JP2011039182A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel capable of constituting an imaging apparatus which is made to be compact in size as a whole without interrupting reduction in the length of the barrel even in the case that lenses are adjacent to each other during the collapse of the lens barrel or the like. <P>SOLUTION: A gear component 94 and a drive cylinder 8 are disposed having a positional relationship in which a rotating shaft of the gear component 94 is positioned outside the drive cylinder 8, and also, a spur gear 94b of the gear component 94 and a gear 8b of the drive cylinder 8 overlap each other in a plane (a plane of view in optical axis direction) is front-projected at a predetermined gap. That is, in the case that a light incident side is regarded as an upper side and an imaging element side is regarded as a lower side in the optical axis direction, the spur gear 94b of the gear component 94 is positioned at the lower side of the gear 8b formed on the outer peripheral surface of the drive cylinder 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lens barrel used in an imaging apparatus such as a digital camera or a video camera.

  2. Description of the Related Art Conventionally, a lens barrel used in an imaging apparatus has a driving cylinder that moves a lens holding frame and a driving apparatus that drives the driving cylinder via a plurality of gears, and the lens holding frame is arranged in the optical axis direction. A device that moves and performs a scaling operation is known.

  In order to design an imaging apparatus using a lens barrel having such a zoom mechanism in a compact manner, for example, in Patent Document 1, a part of a gear in a lens barrel movable in the optical axis direction is within a plane field of view. In this configuration, the lens is stacked on the optical axis side of the fixed lens. That is, the planar space of the entire imaging apparatus is reduced by arranging the gear in the direction of the center of the optical axis so as to overlap the aperture of the lens group.

JP 2007-041405 A

  However, in the prior art disclosed in Patent Document 1, when the lenses are close to each other when retracted, the retracted length of the lens barrel cannot be shortened by the thickness of the gear that overlaps the lens. was there.

  In view of the above-described conventional problems, the present invention provides a lens barrel capable of compactly configuring the entire imaging device without hindering shortening of the lens barrel even when the lenses are close to each other when retracted. The purpose is to provide.

  To achieve the above object, the present invention provides an optical system holding frame for holding an optical system for forming a subject image on an imaging means, a rotating cylinder for moving the optical system holding frame, and the rotating cylinder. A plurality of gear parts in a lens barrel that has a driving device driven through a plurality of gear parts, and performs a zooming operation by moving the optical system holding frame in the optical axis direction with respect to the imaging means. A part of the intermediate gear part that is not connected to the rotating cylinder and a part of the rotating cylinder overlap with a predetermined gap in the plane of the optical axis direction field of view, and a part of the intermediate gear part is rotated It is characterized in that the tube is positioned closer to the image pickup means than the image pickup means side end.

  According to the lens barrel of the present invention, the entire imaging apparatus can be configured in a compact manner without hindering shortening of the barrel.

It is a disassembled perspective view of the lens barrel which concerns on embodiment. It is an assembly perspective view of the zoom drive device 9 according to the present embodiment. It is a disassembled perspective view of the zoom drive device 9 in the present embodiment. FIG. 6 is an enlarged view of the vicinity of gear parts of the zoom drive device 9; It is a longitudinal cross-sectional view which shows the characteristic structure in the lens barrel of 1st Embodiment. It is a longitudinal cross-sectional view which shows the characteristic structure in the lens-barrel of 2nd Embodiment.

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

[Embodiment]
<Overall configuration of lens barrel>
First, with reference to FIG. 1, the structure of the lens barrel in the embodiment of the present invention will be described. FIG. 1 is an exploded perspective view of a lens barrel according to an embodiment of the present invention.

  As shown in FIG. 1, the lens barrel in the present embodiment is a third group lens optical system including a first group lens L1, a second group lens L2, and a third group lens L3. A first group holding frame 1 for holding the first group lens L1, a second group holding frame 2 for holding the second group lens L2, and a third group holding frame 3 for holding the third group lens L3 are provided. In other words, the first group holding frame 1, the second group holding frame 2, and the third group holding frame 3 are optical system holding frames that hold an optical system for forming a subject image on the imaging element.

  Further, the lens barrel includes an aperture device 4, a cam tube 5, a rectilinear tube 6, a fixed tube 7, a drive tube 8, a zoom drive device 9, an image sensor base plate 10, and a cover tube 11. The cam cylinder 5 is rotatably supported by the rectilinear cylinder 6 and moves integrally with the rectilinear cylinder 6. The rectilinear cylinder 6 supports the first group holding frame 1, the diaphragm device 4, and the second group holding frame 2 in a non-rotatable manner. The image pickup element base plate 10 holds an image pickup element (image pickup means) and an optical filter (not shown), and fixes the fixed cylinder 7 and the cover cylinder 11 with screws (not shown). And the gear part 8b formed in the outer peripheral surface of the drive cylinder (rotating cylinder) 8 is connected with the zoom drive device 9 comprised by DC motor (drive means) and several gear components.

  When the drive cylinder 8 is driven by the output of the zoom drive device 9, the cam cylinder 5, the first group holding frame 1, the diaphragm device 4 and the second group holding frame 2 are driven as follows to perform a scaling operation. Is called.

  The cam cylinder 5 has the action of the rectilinear groove 8a of the drive cylinder 8 and the drive pin 5f of the cam cylinder 5 engaged therewith, and the cam pin 5e of the cam cylinder 5 and the cam groove 7a of the fixed cylinder 7 engaged therewith. Due to the action, the optical axis moves while rotating.

  The first group holding frame 1 includes the action of the cam pin 1a of the first group holding frame 1 and the cam groove 5a of the cam cylinder 5 engaged therewith, and the straight movement key of the first group holding frame 1 and the straight movement groove 6a of the straight movement cylinder 6. Due to the action, the optical axis moves without rotating.

  The throttle device 4 rotates by the action of the cam pin 4a of the throttle device 4 and the cam groove 5c of the cam cylinder 5 engaged therewith, and the action of the straight key of the throttle device 4 and the straight groove 6b of the straight cylinder 6. Without moving in the direction of the optical axis.

  The second group holding frame 2 includes the action of the cam pin 2a of the second group holding frame 2 and the cam groove 5b of the cam cylinder 5 engaged therewith, and the rectilinear key of the second group holding frame 2 and the rectilinear groove 6b of the rectilinear cylinder 6. Due to the action, the optical axis moves without rotating.

  The third group holding frame 3 is guided by the guide bars 12 and 10a by the output of the STM motor 14 and moves in the optical axis direction.

<Detailed Configuration of Zoom Driving Device 9>
Next, the configuration of the zoom drive device 9 according to the present embodiment will be described in detail with reference to FIG. 2, FIG. 3, and FIG.

  FIG. 2 is an assembled perspective view of the zoom drive device 9 according to the present embodiment, and FIG. 3 is an exploded perspective view of the zoom drive device 9 according to the present embodiment. FIG. 4 is an enlarged view of the vicinity of the gear parts of the zoom drive device 9.

  As shown in FIGS. 2, 3, and 4, the zoom drive device 9 includes a DC motor 91 and gear parts 92 to 97. The DC motor 91 is fixed to the image pickup device base plate 10 with a screw (not shown), and a gear part 92 having a worm gear is fixed to the shaft tip of the DC motor 91.

  Moreover, as shown in FIG. 3, the gear parts 93-96 are clamped by the image pick-up element base plate 10 and the cover cylinder 11, and are each rotatably supported by the shaft. The gear part 93 is formed with an oblique gear 93a and a spur gear 93b, and the gear part 94 is formed with spur gears 94a and 94b. Further, spur gears 95a and 95b are formed on the gear part 95, and spur gears 96a and 96b are formed on the gear part 96. A spur gear is formed on the gear part 97.

  The meshing relationship of the gear parts 93 to 97 is as follows. That is, the worm gear of the gear part 92 meshes with the inclined gear 93a of the gear part 93, and the spur gear 93b of the gear part 93 and the spur gear 94a of the gear part 94 mesh. Further, the spur gear 94b of the gear part 94 and the spur gear 95a of the gear part 95 are engaged, and the spur gear 95b of the gear part 95 and the spur gear 96a of the gear part 96 are engaged. The spur gear 96b of the gear part 96 and the spur gear 97 are engaged with each other.

  When the DC motor 91 is driven, the gear component 92 fixed to the output shaft of the DC motor 91 is decelerated by the meshing relationship and the output is transmitted to the gear component 97. The drive cylinder 8 is driven by meshing between the gear part 97 and the gear portion 8 b of the drive cylinder 8.

<Characteristic configuration according to the first embodiment>
Next, a characteristic configuration according to the first embodiment will be described with reference to FIG.

  FIG. 5 is a longitudinal sectional view showing a characteristic configuration of the lens barrel of the first embodiment.

  As shown in FIG. 5, an annular rotating shaft 10 c for the gear component 94 is erected on the base portion 10 b of the image sensor base plate 10 integrally with the image sensor base plate 10.

  The gear part 94 in which the spur gears 94a and 94b are formed is a second-stage reduction gear not connected to the drive cylinder 8 among the plurality of gear parts 92 to 97, and the four annular bodies are concentrically tapered. It is in the shape of a single column. That is, the first largest diameter annular body forms a spur gear 94b, and the third annular body forms a spur gear 94a. The shaft core is provided with a bearing hole 94d for supporting the rotary shaft 10c from the first annular body 94b to the second annular body 94c. Further, the fourth annular body constitutes a rotating shaft 94 e fitted into the bearing hole of the cover cylinder 11.

  At the time of assembling the lens barrel in the present embodiment, the rotating shaft 10c that is erected integrally with the imaging element base plate 10 is fitted in the bearing hole 94c of the gear part 94 and is rotatably supported. A rotating shaft 94e of the gear part 94 is fitted in the bearing hole 11a of the cover cylinder 11 and is rotatably supported.

  In such a state after assembling the lens barrel, as shown in FIG. That is, the rotation axis of the gear part 94 is located outside the drive cylinder 8, and a plane (optical axis direction visual field) in which the spur gear 94b of the gear part 94 and the gear portion 8b of the drive cylinder 8 are projected in front with a predetermined gap. The gear part 94 and the drive cylinder 8 are arranged in such a positional relationship as to overlap with each other. That is, when the light incident side is set to the upper side and the imaging element side is set to the lower side in the optical axis direction, the spur gear 94b of the gear part 94 is located at the lower outer peripheral end (image pickup means side end) of the drive cylinder 8. It comes to be located below the formed gear part 8b. More specifically, the tooth portion of the gear portion 8b of the drive cylinder 8 is located in a gap formed by the outer surface of the annular body 94c in the gear part 94 and the outer surface of the spur gear 94b adjacent thereto.

<Advantages of First Embodiment>
According to the present embodiment, since the gear portion 8b of the drive cylinder 8 and a part of the spur gear 94b of the gear part 94 overlap with each other on the plane projected from the front, the plane space in the front projection is reduced. can do. That is, the planar space of the entire imaging apparatus can be reduced without adopting a configuration in which the gear is arranged in the direction of the center of the optical axis so as to overlap the aperture of the lens group as in the prior art. As a result, even when the lenses are close to each other, for example, when retracted, the shortening of the lens barrel is not hindered, and the entire imaging apparatus can be made compact.

  Further, since the rotation shaft of the spur gear 94b is also located outside the drive cylinder 8, the outer diameter of the lens barrel does not increase.

  In addition, since the space directly under the drive cylinder 8 can be used, it is possible to design a large gear rather than arranging the gear parts while avoiding the drive cylinder 8. That is, it is possible to design a gear having a larger reduction ratio with an equivalent module.

  When the gear part 94 is arranged avoiding the drive cylinder 8, the gear ratio is smaller than that of the present embodiment. Therefore, in order to obtain an equivalent output, the front or rear of the spur gear 94b is obtained. It is necessary to obtain a reduction ratio with the reduction gear. However, in order to obtain a large reduction ratio with other gear parts, the gear outer diameter is increased accordingly, so that the plane space in front projection is increased. In particular, when a large reduction gear ratio is obtained with the gear component at the final stage, the load on the gear also increases, so the module also increases, and the increment of the gear outer diameter is much larger than that at the first stage.

  Further, the spur gear 94b in the present embodiment is a second-stage reduction gear, and if it is a gear near the first stage, the load on the gear is small, so that the tooth thickness can be reduced. For this reason, even if the gear part is arranged directly below the drive cylinder 8, there is almost no influence on the increase in the total length of the lens barrel.

[Second Embodiment]
Hereinafter, the lens barrel in the second embodiment of the present invention will be described.

<Configuration of Lens Barrel in Second Embodiment>
Since the lens barrel in the second embodiment has substantially the same configuration as the lens barrel in the first embodiment, only differences from the first embodiment will be described.

  The lens barrel in the second embodiment adopts a configuration in which the fixed cylinder 7 and the drive cylinder 8 are not provided in the configuration shown in FIG. As a result, the three rectilinear keys formed on the lower end of the outer peripheral surface of the rectilinear cylinder 6 engage with the rectilinear grooves formed on the inner peripheral surface of the cover cylinder 11. Further, the three cam pins arranged on the outer peripheral surface of the cam cylinder 25 according to the present embodiment corresponding to the cam cylinder 5 of FIG. 1 engage with the cam grooves formed on the inner peripheral surface of the cover cylinder 11. ing. A gear portion 25 g formed on the outer peripheral surface of the cam cylinder 25 is connected to the zoom drive device 9.

  When the cam cylinder 25 is driven by the output of the zoom drive device 9, the cam cylinder 25 moves in the optical axis direction while rotating by the action of the cam pin of the cam cylinder and the cam groove of the cover cylinder 11. The other lens barrel mechanism and its moving means are the same as those in the first embodiment, and are therefore omitted.

<Characteristic Configuration According to Second Embodiment>
Next, a characteristic configuration according to the second embodiment will be described with reference to FIG.

  FIG. 6 is a longitudinal sectional view showing a characteristic configuration of the lens barrel of the second embodiment. Elements common to those in FIG. 5 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the characteristic configuration of the lens barrel of the second embodiment employs a configuration in which the drive cylinder 8 is replaced with a cam cylinder 25 in the configuration shown in FIG. 5 of the first embodiment. .

  In other words, the rotation axis of the gear part 94 is positioned outside the cam cylinder 25, and a plane (optical axis direction field of view) is projected from the spur gear 94b of the gear part 94 and the gear portion 25g of the cam cylinder 25 with a predetermined gap. The gear part 94 and the cam cylinder 25 are arranged in a positional relationship such that they overlap each other on the plane. That is, when the light incident side is upward and the imaging element side is downward in the optical axis direction, the spur gear 94b of the gear component 94 is positioned below the gear portion 25g formed on the outer peripheral surface of the cam cylinder 25. become. More specifically, the tooth portion of the gear portion 25g of the cam barrel 25 is located in a gap formed by the outer surface of the annular body 94c in the gear part 94 and the outer surface of the spur gear 94b adjacent thereto.

<Advantages of Second Embodiment>
According to the present embodiment, the gear portion 25g of the cam cylinder 25 and a part of the spur gear 94b of the gear part 94 are arranged to overlap each other on the plane projected from the front side, so that it is the same as in the first embodiment. Furthermore, the plane space in front projection can be reduced.

  Since the rotation shaft of the spur gear 94b is also located outside the cam barrel 25, the outer diameter of the lens barrel does not increase. In addition, since the space directly under the cam cylinder 25 can be used, a large gear can be designed as in the first embodiment. The spur gear 94b in the present embodiment is also a second-stage reduction gear, and the tooth thickness can be reduced. For this reason, even if the gear part is arranged directly under the cam barrel 25, the increase in the overall length of the lens barrel is hardly affected.

[Other embodiments]
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary. For example, in the embodiment of the present invention, as an intermediate gear part among the plurality of gear parts, the spur gear 94b that is the second stage reduction gear connected to the first stage gear part 93 has been described as an example. Other intermediate reduction gears may be used without being limited to the second stage.

DESCRIPTION OF SYMBOLS 1 1st group holding frame 2 2nd group holding frame 8 Drive cylinder 8b Gear part 25 Cam cylinder 25g Gear part 92-97 Gear component 94b Spur gear

Claims (4)

An optical system holding frame for holding an optical system for forming a subject image on an imaging means, a rotating cylinder for moving the optical system holding frame, and a driving device for driving the rotating cylinder via a plurality of gear parts; A lens barrel that performs a zooming operation by moving the optical system holding frame in the optical axis direction with respect to the imaging means,
Among the plurality of gear parts, a part of the intermediate gear part that is not connected to the rotary cylinder and a part of the rotary cylinder overlap each other with a predetermined gap on the plane of the optical axis direction field of view. The lens barrel is characterized in that the portion is located closer to the image pickup means than the image pickup means side end of the rotating cylinder.   The lens barrel according to claim 1, wherein a part of the rotating cylinder is a gear portion formed on the rotating cylinder.   3. The lens barrel according to claim 1, wherein a rotation shaft of the intermediate gear part is positioned outside the rotating cylinder. 4.   The lens barrel according to any one of claims 1 to 3, wherein the intermediate gear part is a second-stage reduction gear connected to the first-stage gear part.