JP2005107008A - Lens barrel and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform desired control even when the radius of curvature of the curved part of a flexible wiring board is changed by the state of a lens barrel. <P>SOLUTION: The lens barrel is equipped with a fixed barrel body 2 holding a fixed lens group 10, a moving body for focusing 21 holding a lens group for focusing 13 arranged coaxially with the optical axis L of the lens group 10 and capable of moving in an optical axis direction, and the ribbon-like flexible wiring board 50 trained between the barrel body 2 and the moving body 21, and the flexible wiring board 50 is curved to be U-shaped and also the longitudinal section direction of the curved part 51 is made parallel with the optical axis direction, and one side part of the flexible wiring board 50 is fixed on a fixed-side plane part 61 and the other side part is fixed on a moving-side plane part 60 so that the curved part 51 may hold the same radius of curvature R at both ends in the moving direction of the moving body for focusing 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lens barrel in which a moving body having a moving lens is moved in the optical axis direction with respect to a fixed cylinder having a fixed lens to change a focal length, a video camera including the lens barrel, and a digital still The present invention relates to an imaging apparatus such as a camera, and more particularly to a lens barrel that uses a flexible wiring board to lighten the movement of a moving body and perform stable control operations, and an imaging apparatus including the lens barrel. .

  As a conventional lens barrel of this type of imaging apparatus, for example, there is one described in Patent Document 1. Patent Document 1 describes a zoom lens barrel that can be manufactured at a lower cost than conventional products, and can be reduced in size and weight.

  The zoom lens barrel described in Patent Document 1 includes a first cylinder that is supported so as not to be axially movable and rotatable, and a first lens body that is rotatably fitted to the outer periphery of the first cylinder. Two cylinders, a moving body inserted into the first cylinder so as to be movable in the axial direction, one end fixed to the moving body, and the first cylinder along the inner and outer peripheral surface portions of the first cylinder A zoom lens barrel having a belt-like flexible wiring board disposed in parallel with an axis of the body, wherein the flexible wiring board is disposed between the outer surface of the movable body and the inner surface of the first cylindrical body. A first portion arranged parallel to the axis of the first cylinder, a second portion arranged parallel to the axis of the first cylinder along the outer surface of the first cylinder, and the first portion And an inverted bent portion that continues from one end of the second portion to the one end of the second portion, and the second portion may be fixed to the outer surface of the first cylindrical body. Locked, slits or holes for passing and to form the inverted bent portion is disposed through the outer peripheral surface of the first cylindrical body, and characterized in that.

  According to the zoom lens barrel having such a configuration, the roller and the roller support provided in the conventional zoom lens barrel are not required, and accordingly, the number of parts, the number of assembly steps and the assembly time are reduced. Effects such as reduction, prevention of enlargement of the diameter of the zoom lens barrel, and reduction of manufacturing costs are expected.

  However, in the case of such a zoom lens barrel, the zoom lens barrel has a structure in which a slit or a hole for forming and passing the inverted bent portion of the flexible wiring board is provided on the outer peripheral surface of the first cylindrical body. The reaction force from the flexible wiring board changes depending on the state, resulting in an obstacle to high-accuracy positioning control. That is, when the zoom lens barrel is in the wide (wide angle) state, the radius of curvature of the inverted bent portion is reduced, and the reaction force acting on the moving body from the inverted bent portion is increased. On the other hand, when the zoom lens barrel changes to the tele (telephoto) state, the radius of curvature of the inverted bent portion increases, so the reaction force acting on the moving body from the inverted bent portion decreases.

As described above, in the conventional zoom lens barrel, the reaction force acting on the moving body from the inverted bent portion changes depending on the lens position when the radius of curvature of the inverted bent portion of the flexible wiring board changes according to the lens position. , Was not constant. Therefore, it is necessary to change the output of the drive source for moving the moving body according to the lens position. As a driving source for driving and controlling the moving body, for example, when a driving method using a linear motor and a magnetic sensor is adopted, the reaction force from the flexible wiring board changes depending on the lens position as described above. Since the response to the constant for control is not constant, there is a problem that desired control cannot be performed.
JP-A-2-250012

  The problem to be solved is that when the radius of curvature of the curved portion of the flexible wiring board changes depending on the state of the lens barrel, the reaction force of the curved portion also changes, so the response is not constant with respect to the constant for control. For this reason, the desired control cannot be performed.

  The invention according to claim 1 of the present application is a movement that holds a fixed cylinder holding a fixed lens, a moving lens arranged coaxially with the optical axis of the fixed lens, and is movable in the optical axis direction. And a ribbon-like flexible wiring board spanned between the fixed cylinder and the movable body. The fixed barrel has a fixed-side plane developed parallel to the optical axis direction in the lens barrel. The movable body is provided with a moving side plane portion that is developed in parallel with the optical axis direction and is opposed to the fixed side plane portion to bend the flexible wiring board in a U shape and to change the longitudinal section direction of the bending portion. In parallel with the optical axis direction, one side of the flexible wiring board is fixed to the fixed side flat part and the other side is moved so that the curved part maintains the same radius of curvature at both ends of the moving body in the moving direction. The main feature is that it is fixed to the side plane.

  In the invention according to claim 2 of the present application, the moving body is movably supported by a pair of guide shafts arranged in parallel on both sides of the moving lens, and is deviated from a line connecting the pair of guide shafts. The curved portion is arranged at a position so that the longitudinal cross-sectional direction is inclined so as to intersect the connecting line or the extended line.

  In the invention according to claim 3 of the present application, the moving body is provided with a bearing hole on one side and a bearing groove on the other side so as to sandwich the moving lens, and the bearing hole has a pair of guides. One guide shaft of the shaft is slidably inserted, and the other guide shaft of the pair of guide shafts is slidably engaged with the engagement groove.

  In the invention according to claim 4 of the present application, the moving body is provided with a bearing hole on one side and a bearing protrusion on the other side so as to sandwich the moving lens, and the bearing hole has a pair of guides. One guide shaft of the shaft is slidably inserted, and the bearing projection is slidably brought into contact with the other guide shaft of the pair of guide shafts.

  In the invention according to claim 5 of the present application, the movable body holding the movable lens arranged coaxially with the optical axis of the fixed lens can be moved in the optical axis direction with respect to the fixed cylinder holding the fixed lens. And an imaging apparatus having a lens barrel in which a ribbon-like flexible wiring board is stretched between the fixed cylinder and the moving body, and the fixed cylinder is fixed on the fixed side developed parallel to the optical axis direction. A plane portion is provided, and the moving body is provided with a moving side plane portion that is developed in parallel with the optical axis direction and is opposed to the fixed side plane portion, and the flexible wiring board is bent in a U shape and the longitudinal section direction of the bending portion In parallel with the optical axis direction, one side of the flexible wiring board is fixed to the fixed side flat part and the other side is fixed so that the curved part maintains the same radius of curvature at both ends of the moving body in the moving direction. It is characterized by being fixed on the moving side flat part. .

  According to the invention described in claim 1 of the present application, one side portion of the flexible wiring board curved in a U-shape is fixed to the fixed-side plane portion, and the other side portion is fixed to the moving-side plane portion. Thus, the curved portion of the flexible wiring board maintains the same radius of curvature at both ends of the moving body in the moving direction. Thereby, the curvature radius of the curved portion of the flexible wiring board can always be kept constant regardless of the state of the lens barrel (for example, the wide (wide angle) state and the tele (telephoto) state). As a result, the reaction force of the bending portion of the flexible wiring board is always kept constant without changing, and the response is constant with respect to the constant for control, enabling stable control operation. Desired control can be easily and reliably performed.

  According to the invention described in claim 2 of the present application, the longitudinal cross-sectional direction is inclined at a position deviated from a line connecting the pair of guide shafts supporting the moving body so as to intersect the connecting line or the extension line. Since the urging force based on the elasticity of the bending portion where the bending portion is disposed acts on one surface side of the contact portion between the moving body and each guide shaft, the moving body can always be held in a constant posture. As a result, since the moving body is always urged in one direction, the influence of the dimensional tolerance between the guide shaft and the bearing hole, the bearing groove, etc. can be reduced, and high-precision positioning is possible, and an accurate motor Control can be performed.

  According to the invention described in claim 3 of the present application, one guide shaft is slidably inserted into the bearing hole provided in the moving body, and the other guide shaft is slid into the bearing groove provided in the moving body. By freely engaging, it is possible to realize a highly accurate positioning of the moving body with a simple structure.

  According to the invention described in claim 4 of the present application, one guide shaft is slidably inserted into the bearing hole provided in the moving body, and the bearing protrusion provided on the moving body is slid on the other guide shaft. By freely abutting, the highly accurate positioning of the moving body can be realized with a simple structure, and the moving body can be reduced in size and weight.

  According to invention of Claim 5 of this application, one side part of the flexible wiring board curved in U shape is fixed to a fixed side plane part, and the other side part is fixed to a movement side plane part. By configuring the imaging device using a lens barrel in which the curved portion of the flexible wiring board maintains the same radius of curvature at both ends of the moving body in the moving direction, the flexible wiring board can be used regardless of the state of the lens barrel. The radius of curvature of the curved portion can always be kept constant. As a result, the reaction force of the bending portion of the flexible wiring board is always kept constant without changing, and the response is constant with respect to the constant for control, enabling stable control operation. Thus, it is possible to provide an imaging apparatus capable of easily and reliably performing desired control.

  The curvature radius of the curved portion of the flexible wiring board does not change depending on the state of the lens barrel, and the constant curvature radius of the curved portion is kept constant and the reaction force is kept substantially constant. A lens barrel capable of reliably and easily performing desired control with a constant response and an imaging device including the lens barrel are realized with a simple structure.

  1 to 8 show an embodiment of the present invention. 1 is a perspective view showing an embodiment of a lens barrel of the present invention, FIG. 2 is an explanatory diagram showing a schematic configuration of the lens barrel, and FIG. 3 is a servo of an optical system of an imaging apparatus using the lens barrel. FIG. 4 is an explanatory view of the lens barrel, FIG. 5 is an explanatory view showing a cross section of the main part of the lens barrel, FIG. 6 is a perspective view showing a moving body of the lens barrel, and FIG. And FIG. 8 is a figure which shows the principal part of a moving body.

  A lens barrel 1 shown in FIG. 1 is configured as a lens device (a lens capable of changing a focal length) called a zoom lens capable of image frame adjustment. The lens barrel 1 includes a fixed cylinder 2 formed of a hollow casing, a movable body that is movably held in the fixed cylinder 2, and the like. The fixed cylinder 2 includes a cylindrical intermediate cylinder 4, a front fixed body 5 attached to the front part of the intermediate cylinder 4, and a rear fixed body 6 attached to the rear part of the intermediate cylinder 4. Thus, the image sensor 7 is disposed on the back surface of the rear fixed body 6.

  The internal structure of the lens barrel 1 is as shown in FIG. That is, the lens system in the lens barrel 1 has the same optical axis composed of the first fixed lens group 10, the image frame setting lens group 11, the second fixed lens group 12, and the focusing lens group 13. It is composed of four sets of lens groups 10 to 13 set on the axis. The first fixed lens group 10 is fixed to the front fixed body 5, and the second fixed lens group 12 arranged at a predetermined interval between the lenses is fixed to the intermediate cylinder 4. . An image frame setting lens group 11 is disposed between the first fixed lens group 10 and the second fixed lens group 12, and the focusing lens is disposed between the second fixed lens group 12 and the image sensor 7. Group 13 is arranged.

  The image frame setting lens group 11 and the focusing lens group 13 can be moved in the direction of the optical axis L in the fixed cylinder 2 by lens moving means. In this embodiment, servo motors 14 and 15 are applied as lens moving means. Each of the servo motors 14 and 15 is composed of a linear motor. The image frame setting servo motor 14 is composed of a magnetic circuit 16 and a coil 17, and the focusing servo motor 15 is composed of a magnetic circuit 16 and a coil 18. . The magnetic circuit 16 is used in common for both the servomotors 14 and 15 and is composed of an elongated rod-like magnet and a yoke, and extends in the direction of the optical axis L.

  The coil 17 of the image frame setting servo motor 14 is fixed to an image frame setting moving body 20 that holds the image frame setting lens group 11. The coil 18 of the focus servo motor 15 is fixed to a focus moving body 21 that holds the focus lens group 13. The image frame setting moving body 20 is provided with two bearing portions 22 and 23, and the focusing moving body 21 is provided with two bearing portions 24 and 25. Of these bearing portions 22, 23 and bearing portions 24, 25, one of the two guide shafts 26, 27 held by the fixed cylinder 2 is provided on one bearing portion 22, 24. The other guide shaft 27 is slidably engaged with the other bearing portions 23 and 25.

  In FIG. 2, each optical system of the four lens groups 10 to 13 is simplified by showing one lens, but each lens group is actually composed of a plurality of lenses. In some cases, the lens is composed of a single lens. Further, the positions of the four lens groups 10 to 13 are not limited to the illustrated embodiment.

  A rod-shaped magnet 28 magnetized in a predetermined pattern is attached to the image frame setting moving body 20. An MR (magnetic resistance) sensor 30 is arranged so as to face the magnet 28 with a predetermined gap, and the MR sensor 30 is fixed to the fixed cylinder 2. The MR sensor 30 is a position detector using a two-phase MR (magnetoresistive) element, and an image frame setting for holding the image frame setting lens group 11 based on a position detection signal output from the MR sensor 30. It is possible to determine the movement position of the moving body 20 for use.

  Similarly, a rod-shaped magnet 29 magnetized in a predetermined pattern is attached to the focus moving body 21. An MR sensor 31 is arranged to face the magnet 29 with a predetermined gap, and the MR sensor 31 is fixed to the fixed cylinder 2. The MR sensor 31 is a position detector that similarly uses two-phase MR elements, and the moving position of the focus moving body 21 that holds the focus lens group 13 based on the position detection signal output from the MR sensor 31. Can be judged.

  These MR sensors 30 and 31 detect the position of the image frame setting lens group 11 or the focus lens group 13 by magnetically detecting the position of the image frame setting moving body 20 or the focus moving body 21. It is. Position information detected by each of the MR sensors 30 and 31 is supplied to a servo circuit 37, which will be described later, and used for controlling the just focus state. In FIG. 2, reference numeral S <b> 1 indicates the movement range of the image frame setting moving body 20, and reference numeral S <b> 2 indicates the movement range of the focusing moving body 21.

  The lens barrel 1 having such a configuration is applied as a lens device such as a video camera or a digital still camera as a specific example of the imaging device. An imaging element 7 is disposed on a surface on which an optical image is formed by the lens barrel 1, and the optical image is converted into an electrical imaging signal by the imaging element 7. For example, a CCD (Charge Coupled Device) can be applied as the imaging device 7. When the imaging device is a video camera provided with a video signal recording unit, the obtained video signal is recorded by the recording unit when the imaging signal read from the imaging device 7 is a video camera.

  FIG. 3 shows an embodiment of a control configuration of an optical system of a video camera provided with the lens barrel 1. An imaging signal read from the imaging element 7 disposed at the rear of the lens barrel 1 is converted into digital data by an A / D (analog / digital) converter 33 and then supplied to the imaging signal processing circuit 34. Is done. In the imaging signal processing circuit 34, processing for making an appropriate video signal is performed, and the processed video signal is supplied to a control processing device (CPU) 36. In the imaging signal processing circuit 34, a detection circuit 35 for detecting a predetermined component (for example, high frequency component of luminance) of the imaging signal is provided, and the detection signal of the detection circuit 35 is used for the imaging operation of this imaging device. Is input to the control processing device 36 for controlling

  The control processing device 36 determines the focus state (in-focus state) based on the level of the supplied detection signal, and performs automatic focus control so that the determined in-focus state becomes the just-focus state. In this automatic focus control, target position information of the focus lens group 13 for focus adjustment is supplied from the control processing device 36 to the servo circuit 37, and the servo lens 37 moves the focus lens group 13 to the target position. Servo control processing is performed. Then, a drive signal (voltage signal) for the servo motor 15 is generated, the drive signal is supplied to the servo motor 15, the focus moving body 21 is moved, and the position of the focus lens group 13 is adjusted to a predetermined position. It is realized by.

  Further, the control processing device 36 is supplied with operation information of a zoom operation key (not shown), and the target position of the image frame setting lens group 11 is determined based on the operation information of the zoom operation key and the position information of the MR sensor 30. decide. The control processing device 36 supplies the target position information to the servo circuit 37, and the servo circuit 37 performs servo control processing for moving the image frame setting lens group 11 to the target position. The servo circuit 37 generates a drive signal (voltage signal) for the servo motor 14, supplies the drive signal to the servo motor 14 to move the image frame setting moving body 20, and moves the image frame setting lens group 11. Adjust the position to a predetermined position.

  Even if the zoom lens has the same focus position (distance), when the image frame (focal distance) changes, the position of the focus lens group 13 is not changed, and the just focus state can be maintained. Can not. The correspondence between the focal length and the position of the focusing lens group 13 in the just-focus state is stored in advance in a storage device (memory) 38 connected to the control processing device 36. As a result, when the focal length changes, the control processing device 36 reads the information stored in the storage device 38, supplies a servo control signal for focus adjustment to the servo circuit 37, and sets the position of the focus lens group 13 to a predetermined value. Can be adjusted to the position.

  Next, referring to FIG. 4 to FIG. 8, a specific configuration of the lens barrel 1 having the schematic configuration as described above, particularly a specific example of the intermediate cylindrical body 4 and the movable body of the fixed cylindrical body 2. The shape and structure of the focus moving body 21 shown, and the flexible wiring board 50 spanned between both members will be described in detail. FIG. 4 is a view of the inside of the lens barrel 1 as seen from the rear with the rear fixed body 6 of the lens barrel 1 shown in FIG. 1 removed, and a focus moving body 21 is shown at the center. . FIG. 5 is an enlarged cross-sectional view of the XX line portion of FIG. Further, FIG. 6 is a perspective view showing the focus moving body 21 and a pair of guide shafts and the like appearing in FIG. 7 and 8 are diagrams showing examples of bearing portions provided on the focus moving body 21. FIG.

  As shown in FIG. 4, the intermediate cylinder 4 has a peripheral wall 42 provided with a notch 41 in a part in the circumferential direction, and the focus moving body 21 is placed in a space surrounded by the peripheral wall 42. It is stored. The focus moving body 21 is supported so as to be movable in the direction of the optical axis L of the lens barrel 1 by a pair of guide shafts 26 and 27 arranged at predetermined intervals in the left-right direction in FIG. The pair of guide shafts 26 and 27 are parallel to each other and extend in the optical axis L direction. One end of each guide shaft 26, 27 is supported by the front fixed body 5, and the other end is supported by the rear fixed body 6, and both ends are supported by the fixed cylinder 2.

  As shown in FIG. 6, the focus moving body 21 includes a ring-shaped main body portion 21 a having a circular through hole 43 in the center portion, and a pair of the main body portion 21 a provided continuously on both sides in the diameter direction. Near the first bearing portion 24, the coil fixing portion 44 that is provided continuously to the main body portion 21 a and to which the coil 18 of the servo motor 15 is attached, and the vicinity of the second bearing portion 25. And a guide projection 45 provided continuously to the main body 21a. The focusing lens group 13 is attached to the main body 21a so as to coincide with the through hole 43 of the focusing moving body 21.

  The first bearing portion 24 of the focus moving body 21 is composed of a pipe-shaped shaft portion having a bearing hole 46 penetrating in the longitudinal direction, and the first guide shaft 26 is slidably inserted into the bearing hole 46. Has been. The second bearing portion 25 is composed of an L-shaped bearing piece projecting laterally having a bearing groove 47 opened to the side, and the second guide shaft 27 is slidable in the bearing groove 47. Is engaged. 7A and 7B are enlarged views of the second bearing portion 25. FIG. An upper contact portion 47a and a lower contact portion 47b are provided in the bearing groove 47 of the second bearing portion 25 with a predetermined interval in the vertical direction (a gap larger by a tolerance than the diameter of the first guide shaft 26). It has been. These upper and lower contact portions 47a and 47b are cylindrical surfaces, and are considered so as to reduce the frictional resistance with the first guide shaft 26.

  The coil fixing part 44 of the focus moving body 21 is formed as a frame-like flat part projecting to the outer edge on the one surface side of the main body part 21a, and the coil 18 is attached to the outer surface thereof. The coil 18 is wound with the spiral surface facing outward, and the magnetic circuit 16 is opposed to the coil 18 with a predetermined gap. The magnetic circuit 16 includes a long and narrow bar-shaped magnet 48 and a yoke 49 that are superposed on each other, and is attached to the fixed cylinder 2 with its longitudinal direction parallel to the optical axis L.

  Both ends of the wire rod of the coil 18 are electrically connected to the connecting portion 50 a at the tip of the ribbon-like flexible wiring board 50 disposed inside the coil fixing portion 44, and are connected to the coil 18 via the flexible wiring board 50. Can be energized. Therefore, the base end side connection portion 50 b opposite to the distal end side connection portion 50 a of the flexible wiring board 50 is led out to the outer surface of the intermediate cylinder 4. The middle part of the flexible wiring board 50 is curved in a U shape, and the focus moving body 21 and the intermediate cylinder 4 have a sufficient length so that the focus moving body 21 can move a predetermined distance. It is stretched between.

  In order to ensure that the curvature radius R of the curved portion 51 of the flexible wiring board 50 is always constant, a moving side plane portion extending in the direction of the optical axis L is provided on the outer surface of the guide projection 45 of the focus moving body 21. 60 is provided. Further, on the inner surface of the intermediate cylinder 4, there is provided a fixed-side flat portion 61 that similarly extends in the optical axis L direction so as to face the moving-side flat portion 60. As shown in FIG. 4, the moving-side plane portion 60 and the fixed-side plane portion 61 are opposed to each other so as to be substantially parallel to each other, and are orthogonal to both the plane portions 60 and 61 and in the optical axis L direction ( The virtual circuit board J developed in the longitudinal section of the curved portion 51 is parallel to the virtual guide axis K developed so as to connect the axial lines of the pair of guide shafts 26 and 27. It is arrange | positioned so that it may cross | intersect with appropriate angle (alpha).

  As shown in FIG. 5, the flexible wiring board 50 includes a moving-side front fixing portion D that is wired from the coil 18 along the plane of the main body portion 21 a to the outer edge P of the main body portion 21 a, and this moving-side front fixing portion. The moving side plane fixing part E that extends from the outer edge P to the moving side fixed end Q on the outer surface of the guide projection 45 and the moving side plane fixing part E and that is continuous with the moving side plane fixing part E and that The variable erection part F from the moving side fixed end Q to the fixed side fixed end T from which the bending part 51 moves by the movement is connected to the variable erection part F and along the inner surface of the intermediate cylinder 4. It is comprised from the fixed side fixing | fixed part G until it reaches the base end side connection part 50b.

  The moving-side front fixing portion D of the flexible wiring board 50 is fixed to the focusing moving body 21 by caulking, an adhesive, or other suitable fixing means. The moving side plane fixing portion E of the flexible wiring board 50 is preferably fixed to the guide projection 45 using an adhesive, but may be fixed using a fixing means such as caulking. The variable erection portion F of the flexible wiring board 50 is in a free state without being fixed over the entire length, and can be freely contacted / separated with the moving-side plane portion 60 or the fixed-side plane portion 61 at both ends in the longitudinal direction. Has been. Moreover, although it is preferable to fix the fixed side fixing | fixed part G of the flexible wiring board 50 to the inner surface of the intermediate cylinder 4 using an adhesive agent, you may make it fix using fixing means, such as caulking.

  Reference numeral 55 shown in FIG. 4 is a guide protrusion provided on the focus moving body 21. The guide protrusion 55 has a role of preventing the curved portion 51 of the flexible wiring board 50 from warping and protruding to the opposite side. In this embodiment, the focus moving body 21 is described in detail, and the image frame setting moving body 20 is not described in detail. However, the configuration and operation thereof are the same as those of the focus moving body 21.

  Next, the lens barrel 1 having the above-described configuration, in particular, the focus moving body 21 (the image frame setting moving body 20) housed in the lens barrel 1 is the same, and will be described here. Will be described. In the lens barrel 1, there are a first fixed lens group 10 and a second fixed lens group 12 fixed to the fixed cylinder 2, and an image frame setting which is movable with respect to the fixed cylinder 2. The lens group 11 and the focusing lens group 13 are accommodated, the image frame setting moving body 20 is moved by driving the first servo motor 14, and the focusing moving body 21 is driven by driving the second servo motor 15. Moving. As a result, in the case of an image pickup apparatus having a mechanism for automatically adjusting the focus, the proper focus position can be automatically set by driving the two servo motors 14 and 15.

  In this embodiment, linear motor driving is applied as a method of driving the focus moving body 21, and by energizing the coil 18 opposed to the magnet 48 and the yoke 49 provided in the fixed cylinder 2, the coil Focus adjustment is performed by moving the focus moving body 21 to which the reference numeral 18 is fixed in the direction of the optical axis L by the electromagnetic force generated in the coil 18.

  With this method, the flexible wiring board 50 is used to energize the coil 18 with external power. However, the coil 18 is fixed to the focus moving body 21 that is a movable portion, while the focus moving body 21 is used. Is supported by a fixed cylinder 2 which is a fixed portion. Therefore, in the above-described conventional lens barrel, since the flexible wiring board is bent by providing grooves or holes, the above-described problems have occurred.

  On the other hand, in the present embodiment, the middle portion of the flexible wiring board 50 is bent into a semicircular shape, and both sides of the bent portion 51 are not fixed over a predetermined range, but are contacted in parallel with the optical axis L direction. It was set as the structure supported so that separation | separation is possible freely. Therefore, the bending portion 51 of the flexible wiring board 50 is bent with the same curvature radius R at any position regardless of the movement of the focus moving body 21. Therefore, the force (restoring force) that the flexible wiring board 50 tries to restore to the original planar state can always be maintained at a constant magnitude.

  In addition, as shown in FIG. 4, the restoring force M generated in the direction of the wiring board virtual plane J by the bending portion 51 of the flexible wiring board 50 is the axial center of the pair of guide shafts 26 and 27 that support the focus moving body 21. The guide axis imaginary plane K connecting the lines is configured to intersect with a certain angle α. Therefore, since one side of the bending portion 51 is fixed to the intermediate cylinder 4, the restoring force M acts on the other side of the bending portion 51. As a result, a force directed diagonally to the left in FIG. 4 acts on the focus moving body 21.

  As a result, the lower portion of the bearing hole 46 is pressed against the lower surface of the first guide shaft 26 in the first bearing portion 24 of the focus moving body 21, and the lower contact portion 47 b of the bearing groove 47 is pressed in the second bearing portion 25. It is pressed against the lower surface of the second guide shaft 27. Since such a pressing force is always applied by the restoring force M of the bending portion 51 of the flexible wiring board 50, the guide shafts 26 and 27 are always brought into contact with only one direction in the pair of bearing portions 24 and 25. Therefore, the influence of the dimensional tolerance between the bearing hole 46 and the first guide shaft 26 and the dimensional tolerance between the bearing groove 47 and the second guide shaft 27 can be reduced, and accurate motor control can be achieved.

  8A and 8B show a second embodiment of the second bearing portion of the focus moving body 21. FIG. As described above, since the restoring force M of the bending portion 51 of the flexible wiring board 50 is configured such that only a force from one direction always acts on the pair of bearing portions of the focusing moving body 21 of the present invention. 7A and 7B, one of the bearing pieces of the second bearing portion 25 can be omitted. This is the bearing protrusion 65 as the second bearing portion shown in FIGS. 8A and 8B.

  The bearing protrusion 65 has a shape obtained by cutting out the upper portion of the second bearing portion 25, and a surface facing the second guide shaft 27 is in contact with the lower surface of the second guide shaft 27. A contact portion 66 is provided. A shaft restricting portion 67 that restricts the inward movement of the second guide shaft 27 is provided on the upper portion of the surface of the bearing protrusion 65 that faces the second guide shaft 27.

  According to the second embodiment, the structure of the bearing portion of the moving body can be simplified, and the moving body can be reduced in size and weight.

  The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, an example in which the imaging apparatus is applied to a video camera has been described. However, the present invention can also be applied to a digital still camera other than the video camera. Further, the configuration of the servo motor is not limited to the two-rear motor, and it is needless to say that drive units having other configurations can be used.

It is a perspective view which shows one Example of the lens-barrel of this invention. It is explanatory drawing which shows schematic structure of the lens-barrel shown in FIG. It is a block diagram which shows the servo control structure of the optical system of the imaging device using the lens barrel shown in FIG. It is explanatory drawing which removed the rear part fixing body of the lens-barrel shown in FIG. 1, and was seen from the back surface. It is explanatory drawing which shows the principal part of the lens-barrel shown in FIG. 1 in cross section. FIG. 2 is a perspective view showing a focusing moving body, a pair of guide shafts, a magnetic circuit, and the like of the lens barrel shown in FIG. 1. FIGS. 4A and 4B show a second bearing portion of the focusing moving body shown in FIG. 4, where FIG. A is a side view and FIG. B is a front view. The 2nd Example of the 2nd bearing part of the moving body for a focus which concerns on the lens-barrel of this invention is shown, The figure A is a side view, The figure B is a front view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens barrel, 2 ... Fixed cylinder, 4 ... Intermediate cylinder, 11 ... Image frame setting lens group, 13 ... Focus lens group, 14, 15 ... Servo motor, 16 ... Magnetic circuit, 17, 18 ... Coil, 20 ... moving body for setting an image frame, 21 ... moving body for focusing, 21a ... main body, 22, 23, 24, 25, 65 ... bearing, 26, 27 ... guide shaft, 45 ... guide projection, 46 ... bearing hole, 47 ... bearing groove, 47b ... lower contact part, 50 ... flexible wiring board, 51 ... curved part, 60 ... moving side flat part, 61 ... fixed side flat part, 66 ... contact part, F ... variable installation part , J: Virtual plane of wiring board (longitudinal section direction), K: Virtual plane of guide axis

Claims (5)

A fixed cylinder holding a fixed lens;
A moving body that holds a moving lens disposed coaxially with the optical axis of the fixed lens and is movable in the optical axis direction;
In a lens barrel comprising a ribbon-like flexible wiring board spanned between the fixed cylinder and the movable body,
The fixed cylindrical body is provided with a fixed side plane portion that is developed in parallel with the optical axis direction, and the movable body is provided with a movement side plane that is developed in parallel with the optical axis direction and is opposed to the fixed side plane portion. Set up a section,
The flexible wiring board is bent in a U shape, and the longitudinal direction of the curved portion is parallel to the optical axis direction so that the curved portion maintains the same radius of curvature at both ends in the moving direction of the movable body. A lens barrel characterized in that one side portion of a flexible wiring board is fixed to the fixed-side plane portion and the other side portion is fixed to the moving-side plane portion.   The moving body is movably supported by a pair of guide shafts arranged in parallel on both sides of the moving lens, and the connecting line is extended from a line connecting the pair of guide shafts or an extension thereof. 2. The lens barrel according to claim 1, wherein the bending portion is disposed so that the longitudinal section direction is inclined so as to intersect a line.   The moving body is provided with a bearing hole on one side so as to sandwich the moving lens and a bearing groove on the other side, and the bearing hole slides one guide shaft of the pair of guide shafts. The lens barrel according to claim 2, wherein the lens barrel is slidably engaged, and the other guide shaft of the pair of guide shafts is slidably engaged with the engagement groove.   The moving body is provided with a bearing hole on one side so as to sandwich the moving lens, and a bearing protrusion is provided on the other side, and one guide shaft of the pair of guide shafts is slid into the bearing hole. The lens barrel according to claim 2, wherein the lens barrel is slidably contacted with the other guide shaft of the pair of guide shafts. A movable body holding a moving lens arranged coaxially with the optical axis of the fixed lens can be moved in the optical axis direction relative to the fixed cylinder holding the fixed lens, and the fixed cylinder and the In an imaging device including a lens barrel that spans a ribbon-like flexible wiring board between a moving body,
The fixed cylindrical body is provided with a fixed side plane portion that is developed in parallel with the optical axis direction, and the movable body is provided with a movement side plane that is developed in parallel with the optical axis direction and is opposed to the fixed side plane portion. Set up a section,
The flexible wiring board is bent in a U shape, and the longitudinal direction of the curved portion is parallel to the optical axis direction so that the curved portion maintains the same radius of curvature at both ends in the moving direction of the movable body. An imaging apparatus characterized in that one side of a flexible wiring board is fixed to the fixed-side plane and the other side is fixed to the moving-side plane.

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