JP2012032703A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism capable of precisely fixing a detection element without using any dedicated part for pressing the detection element in an optical axis direction thereby reducing the cost for a lens barrel.SOLUTION: The lens barrel comprises: a diaphragm mechanism 6l that adjusts the diaphragm diameter; a shutter mechanism that opens/closes the imaging optical path; and an image stabilizing mechanism including a detection element 7i that detects an image stabilizing lens and the position of the lens. A holding member 6f for holding the diaphragm mechanism 6l is disposed at the image stabilizing mechanism side, and the holding member 6f is provided with an elastic portion 6c for giving force to the detection element 7i in an optical axis direction.

Description

  The present invention relates to a lens barrel mounted on an imaging apparatus such as a digital camera, and more particularly to a lens barrel including a camera shake correction mechanism.

  Some lens barrels include a camera shake correction mechanism that corrects camera shake during shooting, in addition to an aperture mechanism and a shutter mechanism. The camera shake correction mechanism is so-called feedback control that detects a user's camera shake with a detection element and controls an actuator that drives the photographic lens based on the detection result. Therefore, it is necessary to fix the detection element with high accuracy. Conventionally, in order to fix the detection element with high accuracy, for example, a technique of pressing the detection element in the optical axis direction with a sheet metal has been proposed (Patent Document 1).

JP 2009-175257 A

  However, in Patent Document 1, a dedicated sheet metal for pressing the detection element in the optical axis direction is required, which increases the number of parts and hinders cost reduction of the lens barrel.

  Accordingly, the present invention provides a mechanism that can reduce the cost of the lens barrel by allowing the detection element to be accurately fixed without using a dedicated component for pressing the detection element in the optical axis direction. The purpose is to provide.

  In order to achieve the above object, a lens barrel of the present invention includes an aperture mechanism that adjusts the aperture diameter, a shutter mechanism that opens and closes a photographing optical path, a camera shake correction lens, and a detection element that detects the position of the lens. The camera shake correction mechanism, the holding member holding the aperture mechanism and the holding member holding the shutter mechanism are arranged on the camera shake correction mechanism side, the camera shake correction mechanism side The holding member is provided with an elastic portion for urging the detection element in the optical axis direction.

  According to the present invention, since the detection element can be fixed with high accuracy without using a dedicated component for pressing the detection element in the optical axis direction, the cost of the lens barrel can be reduced.

It is a perspective view for demonstrating the lens-barrel which is an example of embodiment of this invention. It is sectional drawing which follows the optical axis direction of the lens-barrel shown in FIG. FIG. 2 is an exploded perspective view of the lens barrel shown in FIG. 1. It is a disassembled perspective view of an aperture shutter unit and a third group lens unit. It is a disassembled perspective view of a 3 group lens unit. It is a cross-sectional schematic diagram at the time of an assembly of a flexible printed circuit board, a drive coil, and a 3 group lens holder. It is an expansion perspective view of a 4 group lens unit. It is a block diagram for demonstrating the outline of the electrical connection example of a camera main body and a lens-barrel. It is a schematic diagram which shows the example which provided the elastic part in the aperture shutter unit. (A) is the schematic diagram which looked at the shutter mechanism at the time of accommodating a shutter blade | wing in the back space of an aperture shutter unit from the optical axis direction, (b) is a side view of (a). (A) is the schematic diagram which looked at the aperture mechanism at the time of accommodating an aperture blade in the back space of an aperture shutter unit from the optical axis direction, and (b) is a side view of (a).

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  1 is a perspective view for explaining a lens barrel as an example of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the optical axis direction of the lens barrel shown in FIG. 1, and FIG. 3 is a lens shown in FIG. It is a disassembled perspective view of a lens-barrel.

  1 to 3, the first-group rectilinear cylinder 2 holds the first-group lens 1, and the first-group cam groove of the cam cylinder 9 is formed on the outer peripheral portion of the image-side end of the first-group rectilinear cylinder 2. A plurality of cam pins 2a engaging with 9a are provided in the circumferential direction. In addition, an engagement portion (not shown) that is engaged with the rotation restricting portion 8 a of the inner straight advance cylinder 8 and is restricted in rotation is provided on the inner peripheral portion of the first group straight advance cylinder 2.

  The second group lens holder 4 holds the second group lens 3, and a cam pin 4 a that engages with the second group cam groove 9 b of the cam cylinder 9 on the outer peripheral portion of the end of the second group lens holder 4 on the image plane side. Are provided at a plurality of locations in the circumferential direction. An engagement portion (not shown) that is engaged with the rectilinear groove 8 b of the inner rectilinear cylinder 8 and is restricted in rotation is provided on the inner peripheral portion of the second group lens holder 4.

  The third group unit 5 includes an aperture shutter unit 6 and a third group lens unit 7. Here, the diaphragm shutter unit 6 and the third group lens unit 7 will be described with reference to FIGS. FIG. 4 is an exploded perspective view of the aperture shutter unit 6 and the third group lens unit 7.

  The aperture shutter unit 6 is fixed to the third lens unit 7 with screws or the like. The aperture shutter unit 6 is provided with an aperture mechanism for adjusting the aperture diameter and a shutter mechanism for opening and closing the photographing optical path. The aperture mechanism and the shutter mechanism are each driven by an actuator such as a stepping motor (not shown). The diaphragm shutter unit 6 is attached with a flexible printed circuit board 6a for electrically connecting the diaphragm mechanism and an actuator for driving the shutter mechanism to the system controller of the camera body. The flexible printed circuit board 6a is connected to a connector 7b provided on the flexible printed circuit board 7a on the third group lens unit 7 side.

  FIG. 5 is an exploded perspective view of the third group lens unit 7. The third group lens unit 7 is provided with a camera shake correction mechanism. A plurality of urging springs 7f for urging the third group lens holder 7d toward the third group cylinder 7e are attached between the third group lens holder 7d holding the third group lens 7c for correcting camera shake and the third group cylinder 7e. It has been.

  The third group lens holder 7d is integrally provided with a drive magnet 7g. By energizing the drive coil 7j attached to the image plane side of the third group cylinder 7e from the camera body side to generate a magnetic field, the drive magnet 7g receives a magnetic force, and thereby in a direction orthogonal to the optical axis. Camera shake correction is performed by changing the position of the third group lens holder 7d.

  The sensor holder 7h is disposed closer to the subject than the third group lens holder 7d, and is fixed to the third group cylinder 7e with screws or the like. A flexible printed circuit board 7a is attached to the subject side of the sensor holder 7h. The flexible printed circuit board 7a has a detection element 7i (Hall element) that detects the position of the third group lens holder 7d (third group lens 7c) by a magnetic change at a position facing the drive magnet 7g of the third group lens holder 7d. Provided (see FIG. 6).

  The hall element 7i can be fixed to the third group cylinder 7e with high accuracy because the flexible printed circuit board 7a is fixed to the sensor holder 7h and the sensor holder 7h is fixed to the third group cylinder 7e. It becomes possible to detect the position of the holder 7d with high accuracy.

  Further, the third group cylinder 7e includes a plurality of cam pins 7k that engage with the third group cam groove 9c of the cam cylinder 9, a rectilinear regulation key 7l that engages with the rotation regulation groove 11c of the fixed cylinder 11 and is restricted in rotation, and A rotation restriction key 7n for restricting the rotation of the inner straight cylinder 8 is provided.

  FIG. 6 is a schematic cross-sectional view of the flexible printed circuit board 7a, the drive coil 7j, and the third group lens holder 7d when assembled. The soldering portion of the drive coil 7j protrudes toward the subject side so as to straddle the third group lens holder 7d in the optical axis direction, and is electrically connected by the soldering portion A of the flexible printed board 7a. As a result, the Hall element 7i and the drive coil 7j are electrically connected to the flexible printed board 7a.

  In addition, the flexible printed circuit board 7a is provided with an extending part 7m that extends to the outside of the lens barrel at a position that is different in phase from the connecting part connected to the flexible printed circuit board 6a in the rotation direction. A signal from the flexible printed circuit board 6a is supplied from the connector 7b of the flexible printed circuit board 7a to the system controller of the camera body via the extending portion 7m.

  Returning to FIG. 1 to FIG. 3, the inner rectilinear cylinder 8 is attached to the outer periphery of the third lens unit 7. The inner rectilinear cylinder 8 is restricted by the rotation restricting key 7n of the third group cylinder 7e, and is supported so as to be able to advance and retreat only in the optical axis direction with respect to the third group lens unit 7. The inner rectilinear cylinder 8 is provided with a rotation restricting portion 8a that engages with an engaging portion (not shown) of the first group rectilinear cylinder 2 to restrict the rotation of the first group rectilinear cylinder 2. It is supported so that it can advance and retract only in the axial direction. Further, the inner rectilinear cylinder 8 is provided with a rectilinear groove 8 b that engages with an engaging portion (not shown) of the second group lens holder 4 to restrict the rotation of the second group lens holder 4.

  The cam cylinder 9 is disposed on the outer peripheral side of the inner rectilinear cylinder 8 and is held rotatably with respect to the inner rectilinear cylinder 8 in a bayonet structure. For this reason, the inner rectilinear cylinder 8 operates integrally with the cam cylinder 9 in the optical axis direction. A first group cam groove 9 a that engages with a cam pin 2 a of the first group rectilinear cylinder 2 is provided on the outer peripheral portion of the cam cylinder 9. A cam pin 9 d that engages with the cam groove 11 a of the fixed cylinder 11 and a drive pin 9 e that engages with the rotation groove 12 a of the drive cylinder 12 are provided on the outer periphery of the cam cylinder 9. A second group cam groove 9b that engages the cam pin 4a of the second group lens holder 4 and a third group cam groove 9c that engages the cam pin 7k of the third group cylinder 7e are provided on the inner periphery of the cam cylinder 9, respectively. Yes.

  Further, an outer rotating cylinder 10 is provided on the outer peripheral side of the cam cylinder 9 so as to cover the first group rectilinear cylinder 2. The outer rotating cylinder 10 is fixed to the cam cylinder 9 by a patching mechanism, and rotates together with the cam cylinder 9 and moves back and forth in the optical axis direction.

  The fixed cylinder 11 is disposed on the outer peripheral side of the outer rotating cylinder 10. A cam groove 11 a that engages with the cam pin 9 d of the cam cylinder 9 is provided on the inner peripheral portion of the fixed cylinder 11. The fixed cylinder 11 is provided with a drive hole 11b through which the drive pin 9e of the cam cylinder 9 passes. Further, a rotation restricting groove 11c that engages with the rotation restricting key 7l of the third group cylinder 7 and restricts the rotation of the third group cylinder 7e is provided on the inner peripheral portion of the fixed cylinder 11.

  The drive cylinder 12 is rotatably attached to the fixed cylinder 11 on the outer peripheral side of the fixed cylinder 11 and on the inner peripheral side of the lens barrel cover 19. A rotation groove 12 a that engages with the drive pin portion 9 e of the cam cylinder 9 is provided on the inner peripheral portion of the drive cylinder 12. A gear portion 12b is provided on the outer peripheral portion of the drive cylinder 12 to transmit a driving force from a zoom motor 18 (see FIG. 1) provided outside the lens barrel via a gear (not shown). Further, the drive cylinder 12 is provided with a flexible groove 12c for drawing the flexible printed circuit board from the inside of the lens barrel to the outside of the lens barrel.

  The fourth group lens unit 13 is disposed on the image plane side of the fixed cylinder 11. FIG. 7 is an enlarged perspective view of the fourth group lens unit 13. The fourth group lens unit 13 is provided with an image sensor (not shown) and a fourth group lens holder 15 that holds the fourth group lens 14. Further, the fourth group lens holder 15 is held by the two steadying shafts 16 so as to be movable back and forth only in the optical axis direction. The fourth group lens holder 15 includes a drive nut. As a result of energization of the focus motor 17 from the system controller of the camera body, the fourth group lens holder 15 advances and retreats straight in the optical axis direction as the focus motor 17 rotates.

  Next, an example of electrical connection between the camera body and the lens barrel will be described with reference to FIG.

  Power is supplied from the battery 23 of the camera body to the system controller 20 of the camera body. When the power of the camera is turned on, the power supply for driving the aperture mechanism 21 and the shutter mechanism 22 from the system controller 20, the power supply for energizing the drive coil 7j, the power supply for driving the focus motor 17 and the zoom motor 18 Is supplied. Further, the system controller 20 is supplied with a signal from the Hall element 7i.

  Next, an operation example of the lens barrel will be described.

  When the power of the camera is turned on, the zoom motor 18 is rotationally driven, and the driving force is transmitted to the gear 12b of the drive cylinder 12 via a gear (not shown), so that the drive cylinder 12 rotates. When the drive cylinder 12 rotates, the cam cylinder rotates due to the engagement between the drive pin e of the cam cylinder 9 and the rotation groove 12 a of the drive cylinder 12. Further, due to the cam action of the cam pin 9 d of the cam cylinder 9 and the cam groove 11 a of the fixed cylinder 11, the cam cylinder extends in the optical axis direction with respect to the fixed cylinder 11 while rotating.

  As the cam cylinder 9 is extended in the optical axis direction, the inner rectilinear cylinder 8 that rotatably supports the cam cylinder 9 is similarly extended in the optical axis direction. The inner straight cylinder 8 is restricted in rotation by the rotation restriction key 7n of the third group cylinder 7e, and the third group cylinder 7e is engaged with the rotation restriction key 11 of the rotation restriction groove 11c of the fixed cylinder 11 with respect to the fixed cylinder 11. Rotation is restricted. Accordingly, the inner rectilinear cylinder 8 is restricted in rotation with respect to the fixed cylinder 11 via the third group cylinder 7e, and performs only rectilinear advance / retreat.

  When the cam cylinder 9 and the inner rectilinear cylinder 8 are extended in the optical axis direction with respect to the fixed cylinder 11, the first group rectilinear cylinder 2 is driven by the cam action of the cam pin 2 a and the first group cam groove 9 a of the cam cylinder 9. It is possible to feed out to a desired position in the direction. Similarly, the second group lens holder 4 can be extended to a desired position in the optical axis direction without rotating with respect to the fixed cylinder 11 by the cam action of the cam pin 4a and the second group cam groove 9b of the cam cylinder 9. Become. Further, the third group cylinder 7e can be extended to a desired position in the optical axis direction without rotating with respect to the fixed cylinder 11 by the cam action of the cam pin 7k and the third group cam groove 9c of the cam cylinder 9.

  That is, when the zoom motor 18 is energized and the drive cylinder 12 rotates, the first lens group 1, the second lens group 3, and the third lens group 7c can be driven to desired positions, and appropriate zoom photography can be performed. Is possible. The fourth group lens 14 can be independently extended and retracted to a position corresponding to the zoom position by driving the focus motor 17.

  Next, features of the present invention will be described.

  In FIG. 6, the Hall element 7i needs to be fixed in a state in which the accuracy of the distance B is ensured in order to detect a change in magnetic force of the drive magnet 7g of the third group lens holder 7d. As described above, the Hall element 7i is fixed to the sensor holder 7h with high accuracy, but it must be prevented from floating in the optical axis direction.

  Therefore, in the present embodiment, the diaphragm shutter unit 6 is provided with an elastic portion 6c in order to bias the Hall element 7i toward the drive magnet 7g.

  FIG. 9 is a schematic diagram showing an example in which the diaphragm shutter unit 6 is provided with an elastic portion 6c. As shown in FIG. 9, in the aperture shutter unit 6, a front holding member 6d, a middle holding member 6e, and a rear holding member 6f are sequentially arranged in the optical axis direction from the subject side to the image plane side. A front space 6g is provided between the front holding member 6d and the middle holding member 6e, and a rear space 6h is provided between the middle holding member 6e and the rear holding member 6f. Since the third group lens unit 7 is provided with the Hall element 7i, the elastic portion 6c protrudes from the rear holding member 6f to the third group lens unit 7 side.

  In the front space 6g and the rear space 6h, shutter blades or diaphragm blades are accommodated, but it is preferable to accommodate the shutter blades in the front space 6g and the diaphragm blades in the rear space 6h. The reason for this will be described.

  FIG. 10A is a schematic view of the shutter mechanism when the shutter blades are housed in the rear space 6h as seen from the optical axis direction, and FIG. 10B is a side view of FIG.

  As shown in FIG. 10A, two Hall elements 7 i are attached to the third lens unit 7 with a rotation phase of 90 °. Accordingly, the two elastic portions 6c are attached to the rear holding member 6f corresponding to the Hall element 7i with a rotation phase of 90 °.

  The shutter blade 6j rotates between a closed position (broken line) and an open position (solid line) of the photographing optical path. Further, the drive rail 6k of the shutter blade 6j guides the shutter blade 6j from the open position to the closed position of the shutter blade 6j for the purpose of preventing the shutter blade 6j from being caught when the shutter blade 6j is opened and closed and reducing friction during driving. Is provided. Therefore, it is necessary to arrange the elastic portion 6c outside the driving region of the shutter blade 6j so as not to hinder the driving of the shutter blade 6j.

  On the other hand, since the elastic portion 6c presses the Hall element 7i in the optical axis direction by a spring force, it is necessary to lengthen the arm length L1 in order to prevent the spring force from becoming loose. However, if the arm length L1 is increased outside the drive region of the shutter blade 6j, the diaphragm shutter unit 6 becomes larger because it approaches the outer shape of the rear holding member 6f. Therefore, it is not suitable for a small lens barrel.

  FIG. 11A is a schematic view of the aperture mechanism when the aperture blades are housed in the rear space 6h as viewed from the optical axis direction, and FIG. 11B is a side view of FIG.

  The aperture mechanism opens and closes the photographing optical path by rotating aperture blades (not shown) assembled to the aperture wind turbine 6l by the aperture wind turbine 6l. Therefore, the rail portion 6m that contacts the aperture wind turbine 6l in the optical axis direction may be disposed on the rear holding member 6f so that the aperture wind turbine 6l can be opened and closed. In the present embodiment, the throttle wind turbine 61 is supported in the optical axis direction by, for example, three rail portions 6m and supported by the middle holding member 6e.

  Thereby, the position of Hall element 7i and the elastic part 6c can be brought close to a radial inner side (arrow direction) to a position where it does not interfere with the rail part 6m. Therefore, when the outer diameter of FIG. 10 and the rear holding member 6f is the same, the arm length L1 of the elastic part 6c can be lengthened, and the elastic part 6c that is strong against spring force can be obtained. Moreover, when the arm length L1 of FIG. 10 and the elastic part 6c is the same, the outer diameter of the rear holding member 6f can be made small. From the above description, it can be seen that it is preferable for the lens barrel to arrange the diaphragm blades in the rear space 6h.

  As described above, in the present embodiment, the aperture mechanism is disposed on the Hall element 7i side, which is the rear space 6h side of the aperture shutter unit 6, and the shutter mechanism is disposed on the subject side, which is the front space 6g side. As a result, the elastic portion 6c can be provided on the rear holding member 6f without affecting the driving of the aperture shutter unit 6, and the Hall element 7i can be urged toward the drive magnet 7g with high accuracy. As a result, the Hall element 7i can be accurately fixed without using a dedicated component for pressing the Hall element 7i in the optical axis direction, and the cost of the lens barrel can be reduced.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

6 Aperture shutter unit 6c Elastic portion 6j Shutter blade 6l Aperture windmill 7 3rd lens unit 7d 3rd lens holder 7i Hall element

Claims (3)

An aperture mechanism that adjusts the aperture diameter, a shutter mechanism that opens and closes a photographing optical path, and a camera shake correction mechanism that includes a lens for camera shake correction and a detection element that detects the position of the lens,
Either the holding member that holds the diaphragm mechanism or the holding member that holds the shutter mechanism is arranged on the side of the camera shake correction mechanism, and the detection element is placed on the holding member arranged on the side of the camera shake correction mechanism. A lens barrel provided with an elastic portion for urging in the optical axis direction.   The lens barrel according to claim 1, wherein a holding member that holds the aperture mechanism is disposed on a side of the camera shake correction mechanism.   The lens barrel according to claim 1, wherein the aperture mechanism includes an aperture windmill that operates an aperture blade that opens and closes the imaging optical path by rotating.

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