JP2006154511A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus to which a voice coil motor is adopted as a driving source of a focusing lens without causing upsizing and cost increase of the apparatus. <P>SOLUTION: When power of a camera is applied, a lens barrel 100 is turned out toward the object side and a translatory guide ring 24 starts transfer toward the object side in accordance with turn out of the lens barrel 100. A three-group barrel 6 pushed in by the translatory guide ring 24 is transferred toward the object side following the transfer of the translatory guide ring 24 by repulsive force of a coil spring 54. When the three-group lens barrel 6 reaches a reset position, the VCM 114 becomes a state that it can be driven, energization is started to a coil 51 and drive of the three-group lens barrel 6 by the VCM 114 is started. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus having a lens barrel that can be extended from a storage position toward a subject.

  2. Description of the Related Art Conventionally, in an imaging apparatus such as an electronic camera or a video camera, focus adjustment is performed in accordance with subject distance and zoom magnification (hereinafter referred to as zooming) by moving a focus lens in the optical axis direction. Here, the video camera is required to be quiet so that the focusing operation sound is not recorded during moving image recording, and to be fast enough to make the focus lens follow the zooming during moving image recording, In order to achieve both quietness and high speed, a voice coil motor is used as a focus lens drive source. This voice coil motor has a coil held in a focus lens barrel, and a magnet and a yoke arranged in the lens barrel body. By passing a current through the coil in a magnetic field created by the magnet and the yoke, the coil The acting force works. The acting force acting on this coil is used to move the focus lens barrel.

  On the other hand, in an electronic camera, since portability is important, a retractable lens barrel having a structure that can be accommodated in the camera body is often used when not in use. In particular, small cameras are strongly required to make the camera body thickness as thin as possible. To meet this requirement, the total length of the lens barrel during storage is required to be as short as possible. Yes.

  Such a retractable lens barrel will be described with reference to FIG. FIG. 6 is a longitudinal sectional view showing a configuration of a conventional retractable lens barrel.

  The retractable lens barrel, as shown in FIG. 6, performs the focus adjustment with the first group lens barrel 4 and the second group lens barrel 5 that respectively hold the first group lens 1 and the second group lens 2 for zooming. The third group lens barrel 6 holding the third group lens 3 (focus lens), and a fixed cylinder 21 fixed to the CCD holder 11 are provided.

  A cam groove 21 a is formed on the inner peripheral surface of the fixed cylinder 21 along the circumferential direction. The cam groove 21a is slidably engaged with a cam follower pin 22a provided on the movable cam ring 22. The movable cam ring 22 is guided by the cam groove 21a and can advance and retreat in the optical axis direction while rotating. .

  A drive ring 23 is provided on the outer periphery of the fixed cylinder 21, and the drive ring 23 is rotated around the optical axis by a zoom motor (not shown). A guide groove 23 a extending in the optical axis direction is formed on the inner peripheral surface of the drive ring 23. The guide groove 23 a is slidably engaged with a driven pin 22 b fixed to the moving cam ring 22, and transmits the rotation of the driving ring 23 to the moving cam ring 22. Due to the rotation of the drive ring 23, the movable cam ring 22 is rotated.

  The movable cam ring 22 holds the first group lens barrel 4 and the second group lens barrel 5, and the first group lens barrel 4 and the second group lens barrel 5 are optically movable as the moving cam ring 22 advances and retreats in the optical axis direction. Move forward and backward in the axial direction. Cam grooves 22c and 22d for guiding the first group barrel 4 and the second group barrel 5 are provided independently on the inner peripheral surface of the movable cam ring 22, respectively. The first group barrel 4 and the second group barrel 5 are provided with cam follower pins 4a and 5b slidably engaged with cam grooves 22c and 22d of the movable cam ring 22, respectively. 5b is fixed at three locations around the optical axis.

  Further, a rectilinear guide ring 24 that advances and retracts in the optical axis direction integrally with the moving cam ring 22 and is rotatable around the optical axis with respect to the moving cam ring 22 is provided. The straight guide ring 24 is provided with guide grooves 24a and 24b extending in the optical axis direction, and the guide grooves 24a and 24b engage with the first group barrel 4 and the second group barrel 5, respectively. . Accordingly, the first group barrel 4 and the second group barrel 5 are guided to the corresponding guide grooves 24a and 24b. In FIG. 6, the two guide grooves 24a and 24b are drawn in common for convenience. The straight guide ring 24 is further provided with a protrusion 24c. The protrusion 24c is slidably engaged with a guide groove 21b formed on the inner peripheral surface of the fixed cylinder 21 so as to extend in the optical axis direction. . Thereby, the rotation of the rectilinear guide ring 24 around the optical axis is restricted.

  Here, when the drive ring 23 is rotationally driven, the movable cam ring 22 moves along the optical axis direction while rotating along the cam groove 21 a of the fixed cylinder 21, and the linear guide ring moves along with the movement of the movable cam ring 22. 24 also moves. At this time, the rectilinear guide ring 24 is only translated in the optical axis direction because the rotation around the optical axis is restricted. The rotation of the first group barrel 4 and the second group barrel 5 is restricted by the rectilinear guide ring 24 and translates in the optical axis direction with respect to the movable cam ring 22.

  By rotating the drive ring 23 as described above, the first group lens barrel 4 and the second group lens barrel 5 are maintained while maintaining an appropriate positional relationship between the first group lens barrel 4 and the second group lens barrel 5. Can be moved in the optical axis direction.

  The third group lens barrel 6 moves in the optical axis direction while being supported by the main guide shaft 40. The main guide shaft 40 is a shaft member having one end held by the CCD holder 11 and the other end held by a cap 44. A guide (not shown) as a detent is provided integrally with the cap 44 on the opposite side of the main guide shaft 40 with respect to the optical axis. The guide is a part of the third group barrel 6. It engages slidably in a U-shaped groove (not shown). The cap 44 is fixed to the CCD holder 11. The third group barrel 6 is provided with two flange portions 6b protruding in a direction perpendicular to the optical axis direction, and a drive feed nut 42 is inserted in the gap between the flange portions 6b. The feed nut 42 is fixed to the third group barrel 6.

  The feed nut 42 is screwed with a rotary shaft 43a that forms a feed screw. The rotating shaft 43 a extends in parallel with the optical axis, one end thereof is directly connected to the output shaft of the motor 43, and the other end is supported by the cap 44. Here, since the feed nut 42 is fixed to the third group barrel 6, the rotational motion of the rotary shaft 43a is converted into the translational motion of the feed nut 42, and the feed nut 42 translates along the rotary shaft 43a. As the feed nut 42 moves, the third group lens barrel 6 moves in the optical axis direction while being supported by the main guide shaft 40, whereby focusing is performed. Further, a tension spring (not shown) is disposed between the third group barrel 6 and the CCD holder 11, and the third group barrel 6 is urged toward the CCD holder 11 by the spring.

  The CCD holder 11 is equipped with a low-pass filter 7 and a CCD 8 that are arranged coaxially with the optical axis. Light from the subject is imaged on the imaging surface of the CCD 8 via the first group lens 1, the second group lens 2, the third group lens 3, and the low-pass filter 7, and the optical image is converted into an electrical signal and output. To do. An output signal of the CCD 8 is transmitted to a processing circuit via a flexible printed circuit board (hereinafter referred to as FPC) 9. The CCD 8 is held on the CCD holding plate 10.

  In the lens barrel configured as described above, when retracted (stored), the first group barrel 4 and the second group barrel 5 move toward the CCD holder 11, and the intervals between the group lenses 4 and 5 are increased. Narrowed to a minimum. Further, since the total length of the lens barrel at the time of retracting determines the thickness of the camera, the third lens barrel 6 is placed on the entire surface of the CCD 8 in order to further shorten the total length of the lens barrel at the time of retracting. It is configured to move to a position approaching the low-pass filter 7. In this way, the overall length of the lens barrel is shortened.

  Next, the movement range of the third group barrel 6 (focus lens) will be described with reference to FIG. FIG. 7 is a graph showing the relationship between the moving position of the third group barrel 6 (focus lens) in FIG. 6 and the zoom magnification. Here, in FIG. 7, the horizontal axis represents the zoom magnification, and the left end represents the wide end and the right end represents the tele end. The vertical axis represents the position of the third group barrel 6 in the optical axis direction, and the two cam curves (infinite cam and closest cam) represent the position of the third group barrel 6 with respect to subjects at infinite distance and close distance, respectively. . The broken line represents the position when the third group barrel 6 is retracted (stored).

The position of the third group barrel 6 at the time of photographing is far from the position at the time of retracting. As described above, in order to shorten the total length of the lens barrel at the time of retracting, the third group barrel 6 is connected to the CCD. This is because it is moved toward the holder 11. Conversely, this means that the third group barrel 6 must be moved greatly when the retracted state (stored state) changes to the photographing state.
JP-A-8-278440

  In recent years, electronic cameras capable of shooting moving images have appeared, and such electronic cameras are required to reduce driving sound so that focus driving sound during moving image shooting is not recorded. In order to meet this requirement, it is considered effective to use a voice coil motor used in a video camera for driving a focus lens in an electronic camera.

  However, in the retractable lens barrel, as described above, the focus lens position (the position of the third group lens barrel 6) at the time of retracting is greatly different from that at the time of photographing. It is necessary to use a voice coil motor having a long yoke. In addition, a stronger magnet is required to generate a magnetic field in a wide range. As a result, when the voice coil motor is used, the lens barrel is prevented from being miniaturized and the cost is increased.

  In addition, when the power is turned on, the system starts up, starts the zoom motor to extend the lens barrel, and moves the focus barrel to the shooting position. Overly, very much power is required. In order to cope with this, it is necessary to design the power supply circuit and the battery with a margin, which increases the cost and enlarges the apparatus.

  An object of the present invention is to provide an imaging apparatus that can employ a voice coil motor as a drive source of a focus adjustment lens without increasing the size and cost of the apparatus.

  In order to achieve the above object, the present invention incorporates an optical lens group including at least a focus adjustment lens, and has an imaging apparatus having a lens barrel that can be extended from the storage position toward the subject and retracted to the storage position. A first coil for moving the focusing lens forward and backward in the direction of the optical axis over the driveable range of the voice coil motor by using the driving force of the voice coil motor. The focus adjustment lens drive means and the voice coil motor of the first focus adjustment lens drive means have a different type of drive source, and the focus adjustment lens is moved in the optical axis direction using the drive force of the drive source. Second focus adjusting lens driving means for moving the focus adjusting lens back and forth, and the second focus adjusting lens driving means moves the focus adjusting lens to the storage position and the voice coil mode. To provide an imaging apparatus characterized by advancing and retracting between a reference position corresponding to the start of the driving range of the.

  According to the present invention, it is possible to employ a voice coil motor as a drive source for the focus adjustment lens without increasing the size and cost of the apparatus.

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

(First embodiment)
FIG. 1 is a block diagram showing the configuration of an imaging apparatus according to the first embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the moving position of the third group lens (third group lens barrel) in FIG. 3 is a longitudinal sectional view showing the configuration of the lens barrel 100 of FIG. 1, and FIG. 4 is a longitudinal sectional view showing a state in which the lens barrel of FIG. 3 is retracted. In this embodiment, an electronic camera having a two-stage collapsible lens barrel that performs zoom zooming will be described as an example of an imaging apparatus.

  The imaging apparatus includes a lens barrel 100 as shown in FIG. The lens barrel 100 includes a first group lens barrel portion 101 and a second group lens barrel portion 102 that are movable in the optical axis direction for zooming, and a focal point movement caused by zooming magnification by moving in the optical axis direction. And a third group lens barrel 103 for adjusting the focus, an optical aperture 104 having an aperture and adjusting the amount of light by changing the aperture diameter, a shutter 105, and a third group lens barrel 103. A position sensor 106 for detecting the position and a reset switch (RST) 127 for detecting the reset position of the third group lens barrel 103 are provided. Here, the reset position of the third group lens barrel 103 is a reference position corresponding to the start point of the driveable range of the VCM 114 described later.

  As a drive source for moving the first group lens barrel portion 101 and the second group lens barrel portion 102 in the optical axis direction, a zoom motor 110 formed of a small DC motor is used. The zoom motor 110 is driven by a drive signal output from a zoom driver (DR) 111. The zoom driver 111 generates and outputs a drive signal for the zoom motor 110 based on an instruction from the CPU 120 described later.

  As a drive source for the optical aperture 104 and the shutter 105, an aperture shutter drive unit 112 is used, and the aperture shutter drive unit 112 is driven by a drive signal output from an aperture shutter driver (DR) 113. The aperture shutter driver (DR) 113 generates and outputs a drive signal for the aperture shutter drive unit 112 based on an instruction from the CPU 120.

  A voice coil motor (hereinafter referred to as VCM) 114 is used as a driving source for moving the third group lens barrel 103 in the optical axis direction. The VCM 114 includes a coil, a magnet, and a yoke. The VCM 114 is driven by a drive signal output from the VCM driver (DR) 115. The VCM driver 115 generates and outputs a drive signal for the VCM driver (DR) 115 based on an instruction signal from an AF control circuit 126 described later.

  An optical image formed through the first group lens barrel unit 101, the second group lens barrel unit 102, and the third group lens barrel unit 103 of the lens barrel 100 is converted into an electrical signal by a solid-state imaging device, for example, a CCD 107. The electric signal is converted into a digital signal by the A / D converter 121 and then input to the signal processing circuit 122. The signal processing circuit 122 is a circuit that performs predetermined signal processing on the input digital signal. The output signal of the signal processing circuit 122 is given to the AF evaluation circuit 124, the image display device (LCD) 108, and the recording device 123.

  The AF evaluation circuit 124 extracts a high-frequency component from a predetermined range of the image captured based on the output signal of the signal processing circuit 122, and AF for determining the degree of focusing based on the extracted high-frequency component. Generate an evaluation value. The AF evaluation value is input to the AF control circuit 126. Further, the AF control circuit 126 captures the output pulse of the position sensor 106 and the output of the reset switch (RST) 127. The AF control circuit 126 calculates the position of the third group lens barrel 103 by counting the output pulses of the position sensor 106 based on the output of the reset switch 127 (the reset position of the third group lens barrel 103). In addition, the moving speed is calculated from the output pulse of the position sensor 106, and a signal necessary for properly driving the third group lens barrel 103 is fed back to the VCM driver 115. The AF control circuit 126 generates an instruction signal for the VCM driver 115 based on the input AF evaluation value and focus cam data corresponding to the zoom magnification read from the cam storage memory 116.

  In the cam storage memory 116, as shown in FIG. 2, information such as sequence data, matrix data, or an interpolation formula for representing the in-focus position of the third group lens barrel 103 determined by the zoom magnification and the subject distance is the focus data. Is remembered as In addition to the focus position of the third lens group 103, the focus motor drive pulse number corresponding to the focus position may be stored as the focus data.

  The CPU 120 controls the entire apparatus, and instructs the driving direction and driving speed of the third group lens barrel 103 based on the zoom direction and zoom speed specified by the operator via the zoom switch 125. An instruction signal is generated for output to the AF control circuit 126. Further, as described above, the CPU 120 generates and outputs instruction signals for the zoom driver 111 and the aperture shutter driver 113.

  Next, the configuration of the lens barrel 100 will be described with reference to FIG. Here, in the lens barrel 100, the same members as those in the lens barrel shown in FIG. 6 are denoted by the same reference numerals and description thereof is omitted.

  In the lens barrel 100, the first group lens 1 and the first group barrel 4 are the first group lens barrel portion 101 (shown in FIG. 1), and the second group lens 2 and the second group barrel 5 are the second group lens barrel portion. 102 (shown in FIG. 1), the third group lens (focus lens) 3 and the third group barrel 6 constitute the third group lens barrel 103 (shown in FIG. 1). Further, in the lens barrel 100, the coil 51 is held by the third group barrel 6. The coil 51 is connected to a VCM driver 114 (shown in FIG. 1) by an FPC (flexible printed circuit board; not shown), and the coil 51 can be energized in the forward and reverse directions. A yoke 52 made of a magnetic material, a yoke 52 and a magnet 53 are attached to the cap 44, and the magnet 53 is disposed adjacent to the yoke 52. A magnet 53 generates a magnetic field in the gap between the yokes 52. The yoke 52 is positioned with respect to the coil 51 so that a part of the yoke 52 can enter the internal space of the coil 51 as the third group barrel 6 moves. The magnet 53, the yoke 52, and the coil 51 constitute a VCM 114 (shown in FIG. 1) that drives the third group barrel 6 in cooperation with each other. The operation of the VCM 114 is well known and will not be described in detail. However, when an electric current is passed through the coil 51 in a magnetic field, an action force in a specific direction is generated in the coil 51, and 3 The group barrel 6 is driven in the optical axis direction.

  Here, in the present embodiment, an example in which the coil 51 is held by the third group barrel 6 and the yoke 52 and the magnet 53 are fixed to the cap 44 is shown, but instead, the third group barrel is shown. 6, the magnet 53 and the yoke 52 may be held, and the coil 51 may be fixed to the cap 44.

  The third group lens barrel 6 is provided with a protrusion (not shown). When the protrusion crosses the optical path of a photosensor (not shown) fixed to the CCD holder 11, the photosensor is Output a signal. This photosensor is located at a position corresponding to the reset position of the third group barrel 6 (third group lens barrel section 103), and its output signal indicates the reset position of the third group barrel 6. The protrusion and the photosensor constitute a reset switch 127 shown in FIG.

  The relative position of the third group lens barrel 6 with respect to the reset position is detected by a linear sensor such as an MR sensor constituting the position sensor 106 shown in FIG. Used for position control and speed control. If a linear sensor or the like that can detect the absolute position is used, a sensor for detecting reset is unnecessary.

  A coil spring 54 is disposed between the end of the third group barrel 6 and the CCD holder 11. The coil spring 54 is retracted (moved toward the CCD holder 11). ) To generate a repulsive force. Further, the third group barrel 6 is formed with an arm portion 6a that protrudes in a direction orthogonal to the optical axis direction. The arm portion 6a is connected to the end portion of the rectilinear guide ring 24 when the rectilinear guide ring 24 is retracted. Abutted.

  Next, a focus operation and a zoom operation in the present embodiment will be described with reference to FIG.

  When the output of the zoom switch 125 is input to the CPU 120, the CPU 120 determines the zoom direction and zoom magnification based on the output of the zoom switch 125, and gives instructions indicating the determined contents to the zoom driver 111 and the AF control circuit 126. give. The zoom driver 111 generates a drive signal corresponding to the instruction from the CPU 120 and outputs it to the zoom motor 110. The zoom motor 110 is rotationally driven by the drive signal. As a result, the first group lens barrel portion 101 and the second group lens barrel portion 102 are moved to positions where a desired zoom magnification can be obtained.

  The AF control circuit 126 calls cam data for a subject at an infinite distance at the current zoom magnification from the cam data (shown in FIG. 2) stored in the cam storage memory 116, and drives the VCM 114 to drive the current zoom. The third group lens 103 is extended to a position corresponding to the infinite distance subject at the magnification. When the third group lens barrel 103 is moved to a position corresponding to an infinite distance subject at the current zoom magnification, the image pickup signal output from the CCD 107 is taken into the signal processing circuit 122 via the A / D converter 121. Then, image processing is performed on the image pickup signal by the signal processing circuit 122. Then, the AF evaluation circuit 124 extracts a high frequency component from a signal portion corresponding to a region (focus area) in which in-focus determination is performed in the image signal after the image processing, and based on the extracted high frequency component, the in-focus state is extracted. An AF evaluation value for determining the degree is created. This utilizes the fact that the contrast of the photographed image changes depending on the degree of focusing and appears as a change in high-frequency components.

  The AF evaluation value is input to the AF control circuit 126, and the AF control circuit 126 moves the third group lens barrel 103 (third group lens barrel 6) toward the subject side based on the input evaluation value. The operation of obtaining the AF evaluation value for this again is repeated. The AF evaluation value becomes maximum at the position of the third group lens barrel portion 103 corresponding to the subject distance, and before and after that, the AF evaluation value decreases to form a mountain shape. After the third group lens barrel portion 103 (third group barrel 6) is moved and stopped, exposure correction and actual photographing are performed. The focus adjustment operation as described above is generally known as a so-called hill-climbing AF method.

  Next, operations when the lens barrel 100 is retracted and extended will be described with reference to FIGS.

  When the lens barrel 100 is retracted, the first lens barrel 4, the second lens barrel 5, and the third lens barrel 6 are moved toward the CCD holder 11 as shown in FIG. As narrow as possible. As a result, the overall length of the lens barrel is shortened. At this time, the arm portion 6a of the third group barrel 6 is brought into contact with the rectilinear guide ring 24, so that the third group barrel 6 is pushed toward the CCD holder 11 while compressing the coil spring 54. is there. When the power of the camera is turned on from this state, the lens barrel 100 is extended toward the subject side, and accordingly, the linear guide ring 24 starts to move toward the subject side. The third group lens barrel 6 that has been pushed in by the rectilinear guide ring 24 is moved toward the subject by following the movement of the rectilinear guide ring 24 by the repulsive force of the coil spring 54, and is in a state as shown in FIG. . When the coil 51 and the yoke 52 are in the positional relationship as shown in FIG. 3, that is, when the third group barrel 6 reaches the reset position, the VCM 114 becomes drivable and the coil 51 is energized, and the VCM 114 The driving of the third group barrel 6 is started. Here, detection of whether or not the third group lens barrel 6 has reached the reset position (whether or not the VCM 114 is in a driveable state) is performed based on the output of the reset switch 127 as described above.

  When the camera is activated (when the power is turned on), the first group lens barrel 4 and the second group lens barrel 5 (the first group lens barrel section 101 and the second group lens barrel section 102) are moved at the same time as described above. The system is started up, and the third group lens barrel 6 (third group lens barrel section 103) is moved to the reset position in order to shorten the time until the start of photographing. At this time, in the present embodiment, the third group lens barrel 6 is moved to the reset position corresponding to the start point of the VCM drivable range due to the repulsive force of the coil spring 54, thereby reducing the power consumption when starting the camera. Can be made. Therefore, as in the prior art, the drive current for each of the movement of the first group barrel 4 and the second group barrel 5, the start-up of the system, and the movement of the third group barrel 6 overlaps, and a large amount of power is consumed. Can be avoided. Also, when a battery is used as the driving power, if the battery is consumed to some extent, it is conventionally expected that the system will be shut down due to insufficient power when the camera is started. In the embodiment, it is possible to avoid the occurrence of power shortage when starting up the camera as much as possible, and it is not necessary to mount a large capacity battery. As a result, it is possible to prevent an increase in the size of the camera body due to mounting of a large-capacity power source. Note that the third group lens barrel 6 may be configured to be pushed in by another lens barrel member such as the second group lens barrel when retracted.

  Next, the driving range of the third group barrel 6 (third group lens 103) by the VCM 114 will be described with reference to FIG. Here, in FIG. 2, the horizontal axis represents the zoom magnification, and the left end represents the wide end and the right end represents the tele end. The vertical axis represents the position of the third group barrel 6 in the optical axis direction, and the two cam curves (infinite cam and closest cam) represent the position of the third group barrel 6 with respect to subjects at infinite distance and close distance, respectively. . The broken line represents the position when the third group barrel 6 is retracted (stored).

  As shown in FIG. 2, the position of the third group lens barrel 6 at the time of shooting is far from the position at the time of retracting, as described above, in order to shorten the total length of the lens barrel at the time of retracting, This is because the third group barrel 6 is moved toward the CCD holder 11. Conversely, this means that the third group barrel 6 needs to be moved greatly when changing from the retracted state to the photographing state.

  In the present embodiment, the range in which the third group barrel 6 is moved by the repulsive force of the coil spring 54 is shown as a non-VCM drive range. Further, a range in which the third group barrel 6 is moved by the VCM is shown as a VCM drive range, and this VCM drive range is a range in which the third group barrel 6 is driven for the focus operation.

  As described above, in the range other than the VCM driving range for driving the third group barrel 6 for the focusing operation, that is, the non-VCM driving range, the third group barrel 6 is moved by utilizing the repulsive force of the coil spring 54. Therefore, it is possible to reduce the size of the elements constituting the VCM 114, that is, the yoke 52 and the magnet 53, and to reduce the cost and size of the lens barrel 100. Further, since no power is required to drive the third group barrel 6 when the camera is activated (when the power is turned on), the power consumption can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a longitudinal cross-sectional view showing a state in which the lens barrel of the imaging apparatus according to the second embodiment of the present invention is simultaneously depressed.

  In the present embodiment, a magnet is used in place of the coil spring 54 as drive means for moving the third group barrel 6 to the VCM driveable position (reset position). Since the other configuration of the lens barrel 100 is the same as the configuration of the first embodiment (the configuration shown in FIGS. 3 and 4), only different parts will be described here.

  Specifically, as shown in FIG. 5, a magnet 6 c is fixed to the arm portion 6 a of the third group barrel 6, and a magnet 24 e is fixed to the rectilinear guide ring 24. The magnet 24e and the magnet 6c are arranged to face each other so that an attractive force acts on each other. When the lens barrel is extended, the third group barrel 6 is moved toward the subject while following the rectilinear guide ring 24 by the force with which the magnet 24e and the magnet 6c are attracted to each other. When the third group barrel 6 is moved to the VCM drivable position, the coil 51 is energized, and the drive for the third group barrel 6 is switched to VCM drive. Here, as a matter of course, the driving force applied to the third group barrel 6 by the VCM 114 is larger than the force with which the magnet 24e and the magnet 6c attract each other.

  On the other hand, at the time of retracting, the magnet 24e of the rectilinear guide ring 24 is fixed to the magnet 6c of the third group barrel 6 by a magnetic force, and then the rectilinear guide ring faces the third group barrel 6 toward the CCD holder 11 to the retracted position (storage). To the position).

  In such a configuration, when an impact sound is generated at the moment when the magnet 24e and the magnet 6c are fixed, the holding force of the third group barrel 6 is increased, or the third group barrel 6 is moved to the straight guide ring 24. What is necessary is just to employ | adopt the structure which moves toward the CCD holder 11 at substantially constant speed.

  In each of the above embodiments, an electronic camera having a two-stage collapsible lens barrel that performs zoom zooming has been described as the imaging apparatus of the present invention. It may have a lens barrel, or a single-stage or a multi-stage retractable lens barrel having three or more stages.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. 3 is a graph showing the relationship between the moving position of the third group lens (third group lens barrel) in FIG. 1 and the zoom magnification. It is a longitudinal cross-sectional view which shows the structure of the lens-barrel 100 of FIG. It is a longitudinal cross-sectional view which shows the state which the lens-barrel of FIG. 3 retracted. It is a longitudinal cross-sectional view which shows the state in which the lens barrel of the imaging device which concerns on the 2nd Embodiment of this invention sinks simultaneously. It is a longitudinal cross-sectional view which shows the structure of the conventional collapsible lens barrel. It is a graph showing the relationship between the movement position of the 3 group lens barrel 6 (focus lens) of FIG. 6, and zoom magnification.

Explanation of symbols

3 Group 3 lens (focus lens)
6 Group 3 barrel 6a Arm 6c, 24e Magnet 24 Straight guide 51 Coil 52 Yoke 53 Magnet 54 Coil spring 100 Lens barrel 106 Position sensor 114 VCM (voice coil motor)
115 VCM driver 120 CPU
127 Reset switch

Claims (7)

An imaging apparatus having a lens barrel that includes an optical lens group including at least a focus adjustment lens, can be extended from a storage position toward a subject, and can be retracted to the storage position,
A first focus adjustment lens drive that has a voice coil motor, and uses the driving force of the voice coil motor to advance and retract the focus adjustment lens in the direction of the optical axis over the driveable range of the voice coil motor Means,
The second focus adjustment lens drive means has a drive source of a different type from the voice coil motor, and uses the drive force of the drive source to move the focus adjustment lens in the optical axis direction. Focusing lens driving means,
The imaging apparatus according to claim 2, wherein the second focus adjustment lens driving unit moves the focus adjustment lens back and forth between the storage position and a reference position corresponding to a start point of a driveable range of the voice coil motor.   2. The second focus adjustment lens driving unit moves the focus adjustment lens from the storage position to the reference position in conjunction with the extension of the lens barrel from the storage position. Imaging device.   The drive source of the second focus adjustment lens drive means includes biasing means for biasing the focus adjustment lens toward the subject side in the optical axis direction, and the focus adjustment is performed using the biasing force of the biasing means. The imaging apparatus according to claim 2, wherein the lens is moved from the storage position to the reference position.   The image pickup apparatus according to claim 3, wherein the biasing unit releases a biasing force with respect to the focus adjustment lens when the focus adjustment lens reaches the reference position.   The driving source of the second focus adjustment lens driving means includes a magnetizing element that can move in the optical axis direction in conjunction with the extension from the storage position of the lens barrel, and uses the attracting force of the magnetizing element. The imaging apparatus according to claim 2, wherein the focus adjustment lens is moved from the storage position to the reference position. The lens barrel includes a moving member that moves toward the storage position in the optical axis direction in conjunction with the retraction of the lens barrel to the storage position;
The second focus adjustment lens driving unit includes an engagement member that engages with the movement of the moving member, and the focus adjustment lens is moved from the reference position by the engagement of the movement member and the engagement member. The imaging apparatus according to claim 1, wherein the imaging apparatus is moved to the storage position. Detecting means for detecting the position of the focusing lens;
The second focus adjustment lens driving means energizes the voice coil motor when detecting that the focus adjustment lens has reached the reference position based on a detection result of the detection means. The imaging apparatus according to claim 1.

Images