JP5803194B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a lens barrel and an imaging apparatus.

There is an optical device that moves an optical element by a driving force of a feed screw (see Patent Document 1).
[Patent Document 1] JP 2009-139516 A

  When the rotation direction of the feed screw is changed, the driving force may be changed to cause vibration or the like.

As a first aspect of the present invention, a hold member that holds the optical member having an optical axis, it is provided in a position facing each other across the optical member, guiding the hold member in a direction parallel to the optical axis 2 Books and guide shaft of an optical axis disposed parallel to the feed screw, a rotating shaft provided substantially parallel to the optical axis at a position different from the two guide shafts, retained member being engaged with the feed screw coupled to a rotating member which rotates around the shaft rotating, and a member pressing presses against the screw feed the rotating member, rotating shaft, the force Ru pressing the rotating member to the feed screw Is arranged on a tangent line that is substantially perpendicular to the direction and in contact with the outer periphery of the feed screw, and on the plane that is perpendicular to the optical axis, the tangent line is a straight line connecting the two guide axes, and a position closer to the feed screw relative to the optical member. A lens barrel is provided that intersects at.

  As a second aspect of the present invention, there is provided an imaging apparatus including the lens barrel and an imaging element that captures a subject image formed by the lens barrel.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a schematic cross-sectional view of an imaging apparatus 100. FIG. 5 is a perspective view of a support mechanism 500. FIG. 4 is a partial cross-sectional view of a rotating member 550. FIG. 6 is a front view of a support mechanism 500. FIG. 5 is a partial plan view of a support mechanism 500. FIG. 5 is a schematic diagram of a rotating member 550. FIG. 5 is a partially enlarged view of a rotating member 550. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a schematic cross-sectional view of the imaging apparatus 100. The imaging apparatus 100 includes a lens unit 200 and a camera body 300.

  In the following description, in the lens unit 200, the object side is described as “front side” and the image side is described as “rear side”. In the camera body 300, the side on which the lens unit 200 is mounted is referred to as “front side”, and the side on the opposite side where the viewfinder 350, the display unit 340, and the like are disposed is referred to as “rear side” or “rear side”. .

  The lens unit 200 includes a fixed barrel 210, a lens barrel CPU 219, a plurality of lenses 220, 230, 240, 250, 260 and a lens mount 216.

  One end of the fixed barrel 210 is coupled to the body mount 360 of the camera body 300 via the lens mount 216. The coupling between the lens mount 216 and the body mount 360 can be released by a certain operation. Accordingly, another lens unit 200 having the same lens mount 216 can be attached to the camera body 300.

  The lens barrel CPU 219 controls the lens unit 200 and also communicates with the camera body 300. Accordingly, the lens unit 200 attached to the camera body 300 operates in cooperation with the camera body 300. In the lens unit 200 including the vibration isolation unit, the lens barrel CPU 219 calculates the movement direction and movement amount of the lens that cancels the vibration, and controls the vibration isolation actuator.

  The plurality of lenses 220, 230, 240, 250, 260 are arranged on a common optical axis X to form an optical system. By moving a part of the plurality of lenses 220, 230, 240, 250, 260 in the direction of the optical axis X, the magnification and the focal position of the optical system change.

  Here, focusing on one lens 250, the lens 250 is held by the lens holding frame 510, and the lens holding frame 510 is supported from the guide shafts 542 and 544. The guide shafts 542 and 544 are arranged in parallel to each other and each parallel to the optical axis X. Therefore, the lens 250 is supported so as to be movable in a direction parallel to the optical axis X.

  The lens holding frame 510 is coupled to a rotating member 550 that meshes with the feed screw 520. The feed screw 520 is arranged in parallel with the optical axis X and is rotationally driven by a motor 530. Therefore, when the motor 530 is operated, the lens holding frame 510 is driven and moved by the feed screw 520 via the rotating member 550. Further, when the rotation direction of the motor 530 is reversed, the moving direction of the lens holding frame 510 is also reversed.

  The lens 250 is held by the support mechanism 500 so as to be movable in the optical axis direction in the lens unit 200. In the lens unit 200, the lens 250 is driven by the motor 530 and moves in the direction of the optical axis X.

  In FIG. 1, the feed screw 520 and the motor 530 that drive the lens 250 are illustrated, but this does not mean that the other lenses 220, 230, 240, and 260 do not move. Other lenses 220, 230, 240, 260 may also be driven by a feed screw 520 and a motor 530, and other lenses 220, 230, 240, 260 may be replaced with other ultrasonic motors, voice coil motors, etc. A drive scheme may be provided. In addition, some of the other lenses 220, 230, 240, and 260 may have a mechanism that is manually moved by an operation such as a cam structure or a slide structure.

  The camera body 300 includes a mirror unit 370 disposed behind a body mount 360 coupled to the lens unit 200. A focusing optical system 380 is disposed below the mirror unit 370. Further, a focusing screen 352 is disposed above the mirror unit 370.

  A pentaprism 354 is disposed further above the focusing screen 352, and a finder optical system 356 is disposed behind the pentaprism 354. The rear end of the viewfinder optical system 356 is exposed as a viewfinder 350 on the back surface of the camera body 300.

  Behind the mirror unit 370, a shutter device 400, a low-pass filter 332, an image sensor 330, a main substrate 320, and a display unit 340 are sequentially arranged. A display unit 340 formed by a liquid crystal display panel or the like appears on the back surface of the camera body 300. A part of electronic components such as the main body CPU 322 and the image processing circuit 324 is mounted on the main board 320.

  The mirror unit 370 includes a main mirror 371 and a sub mirror 374. The main mirror 371 is supported by a main mirror holding frame 372 that is pivotally supported by a main mirror rotating shaft 373. The sub mirror 374 is supported by a sub mirror holding frame 375 supported by a sub mirror rotating shaft 376. The sub mirror holding frame 375 rotates with respect to the main mirror holding frame 372. Therefore, when the main mirror holding frame 372 rotates, the sub mirror holding frame 375 is also displaced together with the main mirror holding frame 372.

  When the front end of the main mirror holding frame 372 is lowered, the main mirror 371 is positioned obliquely on the incident light beam incident from the lens unit 200. When the main mirror holding frame 372 rises, the main mirror 371 retracts to a position that avoids the incident light beam.

  When the main mirror 371 is positioned on the incident light beam, the incident light beam incident through the lens unit 200 is reflected by the main mirror 371 and guided to the focusing screen 352. Since the focusing screen 352 is disposed at a position conjugate with the optical system of the lens unit 200, a subject image formed by the optical system is connected.

  The image formed on the focusing screen 352 is observed from the viewfinder 350 through the pentaprism 354 and the viewfinder optical system 356. Since the luminous flux of the subject image passes through the pentaprism 354, the subject image on the focusing screen 352 is observed as an erect image from the viewfinder 350.

  The photometric sensor 390 is disposed above the finder optical system 356 and receives a part of the incident light beam branched by the pentaprism 354. The photometric sensor 390 detects the subject brightness and causes the main body CPU 322 to calculate an exposure condition which is a part of the photographing condition. In addition, a part of the incident light beam is measured for each of the three primary colors to be used for calculating the auto white balance.

  The main mirror 371 has a half mirror region that transmits a part of the incident incident light beam. The sub mirror 374 reflects a part of the incident light beam incident from the half mirror region toward the focusing optical system 380. The focusing optical system 380 guides a part of the incident incident light beam to the focus detection sensor 382. Accordingly, the main body CPU 322 determines a target position of the lens 230 when the optical system of the lens unit 200 is focused.

  When the release button is half-pressed in the imaging apparatus 100 as described above, the focus detection sensor 382 and the photometric sensor 390 are enabled, and the subject image can be captured under appropriate imaging conditions. Next, when the release button is fully pressed, the main mirror 371 and the sub mirror 374 move to the retracted position, and the shutter device 400 opens. Thereby, the incident light beam incident from the lens unit 200 passes through the low-pass filter 332 and enters the image sensor 330.

  The image sensor 330 is formed by a photoelectric conversion element such as a CCD sensor (Charge Coupled Device) or a CMOS sensor (Complementary Metal Oxide Semiconductor), and converts the received subject image into an electrical signal and outputs the electrical signal. The electrical signal output from the image sensor 330 is converted into captured image data by the image processing circuit 324.

  FIG. 2 is a perspective view of the support mechanism 500. The support mechanism 500 is a mechanism that moves while supporting the lens 250, and includes a lens holding frame 510, a feed screw 520, guide shafts 542 and 544, and a rotating member 550.

  The lens 250 is held by the lens holding frame 510, and the lens holding frame 510 is supported and guided from the pair of guide shafts 542 and 544 in the fitting portion 512 and the engaging portion 514. That is, the pair of guide shafts 542 and 544 are arranged in parallel with each other and in parallel with the optical axis X of the optical system including the lens 250.

  A pair of fitting portions 512 formed on the lens holding frame 510 are fitted to the guide shaft 542 at two positions separated in the extending direction of the guide shaft 542. Accordingly, the lens holding frame 510 is supported so as to be movable in the optical axis X direction with respect to the guide shaft 542.

  The lens holding frame 510 is inserted through the other guide shaft 544 through a single engaging portion 514. Accordingly, the lens holding frame 510 is restricted from rotating around the guide shaft 542 while maintaining a state in which the lens holding frame 510 can move in the optical axis X direction.

  The rotation member 550 is coupled to the lens holding frame 510 in the vicinity of the fitting portion 512 so as to be rotatable with respect to the lens holding frame 510 about the rotation shaft 552 as a rotation axis. The rotating member 550 meshes with the feed screw 520 in a rack portion 554 formed in the vicinity of its tip.

  When the feed screw 520 is rotated around a rotation axis parallel to the optical axis X, the rotating member 550 is driven by the feed screw 520 to move in the longitudinal direction of the feed screw 520, that is, in the direction parallel to the optical axis X. Driven. As a result, the lens 250 held by the lens holding frame 510 also moves in a direction parallel to the optical axis X. When the rotation direction of the feed screw 520 is reversed, the moving directions of the lens holding frame 510 and the lens 250 are also reversed.

  FIG. 3 is a partial cross-sectional view of the rotating member 550. In FIG. 3, the meshing portion of the rotating member 550 and the feed screw 520 is shown with respect to the PP cross section and the QQ cross section indicated by arrows in the drawing. 3 also shows the lower surface of the rotating member 550 when the rack portion 554 is looked up from below.

  As can be seen from the Q-Q cross section, the feed screw 520 and the rack portion 554 mesh with each other at a pair of meshing positions separated in a direction parallel to the longitudinal direction of the feed screw 520, that is, in a direction parallel to the optical axis X. Thereby, when the feed screw 520 rotates, the driving force in the longitudinal direction of the feed screw 520 is transmitted to the rotating member 550 through the rack portion 554.

  Further, as can be seen from the PP cross section, the feed screw 520 and the rack portion 554 mesh with each other at a single meshing position in the circumferential direction of the feed screw 520. Therefore, when the feed screw 520 rotates, the rotational motion of the feed screw 520 is not transmitted to the rack portion 554, and the axial driving force is transmitted to the rotating member 550.

  FIG. 4 is a rear view of the support mechanism 500 and shows the support mechanism 500 shown in FIG. 2 as viewed from the back side of the imaging apparatus 100. Elements that are the same as those in FIG. 2 are given the same reference numerals, and redundant descriptions are omitted.

  In the support mechanism 500, a pressing spring 560 is disposed between the lens holding frame 510 and the rotation member 550. One end 562 of the pressing spring 560 comes into contact with the rotating member 550 from above. Further, the other end 564 of the pressing spring 560 comes into contact with the vicinity of the fitting portion 512 of the lens holding frame 510 from the side. The pressing spring 560 is biased in a direction in which the end portions 562 and 564 are separated from each other.

  As already described, the lens holding frame 510 is fitted to the guide shaft 542 in the fitting portion 512, and is engaged to the guide shaft 544 in the engaging portion 514. Thereby, the position of the lens holding frame 510 in the plane orthogonal to the optical axis X is determined.

  With respect to such a lens holding frame 510, the rotation member 550 is in contact with the feed screw 520 from one side in the radial direction of the feed screw 520. Therefore, the rotation member 550 is coupled to the lens holding frame 510 so as to be rotatable around the rotation shaft 552. However, since the pressing spring 560 urges the rotating member 550 counterclockwise in the drawing, the rack portion 554 of the rotating member 550 does not generate “ra” on the circumferential surface of the feed screw 520. Pressed.

  FIG. 5 is a partial plan view of the support mechanism 500, and shows a planar arrangement of the support mechanism 500 in the plane indicated by the arrow A in FIG. Elements common to FIGS. 2 and 4 are given the same reference numerals, and redundant description is omitted.

  When the support mechanism 500 is looked down, it can be seen that the rotation shaft 552 of the rotation member 550 is arranged in parallel to the feed screw 520 and the guide shafts 542 and 544. Thus, even when the rotation member 550 rotates around the rotation shaft 552, the driving force transmitted from the feed screw 520 to the pair of rack portions 554 is equally transmitted to the lens holding frame 510.

  Further, when the support mechanism 500 is looked down, the pressing spring 560 has a rotating shaft 552 inserted through a middle coil portion, one end 562 serving as a rotating member 550, and the other end 564 serving as a lens holding frame. 510, respectively. Here, one end 562 of the pressing spring 560 located on the left side in the drawing abuts on the rotating member 550 at the center position of the pair of rack portions 554 in the longitudinal direction of the feed screw 520. As a result, the pressing force generated by the pressing spring 560 acts equally on the pair of rack portions 554.

  In the lens holding frame 510, the center position of the pair of fitting portions 512 is also the same as the center position of the pair of rack portions 554 and is positioned on the plane B parallel to the optical axis X. Further, the center of gravity G of the assembly including the lens holding frame 510 and the lens 250 is also located on the plane B. In this way, since the pair of fitting portions 512 and the center of gravity G of the assembly that are loads with respect to the driving force generated by the feed screw 520 are at the center position of the pair of rack portions 554, the lens is held by the feed screw 520. Even when the moving direction of the frame 510 changes, the resistance force against the movement of the rotating member 550 does not change.

  FIG. 6 is an enlarged schematic view showing the rotating member 550 viewed from the same direction as FIG. Elements that are the same as those in the other drawings are given the same reference numerals, and redundant descriptions are omitted.

  The rotating member 550 is pressed toward the feed screw 520 by the pressing force P of the pressing spring 560. For this reason, the rack portion 554 receives a reaction force F equal to the pressing force P and opposite in direction from the feed screw 520.

  Here, the tangent line T perpendicular to the reaction force F in the position where the rotation member 550 receives the reaction force F, that is, the region E where the rack portion 554 meshes with the feed screw 520 is the rotation axis C of the rotation shaft 552. Intersect. Note that the tangent T referred to here is a general term for a straight line that includes the tangent T with respect to the reference pitch circle of the feed screw 520, passes through a region E where the rack portion 554 and the feed screw 520 are engaged, and is parallel to the tangent T.

  FIG. 7 is a diagram for explaining the operation of the support mechanism 500 having the above-described arrangement, and shows the rotating member 550 partially enlarged. Elements that are the same as those in the other drawings are given the same reference numerals, and redundant descriptions are omitted.

As already described, the reaction force F acts between the feed screw 520 and the rack portion 554. Therefore, when the feed screw 520 rotates in the clockwise direction indicated by the arrow D ₁ in the figure, the frictional force μ ₁ generated by the friction between the feed screw 520 and the rack portion 554 is tangent T to the rotating member 550. Acts on direction. Further, when the feed screw 520 rotates counterclockwise as indicated by an arrow D ₂ in the figure, the frictional force μ ₂ generated by the friction between the feed screw 520 and the rack portion 554 is tangential to the rotating member 550. Acting in the opposite direction to the frictional force μ ₁ in the clockwise direction D ₁ .

As described with reference to FIG. 6, the tangent line T intersects the rotation axis C of the rotation member 550. Therefore, the frictional forces μ _{1 and} μ ₂ generated as described above do not include a component that intersects the tangent line T. Therefore, in the case of the feed screw 520 is rotated in the direction of rotation D _1, in the case of rotating in the direction of rotation D _2, the driving force is not changed from the feed screw 520 transmitted to the rotating member 550.

Therefore, even if the rotation direction of the feed screw 520 changes, chatter, collision noise, and the like do not occur in the feed screw 520 and the rack portion 554. Further, since the load on the motor 530 that drives the feed screw 520 does not change regardless of the rotation directions D ₁ and D ₂ , it is possible to prevent the coil of the motor 530 from generating a roaring sound.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Imaging device, 200 Lens unit, 210 Fixed cylinder, 216 Lens mount, 219 Lens barrel CPU, 220, 230, 240, 250, 260 Lens, 300 Camera body, 320 Main board, 322 Main body CPU, 324 Image processing circuit, 330 Image sensor, 332 low-pass filter, 340 display unit, 350 finder, 352 focusing screen, 354 pentaprism, 356 finder optical system, 360 body mount, 370 mirror unit, 371 main mirror, 372 main mirror holding frame, 373 rotation of main mirror Axis, 374 sub mirror, 375 sub mirror holding frame, 376 sub mirror rotation axis, 380 focusing optical system, 382 focus detection sensor, 390 photometric sensor, 400 shutter device, 500 Holding mechanism, 510 lens holding frame, 512 fitting portion, 514 engaging portion, 520 feed screw, 530 motor, 542, 544 guide shaft, 550 rotating member, 552 rotating shaft, 554 rack portion, 560 pressing spring, 562 564 end

Claims (6)

A hold member that holds the optical member having an optical axis,
Provided in a position opposed to each other across the optical member, two a guide axis for guiding the front Kiho support member in a direction parallel to the front Symbol optical axis,
A feed screw which is arranged parallel to the front Symbol optical axis,
A rotating shaft provided substantially parallel to the optical axis at a position different from the two guide shafts;
A rotating member which rotates the coupled previously Kiho support member while engaged with the feed screw, around the leading Kikai shaft,
A pressing member that presses the rotating member toward the feed screw;
The pivot shaft, said rotating member substantially perpendicular to the direction of Ru pressing force to be placed on a tangent to the outer periphery of the feed screw to the feed screw,
The lens barrel that intersects the straight line connecting the two guide shafts and the optical member at a position closer to the feed screw on the surface orthogonal to the optical axis . The rotating member meshes with the feed screw at a single meshing position in the circumferential direction of the feed screw,
The lens barrel according to claim 1 tangent to the outer periphery of the feed screw, which intersects the front Kikaido axis in said single engagement position. The rotating member meshes with the feed screw at a pair of meshing positions separated in a direction parallel to the optical axis,
The lens barrel according to claim 1, wherein the pressing member causes the pressing force to act on the rotating member at a center of the pair of meshing positions. Before Kiho support member has a pair of fitting portions for fitting to one of the two guide shafts by a pair of mating position separated to the direction parallel to the optical axis,
The lens barrel according to claim 3, wherein a center position of the pair of fitting portions and a center position of the pair of meshing positions are located on a single surface orthogonal to the optical axis. The optical member Kiho support member before holding the, for the optical axis direction, the lens barrel according to claim 4 having a center of gravity in the center of the pair of engagement position. The lens barrel according to any one of claims 1 to 5,
An imaging apparatus comprising: an imaging element that captures a subject image formed by the lens barrel.

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