JP6685786B2 - Anti-vibration device - Google Patents

Description

  The present invention relates to an image stabilization device for image blur correction of a lens device, and more particularly to an image stabilization device using a plurality of ultrasonic motors.

  Conventionally, in a camera module including a lens system and an image sensor mounted on a camera for capturing an image, by driving the lens in a direction perpendicular to the optical axis of the lens system, a camera shake generated during image capturing can be prevented. Techniques for reducing the influence are known. In these optical systems having a camera shake correction function, it is necessary to drive the lens in a direction perpendicular to the optical axis at high speed and with high accuracy, and therefore, a large number of image stabilizing devices including voice coil motors have been proposed.

  Further, in recent years, for the purpose of further improving the accuracy, a vibration isolation device using an ultrasonic motor that utilizes vibration of a vibrator such as an electro-mechanical energy conversion element (piezoelectric element or electrostrictive element) has been proposed. . The ultrasonic motor has a vibrating body formed of a metal elastic body or the like to which an electro-mechanical energy conversion element is joined, and a contact body that comes into pressure contact with the vibrating body. When a plurality of frequency signals having a phase difference are applied to the piezoelectric element, vibration is excited in the vibrating body, and the vibrating body and the contact body move relatively to generate a driving force. Such a drive control method of the vibration type motor includes a method of changing the frequency of the frequency signal applied to the piezoelectric element (hereinafter referred to as frequency control) and a method of changing the phase difference of a plurality of frequency signals applied to the piezoelectric element ( Hereinafter, there is phase difference control). By arranging a plurality of the above ultrasonic motors and combining the driving, a two-dimensional drive device is realized by which the moving body can be moved in the two-dimensional direction, and these are used as a vibration isolator.

  Since the ultrasonic motor is configured to generate a driving force by friction, it has a property that driving performance varies due to variations in constituent parts, and characteristics change as it is used. Therefore, for example, it is necessary to acquire the characteristics before incorporating the ultrasonic motor into the device, change the control parameters individually, and identify the motor whose characteristics have deteriorated due to long-term use, and replace or repair it. is there. The following techniques have been proposed for the above problems.

  For example, Patent Document 1 discloses a technique of determining the life of the ultrasonic motor by integrating the friction work of the friction member and comparing it with a predetermined threshold value.

Japanese Patent No. 4731146

  However, in the conventional technology disclosed in the above-mentioned patent documents, since the work amount is calculated from the speed and acceleration of the driving object driven by the plurality of ultrasonic motors, the characteristics of the ultrasonic motor alone cannot be discriminated. .

  Therefore, an object of the present invention is to provide an anti-vibration device that makes it possible to acquire the characteristics of a single ultrasonic motor even in a state where the anti-vibration device uses a plurality of ultrasonic motors. is there.

  In order to achieve the above-mentioned object, the vibration damping device of the present invention has three or more ultrasonic motors having a driving member provided with an engaging portion protruding in a direction perpendicular to the driving direction, and the ultrasonic motor is fixed. A fixed cylinder and an engaging groove extending in a direction orthogonal to the driving direction of the ultrasonic motor, and the engaging portion is movably engaged in the extending direction, A vibration control device for a lens device, comprising: a lens moving frame supported by the fixed barrel so as to be movable in a plane parallel to the driving direction; and a sensor for measuring a physical quantity corresponding to a displacement of the driving member. The end portion of the engaging groove in the extending direction does not press the lens moving frame in the driving direction by the engaging portion of the ultrasonic motor when driving the corresponding ultrasonic motor in a predetermined driving range. It is characterized in that it is connected to the escape portion.

  According to the present invention, it is possible to provide an anti-vibration device using a plurality of ultrasonic motors, which makes it possible to acquire the characteristics of a single ultrasonic motor even when incorporated in the device.

1 is a perspective view of an ultrasonic motor 50 according to a first embodiment. Perspective view of the ultrasonic motor 50 when the fixing plate 51 is removed from the state of FIG. 2 is a perspective view of the ultrasonic motor 50 when the drive slider 52 and the ball 53 are removed from the state of FIG. The figure which looked at the vibration isolator 1 which concerns on Example 1 from the subject side. Exploded perspective view of the vibration damping device 1 according to the first embodiment. FIG. 4 is a view of the image stabilizing device 1 when the lens moving frame 2 is moved in the F2 direction from the state of FIG. Part A enlarged view of FIG. Exploded perspective view of the vibration damping device 101 according to the second embodiment. The figure which looked at the anti-vibration device 101 which concerns on Example 2 from the to-be-photographed object side. 9 is a view of the image stabilizing device 101 when the lens moving frame 2 is moved in the F5 direction from the state of FIG. First modification of engaging groove 2a and escape groove 2b Second modification of engagement groove 2a and escape groove 2b Third modification of engaging groove 2a and escape groove 2b Modification of Example 2 Diagram when the lens moving frame 20 is moved in the F7 direction from the state of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  Hereinafter, a vibration isolation device using a plurality of ultrasonic motors according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 7.

(Structure of ultrasonic motor)
First, the ultrasonic motor used in the vibration isolator of the first embodiment will be described with reference to FIGS. FIG. 1 shows a perspective view of the ultrasonic motor 50. 2 is a perspective view of the ultrasonic motor 50 shown in FIG. 1 with the fixing plate 51 removed, and FIG. 3 shows the ultrasonic motor 50 shown in FIG. 2 with the drive slider 52 and balls 53 further removed. The perspective view of the ultrasonic motor 50 at this time is shown.

  A vibrator 55 is fixed to a motor base 54 which is a base of the ultrasonic motor 50 (FIG. 3). Further, the drive slider 52 (driving member) is arranged on the upper portion thereof in contact with the protrusions 55a and 55b of the vibrator 55 (FIG. 2). Further, the motor base 54 is provided with a plurality of holes 54a for fixing to a fixed cylinder 3 (FIGS. 4 and 5) described later. The drive slider 52 is provided with an output shaft 52a (engagement portion) that projects in a direction perpendicular to the driving direction F1 and transmits the driving force to the lens moving frame 2 (FIG. 4). Further, the drive slider 52 is provided with a plurality of rolling grooves 52b in which the balls 53 roll. The ball 53 is arranged in the rolling groove 52b, and the fixing plate 51 is arranged from above to press the drive slider 52 against the projections 55a and 55b of the vibrator 55 via the ball 53. It is fixed to 54 with a screw (not shown). The drive slider 52 is in contact with the protrusions 55a and 55b of the vibrator 55, and is pressed into contact with the protrusions 55a and 55b by the fixing plate 51. Although not shown, a rolling groove on which the ball 53 rolls is also provided on the back side of the fixed plate 51 so as to face the rolling groove 52b of the drive slider 52. Due to the guiding action of the rolling groove 52b and the ball 53, the driving direction F1 of the driving slider 52 is regulated in the arrow direction. By applying a voltage by a voltage supply means (not shown), the vibrator 55 generates vibration, and the driving force in the direction of the arrow (driving direction F1) with respect to the driving slider 52 that is in pressure contact with the protrusions 55a and 55b. Can be generated.

(Structure of anti-vibration device)
A vibration isolation device including a plurality of the ultrasonic motors 50 will be described with reference to FIGS. FIG. 4 is a view of the vibration isolator 1 viewed from a direction (subject side) perpendicular to the surface on which the lens moving frame 2 moves, and FIG. 5 is an exploded perspective view of the vibration isolator 1. The anti-vibration lens group (not shown) is held by the lens moving frame 2. The lens moving frame 2 is provided with a plurality of engagement grooves 2a that engage with the output shaft 52a that transmits the driving force of the ultrasonic motor 50 so as to be orthogonal to the driving direction F1 of each ultrasonic motor 50. An escape groove 2b is provided on one end side in the extending direction of the engaging groove 2a so as to determine the characteristics of the ultrasonic motor 50, which will be described later, connected to the engaging groove 2a. In each of the escape grooves 2b, the width of the output shaft 52a engaged with the engagement groove 2a in the direction perpendicular to the driving direction F1 of the ultrasonic motor 50 is larger than the diameter of the output shaft 52a, and A groove extending in a direction parallel to the direction F1 is formed. Even if the corresponding ultrasonic motor 50 drives a predetermined drive range, the escape groove 2b causes the output shaft 52a of the ultrasonic motor 50 to drive the lens moving frame 2 (engagement groove 2a) in the driving direction. It is formed so that it will not be pressed against. Here, the predetermined drive range is determined by another ultrasonic motor 50 having the same drive direction as the ultrasonic motor 50 in which the output shaft 52a is located in the escape groove 2b, that is, the lens to be held in this embodiment. It is preferable that the ultrasonic motor 50 arranged on the opposite side of the sandwiching device is driven.

  Although the engaging groove 2a and the escape groove 2b are through-grooves in the present embodiment, they are not limited to through-grooves, and may be grooves that do not penetrate. Although the escape groove 2b is provided on the optical axis Z side with respect to the engagement groove 2a, it may be provided on the opposite end. The escape groove 2b has a size such that the output shaft 52a does not move the lens moving frame 2 by pressing the end of the escape groove 2b when the output shaft 52a moves in the drive direction F1 in the escape groove 2b. Any cutout (relief part) will do.

  As shown in FIG. 5, when the directions orthogonal to the plane in which the lens moving frame 2 moves with respect to the fixed barrel 3 are the X-axis and Y-axis directions, the fixed barrel 3 has the X-axis and Y-axis of the lens moving frame 2. The encoder 4 for detecting the axial position is fixed. The lens moving frame 2 is provided with a scale 5 on the surface facing the encoder 4. The encoder 4 and the scale 5 constitute a position sensor that detects the displacement of the lens moving frame 2 with respect to the fixed barrel 3. The optical axis of the anti-vibration lens group fixed to the lens moving frame 2 is parallel to the Z axis (the optical axis of a lens device (not shown) in which the anti-vibration device is installed) which is a direction perpendicular to the X axis and the Y axis. Become. A plurality of circumferential grooves 3a are provided on the fixed barrel 3 so as to extend around the Z axis, which is the optical axis direction, in the direction perpendicular to the optical axis (Z axis), and a plurality of them are fixed to the lens moving frame 2 with screws 6. By engaging with the cam follower 7, the movement of the lens moving frame 2 in the Z axis direction, which is the optical axis direction, is restricted. Therefore, the lens moving frame 2 is supported by the fixed barrel 3 in such a manner that it can move within a range regulated by the cam follower 7 and the circumferential groove 3a in a plane parallel to the driving direction of the ultrasonic motor 50. The ultrasonic motor 50 is fixed to the motor fixing member 8 by screws (not shown) through the fool holes 54a (FIG. 1), and the motor fixing member 8 is fixed to the fixed barrel 3 by screws (not shown).

  With the above configuration, by combining the driving forces of the four ultrasonic motors 50, it becomes possible to drive the lens moving frame 2 holding the image stabilizing lens group in the X-axis and Y-axis directions. The image stabilizing device 1 can perform optical correction by driving the lens moving frame 2 and shaking in a vertical, horizontal, or other direction with respect to an image in which an image of a photographing lens (not shown) is shaken. By using this, it is possible to provide a good captured image without shaking.

(Method of distinguishing characteristics of ultrasonic motor)
In the vibration isolator 1 having the above-described configuration, when the anti-vibration function (so-called camera shake correction function) is normally effective, as shown in FIG. 7, the output shaft 52a sets the range of L1 of the engagement groove 2a as the use restriction range. It moves (FIG. 7 is an enlarged view of part A in FIG. 4). That is, the driving direction of the output shaft 52a shown in FIG. 7 is the direction shown as F1a. Which part of the range L1 of the engagement groove 2a is pressed by the output shaft 52a to move the lens moving frame 2 in the direction indicated by F1a depends on the position of the output shaft 52a and the Z axis of ± 90 degrees. Depends on the position in the direction F1b defined by the output shaft 52a arranged at. Therefore, in a state where the image stabilization function is enabled, it is necessary to drive two or more ultrasonic motors 50 in synchronization when the lens moving frame 2 is moved, and only one ultrasonic motor 50 is used. The lens moving frame 2 cannot be moved.

  Based on the above assumptions, a method for determining the characteristics of the ultrasonic motor 50 will be described with reference to FIGS. FIG. 6 shows a state in which the lens moving frame 2 is moved in the F2 direction from the state shown in FIG. In the state of FIG. 6, the output shaft 52a of the ultrasonic motor 50 arranged at the lower left is disengaged from the engagement groove 2a and is positioned in the escape groove 2b. Therefore, the lens moving frame 2 can be driven in the F3 direction by the ultrasonic motor 50 on the upper right alone. Since the lens moving frame 2 is provided with the scale 5 as described above, it becomes possible to move the lens moving frame 2 by the ultrasonic motor 50 alone on the upper right and obtain the velocity characteristic from the position displacement. . The speed characteristic referred to here is, for example, the relationship between the frequency (input) and the speed (output) of the lens movement frame 2 when performing frequency control, or the phase difference (input) and the lens movement when performing phase difference control. This is the relationship of the speed (output) of the frame 2. This speed characteristic is an important index for achieving the characteristics of the ultrasonic motor 50. By repeating the above operation, it is possible to determine the characteristics of all the ultrasonic motors 50 (four in this embodiment) arranged. The flow for determining the characteristics of the ultrasonic motor 50 may be divided into, for example, the normal mode and the measurement mode. In the normal mode, the operation range of the ultrasonic motor 50 is limited to L1 as described above, and the vibration isolation function is effective. In the measurement mode, the ultrasonic motor 50 is driven so that the output shaft 52a is located in the escape groove 2b, and the characteristics of the plurality of ultrasonic motors 50 are determined.

  By using the above configuration, for example, when the performance of the vibration isolator 1 changes, it is possible to identify the ultrasonic motor 50 with the changed characteristics in a state of being incorporated in the apparatus, and thus maintainability is improved. . Further, since the parameters of each ultrasonic motor can be adjusted in the state of being incorporated in the apparatus during the manufacturing process, the assembling property is improved. In addition, the performance of the product is further improved by periodically entering the measurement mode during operation of the vibration isolation device 1, acquiring the characteristics of the ultrasonic motor 50, and resetting the parameters of the ultrasonic motor 50 based on the contents. To do.

  The second embodiment of the present invention will be described below with reference to FIGS. However, the same parts as those in the first embodiment are given the same numbers, and the description thereof will be omitted. FIG. 8 is an exploded perspective view of the vibration damping device 101 according to the second embodiment. The parts different from the vibration isolator 1 in the first embodiment are the ultrasonic motor 60, the encoder 61, and the scale 62. An encoder 61 is attached to each drive slider 63 of the ultrasonic motor 60 (corresponding to the ultrasonic motor 50 of the first embodiment) with a screw (not shown). A scale 62 is attached to the lens moving frame 2 at a position facing each encoder 61. The encoder 61 and the scale 62 constitute a position sensor that detects the displacement of the drive slider 63 with respect to the motor base 54 (fixed cylinder 3).

(Method of distinguishing characteristics of ultrasonic motor)
Next, a method of determining characteristics of the ultrasonic motor according to the second embodiment will be described. FIG. 9 shows a view of the image stabilizing device 101 viewed from a direction (subject side) perpendicular to the surface on which the lens moving frame 2 moves. The state of FIG. 9 is the same as the state of FIG. 4, and is a state in which the output shaft 63a provided in the drive slider 63 and the engagement groove 2a are engaged with each other, and a so-called anti-vibration function is effective. The driving direction of the ultrasonic motor 60 is indicated by an arrow F4. FIG. 10 shows a state after the ultrasonic motor 60 is driven in the F5 direction from the state shown in FIG. The state of FIG. 10 is similar to the state of FIG. At this time, in Example 1, by driving the ultrasonic motor 50 on the upper right in the F3 direction and moving the lens moving frame 2, the speed characteristics of the ultrasonic motor 50 arranged on the upper right in FIG. 6 were acquired. . However, in the second embodiment, the ultrasonic motor 60 arranged at the lower left is driven in the F6 direction, and the speed characteristic is acquired from the output of the encoder 61 attached to the drive slider 63. By repeating the above flow, it is possible to acquire the speed characteristics of each ultrasonic motor 60.

  As the effect of the second embodiment, the same effect as that of the first embodiment can be obtained, and since it is not necessary to move the lens moving frame 2 when acquiring the characteristics of the ultrasonic motor 60, the load on the ultrasonic motor 60 is reduced. Therefore, it is possible to extend the service life.

  In Embodiments 1 and 2, the escape groove 2b provided in the lens moving frame 2 has the shape shown in FIG. 7, but the shape is not limited to this, and for example, the shapes shown in FIGS. But it's okay. In the first modification shown in FIG. 11, the tapered shape 2c is provided at the portion connecting the engagement groove 2a and the escape groove 2b. Further, in the second modification shown in FIG. 12, the R shape 2d is provided in the portion connecting the engagement groove 2a and the escape groove 2b. By providing such a shape, it is possible to prevent the output shaft 52a from being caught when the output shaft 52a returns from the escape groove 2b to the engagement groove 2a, and to smoothly shift to the normal mode. Further, when the output shaft 52a returns to the engagement groove 2a, the output shaft 52a is prevented from being damaged or worn by hitting the corner portion 2e (FIG. 7). Moreover, you may provide the notch 2f in the edge part of the engagement groove 2a like the 3rd modification shown in FIG. By providing the notch 2f, it is possible to reduce the weight of the lens moving frame 2 and reduce the load on the ultrasonic motor 50.

  Further, the escape groove 2b in the second embodiment may be provided as shown in FIG. FIG. 14 is a diagram in which the lens moving frame 2 shown in FIG. 9 is replaced with a lens moving frame 20. The change point of the lens moving frame 20 is the position of the escape groove 2b in the lens moving frame 2. The escape groove 20a formed in the engaging groove with which the output shaft 63a of the opposing ultrasonic motor engages is formed on the end side in the same direction of the engaging groove. By changing to such a shape, it is possible to obtain two characteristics of the ultrasonic motor 60 at the same time without changing the position of the lens moving frame 20. Specifically, the lens moving frame 20 is moved in the F7 direction from the state of FIG. 14 to the state of FIG. In the state of FIG. 15, since the upper right and lower left output shafts 63a are located in the escape groove 20a, it is possible to move independently in the F8 direction, and the encoders 61 attached to the respective drive sliders 63 are provided. The speed characteristic can be obtained independently from the output of. With such a configuration, it is possible to acquire the characteristics of the two ultrasonic motors with one movement of the lens moving frame 20, and it is possible to shorten the flow for determining the characteristics.

  The case where the encoder 4 for detecting the position change is used to acquire the speed characteristic of the ultrasonic motor illustrated in the embodiment is illustrated, but the present invention is not limited to this. Although the embodiment for detecting the change in the position is illustrated, the present invention is also applicable to the case where the physical quantity corresponding to the displacement of the driving member or the lens moving frame such as the position, the speed, or the acceleration is measured even if the position is other than the position. You can enjoy the effect of.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

1 Vibration Isolator 2 Lens Moving Frame 2a Engaging Groove 2b Escape Groove 4 Encoder (Sensor)
5 scale (sensor)
50 ultrasonic motor 52 drive slider (drive member)
52a Output shaft (engagement part)
55 oscillator

Claims (8)

Three or more ultrasonic motors having a driving member having an engaging portion that projects in a direction perpendicular to the driving direction;
A fixed tube to which the ultrasonic motor is fixed,
An engaging groove extending in a direction orthogonal to the driving direction of the ultrasonic motor is provided, and the engaging portion is movably engaged in the extending direction and is parallel to the driving direction. A lens movement frame supported by the fixed barrel so as to be movable in a plane,
A sensor for measuring a physical quantity corresponding to the displacement of the driving member,
In a vibration control device for a lens device having
The end portion of the engaging groove in the extending direction presses the lens moving frame in the driving direction by the engaging portion of the ultrasonic motor when driving the corresponding ultrasonic motor in a predetermined driving range. Not connected to the escape area,
Anti-vibration device characterized by the above.   The escape portion is configured such that the engagement portion of the ultrasonic motor corresponding to the escape portion escapes from the engagement groove by driving the ultrasonic motor other than the ultrasonic motor corresponding to the escape portion. The anti-vibration device according to claim 1, wherein the anti-vibration device is formed at a position where it can be moved to the portion.   The anti-vibration device according to claim 1, wherein the sensor is a sensor that measures a position, a speed, or an acceleration of the lens moving frame.   The anti-vibration device according to claim 1, wherein the sensor is a sensor that measures a position, a speed, or an acceleration of the driving member with respect to the lens moving frame.   In the state where the other ultrasonic motor is driven to move the lens moving frame so that the engaging portion of one or more of the ultrasonic motors is located in the escape portion, the lens is located in the escape portion. The control means for driving one ultrasonic motor different from the ultrasonic motor of the engaging portion to control the sensor to acquire the physical quantity of the lens moving frame is provided. Anti-vibration device described.   In the state where the other ultrasonic motor is driven to move the lens moving frame so that the engaging portion of one or more of the ultrasonic motors is located in the escape portion, the lens is located in the escape portion. The vibration control device according to claim 4, further comprising a control unit that drives the ultrasonic motor of the engagement unit and controls the sensor to acquire the physical quantity.   The vibration isolator according to any one of claims 1 to 6, wherein the engagement groove has a tapered shape such that the width of the engagement groove widens toward the relief portion.   The vibration isolator according to any one of claims 1 to 6, wherein a corner portion of the engagement groove, which connects the engagement groove and the relief portion, is R-shaped.

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