JP2007072067A - Lens barrel and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compact lens barrel free from a change in an energizing force due to the position of a lens frame, even with large shifts in the lens frame, wherein the appropriate, stable energizing force can be secured, and then, a space for an energizing member is saved, regarding the lens barrel introducing a system of shifting the lens frame by using a male screw member and a female screw member. <P>SOLUTION: Regarding the lens barrel, two female screw members are engaged with two male screw members, and a part of a lens frame and the energizing member are arranged between two female screw members, and the energizing member partly energizes the lens frame in the direction of either of the female screw members. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrel configured to move a lens frame in accordance with the movement of a female screw member that is screwed into a male screw member that is rotated by a motor, and an imaging apparatus including the lens barrel. is there.

  In a lens barrel used in an imaging optical system of an imaging apparatus such as a camera, zooming or focusing is performed by moving a lens group in the optical axis direction.

  As a form for moving this lens group, a lens frame holding the lens group is moved along the cam groove by rotation of the cam cylinder, a male screw member extending in the optical axis direction rotated by a motor, Two types are generally used in which the lens group is moved using a female screw member screwed into the male screw member.

As the latter, the lens group is moved using a male screw member and a female screw member, a guide portion that linearly guides to a lens frame that holds the lens group and an engagement portion that engages with the female screw member are formed, and the guide And an urging member for urging the engaging portion toward the female screw member and pressing the female screw member toward one side of the thread of the male screw member. A device that moves the lens frame following the movement of the screw member is known (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-148263 (FIGS. 10 and 15)

  However, when the lens barrel of Patent Document 1 described above is applied to a lens barrel having a large amount of movement during zooming, for example, it is necessary to ensure a large effective operating range of a spring as a biasing member. In this case, the urging force varies greatly between the longest spring (when the spring is fully extended) and the shortest (when the spring is most contracted) due to a change in the position of the lens frame. A motor having a torque exceeding the value is required, and there is a problem that the motor becomes large. In addition, there is a problem that a space for occupying the spring is required outside the moving range of the lens frame, which is an obstacle to miniaturization. The above problem becomes particularly significant in the case of a zoom lens barrel having a high zoom ratio and a large movement amount of the lens group.

  In view of the above problems, in the lens barrel of the type in which the lens frame is moved by using the male screw member and the female screw member, even if the amount of movement of the lens frame is large, the biasing force changes depending on the position of the lens frame. Therefore, an object of the present invention is to obtain a small lens barrel that ensures an appropriate and stable urging force and does not require a space for the urging member.

  The above object is achieved by the following configurations.

  1) A lens group for guiding subject light, a lens frame holding the lens group, a male screw member extending in the optical axis direction, a female screw member screwed into the male screw member, and the male screw member A lens barrel that moves the lens frame in the direction of the optical axis in accordance with the movement of the female screw member, wherein the female screw member is screwed in two with the male screw member, A part of the lens frame and a biasing member are provided between the female screw members, and the biasing member biases a part of the lens frame in one direction of the female screw member. Lens barrel to be used.

  2) A lens group for guiding subject light, a lens frame holding the lens group, a male screw member extending in the optical axis direction, a female screw member screwed into the male screw member, and the male screw member A lens barrel that moves the lens frame in the direction of the optical axis in accordance with the movement of the female screw member, and the lens frame holds the female screw member in the direction of the optical axis. And a biasing member for biasing the female screw member in a direction substantially orthogonal to the rotation axis of the male screw member is provided in the clamping portion.

  3) The lens barrel according to 2), wherein the clamping portion clamps the female screw member with a gap, and a biasing member that biases the female screw member in the optical axis direction is provided in the gap.

  4) An imaging apparatus comprising the lens barrel according to any one of 1) to 3).

  According to the present invention, in the lens barrel of the type that moves the lens frame using the male screw member and the female screw member, even if the amount of movement of the lens frame is large, there is no change in the urging force due to the position of the lens frame, An appropriate and stable urging force is ensured, and a small lens barrel that does not require a space for the urging member can be obtained.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is a diagram illustrating an example of an internal arrangement of main constituent units of a camera 100 that is an imaging apparatus including a lens barrel 50 according to the present embodiment. FIG. 3 is a perspective view of the camera 100 as viewed from the subject side.

  As shown in the figure, in the camera 100, a lens barrel 50 according to the present invention including a foldable imaging optical system capable of zooming is arranged along the front surface as shown in the figure, and the opening 51 captures a subject light flux. Has been placed. Although not shown, a lens barrier that opens and closes the opening 51 is disposed.

  Reference numeral 52 denotes a flash light emission window. Reference numeral 53 denotes a flash unit including a reflector, a xenon tube, other main capacitors, a circuit board, and the like disposed behind the flash light emission window. Reference numeral 54 denotes a card-type image recording memory. A battery 55 supplies power to each part of the camera 100. The image recording memory 54 and the battery 55 can be inserted and removed from a lid (not shown).

  A release button 56 is arranged on the upper surface of the camera 100, and a shooting preparation operation, that is, a focusing operation and a photometric operation are performed by pushing the first button, and a shooting exposure operation is performed by pushing the second button. Reference numeral 57 denotes a main switch that switches the camera 100 between an operating state and a non-operating state. When switched to the operating state by the main switch 57, when a lens barrier is provided, the lens barrier is opened and the operation of each unit is started. When the main switch 57 is switched to the non-operating state, the lens barrier is closed and the operation of each unit is ended.

  On the back surface of the camera 100, an image display unit 58 that is configured by a display element such as an LCD or an organic EL and displays images and other character information is disposed.

  Although not shown, a zoom button for zooming up and down, a playback button for playing back a captured image, a menu button for displaying various menus on the image display unit 58, and a desired function are selected from the display. An operation member such as a selection button is disposed on the back surface. Furthermore, an external input / output terminal, a strap attaching portion, a tripod seat and the like are provided on the side surface.

  In addition, while connecting each part between these main structural units, the circuit board in which various electronic components are mounted is arrange | positioned, and it drives and controls each main structural unit.

  FIG. 2 is a schematic perspective view of a unit state of the lens barrel 50 according to the present embodiment.

  As shown in the figure, the lens barrel 50 is composed of two barrels, a main barrel 10A as a first barrel and a main barrel 10B as a second barrel. A first motor 20 for moving the lens group disposed inside is assembled to the main body 10A, and a second motor 21 for moving other lens groups disposed inside is assembled to the main body 10B. Yes. Reference numeral 6 denotes an image sensor, which is assembled to the main body 10B. Reference numeral 11 denotes a lens arranged closest to the object, and is arranged with the optical axis facing the subject OA.

  The first motor 20, the second motor 21, and the image sensor 6 are connected to a printed circuit board (not shown) and are individually controlled and driven.

  FIG. 3 is a cross-sectional view showing a foldable imaging optical system capable of zooming, which is included in the lens barrel 50 according to the present embodiment. This figure shows a state at the time of widening, which is cut along a plane including two optical axes before and after bending.

  In the figure, OA is the optical axis before bending, and OB is the optical axis after bending. The outside of the lens barrel 50 includes a main barrel 10A that is a first barrel member and a main barrel 10B that is a second barrel member.

  Reference numeral 1 denotes a first lens group. The first lens group 1 includes a prism 11 that is a reflection member that bends the optical axis OA in a substantially right angle direction, a lens 11 that is disposed toward the subject with the optical axis OA, and a prism 12. The lens 13 is disposed with the optical axis OB bent by the optical axis as the optical axis. The first lens group 1 is a lens group fixed to the main body 10A.

  Reference numeral 2 denotes a second lens group, which is incorporated in the second lens group frame 2k. The second lens group is a lens group that moves together with the second lens group frame 2k during zooming (hereinafter also referred to as zooming).

  Reference numeral 3 denotes a third lens group, which is incorporated in the third lens group frame 3k. The third lens group 3 is a lens group that is incorporated in the main body 10B and does not move.

  Reference numeral 4 denotes a fourth lens group, which is incorporated in the fourth lens group frame 4k. The fourth lens group is a lens group that moves integrally with the fourth lens group lens frame 4k during zooming and during focus adjustment (hereinafter also referred to as focusing).

  Reference numeral 5 denotes an optical filter in which an infrared light cut filter and an optical low-pass filter are stacked, and is assembled to the main body 10B. Reference numeral 6 denotes an image sensor, which uses a charge coupled device (CCD) type image sensor, a complementary metal-oxide semiconductor (CMOS) type image sensor, or the like. The imaging element 6 is assembled to the attachment member 8, and the attachment member 8 is assembled to the main body 10 </ b> B together with the imaging element 6. A flexible printed circuit board 7 is connected to the image sensor 6 and is connected to other circuits in the camera. Reference numeral 9 denotes a shutter unit, which is fixed to the main body 10B in the same manner as the third lens group frame 3k.

  The lens barrel 50 according to the present invention will be described below.

(First embodiment)
FIG. 4 is a schematic diagram showing a schematic structure inside the lens barrel 50 according to the first embodiment. This figure shows a state in which the second lens group 2 and the fourth lens group 4 are in the wide position. In the following drawings, in order to avoid duplication of explanation, the same reference numerals are given to the same functional members. In order to make the explanation easy to understand, the position of the motor or the like is moved out of the lens barrel and is schematically illustrated.

  As shown in the figure, a guide shaft 15 is provided through a sleeve 2s formed integrally with the second lens group frame 2k and a sleeve 4s formed integrally with the fourth lens group frame 4k. It has been. Further, the guide shaft 16 engages with a rotation locking portion 2m formed integrally with the second lens group lens barrel 2k and a rotation locking portion 4m formed integrally with the fourth lens group lens frame 4k. Is provided. Thereby, the second lens group lens frame 2k and the fourth lens group lens frame 4k are slidable along the guide shafts 15 and 16 in the direction of the optical axis OB.

  Two female screw members 30 (hereinafter referred to as nuts) are screwed at a predetermined interval to a lead screw 20r that is a male screw member formed on the rotating shaft of the first motor 20 that is a stepping motor. Although not shown, the two nuts 30 are rotationally locked, and are moved by being screwed into the lead screw 20r while maintaining a predetermined interval by the rotation of the first motor 20, that is, the rotation of the lead screw 20r. It is possible to do.

  Between the two nuts 30, a U-shaped portion 2j formed integrally with the sleeve 2s and a compression coil spring 18 as an urging member are disposed. The U-shaped portion 2j is formed so as not to come into contact with the lead screw 20r, and is urged and pressed against one nut 30 by a compression coil spring 18 as illustrated.

  With the above configuration, when the lead screw 20r rotates, the nut 30 is moved while maintaining a predetermined interval, and the U-shaped portion 2j is urged and pressed against one nut 30 by the compression coil spring 18. It is moved with 30. Thus, by controlling the rotation direction and amount of rotation of the lead screw 20r, the second lens group frame 2k can be moved along the guide shafts 15 and 16 in the optical axis OB direction by a desired amount.

  Similarly, two nuts 31 are screwed into the lead screw 21r formed on the rotating shaft of the second motor 21 at a predetermined interval. Although not shown, the two nuts 31 are rotationally locked, and can be moved while maintaining a predetermined interval by the rotation of the second motor 21, that is, the rotation of the lead screw 21r. .

  Between the two nuts 31, a U-shaped portion 4 j formed integrally with the sleeve 4 s and a compression coil spring 19 that is an urging member are disposed. The U-shaped portion 4j is formed so as not to contact the lead screw 21r, and is urged and pressed against one nut 31 by a compression coil spring 19 as shown in the figure.

  With the above configuration, when the lead screw 21r rotates, the nut 31 is moved while maintaining a predetermined interval, and the U-shaped portion 4j is urged and pressed against one nut 31 by the compression coil spring 19, and the nut 31 It is moved with 31. Thus, by controlling the rotation direction and amount of rotation of the lead screw 21r, the fourth lens group lens frame 4k can be moved along the guide shafts 15 and 16 in the optical axis OB direction by a desired amount.

  As a result, the second lens group 2 and the fourth lens group 4 move from the position in the illustrated wide state toward the direction closer to the third lens group 3 by a set amount in each direction, and zooming is performed. Done. Further, the fourth lens group 4 is focused by moving further from the position moved by zooming.

  Although not shown, a position sensor that detects the presence of the second lens group 2 and a position sensor that detects the presence of the fourth lens group 4 are arranged. For example, a photo interrupter is used as the position sensor. In this position sensor, the shielding portions formed on the second lens group lens frame 2k and the fourth lens group lens frame 4k are respectively shielded between the light projecting / receiving systems of the position sensors, or the light projecting / receiving system of the position sensor. The lens group controls the rotation direction and amount of rotation of the first motor 20 and the second motor 21 on the basis of the switching position from the shielding state to the non-shielding state. Position control is performed.

  As described above, two nuts that are female screw members are screwed into lead screws that are male screw members, a part of the lens frame and a compression coil spring that is a biasing member are provided between the two nuts, Since the compression coil spring is configured so that a part of the lens frame is pressed and biased to one of the nuts, the distance between the two nuts does not change even when the lens frame is moved. Instead, the urging force to the lens frame and the nut to be pressed and biased is kept substantially constant regardless of the position of the lens frame. Furthermore, even if the direction of rotation of the lead screw is changed, backlash does not occur and accurate movement control of the lens frame becomes possible.

  Thereby, even if the amount of movement of the lens frame is large, it is possible to obtain a lens barrel in which the biasing force does not change depending on the position of the lens frame and an appropriate and stable biasing force is ensured. Further, since only a small spring is disposed between the nuts, a space-saving small lens barrel can be obtained.

  In the above description, an example in which a compression coil spring is used as an example of the urging member has been described. However, the present invention is not limited to this, and it goes without saying that an elastic member such as a leaf spring or a sponge may be applied. Absent.

(Second Embodiment)
FIG. 5 is a schematic diagram showing a schematic structure inside the lens barrel 50 according to the second embodiment. In the same manner, the second lens group 2 and the fourth lens group 4 are in the wide position. Note that in the second embodiment, only the parts different from the first embodiment will be described.

  As shown in the figure, a female screw member 30 (hereinafter referred to as a nut) is screwed into a lead screw 20r that is a male screw member formed on the rotating shaft of the first motor 20. Although not shown, the nut 30 is rotationally locked, and is moved by being screwed into the lead screw 20r while maintaining a predetermined interval by the rotation of the first motor 20, that is, the rotation of the lead screw 20r. Is possible.

  The nut 30 is clamped by a bifurcated clamping part 2n formed integrally with the sleeve 2s. The bifurcated clamping part 2n is formed so as not to contact the lead screw 20r. Further, the nut 30 is urged by the compression coil spring 18 in a direction substantially orthogonal to the rotation axis of the lead screw 20r. The clamping portion 2n holds the nut 30 with a gap, and a leaf spring 32, which is an urging member that urges the nut 30 in the direction of the rotation axis of the lead screw 20r in the optical axis direction. Is provided.

  Similarly, a nut 31 is screwed onto a lead screw 21r formed on the rotating shaft of the second motor 21. Although not shown, the nut 31 is rotationally locked, and is moved by being screwed into the lead screw 21r while maintaining a predetermined interval by the rotation of the second motor 21, that is, the rotation of the lead screw 21r. Is possible.

  The nut 31 is clamped by a bifurcated clamp 4n formed integrally with the sleeve 4s. The bifurcated sandwiching portion 4n is formed so as not to contact the lead screw 21r. Further, the nut 31 is urged by the compression coil spring 19 in a direction substantially orthogonal to the rotation axis of the lead screw 21r. The clamping portion 4n clamps the nut 31 with a gap, and a leaf spring 33, which is a biasing member that biases the nut 31 in the direction of the rotation axis of the lead screw 21r in the optical axis direction. Is provided.

  FIG. 6 is an enlarged cross-sectional view showing the configuration around the nut 30.

  As shown in the figure, the screw portion of the nut 30 on the compression coil spring 18 side is pressed and urged against the screw portion of the lead screw 20r by the compression coil spring 18, and the other screw portion is separated from the screw portion of the lead screw 20r. It becomes a state. Further, the bifurcated sandwiching portion 2n is sandwiched with a nut 30 with a gap, and a leaf spring 32 is provided in the gap, and the nut 30 is attached to the rotation axis direction of the lead screw 20r that is the optical axis direction. It is fast.

  In this way, by urging the nut 30 in a direction substantially orthogonal to the rotation axis of the lead screw 20r, even if the rotation direction of the lead screw 20r is changed, backlash does not occur, and an accurate lens frame is formed. Movement control is possible. Thereby, even if the amount of movement of the lens frame is large, it is possible to obtain a lens barrel in which the biasing force does not change depending on the position of the lens frame and an appropriate and stable biasing force is ensured. Furthermore, since a small spring is merely disposed in the bifurcated clamping portion, a space-saving small lens barrel can be obtained.

  The lens barrel 50 according to the second embodiment also has the following effects.

  FIG. 7 is a schematic cross-sectional view of the second lens group frame 2k cut along the nut 30. As shown in FIG.

  In the figure, the reaction force of the compression coil spring 18 that urges the nut 30 in a direction substantially orthogonal to the rotation axis of the lead screw 20r acts on the second lens group frame 2k in the direction of the arrow shown. Due to this reaction force, the fitting hole formed in the sleeve 2s and the guide shaft 15 penetrating the fitting hole are in a state of being offset as shown in the figure. Similarly, the rotation locking portion 2m and the guide shaft 16 are also offset as shown in the figure. This state is maintained regardless of the direction of rotation of the lead screw 20r and the direction of movement of the nut 30.

  That is, as shown in the drawing, the arrangement is made so that the reaction force of the compression coil spring 18 acts in a direction intersecting the line connecting the centers of the guide shafts 15 and 16, and the fitting shaft and the guide shaft of the guide shaft 15 and the sleeve 2s. By displacing the gap between 16 and the rotation locking portion 2m to one side, it is possible to eliminate minute shaking in the direction orthogonal to the optical axis when the second lens group frame 2k moves in the optical axis OB direction. It also has an effect of making it possible to prevent image shake during zooming.

  In the above description, the example using the compression coil spring 18 and the leaf spring 32 has been described. However, the present invention is not limited to this, and it is needless to say that an elastic member such as a sponge may be applied.

  In addition, the nut in the second embodiment has been described with a cylindrical female screw formed. However, the present invention is not limited to this, and only the screw portion that is pressed and urged is formed. An arc shape or a rack gear shape may be used.

It is a figure which shows an example of the internal arrangement | positioning of the main structural unit of the camera which is an imaging device provided with the lens barrel which concerns on this Embodiment. It is a schematic perspective view of the unit state of the lens barrel according to the present embodiment. 1 is a cross-sectional view illustrating a foldable imaging optical system that is variable in magnification and is contained in a lens barrel according to the present embodiment. It is a schematic diagram which shows schematic structure inside the lens barrel which concerns on 1st Embodiment. It is a schematic diagram which shows schematic structure inside the lens barrel which concerns on 2nd Embodiment. It is sectional drawing which expanded and showed the structure of the periphery of a nut. It is the schematic sectional drawing which cut | disconnected the 2nd lens group lens frame in the site | part of a nut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 3 3rd lens group 4 4th lens group 5 Optical filter 6 Image pick-up element 9 Shutter unit 10A Main trunk 10B Main trunk 15 Guide shaft 16 Guide shaft 18, 19 Compression coil spring 20 First motor 21 Second motor 30, 31 Nut (female screw member)
50 Lens barrel 100 Camera

Claims (4)

A lens group for guiding subject light, a lens frame holding the lens group, a male screw member extending in the optical axis direction, a female screw member screwed into the male screw member, and the male screw member are rotated. A lens barrel that moves the lens frame in the direction of the optical axis with the movement of the female screw member,
Two female screw members are screwed into the male screw member, a part of the lens frame and a biasing member are provided between the two female screw members, and the biasing member is a part of the lens frame. The lens barrel is urged in the direction of one of the female screw members. A lens group for guiding subject light, a lens frame holding the lens group, a male screw member extending in the optical axis direction, a female screw member screwed into the male screw member, and the male screw member are rotated. A lens barrel that moves the lens frame in the direction of the optical axis with the movement of the female screw member,
The lens frame is formed with a holding portion for holding the female screw member in the optical axis direction, and the female screw member is biased to the holding portion in a direction substantially orthogonal to the rotation axis of the male screw member. A lens barrel comprising an urging member. The said clamping part clamps the said female screw member with a clearance gap, The biasing member which urges | biases the said female screw member to an optical axis direction was provided in the said clearance gap. Lens barrel. An imaging apparatus comprising the lens barrel according to claim 1.

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