JP2006106396A - Lens barrel and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve dust-proof/drip-proof performance in a lens barrel having a lens barrier. <P>SOLUTION: The lens barrel includes: a leading-end cover member 20 having an opening OP for exposing a photographic lens 1; a lens projecting barrier 40 disposed inside the cover member 20 and used to close/open the opening OP; and a barrier pressing member 10b by which the barrier 40 in a closing state is pressed to the cover member 20 side and the part of the barrier 40 apart from the opening OP is pressed to the inside circumferential edge of the opening OP. The barrier pressing member 10 is formed, for example, on a lens holding frame 10. As the barrier is opened, the lens holding frame 10 for holding the lens 1 is extended out in the direction of an optical axis from the cover member 20. Thus, the lens holding frame 10 fills a gap between the lens and the end of the opening. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel having a lens barrier and a camera having the lens barrel, and more particularly to a lens barrel that takes dust and drip-proof properties into consideration.

  The lens barrier protects the lens by closing the lens exposure opening provided on the front surface of the lens barrel from the inside, and opens the opening to expose the lens when the camera is used. The opened barrier is accommodated in a barrier retreat space in the lens barrel. In particular, in Patent Documents 1 and 2, the barrier is opened and closed using a rotating body that rotates around the optical axis.

JP 2001-215559 A Japanese Patent Laid-Open No. 5-19331

  By the way, if dust or moisture enters the lens barrel, the operation and optical performance of each part may be hindered. Therefore, it is necessary to provide the lens barrel with dustproof and dripproof properties. However, the lens barrels of Patent Documents 1 and 2 do not take into account dust and drip proofing in the vicinity of the lens barrier, and there is a risk of inconvenience due to intrusion of dust and moisture. Even if the barrier is in a closed state, there is a gap between the barrier and the peripheral edge of the lens exposure opening, and moisture or the like that has entered from this gap may accumulate in the barrier standby space when it rains. Some cameras have a hole for drainage in the lower part of the lens barrel so that the water accumulated in the barrier retreat space can be naturally dropped from the hole. However, since it is impossible to provide a large hole in the lens barrel, it is not easily drained in a stationary state due to the surface tension of water, and it is necessary to shake out the camera to discharge water.

The lens barrel according to the first to fourth aspects of the present invention includes a tip cover member having an opening for exposing the photographing lens, a lens protection barrier that closes / opens the opening inside the cover member, and a closed state. A barrier pressing member that presses a certain barrier toward the cover member and presses a portion removed from the opening of the barrier against the inner peripheral edge of the opening.
In particular, the invention of claim 2 further includes a closing member for closing the space between the opening end surface and the lens when the barrier is opened.
According to a third aspect of the present invention, the lens holding frame that holds the lens constitutes a closing member, and the lens holding frame is extended in the optical axis direction with respect to the cover member as the barrier is opened. It is intended to be blocked.
The invention of claim 4 is configured to release the pressing by the barrier pressing member prior to opening the barrier.
According to a fifth aspect of the present invention, the barrier pressing member is formed on a lens holding frame that holds a lens.
The lens barrel according to the sixth to eighth aspects of the present invention includes a tip cover member having an opening for exposing a photographing lens, a lens protection barrier that closes / opens the opening inside the cover member, and a lens. And a lens holding frame having a barrier pressing portion at the tip and movable in the optical axis direction, and a drive mechanism for opening and closing the barrier and driving the lens holding frame. The drive mechanism holds the barrier in a closed state during non-photographing, and the barrier pressing portion presses the barrier toward the cover member, so that the portion of the barrier that is removed from the opening is pressed against the inner peripheral edge of the opening. The position of the lens holding frame is set so that the barrier is opened when shifting from the non-shooting state to the shooting state, and the lens holding frame is extended with respect to the cover member, and the lens holding frame closes the gap between the opening end surface and the lens. .
Particularly, the invention of claim 7 is such that when the barrier is opened, the lens holding frame is retracted with respect to the barrier so that the pressure by the barrier pressing portion is released, and then the lens holding frame is extended to the cover member. It is.
According to an eighth aspect of the present invention, the drive mechanism includes a single motor serving as a drive source for both the barrier and the lens holding frame.
A camera according to a ninth aspect of the invention has the lens barrel according to any one of the first to eighth aspects.

  According to the present invention, the barrier in the closed state is pressed to the cover member side, and the portion removed from the opening of the barrier is pressed against the inner peripheral edge of the opening, so that the gap between the opening end and the barrier is closed. In this way, intrusion of dust, moisture, etc. from the gap is prevented, so that the dustproof / dripproof property can be improved.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a partial cross-sectional view of a digital still camera according to this embodiment. Reference numeral 13 denotes a camera body, and reference numeral 14 denotes a camera exterior cover. The camera has a zoom lens barrel LB including a lens barrier 40, and FIG. 1 shows a state where the lens is in a non-photographing position (collapsed position). The extension of the lens from the non-photographing position to the photographing position, zooming at the photographing position, and opening / closing of the barrier are performed using one zoom motor (not shown) as a drive source. Details of each part will be described below.

<Lens drive mechanism>
The fixed barrel 15 of the lens barrel is fixed to the camera body 13 with screws 30, and a cam barrel 16 is provided on the inner peripheral side thereof. The cam cylinder 16 rotates around the optical axis when a driving force of a zoom motor (not shown) is transmitted to the gear portion 16b. The cam follower 16 a provided on the cam cylinder 16 is engaged with the cam of the fixed cylinder 15, so that the cam cylinder 16 advances and retreats in the optical axis direction while rotating with respect to the fixed cylinder 15, that is, the camera body 13. As shown in FIG. 4, the cam cylinder 16 is provided with three types of cam grooves 16 c to 16 e, which contribute to driving of the first group lenses 1 to 3, the second group lenses 4 to 6 and the barrier drive ring 18 described later. To do.

  The rectilinear guide cylinder 17 is rotatably held with respect to the cam cylinder 16 and advances and retreats in the optical axis direction together with the cam cylinder 16. However, the linear guide cylinder 17 does not rotate relative to the fixed cylinder 15 due to a rotation restriction (not shown) provided in the fixed cylinder 15. The straight guide tube 17 is formed with three types of straight guide grooves 17a to 17c (FIG. 4) corresponding to the cam grooves 16c to 16e.

  The first group lenses 1 to 3 are held by the first group lens frame 10, and the cam follower 10 a provided on the first group lens frame 10 penetrates the groove 17 b of the rectilinear guide cylinder 17 and engages with the cam groove 16 c of the cam cylinder 16. is doing. As a result, the first group lens frame 10, that is, the first group lenses 1 to 3 move forward and backward in the optical axis direction with respect to the cam cylinder 16 according to the rotation of the cam cylinder 16. On the other hand, the second group lenses 4 to 6 are held by the second group lens frame 11 together with the shutter 25, and the cam follower 11a of the second group lens frame 11 passes through the groove 17c of the rectilinear guide tube 17 and the cam groove 16d of the cam tube 16. Is engaged. As a result, the second group lenses 4 to 6 and the shutter 25 advance and retract in the optical axis direction with respect to the cam cylinder 16 in accordance with the rotation of the cam cylinder 16. Zooming is performed by the advance / retreat of the first / second group lenses 1 to 6 with respect to the cam cylinder 16 and the advance / retreat of the cam cylinder itself with respect to the fixed cylinder 15.

  The third group lens 7 held by the third group lens frame 12 is a focus lens, and is driven in the optical axis direction by a focus motor (stepping motor) (not shown). Reference numeral 8 denotes an optical low-pass filter, and 9 denotes an image sensor such as a CCD.

<Barrier structure>
The barrier frame 20 provided in front of the first group lens frame 10 is formed with an opening OP for exposing a lens, and a barrier 40 is provided inside thereof. The barrier 40 is composed of four barrier blades 41A, 41B, 42A, and 42B. When the barrier is closed, these barrier blades close the opening OP to protect the lens (FIG. 1). A barrier retracting space is formed between the barrier frame 20 and a blade pressing plate 21 provided behind the barrier frame 20, and when the barrier is opened, the barrier blade is retracted into the retracting space, so that the lens is exposed through the opening OP. (FIG. 3).

  FIG. 8 is a view of the barrier 40 and its opening / closing mechanism as viewed from the image sensor side. The upper barrier blades 41A and 42A are rotatably supported around a shaft 51a protruding from the barrier frame 20, and the lower blades 41B and 42B are rotatably supported by the same shaft 51b. Blade driving springs (torsion springs) 45A and 45B are respectively inserted on the shafts 51a and 51b, and the four barrier blades are urged in the closing direction by their urging forces, and in the closed state, the barrier blades 41A and 41B The tips are in contact with each other, and the barrier blades 42A and 42B are arranged above and below the blades 41A and 41B, respectively.

  When a force in the opening direction is applied to the barrier blades 41A and 41B in the barrier closed state, the barrier blades 41A and 41B begin to open around the shafts 51a and 51b against the urging force of the springs 45A and 45B. Part of the blades 41A and 41B comes into contact with the outer barrier blades 42A and 42B, and the barrier blades 42A and 42B also start to open. When the force to the blades 41A and 41B is cut off with each barrier blade fully open, each blade is closed by the biasing force of the blade drive springs 45A and 45B.

<Barrier drive mechanism>
The barrier blades are opened by transmitting the biasing force of the biasing spring 55 to the blades 41A and 41B via the barrier drive ring 19. The barrier drive ring 19 is rotatable about the optical axis with respect to the first group lens frame 10 and is urged counterclockwise by the urging spring 55 in FIG. FIG. 8 shows a state in which the rotation of the barrier drive ring 19 is prevented by the claw 18b of the barrier drive cylinder 18, and the barrier blades are closed at this time.

  The barrier drive cylinder 18 is rotatably supported by the blade pressing plate 21 described above, and the blade pressing plate 21 is fixed to the barrier frame 20 by a mechanism (not shown). Therefore, the barrier frame 20, the four barrier blades, the blade pressing plate 21, and the barrier driving cylinder 18 are integrated with respect to the optical axis direction and are movable in the optical axis direction with respect to the first group lens frame 10. The cam follower 18a of the barrier drive cylinder 18 passes through the groove 17a of the rectilinear guide cylinder 17 and engages with the cam groove 16e of the cam cylinder 16, and receives rotational force from the cam groove 16e.

  When the claw 18b rotates counterclockwise by the rotation of the barrier drive cylinder 18, the barrier drive ring 19 rotates in the same direction by the urging force of the urging spring 55, and the notched claw portion of the ring 19 contacts the blades 41A and 41B. Apply force in the opening direction. As a result, the barrier blades 41A and 41B are opened as described above, and the barrier blades 42A and 42B are also opened following this. When the barrier drive cylinder 18 rotates in the reverse direction, the barrier drive ring 19 is rotated clockwise against the biasing force of the spring 55, and the force in the opening direction on the barrier blades 41A and 41B is cut off by the claw 18b. The four barrier blades are closed by the biasing force of the blade drive springs 45A and 45B.

<Dust-proof and drip-proof structure>
In FIG. 1, ring-shaped drip-proof rubbers 27, 28, and the like are provided in the gaps between the camera exterior cover 14 and the cam cylinder 16, the cam cylinder 16 and the barrier driving cylinder 18, and the barrier driving cylinder 18 and the first group lens frame 10. 29 is interposed over the entire circumference. These drip-proof rubbers 27 to 29 are attached to the inner peripheral surface of the outer member, respectively, and are in close contact with the inner member by elastic force to prevent water and dust from entering from each gap and are also light-shielding. Also plays a role.

  Further, a projection 10b is formed on the front surface of the first group lens frame 10 as shown in FIG. 9, and when the barrier is closed (when the power is off), the projection 10b pushes the barrier blades 41A and 41B as shown in FIG. It is pushing forward from the inside. Accordingly, the upper and lower portions of the barrier blades 41A and 41B press the barrier blades 42A and 42B, respectively, and the upper and lower portions of the barrier blades 42A and 42B press the inner surface of the barrier frame 20 (the edge of the opening OB). Is done. Accordingly, the gap between the pair of upper and lower barrier blades and the gap between the barrier blades 42A and 42B and the barrier frame 20 are closed, and entry of dust and moisture into the barrier retreat space is prevented.

<Operation>
In the camera configured as described above, when the power of the camera is turned on in the non-shooting state of FIG. 1, the camera rotates a zoom motor (not shown) in a predetermined direction so as to extend the lens to the shooting position. As a result, the cam cylinder 16 moves forward and backward with respect to the fixed cylinder 15 while rotating, and drives the lens and opens the barrier 40 by the cam action.

  4 to 7 are developed views showing the relative positional relationship between the cam grooves 16c to 16e, the rectilinear guide grooves 17a to 17c, and the cam followers 10a, 11a, and 18a. 4 corresponds to the non-photographing state of FIG. 1, and the rotation of the cam cylinder 16 is represented as a movement in the direction of the arrow in the figure. In the following description, a system including the barrier frame 20, the barrier blades, the blade pressing plate 21, and the barrier drive cylinder 18 is referred to as a barrier unit.

  FIG. 5 shows a state when the cam cylinder 16 is rotated to some extent from the non-photographing state. During this time, the barrier drive cylinder 18 rotates around the optical axis via the cam follower 18a, and the first group lens frame 10 passes through the cam follower 10a. Thus, the barrier drive cylinder 18 (barrier unit) is retracted in the optical axis direction. FIG. 2 corresponds to FIG. 5, and it can be seen that the protrusion 10 b is retracted from the barrier blades 41 </ b> A and 41 </ b> B by the retreat of the first group lens frame 10. That is, by releasing the barrier pressing by the protrusions 10b, each of the closed gaps is opened so that the friction load does not act when the barrier is opened. Since the barrier driving cylinder 18 has already started rotating, the barrier is in the middle of opening in FIG.

  FIG. 6 shows a state when the wide end position (photographing position) is reached by further rotation of the cam cylinder 16, and when this position is reached, the zoom motor is stopped and photographing is allowed. Thereafter, zooming can be performed between the wide end and the tele end according to an operation of a zoom button (not shown). At the wide end, it can be seen that the first group lens frame 10 has advanced to the barrier unit side as compared with FIG. At the wide end, the cam follower 18a reaches a portion parallel to the optical axis of the groove 17c, so that the barrier drive cylinder 18 no longer rotates during subsequent zooming.

  FIG. 7 shows an intermediate position between the wide end and the tele end. At this time, the lens barrel is in the state shown in FIG. From the wide end to this state, the cam follower 18a can move in the optical axis direction with respect to the rectilinear guide tube 17. Since the cam groove 16e has the same shape as the 16ca portion of the cam groove 16c, the relative positional relationship between the first group lens frame 10 and the barrier unit does not change, and it does not change during further zooming to the tele side. I understand. That is, immediately after the barrier 40 is fully opened, the front end of the first group lens frame 10 reaches the opening OP of the barrier frame 20 (wide end), and this positional relationship is maintained throughout the zooming. In this positional relationship, as can be seen from FIG. 3, the outer peripheral surface of the front end of the first group lens frame 10 is in contact with the inner peripheral surface of the opening OP, and the entire surface is between the end surface of the opening OP and the lens 1 by the first group lens frame. It becomes the form obstructed over. Therefore, intrusion of dust and moisture from the opening OP is prevented.

  When the power switch of the camera is turned off, the zoom motor is driven and the lens is driven toward the non-photographing position. After reaching the wide end, the first group lens frame 10 moves backward with respect to the barrier unit by an operation reverse to that described above, and when the barrier 40 is closed by the rotation of the barrier driving cylinder 18, the first group lens is closed. The frame 10 slightly advances to press the barrier blades 41A and 41B, and the state shown in FIG. 1 is obtained. Thereafter, the power is turned off.

As described above, in the present embodiment, in addition to the use of the drip-proof rubbers 27 to 29, when the barrier is closed, the barrier 40 is pushed from the inside by the protrusion 10b to prevent dust and drip. The lens frame 10 closes the space between the opening OP and the lens to prevent dust and water. Therefore, a high level of dustproof / drip-proof performance can always be obtained regardless of the state of the lens barrel, which is advantageous for shooting in rainy places or places with a lot of dust. Moreover, according to said structure, it is not necessary to provide the hole for drainage in a lens-barrel, and it is not necessary to perform the troublesome operation | work which a user shakes a camera and discharges water from a hole. Further, in the present embodiment, the barrier is pressed and released, and the opening is closed when the barrier is opened using the existing members (the first group lens frame 10, the cam barrel 16, the zoom motor, etc.). There is no need to add members other than 27 to 29, which is advantageous in terms of space and cost.
The drip-proof rubbers 27 to 29 are not essential requirements of the present invention.

  The barrier pressing protrusion 10b provided on the first group lens frame 10 can be given a role of a lens hood (a function of blocking harmful light) by devising a shape. At that time, it is desirable that the projection amount is suppressed only at the portions corresponding to the four corners so as not to cause vignetting at the four corners of the screen. Moreover, the barrier pressing member is not limited to that provided in the first group lens frame 10, and a member dedicated to pressing may be added. In this case, the barrier pressing member may be driven at an appropriate timing by an actuator other than the zoom motor. Further, the member that closes the gap between the end surface of the opening OP and the lens when the barrier is opened is not limited to the first group lens frame.

  Although the barrier driving ring is used to open and close the barrier, other methods may be used to open and close the barrier. The lens barrier is shown as having four blades, but it may be, for example, two blades. Further, although the zoom lens barrel has been described, it may be a single focus lens that can be moved only at two positions of a non-photographing position (collapse position) and a photographing position, or a non-collapseable lens barrel. Even when the present invention is applied to a non-collapse type single focus lens, it is possible to improve the dustproof / dripproof performance as described above by pressing the barrier from the inside when the barrier is closed.

It is sectional drawing which shows the lens-barrel part of the camera in one Embodiment, and shows a state when a lens exists in a non-photographing position. FIG. 6 is a view similar to FIG. 1 and shows a state where the lens is at an intermediate position between the retracted position and the wide end position. FIG. 6 is a view similar to FIG. 1 and shows a state where the lens is at an intermediate position between the wide end position and the tele end position. FIG. 2 is a development view showing a positional relationship among a cam groove, a rectilinear guide groove, and a cam follower, and corresponds to a non-photographing position in FIG. 4 is a view similar to FIG. 4 and corresponds to the intermediate position of FIG. In the same view as FIG. 4, it corresponds to the wide end position. 4 is a view similar to FIG. 4 and corresponds to the intermediate position of FIG. The figure which shows a lens barrier and its drive mechanism. The front view which shows the front-end | tip part of a 1st group lens frame, and the bb sectional view taken on the line.

Explanation of symbols

1-3 1st group lens 2-6 2nd group lens 10 1st group lens frame 10b Barrier pressing projection 10a, 11a, 18a Cam follower 11 2nd group lens frame 13 Camera body 14 External cover 15 Fixed cylinder 16 Cam cylinder 16c-16e Cam Groove 17 Linear guide cylinder 17a-17c Linear guide groove 18 Barrier drive cylinder 18b Claw 19 Barrier drive ring 20 Barrier frame 21 Blade pressing plate 40 Lens barrier 41A, 41B, 42A, 42B Barrier blade 55 Energizing blade LB Lens barrel OP lens Opening for exposure

Claims (9)

A tip cover member having an opening for exposing the photographing lens;
A lens protecting barrier that closes / opens the opening inside the cover member;
A lens barrel comprising: a barrier pressing member that presses a barrier in a closed state toward the cover member and presses a portion of the barrier that is removed from the opening against an inner peripheral edge of the opening.   The lens barrel according to claim 1, further comprising a closing member that closes a gap between the opening end face and the lens when the barrier is opened.   The closing member is constituted by a lens holding frame for holding the lens, and the lens holding frame is extended in the optical axis direction with respect to the cover member as the barrier is opened, and performs the closing in the extended state. The lens barrel according to claim 2.   The lens barrel according to claim 1, wherein the lens barrel is configured to release the pressure by the barrier pressing member prior to opening the barrier.   The lens barrel according to claim 1, wherein the barrier pressing member is formed on a lens holding frame that holds the lens. A tip cover member having an opening for exposing the photographing lens;
A lens protecting barrier that closes / opens the opening inside the cover member;
A lens holding frame that holds the lens and has a barrier pressing portion at the tip, and is movable in the optical axis direction;
A drive mechanism for opening and closing the barrier and driving the lens holding frame;
The drive mechanism holds the barrier in a closed state during non-photographing, and the barrier pressing portion presses the barrier toward the cover member, so that a portion of the barrier that is removed from the opening is the opening. The lens holding frame is positioned so as to be pressed against the inner peripheral edge, and the barrier is opened when shifting from the non-photographing state to the photographing state, and the lens holding frame is extended to the cover member to hold the lens. A lens barrel, wherein a frame is closed between the opening end face and the lens.   The drive mechanism retracts the lens holding frame with respect to the barrier so that the pressure by the barrier pressing portion is released when the barrier is released, and then extends the lens holding frame with respect to the cover member. The lens barrel according to claim 6, wherein:   The lens barrel according to claim 6 or 7, wherein the driving mechanism includes a single motor serving as a driving source for both the barrier and the lens holding frame.   A camera comprising the lens barrel according to claim 1.

Images