 9. The control unit 6 includes a storage unit 6 a that stores a drive current value for holding the holder 1 in the normal position (initial position), a drive current value stored in the storage unit 6, and a load detected by the load detection unit 5. And a difference calculator 6b for calculating a difference between current values (drive current values).

  The holder 1 is formed of a synthetic resin material, and includes a guide portion 1c (1c-1, 1c-2, 1c-3) as a sliding shaft that slides with a base member 2 to be described later. The permanent magnet 1b is fixed by adhesion or the like by heat caulking.

  The permanent magnet 1b is formed of a plastic magnet formed by injection molding a mixture of Nd—Fe—B rare earth magnetic powder or ferrite and a thermoplastic resin binder such as polyamide. The magnetization direction is the optical axis direction, forms a magnetic circuit with a coil 3 to be described later, and drives the holder 1 in a direction perpendicular to the optical axis.

  The base member 2 is formed of a synthetic resin material in a hollow disk shape, and holds the holder 1 so that the holder 1 can be slid in a direction perpendicular to the optical axis and the movement in the optical axis direction is restricted. (2a-1, 2a-2, 2a-3). The coil 3 is fixed to the surface of the base member 2 that faces the permanent magnet 1b in the optical axis direction.

  In the first embodiment, the shake detection sensors 4a and 4b are constituted by vibration gyros that detect angular velocities. The first shake detection sensor 4a detects the vertical shake of the camera in the direction of the arrow y in FIG. 1, and the second shake detection sensor 4b detects the horizontal shake of the camera in the direction of the arrow x in FIG. To do. The signals output from the first shake detection sensor 4a and the second shake detection sensor 4b are subjected to signal processing by various calculations such as filter processing, integration processing, and sensitivity correction in the shake correction drive signal generation unit 9. Are generated as shake correction drive signals and input to drive units 7a and 7b described later.

  The drive units 7a and 7b apply voltages to the coils 3a and 3b based on the shake correction drive signal generated by the shake correction drive signal generation unit 9 processing the signals from the shake detection sensors 4a and 4b. To do.

  The position detection means 10 is composed of magnetic detection means such as a Hall element or MR element, and is fixed to a fixing member (not shown) at a position facing the permanent magnet 1b fixed to the holder 1 in the optical axis direction. The amount of movement in the direction orthogonal to the optical axis is detected. The holder 1 is driven by feedback control so as to move to a target position for correcting shake based on a signal from the position detection means 10.

  In the first embodiment, the load detection unit 5 detects a driving load from a driving current value or a voltage value supplied to the coils 3a and 3b. When feedback control driving is performed so as to hold the holder 1 at the center of the optical axis based on the signal from the position detecting means 10, a voltage is applied to the coils 3a and 3b by the driving units 7a and 7b. The force required to hold the holder 1 at the center of the optical axis varies depending on the load required to hold the holder 1. The main load is the weight in the driving direction of the holder 1 and the frictional force applied to the guide portion 1c, and the load changes according to the direction of the optical axis of the image blur correction device. The load when the optical axis of the image blur correction apparatus is in the horizontal direction (hereinafter referred to as the positive position) is the largest compared to the direction of each optical axis because the weight of the holder 1 is the main load. In addition, the load when the optical axis is in the vertical direction (hereinafter, upward or downward) is the smallest compared to the direction of each optical axis. The reason is that the weight of the holder 1 is supported by the holding portion 2a of the base member 2 and is not a load, and a frictional force when driving the weight of the holder 1 in the horizontal direction is a main load. . Considering the frictional force generated in the guide portion 1c of the holder 1, when the optical axis of the image blur correcting device is in the horizontal direction, the weight of the holder 1 is not applied in the horizontal direction, so the vertical frictional force is the direction of each optical axis. The smallest compared to. Further, when the optical axis of the image blur correction device is in the vertical direction (upward or downward), the weight of the holder 1 is applied in the vertical direction, so that the horizontal frictional force is the most compared with the direction of each optical axis. growing.

  Generally, the frictional force changes nonlinearly when changing from static friction to dynamic friction. For this reason, if the static frictional force generated in the guide portion 1c of the holder 1 is large, it is difficult to quickly start the holder 1 and accurately control it. In the first embodiment, the load detection unit 5 detects a coil current value or a voltage value corresponding to each posture difference such as a positive position (initial position), an upward direction, or a downward direction of the image blur correction device, and thereby a driving load, particularly a friction. Can detect force. Therefore, the alternating drive at the voltage or frequency according to the frictional force in each attitude | position is attained by the control part 6 mentioned later (refer FIG. 2).

  Further, when the temperature environment is high or low, the frictional force changes due to the expansion or contraction of the material of the holder 1 and the base member 2, which can be detected by the load detection unit 5 (tilt detection means). is there. In the detection method of the first embodiment, by detecting the current value or the voltage value to the coils 3a and 3b during feedback control, in addition to the driving load in each posture, driving by a temperature environment change at a low temperature or a high temperature is performed. The load can also be detected.

  The storage unit 6a of the control unit 6 that sets alternating drive conditions stores a drive current value or a voltage value when the optical axis is horizontal (normal position = initial position). The difference calculator 6b detects the drive current value at a position detected by the load detection unit 5 and inclined at an angle in the direction in which the optical axis is tilted (pitch direction in the case of the normal position and yaw direction in the case of the vertical position). The difference between the voltage value and the stored value is calculated. The control unit 6 treats the difference as a tilt in the tilt direction, further performs signal processing such as amplification, and sets a voltage or frequency that is an alternating drive condition (FIG. 2). As a result, when the optical axis is tilted by a predetermined angle or more in the tilting direction, alternating driving can be started, and the voltage or frequency can be set according to the tilting angle in the tilting direction.

  The effect of alternating drive, which is minute amplitude drive, is not as good as the amplitude of the movable part is large. Increasing the amplitude and driving alternately reduces the resolution of the subject image and degrades the camera's autofocus (automatic focus adjustment) performance, or imparts vibration to the camera exterior, giving the photographer an uncomfortable feeling. End up. Therefore, it is preferable to suppress the amplitude amount of the alternating drive to be equal to or less than the minimum circle of confusion set for the autofocus of the camera. Further, when the frequency of the alternating drive is matched with the natural frequency of the holder 1 which is a movable part, the amplitude of the movable part becomes maximum, but it is difficult to control the amplitude because the movable part resonates, and the noise is large. Therefore, the photographer is uncomfortable. For this reason, the frequency of the alternating drive is preferably a frequency that is larger than the natural frequency of the holder 1 that is a movable part and the amplitude is stabilized. In the first embodiment, the alternating drive voltage or frequency can be set to an alternating drive condition suitable for the inclination of the optical axis of the image blur correction device, the temperature environment change at high or low temperatures, and the drive load. Electric power and low noise can be achieved.

  Next, a flowchart of an image blur correction apparatus that performs minute amplitude driving will be described (FIG. 3).

  In step S101, when SW1 generated by half-pressing a release button (not shown) of the camera is turned on, a shooting preparation operation is instructed, and the position of the holder 1 is centered on the optical axis based on the position information of the position detection means 10. The coil is energized so as to become (S102). In step S103, the drive current value or voltage value when the coil is energized is detected, and in step S104, the difference between the image blur correction device and the previously stored drive current value at the normal position (initial position) is calculated. When the value is less than a certain threshold value, the shake correction driving is performed without performing the alternating driving. If the difference is greater than or equal to the threshold value, the process proceeds to step S105, where the alternating drive voltage or frequency is set as the alternating drive condition based on the difference information in step S104. In step S106, the alternating drive condition is input to the alternating drive signal generation unit 8, and the alternating drive signal is generated and input to the drive unit 7 to perform the alternating drive. This alternating drive is started after an instruction for a shooting preparation operation by pressing SW1 of the release button. In step S107, a shake correction drive signal based on the shake detection means 4 is input to the control unit 6 in a superimposed manner, and shake correction drive is also performed after the alternating drive is started. In step S108, a standby state of SW2 generated by fully pressing the release button of the camera is set.

  In FIG. 3, the alternating drive and the shake correction drive after the start of the alternating drive are performed before the switch SW2 is turned on (instruction of the photographing operation), but after the switch SW2 is turned on (the photographing operation is performed) as shown in the flowchart of FIG. You may go after the instruction).

  As mentioned above, although Example 1 of this invention was demonstrated, this invention is not limited to this Example 1, and a various deformation | transformation and change are possible within the range of the summary.

  Hereinafter, an image blur correction apparatus that is Embodiment 2 of the present invention will be described with reference to FIGS. Since the configuration of the second embodiment is basically the same as the configuration of the first embodiment, in the description of the second embodiment, the configuration of the first embodiment is used, only different portions are described, and the description of the same portions is omitted. To do.

  The image blur correction apparatus includes a base plate 11 as a base member, a substrate 12, position detection means 13, a coil 14 and permanent magnet 15 as drive means, a holder 16 as a holding member for holding a correction lens, a correction lens 17, and a rotation restriction. It is comprised by the rotation control board 18 as a member (FIG. 5).

  The base plate 11 is formed of a synthetic resin material in a hollow disk shape, and has an opening 11a, a fitting portion 11b having an opening in one direction around the optical axis, and an engagement shaft 11c that engages with a rotation restricting plate 18 described later. Have Moreover, it has the engaging shaft 11d engaged with the positioning hole part 12a of the below-mentioned board | substrate 12, and the positioning shaft 11e inserted in the internal diameter hole part 14a of the coil 14 mentioned later.

  The fitting portion 11b has a structure having a beam portion 11b-1 having a larger distance from the center of the optical axis and a small beam portion 11b-2 than a guide bar 16a (sliding shaft) of the holder 16 described later. Thereby, a part of the fitting portion 1b has a structure having an opening in one direction around the optical axis. Therefore, after a guide bar 16a of the holder 16 to be described later is brought into contact with the fitting portion 11b in the optical axis direction, the movement in the optical axis direction is restricted by rotating around the optical axis, and the direction perpendicular to the optical axis Can be movably supported.

  Furthermore, the fitting part 11b has a structure having a guide hole 11b-3 in a direction orthogonal to the optical axis. The engagement shafts 11c and 11d extend in the optical axis direction and each have at least two axes.

  The board 12 is a hard board or a flexible printed board, has a positioning hole 12a with the engaging shaft 11d of the base plate 11, and a position detection means 13 and a terminal of the coil 14 described later are concentrated and wired on the same plane. .

  The position detection means 13 is composed of a magnetic detection means such as a Hall element or an MR element, and is disposed at a position where a permanent magnet 15 integrated with a holder 16 described later overlaps in the optical axis direction, and is orthogonal to the optical axis of the holder 16 described later. Detect movement in the direction of

  The permanent magnet 15 is formed of a plastic magnet formed by injection molding a mixture of Nd—Fe—B rare earth magnetic powder or ferrite and a thermoplastic resin binder such as polyamide. The magnetization direction is the optical axis direction, forms a magnetic circuit with a coil 14 to be described later, and drives the holder 16.

  The holder 16 is formed of a synthetic resin material, and slides with a guide hole 16b-3 of the main plate 11 and slides with a guide bar 16a, an engagement hole 18b of a rotation restricting plate 18 described later, a slidable shaft portion, and an optical axis direction. The engaging part 16b which consists of a collar part which controls a movement is provided. A correction lens 17 (to be described later) is fixed to the holder 16, and a permanent magnet 15 is fixed by adhesion or the like.

  Here, the guide bar 16 a may be formed of a material having good slidability such as metal and may be formed integrally with the holder 16.

  The correction lens 17 is formed of glass or a plastic material, and is fixed to the holder 16 by adhesion or heat caulking.

  The rotation restricting plate 18 is formed in a hollow disk shape with a spring material such as phosphor bronze, and has an engagement hole 18b, a flange 18c, and a base plate 11 that engage with the opening 18a and the engagement portion 16b of the holder 16. And an engagement hole 18d that engages with the engagement shaft 11c. Further, the rotation restricting plate 18 is disposed closer to the subject than the base plate 11.

  Next, the assembly method will be described. The positioning shaft 11d of the base plate 11 is inserted into the positioning hole 12a of the substrate 12, and the base plate 11 and the substrate 12 are fixed by adhesion or the like. The inner diameter hole portion 14a of the coil 14 is inserted into the positioning shaft 11e of the base plate 11, and the coil 14 is fixed to the base plate 11 by adhesion or the like. The terminal of the coil 14 is mounted on the substrate 12.

  Although the terminal part of the position detection means 13 is mounted on the board | substrate 12, it fixes to the base plate 11 or the board | substrate 12 by adhesion | attachment etc. except a terminal part.

  The rotation restricting plate 18 incorporates the engagement hole 18 b into the engagement shaft 16 b of the holder 16. Next, the holder 16 with which the rotation restricting plate 18 is integrated is rotated around the optical axis, and the guide bar 16a is rotated around the optical axis. And the holder 16 is rotated from the state which pressed the surface perpendicular | vertical with respect to the optical axis direction of the collar part 18c of the rotation control board 18 and the surface perpendicular | vertical to the optical axis direction of the positioning axis | shaft 11c of the base plate 11. FIG. Then, the guide bar 16a is inserted into the guide hole 11b-3 of the base plate 11, and is inserted into the engagement shaft 11c of the base plate 11 into the engagement hole 18d of the rotation restricting plate 18 (FIG. 6). Thereby, the movement of the rotation restricting plate 18 around the optical axis is restricted, and the drive of the holder 16 in the optical axis direction is restricted by the guide hole 11b-3 of the base plate 11 (FIG. 7).

  Next, driving of the holder 16 will be described. Since the driving in the 20p direction and the driving in the 20y direction in FIG. 6 are the same, only the driving in the 20y direction will be described. Since the magnetic flux of the permanent magnet 15 penetrates perpendicularly toward the coil 14, when a current is passed through the coil 14, the holder 16 is driven in one direction indicated by the arrow 20y (FIG. 6). When a current is passed through the coil 14 in the opposite direction, the holder 16 is driven in the other direction of the arrow 20y.

  In the configuration of the second embodiment, the guide bar 16a of the holder 16 moves in the guide hole 11b-3 of the base plate 11 and thus generates sliding friction during driving, but is driven from a state where alternating driving that is minute amplitude driving is performed. By doing so, the frictional force can be reduced since the static friction is changed to the dynamic friction.

  In the first and second embodiments, the correction lenses 1a and 17 are used as shake correction means, but an image sensor that can move in a direction orthogonal to the optical axis may be used.

  As mentioned above, although Example 2 of this invention was demonstrated, this invention is not limited to this Example 2, and a various deformation | transformation and change are possible within the range of the summary.

  In the above-described embodiments, the description has been continued by taking the image blur correction device provided in the digital camera as an example. However, the present invention can be applied not only to digital cameras but also to digital video cameras, single-lens reflex cameras, interchangeable lenses for interchangeable lens video cameras, optical devices such as surveillance cameras, web cameras, and imaging devices. Furthermore, it can also be applied to portable terminals such as binoculars and mobile phones. Further, it can be used for aberration correction in a polarizing device and an optical axis rotating device included in an optical device such as a stepper.

DESCRIPTION OF SYMBOLS 1 Holder 2 Base member 4 Shake detection means 5 Load detection part 6 Alternating drive means 7 Drive part 11 Position detection means

Claims (7)

What is a shake detection unit that detects a shake of a device, a shake correction unit that is driven in a direction orthogonal to an optical axis based on a detection result of the shake detection unit, and a detection result of the shake detection unit When it is detected by the alternating drive means that independently drives alternately and the inclination detection means that detects the inclination of the tilt direction of the device, the device is based on the inclination when it is detected that the device is inclined at a predetermined angle or more in the tilt direction. Control means for controlling the driving conditions of the alternating drive means, and an image blur correction device comprising:
The inclination detection means detects a drive current value of the shake correction means;
The control means treats the difference between the drive current value detected by the inclination detection means and the drive current value at the inclination of the initial position of the device as the inclination, and drives the alternating drive means based on the inclination. An image blur correction apparatus characterized by setting conditions.   The inclination detecting means further detects a driving load due to a temperature environment change of the shake correcting means, and the control means sets a driving condition of the alternating driving means based on the inclination and the driving load due to the temperature environment change. The image blur correction apparatus according to claim 1, wherein: A holder that holds a correction lens or an image sensor as the shake correction unit and has a sliding shaft;
A base member that slidably supports the sliding shaft of the holder, a permanent magnet that is integrally attached to the holder, and a coil that is fixed to the base member;
The image blur correction apparatus according to claim 1, wherein the holder is driven by energization of the coil.   4. The alternating drive unit according to claim 1, wherein the alternating drive unit starts alternating drive after an instruction of a photographing preparation operation by the device, and the shake correction unit performs shake correction drive after the alternating drive starts. The image blur correction device according to any one of the preceding claims. The alternating drive means starts alternating drive after an instruction of photographing operation by the device,
5. The image blur correction apparatus according to claim 1, wherein the shake correction unit performs shake correction driving after the start of the alternating drive. 6.   An optical apparatus equipped with the image blur correction device according to claim 1. A control method of an image blur correction apparatus having a shake correction means movable in a direction perpendicular to the optical axis,
A shake detection step for detecting a shake of the device, a drive step for driving the shake correction means based on the detection result of the shake detection step, and the shake correction means for alternating the detection result of the shake detection step. An alternating drive step for driving; an inclination detection step for detecting an inclination of the device in the tilt direction; and when the tilt detection step detects that the device is inclined at a predetermined angle or more in the tilt direction, And a control step for controlling the drive condition in the alternating drive step based on
In the inclination detecting step, a driving current value of the shake correcting means is detected by an inclination detecting means ,
The control step treats the difference between the drive current value detected by the tilt detection means and the drive current value at the tilt of the initial position of the device as the tilt, and the driving condition of the alternating drive means based on the tilt A method for controlling an image blur correction apparatus, characterized in that:

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