JP2008176234A - Lens barrier mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrier mechanism capable of securing high dust-proof properties with a simple constitution. <P>SOLUTION: The lens barrier mechanism includes: a lens holding cylinder (batch lens barrel) 1 holding a lens 3; and a barrier blade driving member 4 located in the side of an object in the lens holding cylinder 1 and rolling with an imaging optical axis as the center. Then, the lens holding cylinder 1 has a rail part 11 circularly formed and surrounding the imaging optical axis, and the barrier blade driving member 4 has a notched part 47 fitted with the rail part 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens barrier mechanism for protecting a lens of an optical device such as a camera.

  Many cameras have been commercially available that provide a lens barrier in front of the photographic lens and close the lens barrier so that sand, dust, etc. are not attached to the photographic lens when shooting is not performed when carrying the camera.

  The lens barrier is opened at the time of shooting, but in a state where shooting is not performed, for example, in a camera with a mechanism in which the lens barrel of the shooting lens advances and retracts, a lens that drives and closes the lens barrier is detected. Barrier opening and closing devices are known.

  Also, in such a lens barrier opening / closing device, in order to secure a space for the lens barrier to retract when opened, a configuration in which two or more lens barriers are arranged symmetrically about the optical axis of the photographing lens is often used. .

  In addition, a mechanism for improving the dustproof property of the lens barrier has been proposed.

  In Patent Document 1, as shown in FIGS. 8 and 9, a lens holder 102 that holds the lens 101 and an exterior member 103 are used by utilizing a mechanism in which the lens 101 closest to the subject advances and retreats in the optical axis direction with a focus ball. To prevent sand dust entry path.

  Further, in Patent Document 2, as shown in FIG. 10, the barrier blade driving member 111 is moved to the subject side and is brought into contact with the exterior member 113 together with the barrier blade 112 to block the sand dust entry path. .

  In addition, providing a sheet or other dedicated member for preventing sand dust from entering the inside of the lens barrel is a known means for improving the dust resistance.

Furthermore, the structure shown in FIG. 11 is also known. FIG. 11 shows the first group lens barrel 1, the lens 3, the barrier blade driving member 4, the sliding surface 12, and the fitting portion 13.
Japanese Patent Laid-Open No. 06-202197 JP 09-061887 A

  The structure described in Patent Document 1 is a condition that the front lens focus is used, and cannot be applied to the mainstream rear lens focus optical device. If the lens fixed to the front lens does not use the forward / backward movement at the time of focusing, a new member for blocking the entry path of sand dust and another mechanism for moving it back and forth are required.

  In addition, the focus ball moves back and forth in the optical axis direction at the time of focus, so the part that blocked the entry of sand debris is released, and when it is re-blocked, the sand debris that has adhered is caught and the barrier function is impaired. There is a risk of coming.

  Unlike the structure of Patent Document 1, the structure described in Patent Document 2 can be applied to devices other than front-lens focus optical devices. However, a mechanism for moving the barrier blade driving member back and forth in the optical axis direction is required, and a space sufficient to move the barrier blade driving member back and forth in the optical axis direction is required, which has been an obstacle to downsizing the camera.

  Furthermore, there is a possibility that sand dust (mainly against the barrier blade driving member) adhering at the time of interruption from the state where the path of the sand dust is interrupted will bite and disturb the barrier function. In particular, the end of the barrier blade drive member exposed at the time of shutoff is a part that rotates while fitting in the radial direction with the lens barrel when it is opened. Can be.

  These conventional examples are basically aimed at blocking the entry of sand debris into the barrier mechanism part, and when the mechanical mechanism completely shuts off and when it cannot be shut off, switching occurs. Sometimes it created a situation that was prone to failure.

  Furthermore, in the structure of FIG. 11, when sand dust enters from the direction of the arrow, it immediately reaches the fitting portion 13 and the sliding surface 12, and the barrier blade driving member 4 cannot rotate and opens and closes the barrier blade 5. Prone to defects.

  An object of the present invention is to provide a lens barrier mechanism that can ensure high dust resistance with a simple configuration.

  In order to achieve the above object, a lens barrier mechanism according to claim 1 includes a lens holding cylinder that holds a lens, and a barrier blade driving member that is positioned on a subject side of the lens holding cylinder and rotates about an imaging optical axis. The lens holding cylinder has a rail portion formed in an arc shape surrounding the imaging optical axis, and the barrier blade driving member has a notch portion into which the rail portion is fitted. It is characterized by that.

  The lens barrier mechanism of the present invention includes a lens holding cylinder that holds a lens, and a barrier blade driving member that is positioned on the subject side of the lens holding cylinder and rotates about the imaging optical axis. The lens holding cylinder has a rail portion formed in an arc shape surrounding the imaging optical axis, and the barrier blade driving member has a notch portion into which the rail portion is fitted.

  With this configuration, high dust resistance can be ensured with a simple configuration.

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

  FIG. 1 is an exploded perspective view of a lens barrier mechanism according to an embodiment of the present invention.

  In FIG. 1, the lens barrier mechanism is fixed to a first group barrel 1, a cam pin 2 for interlocking with a cam barrel (not shown) in order to advance and retract the first group barrel 1 in the optical axis direction, and the first group barrel 1. A lens 3, a barrier blade driving member 4 for driving the barrier blade, and a barrier blade 5 are provided.

  The lens barrier mechanism also includes a drive spring 6 that acts in both directions of opening and closing of the barrier blade 5, a cover member 7 that determines the opening of the barrier and covers the functional members 4 to 6 of the barrier, and a decorative plate 8.

  Other configurations will be described below together with their operations.

  2A and 2B are front views of the lens barrier mechanism of FIG. 1, in which FIG. 2A shows an open state of the barrier, and FIG. 2B shows a closed state of the barrier.

  The barrier opening / closing mechanism will be described below.

  At the time of transition from the camera use state of FIG. 2A to the camera non-use state (collapsed state) of FIG. The portion 41 abuts against a protrusion of a mating member (not shown) and rotates clockwise with respect to the optical axis.

  The barrier blade 5 is pulled by the drive spring 6 hung between the hook portion 51 and the hook portion 42 of the barrier blade driving member 4 and rotates counterclockwise with respect to the rotation center 53, thereby closing the barrier blade 5. . The barrier blade driving member 4 rotates further clockwise (overcharge) even when the two opposing barrier blades 5 are closed, and ensures the stability of the closed state of the barrier blade 5.

  When the camera is not in use in FIG. 2B and the camera is in use in FIG. 2A, the first lens barrel 1 is extended forward, and the contact of the cam 41 of the barrier blade driving member is released. Then, the barrier blade driving member 4 rotates counterclockwise with respect to the optical axis.

  The abutting surface 43 of the barrier blade driving member 4 abuts on the protrusion 52 projecting toward the imaging surface side of the barrier blade 5 and rotates the barrier blade 5 clockwise with respect to the rotation center 53, thereby causing the barrier blade 5 to move. open.

  The opening force of the barrier blade 5 is a rotational moment generated by the tension of the drive spring 6 applied to the barrier blade 5 and the distance from the rotation center 53 of the barrier blade 5 to the point where the force acts (hook portion 51 and projection portion 52). It is caused by the difference.

  That is, the barrier blade 5 is applied with the component force of the tension of the drive spring 6 in the direction in which the barrier blade 5 is closed by the hook portion 51 and the direction in which the barrier blade 5 is opened, and the protrusion portion 52 located farther from the rotation center 53 than the hook portion 51. The rotational moment of is greater. As a result, the barrier blade 5 rotates in the opening direction.

  Next, the shape which improves dustproofness is demonstrated.

  3 is a front view of the first group barrel in FIG. 1, FIG. 4 is a perspective view from the imaging surface side of the barrier blade driving member in FIG. 1, and FIG. 5 is a cross-sectional view taken along line AA in FIG. is there.

  As shown in FIG. 3, rail portions 11 on an arc centered on the optical axis are provided at two locations on the upper and lower sides of the first lens barrel 1, and further, a sliding surface 44 of the barrier blade driving member 4 in FIG. Four contact surfaces 12 are provided.

  The barrier blade driving member 4 is provided with a notch portion (notch portion 47 shown in FIG. 6 described later) into which the rail portion 11 enters, and the bottom surface serves as a sliding surface 44. Further, six fitting portions 13 are provided in the outer diameter direction of the rail portion 11, and the fitting portion 45 which is a side surface on the outer diameter side of the notch portion of the barrier blade driving member 4 extends along the fitting portion 13. Slide and rotate around the optical axis.

  Thus, since the sliding surface 44 in the optical axis direction that determines the movement of the barrier blade driving member 4 and the fitting portion 45 in the radial direction are formed inside the barrier blade driving member 4, malfunction due to sand dust is caused. It has a structure that is difficult to cause.

  6 is a schematic cross-sectional view of the group of lens barrels and the barrier blade driving member in FIG. 1. FIG. 6A is an example of a U-shaped barrier blade driving member, and FIG. An example of an L shape, (c) shows an example in which the barrier blade driving member is an L shape.

  When the structure of FIG. 6A is compared with the conventional structure shown in FIG. 11, since the fitting portion 13 and the sliding surface 12 enter the notch portion 47 of the barrier blade driving member 4, the sand dust entry path is The shape is complicated and it is difficult for sand dust to reach.

  6B and 6C have a structure in which there is no wall of the barrier blade driving member 4 on the side not fitted to the fitting portion 13. Although the structure of FIG. 6A is optimal, even with this structure, it is more difficult for sand dust to reach the fitting portion 13 and the sliding surface 12 than the structure of FIG.

  Although the sliding surface 12 and the fitting portion 13 described above are divided into a plurality of parts for reasons of maintaining dimensional accuracy and reducing sliding resistance with the barrier blade driving member 4, they may be connected. Moreover, as shown in FIG. 5, in this Embodiment, although the outer diameter side of the rail part 11 is fitted with the barrier blade drive member 4, you may make it fit on the inner diameter side.

  Next, in FIG. 1, FIG. 3, and FIG. 4, it will be described that the end portion 14 a or 14 b of the rail portion 11 of the first group barrel 1 functions to restrict the rotation of the barrier blade driving member 4.

  When assembling the barrier parts, first, the barrier blade driving member 4 is assembled on the subject side of the first group barrel 1 in accordance with the assembling phase. At this time, the barrier blade driving member 4 can freely rotate with respect to the rotation direction. However, when the barrier blade driving member 4 is rotated clockwise, the end portion 46b of the barrier blade driving member 4 becomes the end portion 14b of the rail portion 11 of the first lens barrel 1. Further rotation is restricted in contact with.

  On the other hand, when rotating counterclockwise, the end 46a of the barrier blade driving member 4 contacts the end 14a of the rail portion 11 of the first group barrel 1 and further rotation is restricted.

  In the present embodiment, the barrier blade driving member 4 can be incorporated in any position of the retracted state, the WIDE state, and the TELE state. However, in consideration of workability, the WIDE or the charging amount of the driving spring 6 is the smallest. It is desirable to assemble in the TELE state.

  In the WIDE or TELE state, the first group barrel 1 is extended to the subject side, and the cam portion 41 of the barrier blade driving member 4 is not restricted in rotation by the protrusions (not shown), and thus is particularly counterclockwise. It effectively acts as a rotation restricting means.

  Thereafter, the shafts 54 of the two barrier blades 5 are respectively assembled in the rotation center hole 15 of the first group barrel 1, and the drive spring 6 is hooked on the hook portion 51 of the barrier blade 5 and the hook portion 42 of the barrier blade drive member 4. Go.

  When the first drive spring 6 is applied, the barrier blade drive member 4 rotates counterclockwise, and the end 46a of the barrier blade drive member 4 abuts on the end 14a of the rail portion 11 of the first lens barrel 1 and rotates. As a result, the workability of assembling the second drive spring 6 is improved.

  Normally, these rotation restrictions can be freely set between the barrier blade driving member 4 and the first group lens barrel 1, but by providing inside the barrier blade driving member 4, other spaces can be used effectively. There is an advantage that can be.

  Next, the use of the space on the subject side of the rail portion 11 of the first group barrel 1 will be described with reference to FIG.

  7 is a cross-sectional view including a rectilinear member located on the imaging surface side of the first group barrel in FIG.

  In FIG. 7, a notch portion 14 is provided on the subject side of the rail portion 11. The cutout portion 14 includes a rectilinear member 9 that advances and retreats in the optical axis direction on the subject side of the first group barrel 1. The protruding portion 91 can be inserted into the cutout portion 14 of the first lens barrel 1 without opening a through hole in a state in which the moving member 9 is pressed in the retracted state.

  For example, when the rectilinear member 9 is a shutter actuator or the like and the coil stud protrudes in the optical axis direction like the protruding portion 91, the through-hole is formed in the first lens barrel 1 without changing the retracted length. The stud protrusion 91 can be accommodated without opening.

  Here, the reason for avoiding a through hole in the first group barrel 1 is to avoid light leakage and intrusion of sand dust into the first group barrel 1. In this way, it is possible to create a space behind the portion where the rail portion 11 protrudes toward the subject side in the optical axis direction, thereby realizing optimal storage.

It is a disassembled perspective view of the lens barrier mechanism which concerns on embodiment of this invention. It is a front view of the lens barrier mechanism of FIG. FIG. 2 is a front view of a first group barrel in FIG. 1. It is a perspective view from the imaging surface side of the barrier blade drive member in FIG. It is AA sectional drawing of Fig.2 (a). FIG. 2 is a schematic cross-sectional view of the first group barrel and the barrier blade driving member in FIG. It is sectional drawing containing the rectilinear member located in the imaging surface side of the 1 group lens barrel in FIG. It is a block diagram which shows the one aspect | mode of a 1st prior art example. It is a block diagram which shows the other aspect of a 1st prior art example. It is a block diagram of the 2nd prior art example. It is a block diagram of a 3rd prior art example.

Explanation of symbols

1 Group lens barrel (lens holding tube)
4 Barrier blade drive member 5 Barrier blade 6 Drive spring 9 Straight member 12 Sliding surface (second surface) of first lens barrel 1
13 Fitting part (first surface) of first group barrel 1
14 notch 44 sliding surface 45 of barrier blade drive member 4 fitting surface 47 of barrier blade drive member 4 notch 91 protrusion

Claims (6)

In a lens barrier mechanism having a lens holding cylinder that holds a lens, and a barrier blade driving member that is positioned on the subject side of the lens holding cylinder and rotates about an imaging optical axis,
The lens holding cylinder has a rail portion formed in an arc shape surrounding the imaging optical axis,
The lens barrier mechanism, wherein the barrier blade driving member has a notch portion into which the rail portion is fitted.   2. The lens barrier mechanism according to claim 1, wherein the rail portion has a first surface in contact with the barrier blade driving member in a radial direction and a second surface in contact with an optical axis direction.   2. The lens barrier according to claim 1, wherein at least two of the surfaces formed by the notch portions of the barrier blade driving member are in contact with the first surface and the second surface of the rail portion. mechanism.   The lens barrier mechanism according to claim 1, wherein the second surface of the rail portion is located closer to the subject side than the first surface.   The lens barrier mechanism according to claim 1, wherein both ends of the rail portion are rotation restricting means of the barrier blade driving member.   2. The lens barrier mechanism according to claim 1, further comprising a rectilinear member that advances and retreats in an optical axis direction on an image plane side of the lens holding cylinder, and a protrusion of the rectilinear member enters a notch portion of the rail portion. .

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