JP4956254B2 - Vibration correction apparatus and imaging apparatus - Google Patents

Description

  The present invention relates to a shake correction apparatus and an imaging apparatus that correct image shake.

  With the current camera, all the important tasks for shooting such as determining exposure and focusing are automated, and it is very unlikely that people who are unskilled in camera operation will fail to shoot. Recently, a system for preventing camera shake applied to the camera has been studied, and there are almost no factors that cause a photographer to make a shooting mistake.

  Here, a vibration-proof system that prevents camera shake will be briefly described. The camera shake at the time of shooting is usually a vibration of 1 Hz to 10 Hz as a frequency, and it is necessary to be able to take a photograph with no image shake even if such a camera shake occurs at the time of shutter release. As a basic idea for this, it is necessary to detect the camera vibration due to the above-mentioned camera shake and displace the correction lens in accordance with the detected value. Therefore, in order to take a photograph in which image shake does not occur even when camera shake occurs, first, it is necessary to accurately detect camera vibration, and secondly, to correct optical axis changes due to camera shake. Become.

  In principle, the above vibration (camera shake) is detected by detecting the acceleration, angular acceleration, angular velocity, angular displacement, etc., and mounting a means for appropriately calculating the output for camera shake correction. Can be done by. Then, based on this detection information, a shake correction lens that decenters the imaging optical axis is driven to suppress image blur.

  FIG. 11 is an external view of a digital compact camera having an image stabilization system. Image blur correction is performed on the optical axis 41 with respect to the camera vertical shake 42p and the horizontal shake 42y. In the camera body 43, 43a is a release button, 43b is a mode dial (including a main switch), and 43c is a retractable strobe.

  In FIG. 11, the liquid crystal monitor is provided on the back surface of the camera main body 43 so that an image picked up by an image pickup device 44 (to be described later) can be confirmed. The photographer confirms the composition of the photographed image on the LCD monitor, and then performs photographing.

  FIG. 12 is a perspective view showing the structure of the image stabilization system in the image stabilization camera of FIG. 11, and 44 is an image sensor. Reference numeral 53 denotes a shake correction device (details will be described later) that drive the correction lens 52 freely in the directions of arrows 58p and 58y in FIG. 12 to correct image shake in the directions of arrows 42p and 42y in FIG. Reference numerals 45p and 45y denote vibration detection units such as an angular velocity meter and an angular accelerometer that detect vibrations around the arrows 46p and 46y, respectively. Outputs from the vibration detection units 45p and 45y are converted into drive target values for the shake correction device 53 (specifically, the correction lens 52) via calculation units 47p and 47y described later, and input to the coil of the shake correction device 53. Thereby, image blur correction is performed.

  FIG. 13 is a block diagram showing the details of the calculation units 47p and 47y shown in FIG. 12. Since the calculation units 47p and 47y are the same, FIG. 13 will be described using only the calculation unit 47p.

  The calculation unit 47p includes a DC cut filter / amplification unit 48p, a low-pass filter / amplification unit 49p, an A / D conversion unit 410p, a camera microcomputer 411, and a drive unit 420p, which are surrounded by an alternate long and short dash line. The camera microcomputer 411 includes a storage unit 412p, a differential unit 413p, a DC cut filter 414p, an integration unit 415p, a sensitivity adjustment unit 416p, a storage unit 417p, a differential unit 418p, and a PWM duty conversion unit 419p.

  Here, a vibration gyro that detects a camera shake angular velocity is used as the vibration detection unit 45p. The vibration gyro is driven in synchronization with the camera main switch being turned on, and starts detecting a shake angular velocity applied to the camera. The signal of the vibration detection unit 45p is appropriately amplified while the DC bias component superimposed on the signal is cut by the DC cut filter / amplification unit 48p formed of an analog circuit.

  The DC cut filter / amplifier 48p has a frequency characteristic for cutting a signal having a frequency of 0.1 Hz or less, and does not affect the handshake frequency band of 1 to 10 Hz applied to the camera. However, when the characteristic of cutting 0.1 Hz or less is used in this way, it takes nearly 10 seconds until the shake signal is input from the vibration detection unit 45p and the DC is completely cut. Therefore, the time constant of the DC cut filter / amplifier 48p is reduced (for example, a characteristic for cutting a signal having a frequency of 10 Hz or less) until 0.1 second, for example, after the camera main switch is turned on. In this way, DC is cut in a short time of about 0.1 seconds, and then the time constant is increased (only the frequency of 0.1 Hz or less is cut), and the fluctuation is caused by the DC cut filter / amplifier 48p. The angular velocity signal is prevented from deteriorating.

  The output of the DC cut filter / amplifier 48p is appropriately amplified in accordance with the A / D conversion resolution by the low-pass filter / amplifier 49p formed of an analog circuit, and cuts high-frequency noise superimposed on the shake angular velocity signal. Is done. This is to avoid reading errors in the sampling of the A / D converter 410p when the shake angular velocity signal is input to the camera microcomputer 411 due to the shake angular velocity signal noise.

  The output of the low-pass filter / amplifier 49p is sampled by the A / D converter 410p and taken into the camera microcomputer 411. Although the DC bias component is cut by the DC cut filter / amplifier 48p, the DC bias component is again superimposed on the shake angular velocity signal by the subsequent amplification of the low pass filter / amplifier 49p. Therefore, it is necessary to perform DC cut again in the camera microcomputer 411.

  Therefore, for example, a shake angular velocity signal sampled 0.2 seconds after the camera main switch is turned on is stored in the storage unit 412p, and a DC cut is performed by obtaining a difference between the stored value and the shake angular velocity signal by the differential unit 413p. . In this operation, only a rough DC cut can be made (because the shake angular velocity signal stored 0.2 seconds after the main switch is turned on includes not only the DC component but also the actual camera shake). For this purpose, sufficient DC cut is performed by a DC cut filter 414p constituted by a digital filter in the subsequent stage.

  The time constant of the DC cut filter 414p can also be changed in the same manner as the analog DC cut filter / amplifier 48p, and 0.2 seconds after the camera main switch is turned on, it takes another 0.2 seconds. The constant is gradually increased. Specifically, the DC cut filter 414p has a filter characteristic that cuts a frequency of 10 Hz or less when 0.2 seconds have elapsed since the main switch was turned on. Then, the frequency cut by the filter every 50 msec is lowered to 5 Hz, 1 Hz, 0.5 Hz, and 0.2 Hz.

  However, during the above operation, when the photographer presses the shutter release button halfway (sw1 is turned on) and performs photometry and distance measurement, there is a possibility that the image is taken immediately, and time constant is changed over time. Sometimes things are undesirable.

  Therefore, in such a case, the time constant change is stopped halfway according to the shooting conditions. For example, it is found from the photometric result that the photographing shutter speed is 1/60, and the photographing focal length is 150 mm. In this case, since the accuracy of image stabilization is not so required, the DC cut filter 414p is completed when the time constant is changed to the characteristic of cutting a frequency of 0.5 Hz or less (the time is calculated by the product of the shutter speed and the photographing focal length). Control the amount of constant change). As a result, the time for changing the time constant can be shortened, and the photo opportunity can be prioritized. Of course, when the shutter speed is faster or the focal length is shorter, the characteristic of the DC cut filter 414p is completed when the time constant is changed to the characteristic of cutting a frequency of 1 Hz or less. When the shutter speed is slower and the focal length is longer, shooting is prohibited until the time constant is completely changed.

  The integration unit 415p starts integrating the signal from the DC cut filter 414p and converts the angular velocity signal into an angle signal. The sensitivity adjustment unit 416p appropriately amplifies the integrated angle signal based on the focal length and subject distance information of the camera at that time, and converts the integrated angle signal so that the shake correction device 53 operates by an appropriate amount according to the shake angle. Since the photographing optical system changes due to zoom and focus, and the optical axis decentering amount changes with respect to the drive amount of the shake correction device 53, it is necessary to perform this correction.

  The shake correction device 53 starts operating by half-pressing the shutter release button. At this point, care must be taken so that the image blur correction operation by the blur correction device 53 does not start abruptly. The storage unit 417p and the differential unit 418p are provided for this measure. The storage unit 417p stores the deflection angle signal of the integration unit 415p when the shutter release button is half-pressed. The differential unit 418p obtains the difference between the signal of the integration unit 415p and the signal of the storage unit 417p. Therefore, the two signal inputs of the differential unit 418p are equal when the shutter release button is half-pressed, and the drive target value signal of the shake correction device 53 of the differential unit 418p is zero. Is done. The storage unit 417p plays a role of using the integration signal when the shutter release button is half-pressed as the origin. As a result, the shake correction device 53 is not driven rapidly.

  The target value signal from the differential unit 418p is input to the PWM duty changing unit 419p. When a voltage or current corresponding to the shake angle is applied to the coil of the shake correction device 53, the correction lens 52 is driven according to the shake angle. However, PWM driving is desirable for power saving of the shake correction device 53 and power saving of the driving transistor of the coil. Therefore, the PWM duty changing unit 419p changes the coil driving duty according to the target value. For example, when the target value of the differential section 418p is 2048 in PWM with a frequency of 20 kHz, the duty is zero, and when it is 4096, the duty is 100, and the duty is determined according to the target value by equally dividing the duty. Note that the duty is determined not only by the target value, but also finely controlled according to the shooting conditions (temperature, camera posture, battery state) of the camera at that time, so that image blur correction is performed with high accuracy.

  The output of the PWM duty changing unit 419p is input to a known drive unit 420p such as a PWM driver, and the output of the drive unit 420p is applied to the coil of the shake correction device 53 to perform image shake correction. The drive unit 420p is turned on in synchronism with the time when 0.2 seconds have elapsed since the shutter release button was pressed halfway.

  Although not shown in FIG. 13, even when the photographer fully pushes the shutter release button of the camera (sw2 is turned on) and starts exposure, image blur correction is continued as it is. Can be prevented.

  Further, the image blur correction by the shake correction device 53 is continued as long as the shutter release button is half-pressed. When the half-press is released, the storage unit 417p stops storing the signal of the sensitivity adjustment unit 416p (becomes a sampling state), so the sensitivity adjustment unit 416p and the signal of the storage unit 417p input to the differential unit 418p Are equal, and the output of the differential section 418p is zero. Therefore, a zero drive target value is input to the shake correction device 53, and image shake correction is not performed.

  Unless the main switch of the camera is turned off, the integration unit 415p continues the integration, and the storage unit 417p stores the new integration output (signal hold) again by pressing the next shutter release button halfway. The vibration detector 45p stops operating when the main switch is turned off, and the image stabilization sequence ends.

  When the signal of the integration unit 415p becomes larger than a predetermined value, it is determined that the camera is panned, and the time constant of the DC cut filter 414p is changed. For example, a characteristic that cuts a frequency of 0.2 Hz or less is changed to a characteristic that cuts a frequency of 1 Hz or less, and the time constant is restored again in a predetermined time. This amount of time constant change is also controlled by the magnitude of the output of the integrator 415p. That is, when the output exceeds the first threshold, the characteristic of the DC cut filter 414p is set to a characteristic that cuts 0.5 Hz or less, and when the output exceeds the second threshold, the characteristic is set to cut 1 Hz or less. When the threshold value is exceeded, the characteristic is to cut 5 Hz or less.

  Also, when the output of the integration unit 415p becomes very large (for example, when an extremely large angular velocity such as camera panning occurs), the integration unit 415p is temporarily reset to prevent computation saturation (overflow). is doing.

  In FIG. 13, the DC cut filter / amplifier 48p and the low-pass filter / amplifier 49p are provided in the arithmetic unit 47p, but it goes without saying that these may be provided in the vibration detector 45p.

  14 (a) to 14 (c) are diagrams showing the configuration of the shake correction device 53. FIG. 14 (a) is a front view, and FIG. 14 (b) is a view of FIG. FIG. 14C is a cross-sectional view taken along line AA in FIG.

  In FIG. 14, the correction lens 52 is fixed to the support frame 53c. As shown in FIG. 14C, the correction lens 52 forms a group of photographing optical systems by two lenses 52a and 52b fixed to the support frame 53c and a lens 52c fixed to the base plate 54. Yes.

  A yoke 55 made of a ferromagnetic material is attached to the support frame 53c, and permanent magnets 56p, 56y (not actually visible) such as neodymium are attracted and fixed to the back surface of the yoke 55. Further, the three support shafts 53 a extending radially from the support frame 53 c are fitted into long holes 54 a provided in the side wall 54 b of the main plate 54.

  As shown in FIG. 14B, the relationship between the support shaft 53a and the long hole 54a will be described. The correction lens 52 is fitted in the direction of the optical axis 57 and does not play, but is perpendicular to the optical axis 57. A long hole 54a extends in the hole. Therefore, the support frame 53c is restricted in movement in the direction of the optical axis 57 with respect to the base plate 54, but can freely move in a plane orthogonal to the optical axis 57 (arrows 58p, 58y, 58r). However, since the tension coil spring 59 is hung between the pin 53b on the support frame 53c and the pin 54c on the ground plane 54, it is elastically restricted in each direction (58p, 58y, 58r).

  Coils 510p and 510y are attached to the ground plate 54 so as to face the permanent magnets 56p and 56y. The arrangement of the yoke 55, the permanent magnet 56p, and the coil 510p is as shown in FIG. 14C (the permanent magnet 56y and the coil 510y are also arranged in the same manner). When a current is passed through the coil 510p, the support frame 53c is driven in the direction of the arrow 58p, and when a current is passed through the coil 510y, the support frame 53c is driven in the direction of the arrow 58y.

  The amount of driving is determined by a balance between the spring constant of the tension coil spring 59 in each direction and the thrust generated in relation to the coils 510p and 510y and the permanent magnets 56p and 56y. That is, the amount of eccentricity of the correction lens 52 can be controlled based on the amount of current flowing through the coils 510p and 510y.

  By the way, recent digital cameras have been miniaturized year by year, and accordingly, driving accuracy of the shake correction device 53 has been required to be increased. FIG. 9 shows the drive frequency characteristics of the shake correction device 53, where the horizontal axis represents the drive frequency and the vertical axis represents the ratio (gain) of the actual drive with respect to the drive target value. As can be seen from FIG. 9, the resonance point in the vicinity of 80 Hz (the relationship between the total mass of the correction lens 52, the support frame 53 c, the yoke 55, and the permanent magnets 56 p and 56 y, which is the shake correction operation unit) and the spring constant of the tension coil spring 59. It has a peak of about 20 db. For this reason, when a shake near the frequency occurs, the image shake is corrected by about 10 times the target value. Until now, such high-frequency fluctuations were few and did not become a problem. However, with the downsizing of the camera, the vibration frequency band has been widened, and the vibration generated by the strengthening of the actuator (focus drive and zoom drive) in the camera and the camera has become lighter. To trigger. For this reason, the above peak can no longer be ignored.

In view of the above points, in Patent Document 1 (FIG. 4), a viscous means for applying braking in the driving direction to the correction lens for correcting image blur is provided. As a result, as shown in FIG. 10, there is no peak in the vicinity of the resonance point, and image blur correction can be performed with high accuracy.
Japanese Patent Laid-Open No. 08-184870

  However, in the above-described conventional example, a dedicated space is required for mechanically braking. Therefore, it is difficult to reduce the size of the shake correction device.

(Object of invention)
An object of the present invention is to provide a shake correction apparatus and an imaging apparatus capable of performing high-precision image shake correction while achieving a small size.

In order to achieve the above object, the present invention provides an image shake correction operation unit that is movable in a direction orthogonal to the optical axis, a ground plane unit that supports the image shake correction operation unit, the image shake correction operation unit, Drives the image shake correcting operation portion relative to the ground plate portion, which comprises a coil provided on one of the ground plate portions, the image shake correcting action portion, and a permanent magnet provided on the other of the ground plate portions. driving means for, before and viscoelastic members that will be placed in the air-core portion of Kiko yl, partially provided with the coil of the ground plate portion and the image blur correcting action portion while being inserted into viscoelastic member A shake correction comprising the image shake correction action portion and a vibration absorbing member that viscoelastically couples the ground plane portion, which is composed of a protrusion provided between the coil and the permanent magnet without being fixed to a fixed member. It is a device.

  Similarly, in order to achieve the above object, the present invention provides an imaging apparatus having the shake correction apparatus of the present invention.

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

  1 is a front view showing a shake correction apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view taken along line BB of FIG. 1 and 2, 11 (11a, 11b) is a correction lens for image blur correction, 12 is a holding frame for holding the correction lens 11, and 13 is a base plate of the shake correction apparatus. The holding frame 12 is provided with arms 12a, 12b, and 12c in a 120-degree radial direction, and support shafts 14a, 14b, and 14c made of stainless steel having a smooth surface are press-fitted into the arms 12a to 12c.

  The base plate 13 is provided with three side walls 13a, 13b, and 13c. The three support shafts 14a to 14c extending radially from the arms 12a to 12c of the holding frame 12 are fitted in the long holes 13d, 13e, and 13f provided in the side walls 13a to 13c of the base plate 13. (It is the same structure as the long hole 54a of FIG.14 (b), and cannot be seen from the direction of FIG. 1).

  As shown in FIG. 14B, the relationship between the three support shafts 14a to 14c and the long holes 13d to 13f is fitted in the optical axis direction of the correction lens 11 (perpendicular to the plane of FIG. 1). There is no play. However, the long holes 13d to 13f extend in the direction orthogonal to the optical axis (the circumferential direction 13g in the ground plane 13 in FIG. 1). Therefore, although the holding frame 12 is restricted in movement in the optical axis direction with respect to the base plate 13, it can freely move in a plane perpendicular to the optical axis (pitch direction 19p, yaw direction 19y, roll direction 19r).

  However, the arm tip portions 12d, 12e, and 12f of the holding frame 12 are fit-fit with the inner diameters of the compression coil springs 15a, 15b, and 15c. Further, the outer diameters of the compression coil springs 15a to 15c are also fit-fit with spring adjusting members 15g, 15h, and 15i (15g is shown in the sectional view of FIG. 2A), which will be described later. Therefore, it is elastically regulated in each direction (pitch direction 19p, yaw direction 19y, roll direction 19r).

  Here, the interference fit fitting will be described.

  The spring diameters of the compression coil springs 15a to 15c increase as the coil spring is compressed. Now, the outer diameters of the arm tip portions 12d to 12f and the spring adjustment members 15g to 15i of the holding frame 12 are set so as to be fitted in clearance with the coil inner diameter when the compression coil springs 15a to 15c are compressed to the maximum. When the compression coil springs 15a to 15c are maximally compressed and pushed into the arm tip portions 12d to 12f and the spring adjustment members 15g to 15i of the holding frame 12, when the compression of the springs is released, an interference fit is obtained. Therefore, the compression coil springs 15a to 15c, the arm tip portions 12d to 12f of the holding frame 12, and the spring adjustment members 15g to 15i are firmly fixed to each other and do not shift.

  Adsorption plates 17a and 17b made of a ferromagnetic material are attached to the ears 12g and 12h of the holding frame 12 (shown by dotted lines in FIG. 1), and a permanent magnet 110a such as neodymium is provided on the back side of the adsorption plates 17a and 17b. 110b are fixed by suction. Coils 16a and 16b are provided on the side of the base plate 13 facing the permanent magnets 110a and 110b.

  Here, the correction lens 11, the holding frame 12, the suction plates 17a and 17b, the permanent magnets 110a and 110b, the support shafts 14a to 14c, and the compression coil springs 15a to 15c constitute an image blur correction operation unit. Further, the base plate portion is configured by the base plate 13, the spring adjustment screws 15d to 15f, and the spring adjustment members 15g to 15i.

  FIG. 2 illustrates the arrangement of the support shaft 14a, the compression coil spring 15a, the yoke 17a, the permanent magnet 110a, and the coil 16a.

  Since the magnetic circuit of the permanent magnet 110a penetrates perpendicularly toward the coil 16a, when a current is passed through the coil 16a, the holding frame 12 is driven in the direction of the arrow 18c (see FIG. 1), and similarly the current is supplied to the coil 16b. When flowing, the holding frame 12 is driven in the direction of the arrow 18d (see FIG. 1). The driving amount is obtained by balancing the spring constants of the compression coil springs 15a to 15c in each direction with the thrust generated in relation to the driving coils 16a and 16b and the permanent magnets 110a and 110b. That is, the amount of eccentricity of the correction lens 11 can be controlled based on the amount of current flowing through the coils 16a and 16b.

  The feature of the first embodiment is that a vibration absorbing member (hereinafter also referred to as a damper member) is provided between the coil 16a and the permanent magnet 110a in FIG. This damper member is provided through a viscoelastic member 111a such as a UV curable gel or rubber having a large damping effect provided on the air core of the bobbin 16c of the coil 16a, and a pressing member 112b on the permanent magnet 110a side. It consists of a resistance plate 112a. Note that the tip of the resistance plate 112a is inserted into the viscoelastic member 111a.

  Here, the resistor plate 112a extending from the permanent magnet 110a to the ground plane 13 (coil 16a) in the image blur correcting action portion is not directly fixed to the ground plane 13, and the viscoelastic member 111a is not attached to the ground plane 13. Because it can move around freely, it will not interfere with driving.

  FIG. 3 is a plan view of the resistance plate 112a and the viscoelastic member 111a, which are the damper members. A viscoelastic member 111a is provided on the air core portion of the coil 16a via a bobbin 16c, and a resistance plate 112a extending from the permanent magnet 110a (shown semi-transparent) to the vertical side of the drawing is inserted into the viscoelastic member 111a. Has been. Here, the resistance plate 112a extends in the horizontal direction on the paper surface (a plate in which the vertical direction on the paper surface is the thickness direction). Therefore, the contact area between the resistance plate 112a and the viscoelastic member 111a is large in the direction of the arrow 18c, and the resistance of the viscoelastic member 111a is greatly received during driving. That is, the damping effect is great. On the other hand, the contact area between the resistance plate 112a and the viscoelastic member 111a (contact area in the thickness direction of the resistance plate 112a) is narrow in the direction perpendicular to the arrow 18c, and is not easily subjected to the resistance of the viscoelastic member 111a during driving.

  Here, the driving force in the direction of the arrow 18c is generated due to the relationship between the driving coil 16a and the permanent magnet 110a, but since the damping in the driving direction is performed at the center portion (air core portion) of the coil 16a, The points of action of the driving force and the damping force are the same, and stable driving is possible.

  On the other hand, with respect to the driving force generated in the coil 16b and the permanent magnet 110b (in the direction orthogonal to the arrow 18c in FIG. 3, arrow 18d in FIG. 1), the damping force is small as described above. Therefore, the driving force generated by the coil 16b and the permanent magnet 110b does not become unstable due to the resistance plate 112a.

  The resistance plate 112a is formed of a non-magnetic spring such as phosphor bronze, and the spring constant of the resistance plate 112a is set higher than the resonance point in FIG.

Here, the reason why the resistor 112a is made of an elastic material will be described. The viscoelastic member 111a becomes very hard against high frequency input such as impact. For this reason, when such an input occurs, the weight of the image shake correcting action part is supported by the resistance plate 112a (under the above conditions, the damper member is most strongly coupled between the image shake correcting action part and the ground plane part). For). As a result, the following accidents are expected.
・ Damage of resistance plate 112a ・ Peeling of viscoelastic member 111a to bobbin 16c In order to avoid these, the resistance plate 112a is formed of an elastic member, and the resistance plate 112a is bent at the time of impact input, so that the structure absorbs the impact. (See FIG. 4).

  The damper member constituted by the viscoelastic member 111a and the resistance plate 112a as described above is provided not only in the coil 16a but also in the air core portion of the coil 16b with the same structure. The same effect can be expected even if the resistance plate 112a is provided on the coil 16a side and the viscoelastic member 111a is provided on the permanent magnet 110a side. In addition, the permanent magnet 110a is provided on the image shake correcting action side, and the coil 16a is provided on the ground plate side. However, the coil 16a is provided on the image shake correcting action side, and the permanent magnet 110a is provided on the ground plate side. The same effect can be expected with the configuration.

  Here, a case where current is passed through the pair of coils 16a and 16b to drive the holding frame 12 in the pitch direction 19p and the yaw direction 19y will be described.

  FIG. 5 is a block diagram showing the circuit configuration of the drive system for this purpose. The pitch target value 31p and the yaw target value 31y are drive target values for driving the image blur correcting operation unit in the pitch direction 19p and the yaw direction 19y, respectively, and correspond to the output of the differential unit 418p in FIG. The target values 31p and 31y are gain-adjusted by the pitch driving force adjusting unit 32p and the yaw driving force adjusting unit 32y according to the driving force in each driving direction.

  The output of the pitch driving force adjusting unit 32p is input to the coil driving unit 34a (corresponding to the PWM duty conversion unit 419p and the driving unit 420p in FIG. 13) and flows as current through the coil 16a. The output of the pitch driving force adjusting unit 32p is input to the coil driving unit 34b (corresponding to the PWM duty conversion unit 419p and the driving unit 420p in FIG. 13) via the adding unit 33b and flows as current through the coil 16b. That is, the same amount of current flows in the same phase in the coils 16a and 16b by the signal of the pitch drive target value 31a.

  The output of the yaw driving force adjusting unit 32y is input to the coil driving unit 34b (corresponding to the PWM duty conversion unit 419p and the driving unit 420p in FIG. 13) and flows as current through the coil 16b. Further, the output of the yaw driving force adjusting unit 32y is input to the coil driving unit 34a (corresponding to the PWM duty conversion unit 419p and the driving unit 420p in FIG. 13) via the reversing unit 33a and flows as current through the coil 16a. That is, the same amount of current flows in the coils 16a and 16b in opposite phases to each other by the signal of the yaw drive target value 31y.

  When the same amount of current flows in the coils 16a and 16b in the same phase, a driving force is generated in the arrow 18c direction by the coil 16a and a driving force is generated in the arrow 18d direction by the coil 16b, as shown in FIG. Therefore, the resultant force is generated as a driving force along the pitch direction 19p in FIG. Also, since the driving force at this time is such that the two coils 16a and 16b are arranged at 120 degrees, one half of the driving force of each of the coils 16a and 16b is synthesized to either the coil 16a or the coil 16b. It is generated as the same driving force as one coil.

  Further, when the same amount of current flows in the coils 16a and 16b in opposite phases, as shown in FIG. 7, a driving force is generated in the direction of the arrow 18c by the coil 16a, and the direction opposite to the 18d direction (18 ' Direction). Therefore, the resultant force is generated as a driving force along the yaw direction 19y in FIG. Also, since the driving force at this time is such that the two coils 16a and 16b are arranged at 120 degrees, √ (3) / 2 of the driving forces of the coils 16a and 16b are combined to produce the coil 16a or coil. It is generated as a driving force that is √ (3) times that of any of the coils 16b.

  As described above, since the driving force differs in the driving directions (19p and 19y), a pitch driving force adjusting unit 32p and a yaw driving force adjusting unit 32y are provided as shown in FIG.

  The driving force adjusting units 32p and 32y are not provided at the subsequent stage of the target values 31p and 31y as shown in FIG. 5, but the sensitivity adjusting unit 416p shown in FIG. 13 (416y not shown in the yaw direction). You may make adjustments with. With such a configuration, in the case of driving in the yaw direction 19y, a driving force that is √ (3) times that of the coils 16a, 16 is generated, and instead of having a small driving force in this direction, in the pitch direction 19p. In the case of driving, there is no increase in driving force.

  In general, the shake amount in the yaw direction is nearly twice as large as that in the pitch direction.

  The phenomenon that the yaw shake increases with respect to the pitch as described above becomes particularly noticeable when the digital camera is held with one hand and the liquid crystal monitor on the back of the camera is observed for shooting. Since the drive amount is adjusted in accordance with the amount of shake depending on the direction as described above, image blur correction can be performed efficiently.

  Returning to FIG. 2, as described above, the compression coil spring 15a has both ends fitted to the arm distal end portion 12d of the holding frame 12 and the distal outer diameter portion 15j of the spring adjusting member 15g by an interference fit. Therefore, the compression coil spring 15a, the arm tip 12d and the side wall 13a of the holding frame 12 are firmly fixed to each other.

  The spring adjustment member 15g (15g to 15i in FIG. 1) is fitted in the side wall 13a, and can slide only in the support shaft direction 15l. The spring adjustment screw 15d (15d to 15f in FIG. 1) is screwed into the side wall 13a, and the tip part abuts on the adjustment receiving part 15k of the spring adjustment member 15g. Therefore, by screwing the spring adjusting screw 15d, the spring adjusting member 15d moves along the support shaft 14a in the direction of the arrow 151 and adjusts the spring charging force of the compression coil spring 15a in that direction.

  According to the first embodiment described above, the viscoelastic member 111a and the resistance plate 112a, which are damper members, are provided in the air core portions of the coils 16a and 16b. In addition, a mechanism that determines the direction in which the damping effect is effective is employed. Further, the shock is absorbed by the damper member. As a result, it is possible to realize a shake correction device that is small in size, stable in driving, and highly reliable.

  The configuration of the shake correction apparatus according to the first embodiment will be described in detail. The shake correction apparatus is driven in a plane substantially orthogonal to the optical axis 10 to correct an image shake, and an image shake correction unit. It has a base plate part that supports the action part. Further, coils 16a and 16b, which are drive units for driving the image blur correction operation portion relative to the ground plate portion, and air core portions of the coils 16a and 16b, are arranged so that the image shake correction operation portion and the ground plate portion are bonded to each other. It has a damper member to be elastically coupled. The image blur correcting operation unit includes a correction lens 11, a holding frame 12, suction plates 17a and 17b, permanent magnets 110a and 110b, support shafts 14a to 14c, and compression coil springs 15a to 15c. Further, the base plate portion is composed of the base plate 13, spring adjustment screws 15d to 15f, and spring adjustment members 15g to 15i. The damper member includes a viscoelastic member 111a and a resistance plate 112a.

  Further, the image blur correcting action part and the ground plane part are viscoelastically coupled with respect to the first direction (arrow 18c direction), and the damper member is subjected to image blur correction action in the second direction (direction orthogonal to the arrow 18c). Drives integrally with the unit. Thus, the damper member can be configured to have no viscoelasticity effect between the ground plane and the image blur correcting action portion in the second direction.

  Further, the damper member includes a viscoelastic member 111a provided on the base plate portion and a resistance plate 112a provided on the image blur correcting operation portion and inserted into the viscoelastic member 111a and serving as a protruding portion that is not fixed to the base plate portion. Is configured. Then, the resistance plate 112a serving as a protrusion has a viscoelastic portion facing area in the first direction (arrow 18c direction) in which the image blur correction action unit is driven, and a second direction (arrow 18c) different from the first direction. The viscoelastic part opposing area with respect to the direction orthogonal to the direction is made different.

  The damper is composed of a viscoelastic member 111a provided on the base plate portion and a resistance plate 112a which is provided on the image blur correcting action portion and is inserted into the viscoelastic member 111a and serves as an elastic protrusion which is not fixed to the base plate portion. It constitutes a member. Alternatively, the viscoelastic member 111a provided in the image shake correcting action unit and the resistance plate 112a provided in the base plate part and inserted into the viscoelastic member 111a and serving as an elastic protrusion not fixed to the image shake correcting action part. And constitutes a damper member.

  As described above, a highly reliable shake correction apparatus that is compact and can be driven stably has been realized.

  8A and 8B are a plan view and a cross-sectional view showing the vicinity of a damper member provided in the shake correction apparatus according to the second embodiment of the present invention. Specifically, FIG. 8A is a plan view of the coil 16a, the permanent magnet 110a and the damper member (comprising the resistance plate 112a and the viscoelastic member 111a), and FIG. 8B is a cross-sectional view thereof. In FIG. 8, the coil 16 a may be attached to the image shake correcting operation unit, and the permanent magnet 110 a may be attached to the base plate unit, or vice versa.

  The shake correction apparatus according to the second embodiment of the present invention differs from the first embodiment in the following points.

  A case 111b for housing the viscoelastic body 111a is provided, and the case 111b is fixed in the direction of the arrow 18c in the bobbin 16c of the coil 16a (because it is sandwiched between the bobbins 16c), and freely slid in the direction orthogonal thereto. It has a movable configuration.

  Further, the resistance plate 112a extending from the permanent magnet 110a has an elastic rod shape. That is, the resistance plate 112a does not have a shape that determines the directionality of damping, but is configured to move integrally with the image blur correcting action portion in a direction in which the viscoelastic member 111a does not want to effect damping. .

  In FIG. 8, 111 a ′ and 112 a ′ indicate positions after sliding of the viscoelastic member 111 a and the resistance plate 112 a when the image blur correcting action portion moves in a direction orthogonal to the arrow 18 c. As described above, the damping action is not effective at all in the driving in the direction orthogonal to the arrow 18c.

  The driving force in the direction of the arrow 18c is generated by the coil 16b. However, if the damper on the coil 16a side performs the damping of the driving force, the driving accuracy deteriorates due to the deviation of the driving thrust direction and the damping position (rotation in the rolling direction 19r in FIG. 1). In the damping configuration as shown in FIG. 8, the damping resistance of the damper member provided in the coil 16a does not occur with respect to the driving force of the coil 16b. The damping resistance of the damper member provided in the coil 16b does not occur with respect to the driving force of the coil 16a.

  Damping of the coil 16a in the thrust direction 18c is performed by a damper member provided in the air core portion of the coil 16a, and damping in the thrust direction 18d of the coil 16b is performed by a damper member provided in the air core portion of the coil 16b. As a result, it is possible to realize driving with the straight frequency characteristics shown in FIG.

  Since the resistance plate 112a is an elastic rod, when a high frequency input such as an impact is received, the resistance plate 112a absorbs the resistance plate 112a. Therefore, failure due to impact can be prevented.

  According to the second embodiment described above, a damper member is provided in the air core portions of the coils 16a and 116b, and a mechanism that can determine the direction in which the damping effect is effective is achieved. A shake correction device can be realized.

  The configuration of the shake correction apparatus according to the second embodiment will be described in detail. The shake correction apparatus is driven in a plane substantially orthogonal to the optical axis 10 to correct an image shake. It has a ground plane part that supports the shake correction action part. Further, the base plate portion is viscoelastically coupled with respect to the first direction (arrow 18c) and the second direction (direction orthogonal to the arrow 18c) is driven integrally with the image blur correcting operation portion to be connected to the base plate portion and the image. The damper member has a configuration that does not cause a viscoelastic effect between the shake correcting action portions.

  Therefore, a shake correction apparatus that can perform highly accurate shake correction drive can be realized.

  Finally, the effect of the first and second embodiments will be described again. By disposing a damper member in the air core portions of the coils 16a and 16b, which are dead spaces, efficient braking can be performed without changing the size of the device. Further, by determining the direction in which the damper member acts, the driving direction is prevented from becoming unstable due to braking. Furthermore, the damper member becomes extremely hard against high-frequency disturbances, so that even when such disturbances are input, the shake correction device is prevented from being damaged.

In other words,
1) Downsizing of the damping mechanism (no special space is required for the shake correction device)
2) Stabilization of damping direction (determining the direction in which damping is effective)
3) Improvement of driving accuracy (matching the driving force and damping force generation position)
4) Measures against accidents (preventing damage during impact or dropping)
Thus, a shake correction apparatus capable of realizing the following four effects can be obtained.

(Correspondence between the present invention and the embodiment)
The correction lens 11, the holding frame 12, the attracting plates 17a and 17b, the permanent magnets 110a and 110b, the support shafts 14a to 14c, and the compression coil springs 15a to 15c correspond to the image blur correction operation unit of the present invention. The base plate 13, the spring adjustment screws 15d to 15f, and the spring adjustment members 15g to 15i correspond to the base plate portion. The yokes 17a and 17b, the permanent magnets 110a and 110b, and the coils 16a and 16b correspond to driving means. Further, a damper member composed of a viscoelastic member 111a corresponding to the viscoelastic portion and a resistance plate 112a corresponding to the protrusion corresponds to the vibration absorbing member of the present invention. The viscoelastic part is provided on one of the ground plane part and the image blur correcting action part. Further, the protrusion is provided on the other of the image shake correcting action part and the ground plate part, and is inserted into the viscoelastic part and is not fixed to the ground plate part or the shake correcting action part.

  The description has been continued with the digital camera image stabilization system as an example. However, since the apparatus of the present invention can be integrated into a small and highly stable mechanism, it can be developed not only for digital cameras but also for digital video cameras, surveillance cameras, Web cameras, mobile phones, and the like.

It is a top view which shows the shake correction apparatus which concerns on Example 1 of this invention. It is BB sectional drawing of FIG. It is a top view which shows the damper member comprised in the shake correction apparatus which concerns on Example 1 of this invention, and its vicinity. It is sectional drawing which shows the mode of a damper member at the time of the impact input of the shake correction apparatus which concerns on Example 1 of this invention. 1 is a block diagram illustrating a drive system of a shake correction apparatus according to Embodiment 1 of the present invention. It is a figure for demonstrating the pitch direction drive balance in the shake correction apparatus which concerns on Example 1 of this invention. It is a figure for demonstrating the yaw direction drive balance in the shake correction apparatus which concerns on Example 1 of this invention. It is the top view and sectional drawing which show the damper member with which the shake correction apparatus which concerns on Example 2 of this invention is equipped, and its vicinity. It is a figure which shows the frequency characteristic of the conventional shake correction apparatus. It is a figure which shows the frequency characteristic of the improved shake correction apparatus. It is a perspective view which shows the external appearance of the conventional vibration-proof camera. It is a perspective view which shows the outline of the anti-vibration system structure of the anti-vibration camera of FIG. It is a block diagram which shows the circuit structure of the image stabilization system with which the image stabilization camera of FIG. 11 is equipped. FIG. 12 is a plan view, a side view, and a cross-sectional view of a shake correction apparatus provided in the image stabilization camera of FIG. 11.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical axis 11 Correction lens 12 Holding frame 13 Base plate 14a, 14b, 14c Support shaft 15a, 15b, 15c Compression coil spring 15d, 15e, 15f Spring adjustment screw 15g, 15h, 15i Spring adjustment member 16a, 16b Coil 17a, 17b Suction plate 110a, 110b Permanent magnet 111a Viscoelastic member 111b Case 112a Resistance plate

Claims (7)

An image stabilization unit that is movable in a direction perpendicular to the optical axis;
A base plate portion that supports the image shake correcting operation portion;
The image stabilization unit comprising the coil provided on one of the image stabilization unit and the ground plate, and the permanent magnet provided on the other of the image stabilization unit and the ground plate is disposed on the ground plate. Drive means for driving relative to the part;
Before and viscoelastic members that will be placed in the air-core portion of Kiko yl respect member to which the coil is provided of the ground plate portion and the image blur correcting action unit with a portion is inserted into the viscoelastic member And a vibration absorbing member that includes a projection provided between the coil and the permanent magnet without being fixed, and a vibration absorbing member that viscoelastically couples the ground plate portion. apparatus. The vibration absorbing member, dissipate viscoelastic coupled to the drive force generating direction of the coil, the terms that better direction to perpendicular to the driving force generating direction and the optical axis is driven integrally with the image blur correction effect unit The shake correction apparatus according to claim 1, wherein the shake correction apparatus is configured to prevent a viscoelastic action between the ground plane and the shake correction action part. The protrusions claim 2, characterized in that the viscoelastic unit counter area to the driving force generating direction, and the viscoelastic unit combat area for better direction you orthogonal to the driving force generating direction and the optical axis is different The shake correction device described in 1. The vibration absorbing member further includes a storage member that stores the viscoelastic member,
The storage member is disposed on the coil so as to be movable in the driving force generation direction and the direction orthogonal to the optical axis so that the storage member is fixed with respect to the driving force generation direction of the coil. The shake correction apparatus according to claim 2. The shake correction device according to claim 4, wherein the protrusion has a configuration in which a damping resistance by the viscoelastic member does not depend on a driving direction. Before SL protrusions stabilizing device according to any one of claims 1 to 5, characterized in that it is constituted by an elastic member. Imaging apparatus characterized by having a stabilizing device according to any one of claims 1 to 6.

Images