JP2017003931A - Drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive unit which facilitates current control of a voice coil motor (VCM), and features greater regenerative force generated on a coil when energization of the VCM is stopped to allow for putting a brake on movement of a movable element within a device.SOLUTION: A drive unit has a VCM as a driver for driving a lens, or a movable element, and a coil assembly 16 constituting a movable motor part 15 of the VCM comprises a plurality of coils (first coil 17 and second coil 18). The drive unit also includes coil switching means 6 (61, S1, S2) which allows a drive controller 4 to energize the first coil 17 when VCM is driven, and switches to short-circuit the first coil 17 and the second coil 18 when the VCM is unenergized. Regenerative force is generated on the first coil 17 and the second coil 18 when moved by external force, which puts a brake on movement of an optical element.SELECTED DRAWING: Figure 4

Description

  The present invention is provided in an optical apparatus such as a digital camera, and is preferably applied to a driving device for driving an optical element, preferably a driving device for driving a lens in a lens barrel. The present invention relates to a drive device that can

  A lens barrel of an optical device such as a digital camera is provided with a driving device for moving the lens in the optical axis direction in the lens barrel in order to perform zooming and focusing. As a drive source of this type of drive device, a direct current motor or an ultrasonic motor is used, but in recent years, a voice coil motor (VCM) that can be configured to be light and small is used. This VCM utilizes Lorentz force (driving force generated in the coil by Fleming's left-hand rule) generated by controlling the current supplied to the coil in the magnetic field.

  However, in this driving device using the VCM, when the energization to the coil is stopped, the Lorentz force is lost and the movement of the coil cannot be restricted, and the lens supported by the coil is fixed at a predetermined position. Can not be held in. For this reason, when energization is stopped, the lens is moved in the lens barrel due to external forces such as vibration and impact applied to the lens barrel, and the lens collides with the lens barrel fixing portion of the lens barrel at the moving direction end. Doing so may cause damage.

  In order to prevent such damage to the lens, it is conceivable to provide a mechanical locking mechanism, but the structure is complicated, which is disadvantageous for downsizing of the optical apparatus. Therefore, it is considered to brake the movement of the lens by using a regenerative force generated in the coil (a driving force in a direction opposite to the moving direction caused by the self-inducing action of the coil). For example, Patent Document 1 uses a regenerative force generated in a motor coil in a changer mechanism in which an elevator is moved up and down using a stepping motor when the motor is de-energized. This is the technology to brake the elevator. Further, Patent Document 2 is a technique in which a voice coil is short-circuited at the time of retraction in a disk drive device using a VCM as a drive source, and the regenerative force generated at that time is used to perform braking in the direction of the retracted position of the head. is there. By applying the regenerative force technology of Patent Documents 1 and 2 to the VCM in the lens barrel, it becomes possible to prevent damage due to lens collision.

Japanese Patent Laid-Open No. 11-149695 JP 2008-293557 A

  In the present inventor, when such regenerative force technology is applied to the VCM used in the lens barrel, it is actually possible to obtain an effective regenerative force in order to effectively brake the lens in the coil of the VCM. It turned out to be difficult. That is, normally, the self-inductance of the VCM is designed to be an appropriate value for obtaining a driving force suitable for driving the lens. In a coil designed in this way, the value of the self-inductance is not necessarily a large value, so that the regenerative force obtained by the coil is small and not always sufficient to effectively prevent a collision at the end of the moving direction of the lens. .

  If a coil with a large regenerative force is designed to obtain the braking force necessary to prevent the lens from colliding, the self-inductance of the coil increases, and accordingly, the power consumption when driving the VCM increases. There's a problem. At the same time, the driving force of the VCM also increases, so that when controlling the current of the VCM, the lens can be moved at high speed even with a minute current change, and the current for finely controlling the movement of the lens at a desired speed. Control is difficult, and lens control in the lens barrel becomes difficult.

  The object of the present invention is to facilitate the current control of the VCM, while increasing the regenerative force generated in the coil when the power supply to the VCM is stopped, and to damage the driving device due to an external force, for example, a lens in a lens barrel. It is an object of the present invention to provide a drive device that can avoid damage caused by a collision.

  The drive device of the present invention includes a VCM as a drive source of the drive device, and the coil body constituting the movable portion of the VCM is configured by a plurality of integrated coils, and at least one coil is provided when the VCM is driven. It is characterized by comprising a coil switching means that enables energization in the drive control unit and switches a plurality of coils to a short-circuit state when energization to the VCM is stopped. The coil switching means can switch a plurality of coils to a state of serial connection or parallel connection.

  As a preferred embodiment of the present invention, the coil body includes a first coil as a drive coil and a second coil as a braking coil, and the coil switching means enables energization of the first coil when the VCM is driven. The first coil and the second coil are connected in series or in parallel when the power supply to the power supply is stopped to form a closed loop. Or it is good also as a structure which enables electricity supply to a 1st coil and a 2nd coil at the time of the drive of VCM.

  For example, both ends of the first coil are connected to the drive controller and one end thereof is connected to one end of the second coil, and the coil switching means is interposed between one end and the other end of the first coil. And a second switch interposed between one end and the other end of the second coil. In this case, a third switch interposed between one end of the first coil and the drive control unit may be provided.

  Alternatively, the first coil and the second coil are connected in parallel and commonly connected to the drive control unit, and then the first switch is connected in parallel to the first coil and the second coil, and is connected in series with the second coil. And a second switch is connected.

  According to the present invention, even if the first coil is designed so that the driving force of the VCM is a suitable driving force, the regenerative force obtained by the first coil and the second coil can be obtained as a braking force during the system. . As a result, a braking force greater than the driving force can be obtained, and a driving device with a large regenerative force when energization to the VCM is stopped can be obtained while facilitating the current control of the VCM.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of Embodiment 1 which applied this invention to the lens-barrel of the camera, (a) is a schematic sectional drawing along an optical axis, (b) is a cross section along the B1-B1 line | wire of (a) figure. Figure. The schematic perspective view which decomposed | disassembled a part of lens drive device. The expanded sectional view of a part of Drawing 1 (a) in VCM. The block circuit diagram of a lens drive device. FIG. 5 is a circuit diagram of the main part of FIG. 4 for explaining the operation of the first embodiment. FIG. 6 is a circuit diagram of a main part for explaining the configuration and operation of the second embodiment. Sectional drawing of the modified example from which a coil body differs. FIG. 6 is a circuit diagram of a main part for explaining the configuration and operation of a third embodiment. FIG. 9 is a circuit diagram of a main part for explaining the operation of the third embodiment. It is a figure of the principal part of Embodiment 4, (a) is the front view, (b) is the B2-B2 sectional view taken on the line of (a) figure.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a first embodiment in which the present invention is applied to a lens barrel of a still camera or a movie camera (video camera). As an example of a driving device according to the present invention, the lens barrel LL is installed in a lens barrel. It is a figure of embodiment applied to the lens drive device 1 of the focus lens which performs focusing (focusing) automatically. FIG. 1A is a schematic cross-sectional view along the optical axis direction. The lens barrel LL includes a first lens group L1, a second lens group L2, and a third lens group L3. The second lens unit L2 is configured as a focus lens as an optical element that is driven by the lens driving device 1. The focus lens (second lens group) L2 is moved by the lens driving device 1 in the optical axis direction of the lens barrel LL, and is mounted in the camera body CB to which the lens barrel LL is mounted. Focusing is to be performed. Since the first lens unit L1 and the third lens unit L3 are not configured to be driven by the lens driving device 1, detailed description thereof is omitted.

  FIG. 1B is a diagram in which the focus lens (second lens group) L2 and the lens driving device 1 are extracted, and is a cross-sectional view taken along line B1-B1 of FIG. FIG. 2 is a schematic perspective view in which a part of the main part is disassembled. As shown in FIGS. 1 and 2, the focus lens L2 is fixedly supported by the lens frame 2, and a pair of guide rods 3 are respectively extended in the optical axis direction at left and right positions in the radial direction. Is inserted loosely. These guide rods 3 are fixedly supported by the lens barrel fixing portion 31 of the lens barrel LL, and the lens frame 2 is movable along the guide rods 3 in the optical axis direction.

  The lens driving device 1 is mainly composed of a linear (linear) type voice coil motor (VCM) disposed over the movement region in the optical axis direction of the lens frame 2 in the upper region of the lens frame 2. . The VCM includes a long plate-like magnet 11 extended along the optical axis direction, and a yoke 12 made of a magnetically permeable material that supports the magnet 11, and the magnet 11 and the yoke 12. Thus, a motor fixing portion (stator) 10 of the VCM is configured.

  The yoke 12 is formed endlessly by a horizontal U-shaped yoke 13 extended in the optical axis direction and an I-shaped yoke 14 connecting the open ends of the horizontal U-shaped yoke 13. The pair of side pieces 13o and 13i forming 13 pairs are fixedly supported in the lens barrel LL in a state of being directed in the radial direction of the lens barrel LL. The lengths of the horizontal U-shaped yoke 13 and the magnet 11 in the optical axis direction are designed to correspond to the movement distance of the focus lens L2 in the optical axis direction.

  As shown in the enlarged cross-sectional view of FIG. 3, the magnet 11 has one magnetic pole of the S pole and the N pole, here the N pole is directed in the inner diameter direction, and the other magnetic pole ( S pole) is fixed to the inner surface of the side piece 13o on the outer diameter side of the horizontal U-shaped yoke 13. As a result, the magnet 11 and the yoke 12 form a magnetic field H composed of magnetic lines directed in the radial direction over a predetermined length region in the lens barrel LL.

  The motor movable portion (rotor) 15 of the VCM is composed of a coil body 16 formed of a square tube type air-core coil, and this coil body 16 is integrally supported by a part of the lens frame 2 in the radial direction. In addition, the air core portion is disposed so as to insert the side piece portion 13 i on the inner diameter side of the horizontal U-shaped yoke 13. When the coil body 16 moves in the magnetic field H, that is, when it moves in the direction of the optical axis within the gap between the side piece 13 i of the lateral U-shaped yoke 13 and the magnet 11, friction resistance is generated between them. It is preferable that they are arranged so as not to contact each other so as not to occur. In addition, a thin flexible printed circuit board (FPC) 19 having a flexible band shape is connected to the coil body 16, and the coil body 16 is electrically connected to a lens drive control unit 4 to be described later via the FPC 19. It is connected. Since the FPC 19 is elastically deformed in the plate thickness direction following the movement of the lens frame 2 in the optical axis direction, that is, the movement of the coil body 16 in the optical axis direction, the FPC 19 is involved in the movement of the coil body 16 in the optical axis direction. The electrical connection state is maintained.

  As shown in FIG. 2, the coil body 16 includes a first coil 17 and a second coil 18 having substantially the same shape. Here, the first coil 17 and the second coil 18 are configured as rectangular tube-shaped air-core coils having substantially the same external dimensions, and both the coils 17 and 18 are fixedly supported by the lens frame 2. Are integrated with each other. The first coil 17 and the second coil 18 are arranged in the optical axis direction with their cores (coil axes) in the same direction, and the winding directions of the first coil 17 and the second coil 18 are in the same direction. It has been.

  On the other hand, the number of turns of the first coil 17 and the number of turns of the second coil 18 are appropriately designed. That is, as will be described later, the first coil 17 is configured as a drive coil for driving the focus lens L2, and the number of turns thereof is suitable for self-inductance to obtain a suitable lens driving force by controlling the current. Designed to be a coil. Further, the second coil 18 is configured as a braking coil, and the number of turns is designed to be a self-inductance coil capable of obtaining a suitable braking force, as will be described later.

  FIG. 4 is a block circuit diagram of the lens driving device 1. The first coil 17 and the second coil 18, that is, the drive coil 17 and the braking coil 18 are electrically connected to the lens drive control unit 4. In the first embodiment, the drive coil 17 and the brake coil 18 are connected in series with one end thereof connected to each other, and one end and the other end of the drive coil 17 are connected to the lens drive control unit 4. The lens drive control unit 4 supplies a drive current for driving the VCM.

  The lens drive control unit 4 supplies a drive current to the drive coil 17 based on a focusing signal output from the camera control unit 5. Although a detailed description of the camera control unit 5 is omitted, a distance measuring sensor (AF sensor) when a release button (not shown) provided on the camera body BD (see FIG. 1) is half-pressed. Ranging is performed based on the SS ranging signal, and a focusing signal is generated based on the obtained ranging signal. Further, when the main switch SW of the camera is operated and the power source (battery) BAT is turned on / off, a power on / off signal is output to the lens drive control unit 4.

  The lens driving device 1 is provided with coil switching means 6 for switching the connection state between the driving coil 17 and the braking coil 18. The coil switching means 6 includes first and second switches S1 and S2 and a coil switching unit 61 that controls on / off of these switches. In the first embodiment, a first switch S1 is connected between one end and the other end of the drive coil 17, and a second switch S2 is connected between one end and the other end of the braking coil 18. Yes.

  The first switch S1 and the second switch S2 are constituted by relay switches, and the on / off of the switch contact SC is switched by controlling energization to the relay coil REL of the relay switch. Here, each of the first switch S1 and the second switch S2 is a normally closed switch that turns on the switch contact SC when the relay coil REL is not excited. When the current to be switched is a small current, the first switch S1 and the second switch S2 may be constituted by electronic switches such as transistors or MOSs.

  The coil switching unit 61 switches and controls the first switch S1 and the second switch S2 in sequence according to the control state in the lens drive control unit 4. That is, when the lens drive control unit 4 drives the VCM to perform focusing control, the coil switching unit 61 turns off (opens) the first switch S1 and the second switch S2. When focusing is not performed or when the power is turned off, the coil switching unit 61 turns on (closes) the first switch S1 and the second switch S2. FIG. 4 shows a state where the switches S1 and S2 are turned off to perform focusing.

  The operation of the lens driving device 1 according to the first embodiment having the above configuration will be described. As shown in FIG. 4, when the power BAT is turned on by the main switch SW of the camera, the lens drive control unit 4 controls the coil switching unit 61 based on the input power-on signal, and the coil switching unit 61 The first switch S1 and the second switch S2 are turned off. As a result, as shown in FIG. 5A, both ends of the drive coil 17 are connected to the lens drive control unit 4, and the braking coil 18 is opened.

  Therefore, when the release button of the camera is half-pressed, the AF sensor SS performs distance measurement, and the camera control unit 5 performs an appropriate optical axis position of the focus lens L2 based on the obtained distance measurement signal. The focus position is calculated to generate a focusing signal and output to the lens drive control unit 4. The lens drive control unit 4 controls the current flowing through the drive coil 17 based on the input focusing signal. As a result, the drive coil 17 is controlled in the position in the optical axis direction with respect to the motor fixing unit 10, that is, the magnet 11 and the yoke 12, according to the energized current, and the VCM is in a drive state. The optical axis position of the lens frame 2 in other words, that is, the focus lens L2, is controlled to perform focusing.

  At this time, by appropriately designing the self-inductance of the drive coil 17, the drive force of the drive coil 17 itself generated by the current flowing through the drive coil 17 is controlled, and the focus lens L2 is moved in the optical axis direction. The moving position can be suitably controlled, and lens control is facilitated. At this time, if the driving force generated in the driving coil 17 is excessive, the moving speed of the focus lens L2 becomes high and it is difficult to accurately move the focus lens L2 to a desired optical axis position. On the other hand, if the driving force is too small, it becomes difficult to quickly move and control the focus lens L2 to the desired optical axis position.

  On the other hand, when the power supply BAT is turned off by the main switch SW as in the case of not using the camera, the lens drive control unit 4 controls the coil switching unit 61 based on the inputted power supply off signal, and FIG. ), The coil switching unit turns on the first switch S1 and the second switch S2. Thereby, both ends of the drive coil 17 and the brake coil 18 are short-circuited, and both the coils 17 and 18 are in a closed loop state. The drive coil 17 stops operating as a VCM because the current supply from the lens drive control unit 4 is stopped. As a result, the drive coil 17 and the brake coil 18, that is, the coil body 16, are in a state of being freely moved with respect to the motor fixing portion 10 including the magnet 11 and the yoke 12, and as a result, the lens frame 2 integrated with the coil body 16 In other words, the focus lens L2 is moved without moderation in accordance with the external force in the lens barrel LL.

  Therefore, in such a power-off state, when an external force such as vibration or impact is applied to the lens barrel LL, the focus lens L2 is moved in the optical axis direction. However, due to the movement of the focus lens L2, that is, the movement of the coil body 16 integrated with the lens frame 2, electromotive force (Lorentz force: Fleming's left-hand rule) is generated in the driving coil 17 and the braking coil 18, respectively. Electromagnetic force due to current in a direction that cancels the current) is generated, and a force generated by the self-induction action on the electromotive force, that is, a regenerative force is generated. This regenerative force acts as a braking force with respect to the moving direction of the coil body 16.

  At this time, in this embodiment, since the winding direction of the drive coil 17 and the braking coil 18 is the same direction, the regenerative force is generated in the same direction in each of the coils 17 and 18, and the regenerative force of both the coils 17 and 18 is A large added braking force is obtained. As a result, the movement of the focus lens L2 due to the external force is braked, and the focus lens L2 collides with the lens barrel fixing portion of the lens barrel LL at the end in the movement direction and is suppressed or prevented from being damaged.

  Accordingly, even when it is difficult to design the self-inductance of the drive coil 17 with priority given to appropriately setting the driving force of the VCM at the time of focusing, the coil body 16 at the time of power-off is provided by providing the braking coil 18. , That is, the combined inductance of the drive coil 17 and the braking coil 18 can be greater than the self-inductance of the drive coil 17 alone, the regenerative force by the coil body 16 can be increased, and damage to the focus lens L2 can be reduced. It can be effectively suppressed or prevented. The regenerative force obtained in the coil body 16 is the same when the focus lens L2 is moved in any optical axis direction in the lens barrel LL, and the focus lens L2 is a lens at both end positions in the optical axis direction. It is possible to suppress or prevent damage when colliding with the lens barrel fixing portion of the lens barrel LL.

  FIG. 6 is a circuit configuration diagram of Embodiment 2 in which the drive device according to the present invention is modified. In the second embodiment, as shown in FIG. 6 (a), only the main part of the circuit of the lens driving device is shown, and a third portion is provided between the one end of the driving coil 17 and the braking coil 18 connected to each other and the lens driving control unit 4. A switch S3 is interposed, and the third switch S3 is configured to be turned on / off in the coil switching unit 61 (see FIG. 4). Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

  In the second embodiment, at the time of lens control, as shown in FIG. 6A, the coil switching unit 61 turns off the first switch S1 and the second switch S "and turns on the third switch S3. As a result, only the drive coil 17 is connected to the lens drive control unit 4, and a control current is supplied to the drive coil 17. This is the same as in the lens control of Embodiment 1, and the coil body 16 is the drive coil. Only 17 is configured as a drive coil of the VCM, and lens control by the VCM can be realized.

  Moreover, at the time of lens control, as shown in FIG. 6B, the coil switching unit 61 may turn off the first switch S1 and the third switch and turn on the second switch S2. As a result, the drive coil 17 and the brake coil 18 are connected in series, and both the coils 17 and 18 are connected in series to the lens drive control unit 4, and a control current is passed through the coils 17 and 18. That is, the drive coil 17 and the brake coil 18 are integrated to form a VCM drive coil, the number of turns as the VCM drive coil is increased, and the self-inductance is increased. Therefore, the driving force of the VCM with respect to the current supplied to the coil body 16 at the time of lens control is increased, and the moving speed when moving the focus lens L2 in the optical axis direction is increased, thereby realizing quick lens control. it can.

  On the other hand, when the power is turned off, in Embodiment 2, the coil switching unit 61 turns on the first switch S1 and the second switch S2 and switches off the third switch S3 as shown in FIG. Thus, the drive coil 17 and the braking coil 18 are connected in series, and both the coils 17 and 18 are configured as a coil body 16 having a single closed loop configuration in which both ends are short-circuited. Therefore, when the focus lens L2 is moved in the optical axis direction, a regenerative force based on the combined inductance of the drive coil 17 and the brake coil 18 is generated in the coil body 16 that is moved together with the focus lens L2. A braking force greater than the case can be obtained.

  In the first and second embodiments, an example in which the drive coil 17 and the brake coil 18 constituting the coil body 16 are arranged in the optical axis direction is shown. However, as shown in FIG. Alternatively, the brake coil 18 may be arranged coaxially, and both the coils 17 and 18 may be configured as a coil body 16A arranged in the radial direction. Alternatively, as shown in FIG. 7 (b), the coil is double-wrapped in a concentric state with two conductive wires, and each coil is configured as a coil body 16B in which a drive coil 17 and a braking coil 18 are configured. Good. In any case, since the driving coil 17 and the braking coil 18 are configured as independent coils, lens control can be realized as in the first and second embodiments. Moreover, by doing in this way, the dimension of the optical axis direction of coil body 16A, 16B can be reduced rather than the coil body 16 of Embodiment 1, and the optical axis direction required for coil body 16A, 16B to move is carried out. It is possible to reduce the dimension in the optical axis direction of the motor fixing portion 10 composed of the magnet 11 and the yoke 12 for satisfying the length of the lens, which is effective in shortening the length of the lens barrel LL.

  In the present invention, the coil constituting the coil body is not necessarily composed of the first coil and the second coil as in the first and second embodiments. For example, by attaching a third coil and appropriately controlling the number of coils connected to the lens drive control unit during lens control, the VCM is set to a desired driving force and the moving speed of the focus lens is set to a desired speed. can do. Moreover, the braking force obtained can be arbitrarily set by appropriately controlling the number of coils that are short-circuited when the power is turned off.

  In the coil body of the present invention, the driving coil and the braking coil may be connected in parallel. For example, FIG. 8A (a) is a circuit diagram of the third embodiment showing an example thereof. The drive coil 17 and the braking coil 18 constituting the coil body 16 are connected in parallel, and both ends are commonly connected to the lens drive control unit 4. On the other hand, a first switch S1 is interposed between the driving coil 17 and the braking coil 18 between the lens driving control unit 4. Further, one end of the braking coil 18 is connected to one end of the driving coil 17 via the second switch S2. Needless to say, the third embodiment also includes the camera control unit 5 and the coil switching unit 61 shown in FIG.

  The lens drive control unit 4 controls the coil switching unit 61 based on the input power-on signal, turns on the first switch S1 and turns off the second switch S2, as shown in FIG. 8A (b). As a result, both ends of the drive coil 17 are connected to the lens drive control unit 4, and the brake coil 18 is opened. Therefore, the lens drive control unit 4 controls the current flowing through the drive coil 17 based on the input focusing signal, and the drive coil 17 sets the VCM in the drive state according to the energized current. A focusing operation is performed.

  When the power is turned off, the lens drive control unit 4 controls the coil switching unit 61 to turn off the first switch S1 and turn on the second switch S2, as shown in FIG. 8B (a). As a result, the drive coil 17 and the braking coil 18 are short-circuited, that is, connected in series. Therefore, an electromotive force is generated in each of the drive coil 17 and the braking coil 18 by the movement of the coil body 16 integrated with the lens frame 2 (see FIG. 1) of the focus lens L2, and the self-induction action for this electromotive force. As a result, a regenerative force in the moving direction of the coil body 16 is generated, and this acts as a braking force. As a result, a large braking force obtained by adding the regenerative forces of both the coils 17 and 18 is obtained, and the movement due to the external force of the focus lens L2 is braked. At the end in the movement direction, the focus lens L2 is attached to the lens barrel LL. Prevents or prevents damage from colliding with the lens barrel fixing part

  In the fourth embodiment, as shown in FIG. 8B (b), the lens drive control unit 4 may control the coil switching unit 61 during the focusing operation to turn on both the first switch S1 and the second switch S2. . By doing so, the drive coil 17 and the braking coil 18 are connected in parallel to the lens drive control unit 4. When the lens driving control unit 4 controls the current of the driving coil 17 to drive the VCM, the braking coil 18 functions as a driving coil by controlling the current to the braking coil 18 at the same time. . Thereby, a large driving force obtained by adding the driving forces of the driving coil 17 and the braking coil 18 can be obtained.

  FIGS. 9A and 9B are a front view of the lens driving device according to the fourth embodiment viewed from the optical axis direction and a cross-sectional view taken along line B2-B2. In addition, the same code | symbol is attached | subjected to the part equivalent to Embodiment 1, and these detailed description is abbreviate | omitted. In the third embodiment, magnets 11 and yokes 12 constituting the motor fixing portion 10 of the VCM are respectively disposed at four locations in the circumferential direction surrounding the lens frame 2 of the focus lens L2 in the direction around the optical axis. The coil body 16 constituting the motor movable portion 15 is configured as a polygonal air-core coil wound along the circumferential direction so as to surround the lens frame 2 in the direction around the optical axis.

  The four motor fixing portions 10 have a point-symmetrical configuration with respect to the optical axis, and each magnet 11 has one of S or N magnetic poles oriented in the inner diameter direction, and each yoke 12 is formed by each magnet 11. The magnetic field is configured to be formed in the radial direction. Similarly to the first embodiment, the coil body 16 includes a drive coil 17 and a brake coil 18, and both the coils 17 and 18 are arranged in the optical axis direction and integrated with the lens frame 2. As shown in FIG. 4, the drive coil 17 and the brake coil 18 are connected to the lens drive control unit 4, the coil switching unit 61, the first switch S1 and the second switch S2, or the third switch S3. Is the same as in the first or second embodiment.

  According to the fourth embodiment, when the VCM is driven, driving forces are generated at four locations in the circumferential direction of the drive coil 17, that is, at locations where the four motor fixing portions 10 are disposed. The added large driving force can be obtained. Therefore, it can be applied to a lens driving device that drives a large or heavy lens. Further, since the regenerative force generated in the coil body 16, that is, the drive coil 17 and the braking coil 18 when the power is turned off is also generated at four locations in the circumferential direction, it is possible to obtain a large regenerative force obtained by adding these regenerative forces. Further, since these driving force and regenerative force are evenly generated at four locations around the optical axis, the lens frame 2 is prevented from falling, that is, the focus lens L2 is prevented from being inclined with respect to the plane orthogonal to the optical axis. But it is effective.

  In the above embodiments, the present invention is applied to a lens driving device for driving a focus lens provided in a lens barrel as an optical element. For example, a zoom provided in a lens barrel for zooming is performed. It can also be applied as a lens driving device for a lens. Further, the present invention is not limited to a lens driving device, and can be configured as a driving device for an optical device in which VCM is applied as a driving source for driving various optical elements built in an optical device including a camera. Further, it goes without saying that the present invention can be applied to a drive device capable of suppressing the movement of the moving element in devices other than optical devices.

  In the above embodiment, the VCM according to the present invention is configured as a linear CVM that moves linearly. However, the moving element built in the device moves in a curved line, particularly on a circular orbit centered on a predetermined position. When the arc is moved, the VCM may be configured as a rotary (rotary) type VCM. Even in this case, a coil body in which the braking coil is integrated with the driving coil is configured, and the connection state of these coils is switched by the coil switching unit, thereby obtaining a braking effect for suppressing the movement of the moving element. be able to.

1 Lens drive device (Drive device: Voice coil motor (VCM))
2 Lens frame (optical element)
3 Guide rod 4 Lens drive control unit (drive control unit)
5 Camera control unit 6 Coil switching means 10 Motor fixing unit 11 Magnet 12 Yoke 15 Motor movable unit 16 Coil body 17 Drive coil (first coil)
18 Braking coil (second coil)
19 Flexible printed circuit board 61 Coil switching part LL Lens barrel L2 Focus lens (moving element)
S1 to S3 1st to 3rd switch

Claims (17)

  A drive device comprising a voice coil motor as a drive source for driving a moving element, wherein a coil body constituting a motor movable part of the voice coil motor is composed of a plurality of integrated coils, A driving apparatus comprising: a coil switching unit that switches to a state in which at least one coil is energized from the drive control unit during driving and switches a plurality of coils to a short-circuited state when energization to the voice coil motor is stopped.   The drive device according to claim 1, wherein the coil switching unit switches a plurality of coils to a state of serial connection or parallel connection.   The coil body includes a first coil as a driving coil and a second coil as a braking coil, and the coil switching means enables energization of the first coil when the voice coil motor is driven, 3. The drive device according to claim 1, wherein when the energization of the coil motor is stopped, the first coil and the second coil are connected in series, and both ends thereof are short-circuited to form a closed loop.   The first coil has both ends connected to the drive control unit and one end connected to one end of the second coil, and the coil switching means is between the one end and the other end of the first coil. The driving device according to claim 3, further comprising: a first switch interposed between the first coil and a second switch interposed between one end and the other end of the second coil.   The coil switching means turns off the first switch and the second switch when the voice coil motor is driven, and turns on the first switch and the second switch when the energization of the voice coil motor is stopped. Drive device.   The coil body includes a first coil as a driving coil and a second coil as a braking coil, and the coil switching means connects the first coil and the second coil in series when the voice coil motor is driven. In addition, it is possible to energize the first coil and the second coil from the drive control unit, and short-circuit both ends of the first coil and the second coil connected in series when the energization of the voice coil motor is stopped. The drive device according to claim 1 or 2 which constitutes a closed loop.   The first coil has both ends connected to the drive control unit and one end connected to one end of the second coil, and the coil switching means is between the one end and the other end of the first coil. A first switch interposed between the one end and the other end of the second coil, and between the one end of the first coil and the control unit. The drive device according to claim 6, further comprising a third switch.   The coil switching means turns off the first switch and the second switch or the first switch and turns on the third switch when the voice coil motor is driven, and turns on the third switch when the voice coil motor is stopped. The driving device according to claim 7, wherein the second switch is turned on and the third switch is turned off.   The coil body includes a first coil as a driving coil and a second coil as a braking coil, and the coil switching means energizes only the first coil from the drive control unit when driving the voice coil motor. Or the first coil and the second coil are connected in parallel to enable energization of the first coil and the second coil, and when the energization of the voice coil motor is stopped, the first coil and the second coil The drive device according to claim 1, wherein both ends of the second coil are short-circuited to form a closed loop.   The first coil and the second coil are connected in parallel to the drive control unit, the first switch connected in parallel to the first coil and the second coil, and connected in series to the second coil. The drive device according to claim 9, further comprising a second switch.   The coil switching means turns on the first switch and turns on or off the second switch when the voice coil motor is driven, and turns off the first switch and turns off the second switch when the energization of the voice coil motor is stopped. The drive device according to claim 10 which is turned on.   12. The driving apparatus according to claim 1, wherein the optical device is an imaging apparatus, and is configured as a driving apparatus that moves an optical element built in the imaging apparatus by the voice coil motor. .   The optical device is a lens barrel of an imaging device, and is configured as a lens driving device that moves a lens as the optical element in an optical axis direction by the voice coil motor. Drive device.   The drive device according to claim 13, wherein the voice coil motor is configured as a linear voice coil motor in which a motor movable portion moves linearly.   The drive device according to claim 14, wherein the plurality of coils have a coil axis directed in the same direction and a winding direction directed in the same direction.   The voice coil motor includes a magnet and a yoke as a motor fixing portion supported by a lens barrel fixing portion of the lens barrel and extending in the optical axis direction, and the coil body is integrated with a lens frame of the lens. The drive device according to claim 12, wherein the drive device is configured to be movable in an optical axis direction with respect to the motor fixing portion. A driving device configured in a lens barrel having a lens that is moved in an optical axis direction with respect to a lens barrel fixing portion of the lens barrel, the motor fixing comprising a magnet and a yoke supported by the lens barrel fixing portion And a voice coil motor composed of a motor movable part including a coil body composed of a first coil and a second coil integrally supported by the lens frame of the lens, and driving the voice coil motor by energizing the coil body And a lens switching control unit that switches a connection state between the first coil and the second coil, and the coil switching unit controls at least the first coil when the voice coil motor is driven. A drive unit that is connected to the first part and switches the first coil and the second coil to a short-circuited state when energization of the voice coil motor is stopped.

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