JP4886382B2 - Image blur prevention device - Google Patents

Description

  The present invention relates to an image blur prevention device for preventing image blur caused by camera shake in a camera or an optical apparatus, and more particularly to a structure of an image blur prevention device installed in a lens barrel in order to correct image vibration.

  The mechanism that moves some of the correction lenses that make up the photographic lens in the direction perpendicular to the optical axis predicts image blur by, for example, detecting the camera shake acceleration that causes image blur in the camera. Based on the above, a vibration isolator that suppresses image blur by moving the lens in a direction perpendicular to the optical axis has been proposed and commercialized.

Various methods have been proposed for these anti-vibration devices, but a mechanism that can move the correction lens in a direction perpendicular to the optical axis in any direction is desirable depending on the shooting posture of the photographer as described above. For example, as shown in Japanese Patent Application Laid-Open No. 10-26783, guide shafts 12a are provided radially from three locations on the side surface of the correction lens frame to correct image blur, and 3 provided on the side surface of the vibration isolator main body. A system has been proposed in which each is inserted into each guide groove 13a and the amount of movement and direction perpendicular to the optical axis is determined by the combined force of the moving coils 16y and 16p for movement in the X and Y directions. Although it has also been proposed to reduce the contact resistance during movement by installing a roller on the shaft 12a, an allowable error of the guide shaft 12a including the roller in the guide groove 13a in order to improve accuracy. When the pressure is kept as small as possible, the moving load increases. Depending on the direction, if a combined force perpendicular to the roller rotation direction is applied, the roller surface and the guide groove surface exhibit a large frictional resistance, and the moving load increases and is corrected. Depending on the movement direction of the optical axis of the lens, there is a problem that the moving speed is delayed, and the accurate function of the image blur prevention device cannot be exhibited. As shown in Japanese Patent Application Laid-Open No. 2003-307761, the present applicant uses a correction lens. The surface holding structure in the guide groove is changed so that it can move in a plane perpendicular to the optical axis, the correction lens is supported by a single hinge shaft installed in parallel to the optical axis, and the shaft can be tilted in all directions. Proposed an image blur prevention device that enables movement of the correction lens.
JP-A-10-26783 JP2003-307761

  There is a need for a mechanism that can move the correction lens in a lighter and more precise manner in any direction, and the cause of variations in the movement of the correction lens is the friction resistance and the complexity of the mechanism in the holding structure of the correction lens. Therefore, it is necessary to have a simple structure that further reduces frictional resistance.

An image blur prevention apparatus that solves the above-described problems is obtained from a correction lens that is installed in a lens barrel and decenters an optical axis, vibration detection means that detects vibration applied to the lens barrel, and the vibration detection means. An image blur prevention apparatus including a control unit configured to drive the correction lens based on a signal and prevent image blur; and a support frame capable of decentering the correction lens with respect to an optical axis of the lens barrel ; A holding frame for holding the supporting frame, and each of the supporting frame and the holding frame has a plurality of independent spherical sliding surfaces around the correction lens , and the supporting frame has the spherical shape. The spherical surface of the spherical sliding surface independent of the support frame and the correction lens are moved by performing an eccentric movement while moving the circular arc having a fulcrum on the optical axis of the lens barrel by sliding of the sliding surface. The distance from the optical axis is greater than 0, It was configured characterized spheres axis independent the spherical sliding surface of the lifting frame with larger or smaller than the distance between the optical axis of the lens barrel. The independent spherical sliding surface of the holding frame is a surface of a sphere disposed on the holding frame, and the spherical body includes a plurality of independent spherical sliding surfaces provided on the support frame. It was set as the structure arrange | positioned in the position which opposes. Further, the sphere is held by a sphere receiver provided on the holding frame.

  A simple structure without the need for a surface holding structure in the guide groove so that the correction lens can be moved in a plane perpendicular to the optical axis and a single hinge shaft for setting the correction lens parallel to the optical axis. The correction lens is provided with a support frame that can be moved eccentrically with respect to the optical axis, and a holding frame that holds the support frame. Since it is moved, it is possible to move the correction lens with less frictional resistance by always making point contact than when sliding between planes, and the movement function is delayed, and the accurate function of the image blur prevention device is demonstrated. can do. Furthermore, the correction lens can be operated in an arc by shifting the axis of the paired ball and the axis of the spherical sliding surface, and a fulcrum is provided on either the image plane side or the object side in the axis shifting direction. The arc can be moved, and the radius of the arc can be changed by changing the shift amount of the shaft, so that the correction lens can be moved with a simple structure and low frictional resistance.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a correction lens moving mechanism in a vibration isolator to which the present invention is applied, and FIG. 2 is a perspective view showing a spherical sliding surface side of a support frame. 3 and 4 are cross-sectional views taken along the lines AC and BC in FIG. 1, showing how the correction lens moves in the image stabilizer.

  The moving mechanism of the correction lens 2 in the image blur prevention apparatus shown in FIG. 1 is corrected so that it can be moved almost perpendicularly to the optical axis and in all directions inside the holding frame A3 on the fixed side of the lens barrel. A support frame 5 having a lens 2 is installed between a holding frame A3 and a holding frame B (not shown). Spring support portions 5a, 5b, and 5c are provided on the support frame 5 to apply springs that are pressure-bonded to the holding frame A3. Yes, the springs 7a, 7b, 7c are hooked and fixed to the spring hooks 6a, 6b, 6c of the corresponding spring hook ring 6. As a result, the correction lens 2 can slide in a direction substantially perpendicular to the optical axis with respect to the holding frame A3.

  There are three independent spherical sliding surfaces (not shown) in the vicinity of the spring hooks 5 a, 5 b, 5 c installed on the support frame 5. The holding frame 3A is connected to the above-described springs 7a, 9b, 9c (not shown) and ball receivers 8a, 8b, 8c (not shown) fitted in the holes 3a, 3b, 3c (not shown). 7b and 7c are pressure-bonded to the three spherical sliding surfaces of the support frame 5.

  Next, the support frame 5 supporting the correction lens 2 has coil holding frames 5d and 5e as shown in the figure. The drive coil 14 is fixed, the magnet 13 fixed to the yoke 16a installed and fixed to the holding frame A3 is opposed to the Y drive coil 12, and the magnet 15 fixed to the yoke 16b is opposed to the X drive coil 14, and each coil is fixed. A magnetic path is formed by yokes 17a and 17b which are installed and fixed to a holding frame B4 (not shown), and can be moved in the X direction when the X drive coil 14 is energized, and can be moved in the Y direction when the Y drive coil is energized. The X drive coil 14 and the Y drive coil 12 can be moved in all directions by combining the current direction and the current amount.

  Next, a support frame having an independent spherical sliding surface, which is a feature of the present invention, will be described. In the perspective view showing the spherical sliding surface side of the support frame 5 in FIG. 2, the support frame 5 includes a coil holding frame 5 d that holds the Y drive coil 12, a coil holding frame 5 e that holds the X drive coil 14, and a guide bearing 18. The support portion 11 has elongated holes 11a and 11b for passing the guide shaft 20 therebetween. The spherical sliding surfaces 10a, 10b, 10c of the support frame 5 on the moving side of the correction lens 2 are three holes 3a, 3b, 3c (not shown) of the holding frame A3 and ball receivers 8a, 8b, 8c (not shown). It is provided at a position opposite to the balls 9a, 9b, 9c (not shown) supported by (illustrated) and is configured to be pressed by springs 7a, 7b, 7c hooked on the spring hanging portions 5a, 5b, 5c.

  FIG. 3 is a cross-sectional view taken along the line AC of FIG. 1 showing the movement of the correction lens of the image stabilizer. FIG. 3 (I) shows the state where the correction lens is not moved, and FIG. 3 (II) shows the correction. FIG. 3 (III) shows a state in which the lens has moved downward, and FIG. 3 (III) shows a state in which the correction lens has moved downward.

  In the state of FIG. 3I, the axes of the balls 9a and 9b and the spherical sliding surfaces 10a and 10b remain parallel to the optical axis 1, but the spherical sliding surfaces 10a and 10b have It is outside the axis of the balls 9a, 9b. In the state of FIG. 3 (II), when current flows through the X drive coil 14 as shown in FIG. 4 (II), the support frame 5 moves to the X drive coil 14 by the action of magnetic lines formed by the magnet 15 and the yokes 16b and 17b. Since the thrust is generated and moved upward, the ball 9b slides in a direction in which the axis of the spherical sliding surface 10b coincides, and the axis of the ball 9a and the axis of the spherical sliding surface 10a slide in a direction away from each other. To do. The balls 9 a and 9 b slide on the spherical sliding surfaces 10 a and 10 b, so that the correction lens moves in an arc shape with a fulcrum on the image plane side on the optical axis 1 with respect to the optical axis 1. In the state of FIG. 3 (III), when current flows through the X drive coil 14 as shown in FIG. 4 (III), the support frame 5 moves to the X drive coil 14 by the action of magnetic lines formed by the magnet 15 and the yokes 16b and 17b. Since the thrust is generated and moved downward, the ball 9a and the spherical sliding surface 10a slide in a direction in which they coincide, and the ball 9b and the spherical sliding surface 10b slide in a direction away from each other. To do. As the balls 9a and 9b slide on the spherical sliding surfaces 10a and 10b, the correction lens similarly operates in an arc having a fulcrum on the object side on the optical axis 1 with respect to the optical axis 1.

  The state in which the axis of the spherical sliding surfaces 10a, 10b is outside the axis of the balls 9a, 9b has been described, but the axis of the spherical sliding surfaces 10a, 10b is inside the axis of the balls 9a, 9b. In this state, the correction lens moves in a circular arc with a fulcrum on the object side on the optical axis 1 with respect to the optical axis 1.

Next, the actual operation will be described. When the image blur prevention mode is set, the vibration direction and magnitude are calculated based on the signal obtained from the vibration detection means by the vibration detection means not shown in the lens barrel. The drive current is output to the X drive coil 14 and the Y drive coil 12. When a current in a certain direction flows in the X drive coil 14 now, a thrust in the first direction is generated in the X drive coil 14 by the action of the magnetic force lines formed by the magnet 15 and the yokes 16b and 17b. If it is outside, a thrust is generated in the plus direction, and if it is a reverse current, a thrust is generated in the minus direction on the inside. With the correction lens 2, the support frame 5 slides according to the spherical sliding surfaces and the pinions 21, 22 and the guide shaft 20. Will do.

  Next, when a current is output to the Y drive coil 12, the thrust in the second direction perpendicular to the first direction is applied to the Y drive coil 12 by the action of the lines of magnetic force formed from the magnet 13 and the yokes 16a and 17a. If this is outside the optical axis 1, thrust is generated in the plus direction, and if it is reverse current, thrust is generated in the minus direction on the inside, and with the correction lens 2, the support frame 5 has a spherical sliding surface. And it slides according to the pinions 21 and 22 and the guide shaft 20.

  Since the other direction is obtained by the combined vector of the first and second directions, the X driving coil 14 and the Y direction are detected by the moving direction and moving amount detecting means (not shown). This is obtained by controlling the current output to the drive coil 12.

  For the sake of simplicity, FIG. 4 shows the operation in the first direction caused by the current passed through the X drive coil 14, but FIG. 4 (I) shows the optical axis of the correction lens 2 in the normal state outside the operation. Is aligned with the optical axis 1 of the lens barrel. The correction lens 2 and the support frame 5 are supported by a right pinion 21, a left pinion 22 and a guide shaft 20 that are press-fitted to the guide shaft 20 with respect to the holding frame A3 on the fixed side.

Now, the current flows in the X drive coils 14, the direction toward the optical axis 1, that is, thrust in the upward direction as in FIG. 4 (II) acts, spherical sliding surface 10 b slides over the ball 9 b The holding frame 5 having the correction lens 2 is displaced by sliding in the apex direction.

Further, the current flowing through the X driving coil 14, acts under the direction of thrust as shown in FIG. 4 (III), spherical sliding surface 10 b remains the ball 9 b and point contact slides on the inner circumferential direction As a result, the holding frame 5 having the correction lens 2 is shifted.

  As described above, FIG. 4 considered the operation in the first direction acting on the X drive coil 14, but the same applies to the operation in the second direction acting on the Y drive coil 12. When the optical axis moves, the optical axis 1 is corrected as a fulcrum. The lens 2 and the support frame 5 are moved by a small amount, and the correction lens 2 and the support frame 5 are also moved during the omnidirectional movement in which the first and second directions are combined.

  A guide bearing 18 that holds the guide shaft 20 of the support frame 5 is fixed to the holding frame 3A. The guide shaft 20 passes through a guide hole (not shown) of the guide bearing 18 from the elongated hole 11a of the support portion 11 to the other elongated hole 11b of the support portion 11, and a right pinion 21 and The left pinion 22 is fixed. The pinions 21 and 22 mesh with the racks 18c and 18d (not shown) of the guide receiver 18, the right pinion 21 meshes with the right rack 18c, and the left pinion 22 meshes with the left rack 18d (not shown). 5 can move relative to the guide receiver 18 without being twisted by the pinions 21 and 22 rolling on the left and right racks.

  The X drive coil 14 and the Y drive coil 12 on the support frame 5 supported by the guide shaft 20 and the guide bearing 18 are magnets 13 and 15 of yokes 16a and 16b and upper yokes 17a and 17b fixed to the holding frame A3. Therefore, when an electric current is passed through the X drive coil 14 and the Y drive coil 12, a driving force is generated by electromagnetic action, and is supported by this composite vector. The frame 5 can be moved. The moving form by this driving force is when the guide shaft 20 penetrating the elongated holes 11a and 11b of the support portion 11 of the support frame 5 rolls on the right rack 18c and the left rack 18d (not shown) by the rotation of the pinions 21 and 22. When the guide bearing 18 moves up and down and slides left and right on the guide shaft 20, the guide bearing 18 moves left and right. Therefore, the rotation of the pinions 21 and 22 and the sliding operation of the guide bearing 18 on the guide shaft 20 are combined. Thus, it can be seen that the support frame 5 can move in all directions without any rotational component.

It is a disassembled perspective view which shows the Example of the correction | amendment lens moving mechanism in the vibration isolator which applied invention. It is a perspective view which shows the spherical sliding surface side of a support frame. Is A -C sectional view of FIG. 1 showing how the correction lens moving anti-vibration device. FIG. 5 is a cross-sectional view taken along the line B- C in FIG.

Explanation of symbols

1 Optical axis 2 Correction lens 3 Holding frame A
4 Holding frame B
DESCRIPTION OF SYMBOLS 5 Support frame 6 Spring hook ring 7a Spring 7b Spring 7c Spring 8a Ball receiver 8b Ball receiver 9a Ball 9b Ball 10a Spherical slide surface 10b Spherical slide surface 10c Spherical slide surface 11 Support part 12 Y drive coil 13 Magnet 14 X drive coil 15 Magnet 16a Yoke 16b Yoke 17a Yoke 17b Yoke

Claims (3)

A correction lens installed in the lens barrel and decentering the optical axis; vibration detection means for detecting vibration applied to the lens barrel; and driving the correction lens based on a signal obtained from the vibration detection means ; An image blur prevention device comprising a control means for preventing image blur, comprising: a support frame capable of eccentrically moving the correction lens with respect to an optical axis of the lens barrel; and a holding frame for holding the support frame and are respectively the support frame and the holding frame has a plurality of independent spherical sliding surface on the periphery of the correction lens, the supporting frame the lens barrel by the sliding of the spherical sliding surface Eccentric movement while moving in a circular arc with a fulcrum on the optical axis ,
The distance between the spherical axis of the independent spherical sliding surface of the support frame and the optical axis of the correction lens is greater than 0, and the spherical axis of the independent spherical sliding surface of the holding frame and the lens mirror An image blur prevention device characterized in that it is larger or smaller than the distance from the optical axis of the tube . The independent spherical sliding surface of the holding frame is a surface of a sphere disposed on the holding frame, and the sphere faces a plurality of independent spherical sliding surfaces provided on the support frame. The image blur prevention device according to claim 1, wherein the image blur prevention device is disposed at a position . The image blur prevention device according to claim 2 , wherein the sphere is held by a sphere receiver provided in the holding frame .

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