JP2009229703A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress transient response up to when a lens is stopped at a desired position by taking a countermeasure against mechanical dumping different from a change in the strength of a leaf spring. <P>SOLUTION: A lens drive device 1 includes: a moving body (a sleeve 13 or the like) which holds a lens; a support (a yoke or the like) which is formed so as to cover at least the circumferential side of the moving body and supports the moving body so as to move it in the optical axis direction of the lens; and a coil 18 and a magnet 17 which drive the moving body in the optical axis direction of the lens. Extension parts 131 and 132 extended to the circumferential side are formed in the moving body, the moving body and the extension parts 131 and 132 are arranged with respect to the magnet 17 through a gap, and the extension parts 131 and 132 are arranged with respect to the support through a gap as well. An air resistance part (a tape 40 or the like) which restricts the movement of the moving body in the direction of the optical axis L of the lens is formed in the extension parts 131 and 132. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens driving device that forms an image of a subject by driving a lens in the direction of an optical axis.

  In recent years, as camera-equipped mobile phones equipped with cameras have become popular, opportunities for photographing various subjects using the mobile phones have increased. For example, you can shoot a subject that is far away from the camera lens, such as a friend or landscape (normal shooting), or a subject that is close to the camera lens, such as a bus timetable or petals (close-up shooting) There is a case.

  In close-up photography (macro photography), the lens position of the camera needs to be slightly closer to the subject side than the lens position during normal photography. For this reason, this type of photographic lens system includes a drive mechanism that drives the lens to move in the direction of the optical axis, so that the lens can be moved in the direction of the optical axis by driving the drive mechanism by switching a switch. (For example, refer to Patent Document 1).

  The camera-equipped mobile phone disclosed in Patent Document 1 includes a holder having a cylindrical portion, a coil positioned around the cylindrical portion, a yoke having a permanent magnet facing the coil, and a pair of leaf springs. The lens is energized, and the position of the lens can be adjusted in the optical axis direction by the interaction between the magnetic field of the permanent magnet and the magnetic field generated by the current flowing through the coil.

  Here, when the current flowing through the coil changes abruptly (for example, when the coil for focusing is energized), a phenomenon in which the lens vibrates in the optical axis direction (transient response) occurs, resulting in convergence of the damping of the lens driving device. It may take time. In order to suppress this, the camera-equipped mobile phone disclosed in Patent Document 1 is provided with a transient response suppressing means for suppressing the transient response. Specifically, a capacitor connected in parallel with the coil is used to relieve a rapid change in the current flowing through the coil and suppress a transient response.

JP 2006-258969 A (paragraphs [0006], [0035], [0036])

  However, the transient response suppressing means described above is an electrical damping measure, and is not a mechanical damping measure using, for example, a component of the lens driving device.

  As a mechanical damping measure, for example, management by the strength of the leaf spring (spring constant) may be considered. However, since it is necessary to ensure the sleeve stroke (lens moving distance), it is difficult to change the strength of the leaf spring by paying attention only to damping measures.

  The present invention has been made in view of the above points, and its purpose is to provide a transient response until the lens stops at a desired position by taking a mechanical damping measure different from a change in strength of the leaf spring. It is an object of the present invention to provide a lens driving device capable of suppressing the above-described problem.

  In order to solve the above problems, the present invention provides the following.

  (1) A movable body that holds a lens, a support that is formed so as to cover at least the outer peripheral side of the movable body, and that supports the movable body so as to be movable in the optical axis direction of the lens; A driving mechanism including a coil and a magnet for driving in an optical axis direction, wherein the magnet is attached to the support body and disposed at four corners, and the movable body is extended to the outer peripheral side. And the movable body and the extension portion are arranged with a gap between the magnet and the extension portion is also arranged with a gap between the support body and the lens. Air resistance that restricts movement of the moving body in the optical axis direction of the lens is attached to any position within the length of the magnet in the optical axis direction Lens driving apparatus characterized by There are formed.

  According to the present invention, in the lens driving device provided with the moving body, the support body, and the driving mechanism, the moving body is formed with the extended portion extended to the outer peripheral side, and this extended portion is at least the outer periphery of the moving body. It arrange | positions through the support part formed so that the side might be covered, and a clearance gap. Moreover, the magnets arranged at the four corners of the support are also arranged via gaps. On the other hand, the moving body is also arranged with the magnet and a gap. In such an arrangement state, since the expansion portion is provided with an air resistance portion that restricts the movement of the moving body, the outlet (flow path) of the air flow generated by the movement of the moving body is restricted to the gap described above. become. As a result, the flow velocity and pressure of the air flowing through the gap between the magnet and the expansion portion increase (so-called orifice effect), the acceleration on the moving body is moderated moderately, and mechanical damping measures can be taken.

  In addition, since it is different from countermeasures for electrical damping as in the prior art, it provides a damping effect and, for example, a member disposed through a gap such as a support can be used as a countermeasure. It is also effective.

  Furthermore, since the measure depends on the strength of the leaf spring, it is possible to prevent the degree of freedom of design related to the strength of the leaf spring from being lowered.

  Here, the “air resistance portion” may be in any form as long as it has a function of regulating the movement of the moving body. For example, holes, grooves, and notches formed in the extended portion may be closed with tape, or a member such as an adhesive or resin may be embedded therein. Further, the shape of the “support” formed so as to cover at least the outer peripheral side of the movable body may be any shape. For example, it may be a rectangular parallelepiped shape or a shape having unevenness on the side surface.

  (2) On the surface of the support body that faces the extension portion in a direction orthogonal to the optical axis direction of the lens, a movement path that allows the extension portion to move when the moving body moves is formed. A lens driving device.

  According to the present invention, on the surface of the support described above that faces the extension in the direction orthogonal to the optical axis direction of the lens, a movement path that allows the extension to move when the moving body moves is formed. Therefore, the damping effect can be enhanced.

  More specifically, in relation to the extended portion, the moving body in which the extended portion is formed, and the magnets disposed at the four corners of the support body, the magnets are disposed on both sides of the moving path (for example, bonded and fixed). The moving path is almost sealed by the moving body. And the expansion part of a moving body will be located in the substantially sealed moving path. As a result, the damping of the moving body can be suppressed by the air resistance part formed in the extension part and partially or entirely accommodated in the moving path.

  Here, the shape of the “movement path” may be a groove shape that accommodates part or all of the extended portion. Further, the position of the air resistance portion in the movement path may be any position, but it is preferable that the position of the air resistance section is located near the center rather than the end of the movement path. Thereby, while a damping effect increases, it becomes easy to maintain the balance at the time of a moving body moving.

  (3) The lens driving device characterized in that the moving path and the extended portion are formed at a plurality of locations, and at least one or more air resistance portions are formed in the extended portion.

  According to the present invention, the moving path and the extension portion described above are formed at a plurality of locations, and at least one or more air resistance portions are formed at the extension portion, so by providing an air resistance portion at a plurality of locations, The damping effect can be enhanced.

  (4) The coil is attached to the moving body, and the extension part has a notch part formed as a guide part for guiding the coil in the optical axis direction of the lens, and the air resistance part is The lens driving device is formed so as to cover at least a part of the notch.

  According to the present invention, the extension portion described above is provided with a notch portion that is formed as a guide portion that guides the coil attached to the moving body in the optical axis direction of the lens. Since at least a part of the cutout portion is covered, the extension portion can be used also as a guide portion (or flange portion) of the coil. As a result, it is not necessary to separately provide an extended portion as a separate member on the moving body, and a mechanical damping effect can be ensured while reducing the number of parts.

  (5) The lens driving device characterized in that, in the moving path, the expansion portion is substantially occupied by the air resistance portion in a predetermined cross-sectional area cut in a direction orthogonal to the optical axis direction of the lens.

  According to the present invention, in the predetermined cross-sectional area cut in the direction orthogonal to the optical axis direction of the lens in the moving path, the extended portion is almost occupied by the air resistance portion. The outlet of the generated air flow can be effectively narrowed to the above-described gap, and thus the damping effect can be enhanced.

  (6) The lens driving device characterized in that, in the optical axis direction of the lens, the thickness of the air resistance portion is thinner than the thickness of the extension portion.

  According to the present invention, in the optical axis direction of the lens, since the thickness of the air resistance portion is thinner than the thickness of the extension portion, it is not necessary to provide the air resistance portion in the extension portion, and the damping is performed while reducing the weight. Measures can be taken.

  (7) The lens driving device, wherein the moving body includes a sleeve for holding a lens, the extension portion is formed in the sleeve, and the moving path is formed in the support.

  According to the present invention, the moving body described above includes a sleeve for holding the lens, the extension portion is formed on the sleeve, and the moving path is formed on the support body, so that mechanical damping measures are taken. be able to. That is, by forming the expansion portion and the air resistance portion in the sleeve that is the member at the outermost peripheral portion in the radial direction of the moving body, the air resistance effect can be effectively and stably achieved.

  According to the lens driving device of the present invention, the extended portion formed in the moving body is formed with the air resistance portion that restricts the movement of the moving body in the optical axis direction of the lens. In addition to hindering the flow of air, the flow velocity and pressure of the air flowing through the gap between the magnet and the extension can be increased, and as a result, mechanical damping measures can be taken by the orifice effect.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Machine configuration]
FIG. 1 is a perspective view showing an external configuration of a lens driving device 1 according to an embodiment of the present invention. FIG. 2 is a diagram showing a state where the yoke 11 is removed from the lens driving device 1 shown in FIG. FIG. 3 is a cut plan view of the lens driving device 1 shown in FIG. 2 when cut along AA ′. FIG. 3 shows a cross-sectional view when the yoke 11 is attached to the lens driving device 1 for convenience of explanation.

  1 to 3, the lens driving device 1 includes a yoke 11, a cover 12, a sleeve 13, a first leaf spring 14, a second leaf spring (not shown), a wire spring 16, A magnet 17, a coil 18 (first coil 181 and second coil 182), and a holder 19 are provided.

  Note that the illustration of a lens barrel (lens barrel) incorporating a lens is omitted. The lens driving device 1 also moves the sleeve 13 along the direction of the optical axis L in the A direction (front side) approaching the subject (imaging target) and the B direction (rear side) approaching the opposite side (image side) from the subject. (See FIG. 1). A sleeve 13 holding a lens barrel (not shown as described above) in which one or a plurality of lenses are incorporated is configured to be movable in the direction of the optical axis L of the lens together with the wire spring 16 and the like. This corresponds to an example of a “moving body”. Further, the yoke 11, the cover 12, the holder 19 and the like are examples of a “support” that supports the sleeve 13 and the like so as to be movable in the direction of the optical axis L via the first plate spring 14 and the second plate spring. Equivalent to. The sleeve 13 and the like include a coil 18 and a magnet 17 held by the sleeve 13 and are driven by a “drive mechanism” that allows the sleeve 13 to move in the direction of the optical axis L of the lens by magnetic interaction. .

  The yoke 11 is made of a ferromagnetic plate such as a steel plate. Further, the yoke 11 is exposed at the front and side surfaces of the lens driving device 1, and a circular incident window 111 is formed at the center of the yoke 11 for taking reflected light from the subject into the lens. As shown in FIGS. 1 and 2, the yoke 11 covers the outer peripheral side of the sleeve 13 and also covers a part of the front end surface of the sleeve 13. That is, the yoke 11 is formed so as to cover at least the outer peripheral side of the moving body.

  On the other hand, the cover 12 is attached to the yoke 11, and a circular incident window 121 is formed at the center of the cover 12 for taking reflected light from the subject into the lens. The holder 19 holds an image sensor (not shown) on the image side.

  The coil 18 includes a first coil 181 and a second coil 182, which are arranged in two stages in the direction of the optical axis L, both of which are annular. Then, it is wound around the outer peripheral surface of the sleeve 13 at a predetermined interval in the optical axis direction. In addition, eight magnets 17 are arranged in two stages in the optical axis direction. The magnets 17 of each stage are arranged such that the front magnet 17 is against the first coil 181 and the rear magnet 17 is the first. As shown in FIG. 3, it is fixedly attached to four corner portions (four corners) of the inner peripheral surface of the yoke 11 whose outer shape is substantially rectangular.

  In the present embodiment, the magnet 17 is magnetized to poles whose inner surface and outer surface are different from each other. For example, the four magnets 17 arranged on the front side are magnetized with the N pole on the inner surface, the outer surface is magnetized with the S pole, and the four magnets 17 arranged on the rear side have an S inner surface. The pole is magnetized and the outer surface is magnetized to the N pole. Further, as shown in FIG. 3, the four magnets 17 are arranged in a state of being separated from each other (a state having a gap).

  Since the yoke 11 is larger than the dimension in the optical axis direction of the region where the first coil 181 and the second coil 182 are arranged, and the dimension in the optical axis direction of the magnet 17, the front magnet 17. Leakage flux from the magnetic path configured between the first coil 181 and the magnetic path configured between the rear magnet 17 and the second coil 182 can be reduced. As a result, the linearity between the amount of movement of the sleeve 13 and the current flowing through the first coil 181 and the second coil 182 can be improved.

  The lens driving device 1 includes an annular wire spring 16. The wire spring 16 applies a biasing force in the direction of the optical axis L to the sleeve 13 by a magnetic attractive force acting between the wire spring 16 and the magnet 17. For this reason, it is possible to prevent the moving body (sleeve 13 or the like) from being displaced by its own weight when the coil is not energized, and as a result, the moving body (sleeve 13 or the like) can be maintained in a desired posture. Yes. Furthermore, impact resistance can be improved.

  Here, in the lens driving device 1 according to the present embodiment, as shown in FIG. 2, the sleeve 13 is provided with expansion portions 131 and 132 formed integrally with the sleeve 13. More specifically, the extension portions 131 and 132 are extended to the outer peripheral side of the sleeve 13 and are attached to a position near the center of the length of the magnet 17 in the optical axis L direction of the lens. As will be described in detail below, since the sleeve 13 is disposed between the magnets 17, the expansion portions 131 and 132 are formed between the magnets 17. As a result, if it is within the height range of the magnet 17 in the direction of the optical axis L, the flow velocity and pressure of the air flowing through the gap between the magnet 17 and the expansion portions 131 and 132 are increased, so that the acceleration applied to the sleeve 13 is increased. Is alleviated. On the other hand, when the extension part is removed (formed) outside the height range of the magnet 17, the space between the yoke 11 and the extension parts 131 and 132 may be within a sealed space. There is no gap to increase the air flow rate and pressure. Furthermore, in the present embodiment, the positions of the extended portions 131 and 132 are set near the center of the length of the magnet 17 in the optical axis L direction. Any position may be used as long as the position is any of the positions.

  More specifically using FIG. 3, the sleeve 13 is disposed between the magnet 17 via the gap w <b> 1, and the expansion portions 131 and 132 are also disposed between the magnet 17 via the gap w <b> 2. Has been. The extension parts 131 and 132 are also arranged between the yoke 11 and the gap w3.

  Further, the positions of the expansion portions 131 and 132 in the lens driving device 1 are located in one of the gaps formed between the four magnets 17 (the lower left magnet in FIG. 3). 17 and the lower right magnet 17). And the extended parts 131 and 132 have the notch part 30 formed as a guide part which guides the coil 18 attached to the sleeve 13 in the optical axis L direction of a lens (refer FIG. 2).

  In the present embodiment, the extension portions 131 and 132 are arranged in one of the gaps formed between the four magnets 17. For example, the extension portions 131 and 132 are formed between the four magnets 17. Two of the gaps (for example, in FIG. 3, for example, the convex portion 133 can be combined as an extended portion) or more than that may be arranged. Further, of the magnets 17, two adjacent magnets 17 without passing through the expansion portions 131 and 132 (in FIG. 3, the upper left magnet 17 and the lower left magnet 17 or the upper right magnet 17 and the lower right magnet 17 The magnet 17) is disposed through a gap (without any intervening). In the direction opposite to the direction through the extension portions 131 and 132, the magnets (in FIG. 3, the upper left magnet 17 and the lower left magnet 17 or the upper right magnet 17 and the lower right magnet 17 The magnet 17) may be joined (in a state where no gap is provided). In this case, since the flow rate of air becomes smaller, the flow rate of air flowing through the gap between the magnet 17 and the expansion portions 131 and 132 and As the pressure increases, the acceleration applied to the sleeve 13 can be further alleviated.

  In addition, on the surface of the yoke 11 that faces the expansion portions 131 and 132 in a direction orthogonal to the optical axis direction of the lens, there is a moving path 112 that allows the expansion portions 131 and 132 to move when the sleeve 13 moves. Is formed. Part of the extended portions 131 and 132 (a part on the outer peripheral side) is accommodated in the moving path 112.

  In such a configuration, as an example of an “air resistance portion” that restricts the movement of the sleeve 13 in the direction of the optical axis L of the lens, the tape 40 is attached to the expansion portions 131 and 132 as shown in FIG.

  FIG. 4 is a diagram illustrating a state when an air resistance unit is provided in the lens driving device 1 according to the present embodiment.

  In FIG. 4, the tape 40 is formed so as to cover the entire cutout 30. In the present embodiment, it is formed so as to cover the entire surface of the notch 30, but it may be a part. FIG. 5 is a diagram illustrating a state when the lens driving device 1 illustrated in FIG. 4 is viewed from an obliquely rear side.

  As shown in FIGS. 4 and 5, in this embodiment, both the front end surface and the rear end surface of the extended portions 131 and 132 are covered, but only one of the front end surface and the rear end surface is covered. It doesn't matter. In the present embodiment, the moving path 112 and the extended portions 131 and 132 are formed in one place, and the two tapes 40 are attached to the extended portions 131 and 132. However, the present invention is not limited to this. As described above, a moving path or an extended portion may be provided at the position of the convex portion 133 (see FIG. 3). Further, in the present embodiment, when the sectional area when the moving path 112 is cut in a direction orthogonal to the direction of the optical axis L of the lens, the ratio between the expanded portions 131 and 132 and the tape 40 is approximately 1: 1. However, the present invention is not limited to this. For example, the tape 40 is attached to the entire front end surface or rear end surface of the extension portions 131 and 132, and the extension portions 131, 132 may be substantially occupied by the tape 40.

  As described above, the extension portions 131 and 132 are formed in the sleeve 13 of the moving body, the moving path 112 is formed in the yoke 11 of the support body, and the extension portions 131 and 132 have a lens. A tape 40 that restricts the movement of the sleeve 13 in the direction of the optical axis L is attached. Thereby, the exit (flow path) of the air flow generated by the movement of the sleeve 13 is narrowed to the gaps w1 to w3. As a result, the flow velocity and pressure of the air flowing through the gap w2 between the magnet and the expanded portion increase (due to the so-called orifice effect), the acceleration on the sleeve 13 is moderated moderately, and mechanical damping measures can be taken.

  In the present embodiment, the air resistance portion is configured by attaching the tape 40 to the notch 30. However, the present invention is not limited to this, for example, the notch 30 may be filled with resin, Adhesives may be packed. Moreover, you may provide the hole for inserting the coil 18 in the tape 40 shown in FIG.4 and FIG.5 in the range which has an orifice effect.

[basic action]
In the lens driving device 1 according to the present embodiment, the moving body is normally located on the image sensor side (image side) (when the first coil 181 and the second coil 182 are not energized). At this time, the wire spring 16 regulates the displacement of the moving body by a magnetic attractive force acting between the wire 17 and the magnet 17. However, since the distance between the wire spring 16 and the magnet 17 is maintained to some extent, the magnetic attractive force between the wire spring 16 and the magnet 17 does not become too strong. As a result, it is possible to prevent the center axis of the moving body from being shifted, and thus to prevent the tilt characteristics from deteriorating.

  In such a state, when a current is passed through the first coil 181 and the second coil 182 so that the moving body moves upward, the first coil 181 and the second coil 182 are directed upward (front side), respectively. Will receive the electromagnetic force. The first coil 181, the second coil 182, and the sleeve 13 start to move toward the subject side (front side).

  At this time, an elastic force that restricts the movement of the sleeve 13 is generated between the first leaf spring 14 and the front end of the sleeve 13 and between the second leaf spring and the rear end of the sleeve 13. For this reason, when the electromagnetic force that moves the sleeve 13 forward and the elastic force that restricts the movement of the sleeve 13 are balanced, the sleeve 13 stops. In addition, when a reverse current is passed through the first coil 181 and the second coil 182, the first coil 181 and the second coil 182 receive a downward (rear) electromagnetic force, respectively. .

  At that time, by adjusting the amount of current flowing through the first coil 181 and the second coil 182 and the elastic force acting on the sleeve 13 by the first leaf spring 14 and the second leaf spring, the sleeve 13 (moving body) ) Can be stopped at a desired position.

[Main effects of the embodiment]
According to the lens driving device 1 according to the present embodiment, since the tape 40 is attached as the air resistance portion to the expansion portions 131 and 132, the acceleration when the sleeve 13 moves is moderated moderately, and the transient response is suppressed. As a result, mechanical damping measures can be taken. That is, when considering a camera-equipped mobile phone equipped with the lens driving device 1, the time required for damping of the drive parts is shortened, and accordingly, the time from when the shutter is pressed until the image is captured can be shortened. .

  In addition, with a mechanical configuration, damping can be reduced even when the camera-equipped mobile phone on which the lens driving device 1 is mounted is hit against a wall or floor. In addition, the present invention is not a measure that depends on the strength of the first leaf spring 14 or the second leaf spring (not shown) (this is not intended to exclude a measure that depends on the strength of the leaf spring). Therefore, it is possible to prevent the degree of freedom of design related to the strength of the leaf spring from being lowered.

  Further, in this embodiment, a part of the extended portions 131 and 132 are accommodated in the moving path 112 and the sealing property is enhanced, and the tape 40 is applied to the extended portions 131 and 132, so that the air flowing through the gap The flow velocity and pressure of the can be increased, and a higher damping effect can be achieved.

  Further, in this embodiment, since the air resistance portion is configured by covering the notch portion 30 with the tape 40, there is no need to separately provide separate members as the expansion portions 131 and 132, and the number of parts can be reduced. The mechanical damping effect can be ensured while aiming.

[Example]
FIG. 6 is a diagram illustrating experimental results regarding the damping evaluation of the lens driving device 1. FIG. 7 is a circuit diagram showing a damping measurement circuit used in an experiment related to damping evaluation.

  First, actual damping evaluation will be described. As shown in FIG. 7, the lens driving device 1 (indicated by LA) was connected to a programmable power supply (power supply voltage), and a 47 [μF] bypass capacitor capacitor was connected in parallel therebetween. The power supply voltage limit was set to 2 [V]. As software settings, the low-pass filter, the high-pass filter, the simple optical filter, and the average number of times were all OFF, and the sampling rate was 1000 s / s. The energization time is 150 ms. As a comparison object, the product (X) and the product (Y) according to this embodiment were compared, and the number of samples was three. Moreover, the case which comprises an air resistance part with the tape 40, and the case comprised by adhesion hole filling of resin etc. were considered. The latter is for product X only.

  The experimental results are as shown in FIG. According to FIG. 6A, it can be seen that the amplitude amount at the 90 ms time point is greatly improved by applying the tape for both the product X and the product Y. Looking at the average of the three, the product X is 13.92 [μm] → 4.17 [μm], and the product Y is 13.59 [μm] → 2.63 [μm]. Yes.

[Modification]
In the above-described embodiments and examples, as the air resistance portion, the adhesive hole filling with the tape 40 or the resin is considered. However, the air resistance portion can be configured without using these by changing the shape of the expansion portions 131 and 132. It is possible to do. For example, in the direction of the optical axis L of the lens, by making the thickness of the air resistance portion thinner than the thickness of the expansion portion (for example, the portion of the tape 40 is constituted by the expansion portion), the expansion portion has an air resistance. There is no need to provide a portion, and damping measures can be taken while reducing the weight.

  In addition to the camera-equipped mobile phone, the lens driving device 1 can be attached to various electronic devices. For example, PHS, PDA, bar code reader, thin digital camera, surveillance camera, vehicle rear view confirmation camera, door with optical authentication function, and the like.

  The lens driving device according to the present invention is useful as a device capable of taking a mechanical damping measure.

It is a perspective view which shows the external appearance structure of the lens drive device which concerns on embodiment of this invention. It is a figure which shows a mode that the yoke was removed from the lens drive device shown in FIG. In the lens drive device shown in FIG. 2, it is a cutting | disconnection top view when cut | disconnecting by AA '. It is a figure which shows a mode when an air resistance part is provided in the lens drive device which concerns on this embodiment. It is a figure which shows a mode when the lens drive device shown in FIG. 4 is seen from the diagonally back side. It is a figure which shows the experimental result regarding damping evaluation of a lens drive device. It is a circuit diagram which shows the damping measurement circuit used for the experiment regarding dumping evaluation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 11 Yoke 12 Cover 13 Moving body (sleeve)
14 First plate spring 16 Wire spring 17 Magnet 18 Coil 19 Holder 30 Notch 40 Tape 131, 132 Expansion part

Claims (7)

A moving body that holds the lens, a support that is formed so as to cover at least the outer peripheral side of the moving body, and supports the moving body so as to be movable in the optical axis direction of the lens, and the moving body in the optical axis direction of the lens A lens driving device having a coil and a magnet driving mechanism.
The magnet is attached to the support and is arranged at four corners,
The moving body is formed with an extended portion extended to the outer peripheral side,
The movable body and the extension portion are arranged with a gap between the magnet and the magnet,
The extension portion is disposed between the support body via a gap, and is attached at any position within the length of the magnet in the optical axis direction of the lens.
The lens driving device according to claim 1, wherein an air resistance portion that restricts movement of the moving body in the optical axis direction of the lens is formed in the extension portion.   On the surface of the support body that faces the extension portion in a direction orthogonal to the optical axis direction of the lens, a movement path that allows the extension portion to move when the moving body moves is formed. The lens driving device according to claim 1. The moving path and the extended portion are formed at a plurality of locations,
The lens driving device according to claim 2, wherein at least one of the air resistance portions is formed in the extension portion. The coil is attached to the moving body,
The extension part has a notch part formed as a guide part for guiding the coil in the optical axis direction of the lens,
4. The lens driving device according to claim 2, wherein the air resistance portion is formed so as to cover at least a part of the notch portion.   5. The expansion portion is substantially occupied by the air resistance portion in a predetermined cross-sectional area cut in a direction perpendicular to the optical axis direction of the lens in the moving path. The lens driving device described.   6. The lens driving device according to claim 1, wherein a thickness of the air resistance portion is thinner than a thickness of the extension portion in an optical axis direction of the lens.   The said moving body is provided with the sleeve holding a lens, The said extension part is formed in the said sleeve, and the said moving path is formed in the said support body, The Claim 1 characterized by the above-mentioned. Lens drive device.

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