JP2011138077A - Lens barrel and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a lens barrel, without reducing the operability of a barrier blade and the degree of freedom in design of the lens barrel. <P>SOLUTION: The lens barrel includes a barrier drive spring 43 attached between the spring hook part 41b of a barrier cover 41 and the spring hook part 42a of a barrier blade 42. The rotational hole 42b of the barrier blade 42 is rotatably supported by a rotational shaft provided in a barrier drive member, and the barrier drive spring is provided so that the charge amount of the barrier drive spring 43 is gradually decreased according to the opening operation of the barrier blade 42 accompanying the movement of the barrier drive member in the direction of an arrow B, when the barrier drive member is moved in the direction of an arrow A in such a state that the barrier blade 42 is restrained in an opening direction, the charge amount of the barrier drive spring 43 is gradually increased and when the barrier blade 42 is opened in such a state that the barrier drive member is restrained in the direction of the arrow A, the charge amount of the barrier drive spring 43 is gradually increased. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lens barrel and an imaging apparatus including a barrier blade that covers an imaging opening for allowing light to enter an imaging lens so as to be freely opened and closed.

  2. Description of the Related Art Conventionally, an imaging apparatus such as a digital video camera or a digital still camera forms a subject image with an imaging lens, and a CCD (Charge Coupled Device Image Sensor) image sensor or a CMOS (Complementary Metal Oxide) disposed at the rear of the imaging lens. Semiconductor) A subject image is captured by an image sensor such as an image sensor. In order to protect the imaging lens, the imaging device is provided with a barrier blade at the front of the imaging lens.

  Here, the barrier blade is closed when not photographing to protect the imaging lens, and is opened only when photographing so that light enters the imaging lens. As such a barrier blade opening / closing mechanism, a technique using a barrier drive ring and a spring has been conventionally known. Specifically, a barrier closing spring is provided between the barrier blade and the barrier driving ring, and a barrier opening spring is provided between the barrier driving ring and the lens barrel cover. The barrier blade is closed when the barrier drive ring is rotated clockwise, and the barrier blade is opened when the barrier drive ring is rotated counterclockwise.

  Also known is a technique in which a barrier drive spring is provided between the barrier drive member and the barrier blade so that the barrier drive spring functions as both a closing spring and an opening spring. Specifically, the distance from the rotation axis of the barrier drive member to the contact position between the barrier drive member and the barrier blade is L1, and the distance from the rotation axis of the barrier drive member to the action point of the barrier drive spring in the barrier drive member. L2, when the distance from the pivot axis of the barrier blade to the contact position between the barrier blade and the barrier drive member is L3, and the distance from the pivot axis of the barrier blade to the point of action of the barrier drive spring on the barrier blade is L4 In addition, the technique satisfies the relationship of L2 × L3> L1 × L4. The relational expression L2 × L3> L1 × L4 indicates that the moment Mo (= P × L2) to rotate in the opening direction> rotation in the closing direction when the tension acting on the barrier driving member by the barrier driving spring is P. It is derived from the moment Mc (= P × (L4 / L3) × L1).

JP-A-7-159856 JP 2008-33152 A

  However, the technique disclosed in Patent Document 1 requires two springs, a barrier closing spring and a barrier opening spring, which increases the number of parts and increases the cost. Further, the barrier closing spring is provided to absorb the escape movement of the barrier driving ring with respect to the barrier blade when the barrier blade cannot be rotated in the closing direction by some obstacle during the closing operation of the barrier blade. A space dedicated to the barrier closing spring is required. Therefore, there is also a problem that the lens barrel is increased in size.

On the other hand, in the technique of the above-mentioned Patent Document 2, since the barrier drive spring functions as both a closing spring and an opening spring, there is no problem of high cost due to providing two springs.
However, in order to reduce the diameter of the lens barrel, L1 + L3 is often limited. Therefore, if L1 is increased, L3 must be relatively decreased. Therefore, Mc = P × (L4 / L3) × L1 is increased, and the remaining force of the moment Mo that rotates the barrier driving member in the opening direction is reduced, so that the opening operation of the barrier blade tends to be unstable. On the other hand, when L3 is increased, L1 must be relatively decreased, so that the contact portion of the barrier blade approaches the photographing opening. As a result, it is not suitable for widening the angle, and the degree of freedom in designing the lens barrel is reduced.

  Therefore, the problem to be solved by the present invention is to enable the lens barrel to be reduced in size without reducing the operability of the barrier blades and the degree of freedom in designing the lens barrel.

The present invention solves the above-described problems by the following means.
According to a first aspect of the present invention, there is provided a photographing aperture member that is disposed at a front portion of the imaging lens and has a photographing aperture for allowing light to enter the imaging lens, the photographing aperture member, and the imaging lens. A barrier blade that is disposed between the barrier blade and that freely opens and closes the opening, a barrier driving member that opens and closes the barrier blade in response to switching between the photographing position and the standby position, and the photographing opening member and the barrier blade. A barrier driving spring mounted therebetween, and the barrier blade is rotatably supported on a rotating shaft provided on the barrier driving member, and the barrier driving member is rotated around the photographing aperture member. When it is supported in a movable manner and when it is switched to the standby position, it moves to the closed position for closing the barrier blade with respect to the opening, and when it is switched to the photographing position, The barrier drive spring moves to an open position for opening the barrier blade, and the barrier drive spring is charged according to the opening operation of the barrier blade in accordance with the movement of the barrier drive member from the closed position to the open position. When the barrier drive member is moved to the closed position while the barrier blades are restrained in the opening direction, the barrier drive spring moves according to the movement of the barrier drive member to the closed position. When the barrier blade is opened in a state where the barrier drive member is restrained in the moving direction to the closed position, the barrier drive spring is moved according to the opening operation of the barrier blade. This is a lens barrel provided so that the amount of charge increases gradually.

  According to a fourth aspect of the present invention, there is provided an imaging apparatus comprising a photographing aperture member, a barrier blade, a barrier driving member, and a barrier driving spring similar to those of the first aspect of the invention.

(Function)
According to the first and fourth aspects of the present invention, a photographing aperture member for allowing light to enter the imaging lens, a barrier blade disposed between the photographing aperture member and the imaging lens, and opening and closing the barrier blade And a barrier driving member to be driven. A barrier drive spring is attached between the photographing aperture member and the barrier blade. Therefore, it is not necessary to attach a barrier drive spring to the barrier drive member. One barrier driving spring can serve as both functions of a conventional closing spring and opening spring.

  According to the present invention, since it is not necessary to attach a barrier drive spring to the barrier drive member, the degree of freedom in designing the lens barrel is improved. Also, one barrier driving spring can be provided. Therefore, it is possible to achieve both the downsizing of the lens barrel and the operability of the barrier blades.

It is a front view which shows the structure of the digital still camera as one Embodiment (1st Embodiment) of the imaging device of this invention. It is the perspective view and sectional drawing which show the lens barrel of the digital still camera shown in FIG. 1, and shows the retracted state at the time of non-photographing. FIGS. 2A and 2B are a perspective view and a sectional view showing a lens barrel of the digital still camera shown in FIG. It is the perspective view and sectional drawing which show the lens barrel of the digital still camera shown in FIG. 1, and shows the pay-out state at the time of tele photography. 1 is an exploded perspective view showing a main part of a lens barrel for a digital still camera as an embodiment of a lens barrel of the present invention. FIG. 6 is a front view showing a state in which the barrier blades are fully closed in the barrier unit of the lens barrel shown in FIG. 5. FIG. 6 is a rear view showing a state in which the barrier blades are fully closed in the barrier unit of the lens barrel shown in FIG. 5. FIG. 6 is a front view showing a state where the barrier blades are fully opened in the barrier unit of the lens barrel shown in FIG. 5. FIG. 6 is a rear view showing a state where the barrier blades are fully opened in the barrier unit of the lens barrel shown in FIG. 5. 6 is a graph showing a relationship between an open / close state of a barrier blade and a charge amount of a barrier drive spring in the barrier unit of the lens barrel shown in FIG. FIG. 6 is an explanatory diagram illustrating a relationship between a barrier blade in a fully closed state and a barrier drive spring in the barrier unit of the lens barrel illustrated in FIG. 5. FIG. 6 is an explanatory diagram showing a relationship between a barrier blade and a barrier drive spring in a state in which the lens barrel shown in FIG. 5 starts to open from a fully closed state. FIG. 6 is an explanatory diagram showing a relationship between a barrier blade and a barrier drive spring in a fully opened state in the lens barrel barrier unit shown in FIG. 5. FIG. 6 is an explanatory diagram showing a relationship between a barrier blade and a barrier driving spring in a state where the barrier blade is forcibly opened in the barrier unit of the lens barrel shown in FIG. 5. FIG. 6 is an explanatory diagram showing an opening / closing operation of barrier blades in a state where a barrier driving member is eccentric in the barrier unit of the lens barrel shown in FIG. 5. It is a perspective view which shows the peripheral part of the lens barrel in a digital video camera as one Embodiment (2nd Embodiment) of the imaging device of this invention, and shows the state at the time of imaging | photography. It is a perspective view which shows the peripheral part of the lens barrel in a digital video camera as one Embodiment (2nd Embodiment) of the imaging device of this invention, and shows the state at the time of standby.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Here, it is assumed that the imaging apparatus according to the present invention is a digital still camera 10 and a digital video camera 110 in the following embodiments. In the following embodiments, the lens barrel in the present invention is assumed to be the lens barrel 20 for the digital still camera 10 and the lens barrel 120 for the digital video camera 110.
The description will be given in the following order:

1. First embodiment (imaging apparatus: digital still camera 10)
2. Second embodiment (imaging device: digital video camera 110)

<1. First Embodiment>
[External appearance of imaging device]

FIG. 1 is a front view showing a configuration of a digital still camera 10 as an embodiment (first embodiment) of an imaging apparatus of the present invention.
As shown in FIG. 1, the digital still camera 10 includes a rectangular parallelepiped body 11 constituting an exterior. A lens barrel 20 is incorporated on the right side of the body 11. In the non-photographing state shown in FIG. 1, the front side of the lens barrel 20 is covered with the barrier unit 40.
In the digital still camera 10 shown in FIG. 1, the left and right refer to the left and right viewed from the front side shown in FIG.

  Further, for example, a strobe light emitting unit 12 is built in the upper left of the lens barrel 20, and for example, a switch unit 13 is built in the left of the strobe light emitting unit 12. Furthermore, on the right side of the lens barrel 20, for example, an AF (Auto Focus) auxiliary light unit 14 is incorporated, and on the left side of the lens barrel 20, for example, a battery 15 is incorporated. Furthermore, for example, a condenser microphone 16 is incorporated in the lower right of the lens barrel 20.

[External appearance of lens barrel]

2 is a perspective view and a cross-sectional view showing the lens barrel 20 of the digital still camera 10 shown in FIG. 1, and shows a retracted state at the time of non-photographing.
FIG. 3 is a perspective view and a cross-sectional view showing the lens barrel 20 of the digital still camera 10 shown in FIG. 1, and shows the extended state during wide shooting.
Furthermore, FIG. 4 is a perspective view and a cross-sectional view showing the lens barrel 20 of the digital still camera 10 shown in FIG.
As shown in FIGS. 2 to 4, the lens barrel 20 is a retractable type. The imaging optical system of the lens barrel 20 includes a first lens group 21 (corresponding to an imaging lens in the present invention), a second lens group 22, an automatic exposure device 24, and a third lens group 23 arranged in order from the subject side. , And the image sensor 25.
For example, a CCD image sensor or a CMOS image sensor is used as the image sensor 25.

  Here, the second lens group 22 is movable in a direction perpendicular to the optical axis 20a in order to realize a camera shake prevention function. The automatic exposure device 24 is a light amount adjustment device having a shutter function and an iris function. The automatic exposure device 24 is held so as to be relatively movable in the direction of the optical axis 20a and is urged in a direction away from the second lens group 22 by a spring 26. ing. 2, a part of the second lens group 22 is housed in the opening of the automatic exposure device 24 at the time of non-photographing, and at the time of photographing shown in FIGS. The second lens group 22 moves relatively away from the optical axis 20a. Therefore, the second lens group 22 is retracted from the opening of the automatic exposure device 24.

Further, the first lens group 21 is extended with respect to the imaging element 25 fixed in the direction of the optical axis 20a at the time of photographing shown in FIGS. Then, the zooming operation of the optical system is performed by moving the second lens group 22 by a predetermined amount in the direction of the optical axis 20a. Furthermore, the focusing operation of the optical system is performed by moving the third lens group 23 by a predetermined amount in the direction of the optical axis 20a. Further, the front side of the first lens group 21 is protected by the barrier unit 40 during non-photographing shown in FIG.
Note that the extension of the first lens group 21, the zooming operation by the movement of the second lens group 22, and the opening and closing of the barrier unit 40 are realized by control of a drive motor (not shown).

[Configuration example of lens barrel]

FIG. 5 is an exploded perspective view showing a main part of a lens barrel 20 for a digital still camera as an embodiment of the lens barrel of the present invention.
As shown in FIG. 5, the lens barrel 20 includes, in order from the subject side, a decorative ring 31, a barrier cover 41 (corresponding to a photographing aperture member in the present invention), a pair of upper and lower barrier blades 42, a barrier drive spring 43, and a barrier drive. A member 44, a lens frame 32 that holds the first lens group 21, a moving frame 33, a rectilinear guide ring 34, a rotating ring 35, a fixed ring 36, a rear barrel 37, and the like are provided. The barrier cover 41 disposed in the front part of the first lens group 21 is formed with a photographing opening 41a for allowing light to enter the first lens group 21 and the like.
In FIG. 5, the second lens group 22 and the like shown in FIGS. 2 to 4 are not shown for convenience of explanation.

Here, the decorative ring 31 is fixed to the moving frame 33 to adjust the appearance of the lens barrel 20, and also protects the barrier unit 40 including the barrier cover 41, the barrier blade 42, the barrier driving spring 43, and the barrier driving member 44. To do. The decorative ring 31 is fixed by sticking a double-sided tape with release paper on the front surface of the barrier cover 41 fixed to the moving frame 33, peeling the release paper, and then covering the decorative ring 31 on the moving frame 33. And it is firmly fixed to the moving frame 33 via the barrier cover 41 by the adhesive force of the double-sided tape.
In addition, as a material of the decorative ring 31, various metals, such as an aluminum alloy and stainless steel, are suitable, but engineering plastics can also be used.

  The barrier unit 40 protects the photographing optical system by closing an optical path that is a photographing aperture when not photographing. Specifically, the barrier drive spring 43 attached between the barrier cover 41 and the barrier blade 42 and the barrier drive member 44 constitute an opening / closing mechanism for the barrier blade 42. The barrier driving member 44 drives the barrier blades 42 to open and close in accordance with switching between the photographing position and the standby position. Therefore, by switching (rotating) the barrier driving member 44 to the photographing position (open position, arrow B direction) or standby position (closed position, arrow A direction), the pair of barrier blades 42 supported to be rotatable are provided. Open and close. At the time of photographing, the barrier blade 42 that is disposed between the barrier cover 41 and the first lens group 21 and covers the opening 41a of the barrier cover 41 so as to be freely opened and closed opens the opening 41a, and the first lens group 21 and the like. Make light incident on. On the contrary, at the time of non-photographing, the barrier blade 42 is closed and the opening 41a is closed to protect the first lens group 21.

  The first lens group 21 is attached to a lens frame 32, and the lens frame 32 is held by a moving frame 33. The moving frame 33 is retracted or extended along the direction of the optical axis 20a according to the operation of the photographer. For this reason, the moving frame 33 is provided with cam pins at three locations, and engages with the three cam grooves provided on the inner peripheral side of the rotating ring 35 that can rotate around the optical axis 20a. ing. Further, the moving frame 33 is also engaged with the rectilinear groove of the rectilinear guide ring 34 so as not to be simultaneously rotated by the rotation of the rotating ring 35.

  Further, the rotation ring 35 and the straight guide ring 34 are bayonet-fitted, so that the straight guide ring 34 can be moved straight without being restricted with respect to the rotation of the rotary ring 35. Furthermore, with respect to the movement of the rotating ring 35 in the direction of the optical axis 20a, the linear guide ring 34 also moves together. Specifically, three cam pins are provided on the rotating ring 35 and are respectively fitted with three cam grooves provided on the inner peripheral side of the fixed ring 36. As the rotating ring 35 rotates with respect to the fixed ring 36, the rotating ring 35 moves in the direction of the optical axis 20a along the locus of the cam groove of the fixed ring 36. Further, the straight guide ring 34 has five convex portions for fitting with the fixed ring 36, and the five convex portions and the five straight grooves provided on the fixed ring 36 are respectively provided. Mating. Therefore, the linear guide ring 34 can only move in the direction of the optical axis 20a with respect to the fixed ring 36, and movement in the rotational direction is restricted.

  Therefore, when the rotating ring 35 is rotated, the rotating ring 35 moves in the direction of the optical axis 20 a while rotating with respect to the fixed ring 36. Further, the rectilinear guide ring 34 moves integrally with the rotating ring 35 in the direction of the optical axis 20a without rotating. Furthermore, the moving frame 33 moves in the direction of the optical axis 20a along the cam groove of the rotating ring 35 without rotating. As a result, the moving frame 33 moves in the direction of the optical axis 20a according to the rotation of the rotating ring 35 and its position, and retracts or extends. Further, the rear barrel 37 is held on the fixed ring 36, and the distance between the moving frame 33 and the rear barrel 37 is widened at the photographing position, and the distance between the moving frame 33 and the rear barrel 37 is widened at the standby position. It is becoming narrower.

  In addition, a cam surface 37 a is formed on the rear barrel 37, and this cam surface 37 a abuts on the cam surface 44 a formed on the barrier drive member 44. When the moving frame 33 is retracted and the distance from the rear barrel 37 is reduced, the barrier driving member 44 is gradually charged while the barrier driving spring 43 is gradually charged by the contact between the cam surface 37a and the cam surface 44a. Rotate in the A direction and close the barrier blade 42. Conversely, when the moving frame 33 is extended and the distance from the rear barrel 37 is increased, the cam surface 37a and the cam surface 44a are separated from each other, so that the charge of the barrier drive spring 43 is gradually released and the barrier drive member 44 is moved. It rotates in the direction of arrow B, and the barrier blade 42 is opened.

FIG. 6 is a front view showing a state in which the barrier blades 42 are fully closed in the barrier unit 40 of the lens barrel 20 shown in FIG.
FIG. 7 is a rear view showing a state in which the barrier blades 42 are fully closed in the barrier unit 40 of the lens barrel 20 shown in FIG.
FIG. 8 is a front view showing a state in which the barrier blades 42 (see FIG. 6) are fully opened in the barrier unit 40 of the lens barrel 20 shown in FIG.
Further, FIG. 9 is a rear view showing a state in which the barrier blades 42 (see FIG. 7) are fully opened in the barrier unit 40 of the lens barrel 20 shown in FIG.
As shown in FIGS. 6 to 9, the barrier unit 40 includes a barrier cover 41, a barrier blade 42, a barrier drive spring 43, and a barrier drive member 44.

  The barrier cover 41 is formed with a photographing opening 41a for allowing light to enter the first lens group 21 (see FIG. 5). A pair of upper and lower barrier blades 42 disposed between the barrier cover 41 and the first lens group 21 covers the opening 41a so as to be freely opened and closed. Specifically, each barrier blade 42 is rotatably supported on a rotation shaft 44 b provided on the barrier drive member 44. Each barrier blade 42 is fully closed when the lens barrel 20 is in a retracted state (see FIG. 2) when not photographing, and covers the opening 41a of the barrier cover 41 (see FIGS. 6 and 7). Conversely, when the lens barrel 20 is in the extended state during shooting (see FIGS. 3 and 4), the opening 41a is opened (see FIGS. 8 and 9).

  In this embodiment, the barrier drive spring 43 is a tension coil spring, and is attached between the barrier cover 41 and each barrier blade 42. Specifically, one end of the barrier drive spring 43 is hooked on a spring hooking portion 42 a provided on the barrier blade 42, and the other end is hooked on a spring hooking portion 41 b provided on the barrier cover 41. The barrier drive spring 43 increases or decreases the charge amount according to the opening / closing operation of each barrier blade 42, and the barrier driving spring 43 interlocks the rotation of the barrier driving member 44 with the opening / closing (turning) operation of each barrier blade 42. It is supposed to be.

The barrier driving member 44 is formed in a substantially annular shape, can be rotated on a plane perpendicular to the optical axis 20a (see FIG. 5) on the back side of the barrier cover 41, and is regulated in the thrust direction. It is supported. And when it switches to a standby position, it moves to a closed position and closes each barrier blade | wing 42 with respect to the opening 41a (refer FIG.6 and FIG.7). Conversely, when the camera is switched to the photographing position, it moves to the open position and opens each barrier blade 42 with respect to the opening 41a (see FIGS. 8 and 9).
Hereinafter, the phase of the barrier driving member 44 when each barrier blade 42 is fully opened is referred to as a “barrier opening phase”, and the barrier frame 42 (see FIG. 5) is retracted and the barrier blade 42 is fully closed. The opening / closing operation of the barrier blade 42 will be described with the phase of the driving member 44 as the “barrier closing phase”.

  In the barrier unit 40, the barrier driving spring 43 is charged according to the opening operation of the barrier blade 42 according to the movement of the barrier driving member 44 from the “barrier closing phase” (closed position) to the “barrier opening phase” (open position). The amount is provided so as to gradually decrease. When the barrier driving member 44 is moved to the closed position with the barrier blade 42 restricted in the opening direction (from the “barrier opening phase” to the “barrier closing phase”), the barrier driving member 44 is moved to the closed position. The amount of charge of the barrier drive spring 43 is provided so as to gradually increase as the movement of. Furthermore, when the barrier blade 42 is opened with the barrier drive member 44 restrained in the moving direction to the closed position, the charge amount of the barrier drive spring 43 gradually increases according to the opening operation of the barrier blade 42. It is provided to increase.

  Here, when the moving frame 33 shown in FIG. 5 is retracted, the cam surface 37a of the rear barrel 37 and the cam surface 44a of the barrier drive member 44 come into contact with each other. Therefore, the barrier driving member 44 is forcibly rotated in the arrow A direction to the “barrier closing phase” while gradually charging the barrier driving spring 43. At this time, each barrier blade 42 is rotated (closed) in a closing direction in conjunction with the rotation of the barrier driving member 44. By this rotation, each barrier blade 42 is fully closed and the opening 41a is covered. Is called.

  On the other hand, when the moving frame 33 shown in FIG. 5 is extended, the cam surface 37a of the rear barrel 37 and the cam surface 44a of the barrier driving member 44 are separated. Therefore, the charge of the barrier drive spring 43 is gradually released, and the barrier drive member 44 rotates in the arrow B direction until the “barrier opening phase”. At this time, each barrier blade 42 is rotated (opening operation) in the opening direction in conjunction with the rotation of the barrier driving member 44. By this rotation, the barrier blade 42 is fully opened and the opening 41a is opened. .

  When the moving frame 33 (see FIG. 5) is retracted in a state where the open barrier blades 42 are restrained so as not to close (restrained in the opening direction), the barrier drive member 44 gradually moves the barrier drive spring 43. While charging, it rotates in the direction of arrow A until “barrier closing phase”. When the restraint of the barrier blade 42 is released in this state, the charge of the barrier drive spring 43 is gradually released and the barrier blade 42 is closed.

  Furthermore, when the barrier blade 42 is forcibly opened when the moving frame 33 (see FIG. 5) is retracted, the barrier blade 42 opens while the barrier drive spring 43 is gradually charged. When the forced opening of the barrier blade 42 is released, the charge of the barrier drive spring 43 is gradually released and the barrier blade 42 is closed.

  Thus, the opening / closing operation of the barrier blade 42 is related to the charge amount of the barrier drive spring 43. Therefore, the barrier unit 40 of the present embodiment is configured so that the barrier blades 42 can be smoothly opened and closed by the biasing force of the charged barrier driving spring 43.

FIG. 10 is a graph showing the relationship between the open / close state of the barrier blade 42 and the charge amount of the barrier drive spring 43 in the barrier unit 40 of the lens barrel 20 shown in FIG.
As shown in FIG. 10, the charge amount of the barrier drive spring 43 satisfies the relationship of (forced open state in “barrier closed phase”)> (closed state)> (open state).

  Here, the barrier drive spring 43 acts in a direction in which the charge amount decreases. Therefore, in a state where the moving frame 33 shown in FIG. 5 is retracted and the barrier driving member 44 is rotated in the “barrier closing phase” in the direction of arrow A, the barrier blades 42 are closed by the gradually charged barrier driving springs 43. Be energized by. Conversely, when the moving frame 33 is extended and the cam surface 37a of the rear barrel 37 and the cam surface 44a of the barrier driving member 44 are separated, the barrier blade 42 gradually releases the charge of the barrier driving spring 43. Is biased in the opening direction.

  As described above, the barrier blade 42 obtains an opening force by releasing the charge stored in the barrier drive spring 43. Therefore, if there is an aspect in which the amount of charge of the barrier drive spring 43 increases in the process of opening the barrier blade 42, the force to open the barrier blade 42 cannot be obtained in that state.

  Therefore, the amount of charge of the barrier drive spring 43 needs to monotonously decrease as the barrier blade 42 opens. Further, when the barrier blade 42 is constrained not to be closed, the moving frame 33 is retracted in this state, and then the barrier blade 42 is released from the restraint, the charge amount needs to decrease monotonously as the barrier blade 42 is closed. There is.

In this regard, as shown in FIG. 10, the charge amount of the barrier drive spring 43 is (forced open state in “barrier closed phase”)> (closed state)> (open state). Therefore, in the barrier unit 40 of this embodiment, the barrier blades 42 are smoothly opened by the biasing force of the barrier drive spring 43.
Next, the relationship between the operation of the barrier blade 42, the barrier drive spring 43, and the barrier drive member 44 and the charge amount of the barrier drive spring 43 will be described.

FIG. 11 is an explanatory diagram showing the relationship between the barrier blade 42 and the barrier drive spring 43 in the fully closed state in the barrier unit 40 of the lens barrel 20 shown in FIG.
FIG. 12 is an explanatory diagram showing the relationship between the barrier blade 42 and the barrier drive spring 43 in a state where the barrier unit 40 of the lens barrel 20 shown in FIG.
Furthermore, FIG. 13 is an explanatory diagram showing the relationship between the barrier blades 42 and the barrier drive springs 43 in the fully opened state in the barrier unit 40 of the lens barrel 20 shown in FIG.
Further, FIG. 14 is an explanatory diagram showing the relationship between the barrier blades 42 and the barrier drive springs 43 that are forcibly opened in the barrier unit 40 of the lens barrel 20 shown in FIG.
As shown in FIGS. 11 to 14, the barrier blade 42 has a rotation shaft 42 b (see FIGS. 6 and 8) in which a rotation hole 42 b is provided in the barrier driving member 44 (see FIGS. 7 and 9). It is rotatably supported.

  Further, in the vicinity of the rotation hole 42b of the barrier blade 42, a first contact portion 42c (corresponding to a contact portion in the present invention) that contacts the contact portion 41d formed on the convex portion 41c of the barrier cover 41 is provided. Is provided. Specifically, the barrier cover 41 is provided with a pair of convex portions 41c spaced apart from each other by 180 ° in the circumferential direction, and a contact portion 41d is formed on the wall surface of the convex portion 41c facing the circumferential direction. Has been. Further, when the barrier drive member 44 (see FIG. 7) is rotated so as to move between the closed position and the open position, the rotation shaft 44b (see FIG. 6) of the barrier drive member 44 on which the barrier blade 42 rotates. The barrier blade 42 is driven to open and close using the spring contact portion 42a of the barrier blade 42 to which the barrier drive spring 43 is attached as a force point and the first contact portion 42c between the barrier blade 42 and the barrier cover 41 as a fulcrum. It is formed to do.

FIG. 11 shows a state where the barrier blade 42 is fully closed. In this state, the barrier drive spring 43 causes the first contact portion 42 c of the barrier blade 42 to contact the contact portion 41 d of the barrier cover 41. The barrier blade 42 is maintained in a fully closed state by the biasing force. In this respect, the barrier drive spring 43 plays the same role as a conventional barrier closing spring. In other words, the barrier drive member 44 has a contact surface between the barrier blades 42 as a fulcrum, a spring hooking portion 42a of the barrier blade 42 as a force point, and a rotation hole 42b of the barrier blade 42 by the biasing force of the barrier drive spring 43. The barrier drive member 44 is urged in the rotation direction indicated by the arrow B with the rotation shaft 44b as an action point.
In the retracted state of the moving frame 33 shown in FIG. 5, the rotation of the barrier drive member 44 in the arrow B direction is restricted by the action of the cam surface 37 a of the rear barrel 37.

  Here, when the moving frame 33 (see FIG. 5) slightly extends and the barrier blades 42 begin to open, the state shown in FIG. 12 is obtained. In this state, the barrier drive member 44 and the rear barrel 37 shown in FIG. 5 are relatively moved away from each other as compared with the retracted state of the movable frame 33 (the state shown in FIG. 11). 37, the barrier drive member 44 is slightly moved in the direction of arrow B by the cam surface 37a. Therefore, the barrier blade 42 slightly moves in the arrow B direction through the rotation hole 42b by the rotation shaft 44b (see FIG. 6) of the barrier drive member 44. As a result, as shown in FIG. 12, the first contact portion 42 c of the barrier blade 42 comes into contact with the contact portion 41 d of the barrier cover 41. Then, the charge amount of the barrier drive spring 43 at this time is smaller than the state shown in FIG.

Next, the force exerted by the urging force of the barrier drive spring 43 on the barrier blades 42 and the barrier drive member 44 (see FIG. 7) in the state shown in FIG. 12 will be described.
In the state shown in FIG. 12, the contact point between the contact part 41d of the barrier cover 41 and the first contact part 42c of the barrier blade 42 is supported by the biasing force of the barrier drive spring 43, and the spring hooking part 42a of the barrier blade 42 is used. The barrier drive member 44 is rotated in the direction of arrow B (opening direction) with the engagement point between the rotation hole 42b of the barrier blade 42 and the rotation shaft 44b (see FIG. 6) of the barrier drive member 44 as an action point. Is being energized. Therefore, the barrier drive member 44 rotates in the direction of arrow B as the cam surface 44a of the barrier drive member 44 and the cam surface 37a of the rear barrel 37 shown in FIG.

  Here, the tension (biasing force) of the barrier drive spring 43 in the state shown in FIG. Then, the rotation of the barrier drive member 44 in which the barrier blade 42 rotates from the rotation center of the barrier drive member 44 (see FIG. 7) in the direction perpendicular to the direction of the tension P acting on the barrier blade 42 by the barrier drive spring 43. The distance to the moving shaft 44b (see FIG. 6) is L1. More specifically, from the rotation center of the barrier drive member 44, the fitting position between the rotation shaft 44b and the rotation hole 42b (the tension of the barrier drive spring 43 is transmitted to the barrier drive member 44 through the barrier blades 42). L1 is the distance to the action point).

  Further, from the rotation center of the barrier driving member 44 (see FIG. 7), a first contact portion 42c where the barrier blade 42 and the barrier cover 41 abut (the contact portion 41d serving as a pivot point of rotation and the first contact portion). The distance to the contact position with the contact portion 42c is L2. Furthermore, the contact portion 41d of the barrier cover 41 and the first contact of the barrier blade 42 from the fitting position of the rotation shaft 44b (see FIG. 6) of the barrier drive member 44 and the rotation hole 42b of the barrier blade 42. The distance to the contact position with the part 42c is L3. Furthermore, from the first contact portion 42c of the barrier blade 42 (the contact position between the first contact portion 42c and the contact portion 41d), the spring hooking portion 42a (power point) of the barrier blade 42 to which the barrier drive spring 43 is attached. ) To L4. The distance from the rotation shaft 44b of the barrier drive member 44 (the fitting position between the rotation shaft 44b and the rotation hole 42b) to the spring hooking portion 42a of the barrier blade 42 is L5.

As described above, when the tension P and the distances L1 to L5 are defined, the moment Mo that rotates the barrier driving member 44 (see FIG. 7) in the opening direction (arrow B direction) is as follows.
Mo = P × (L4 / L3) × L1
On the other hand, the moment Mc that rotates the barrier driving member 44 in the closing direction (arrow A direction) is as follows.
Mc = P × (L5 / L3) × L2

Therefore, when the moment Mo rotated in the opening direction (arrow B direction) is larger than the moment Mc rotated in the closing direction (arrow A direction), that is,
Mo> Mc
= P * (L4 / L3) * L1> P * (L5 / L3) * L2
= L1 × L4> L2 × L5 (1) In the formula (1), the force for rotating the barrier driving member 44 (see FIG. 7) overcomes the force for rotating the barrier blade 42 in the closing direction. Thereby, the barrier drive spring 43 functions to rotate the barrier drive member 44 in the opening direction, and the barrier drive spring 43 functions in the same manner as a conventional barrier open spring. At this time, when the barrier blade 42 is opened, the amount of charge of the barrier drive spring 43 decreases.
In this embodiment, two barrier drive springs 43 are used, but the moment Mo in the opening direction and the moment Mc in the closing direction acting on the barrier drive member 44 are each doubled. 1) The relationship of the formula does not change.

  As described above, in the barrier unit 40 of the present embodiment, the barrier blade 42 rotates when the barrier driving member 44 (see FIG. 7) rotates so as to move between the closed position and the open position. The pivot 44b (see FIG. 6) of the drive member 44 is the point of action, the attachment portion (spring hooking portion 42a) of the barrier blade 42 to which the barrier drive spring 43 is attached is the force point, and the contact between the barrier blade 42 and the barrier cover 41 The barrier blades 42 are configured to open and close with the contact portions (the contact portions 41d and the first contact portions 42c) as fulcrums. Moreover, it is comprised so that the relationship of said Formula (1) (L1 * L4> L2 * L5) may be satisfy | filled. Therefore, when the moving frame 33 (see FIG. 5) is further extended from the state shown in FIG. 12, the barrier blades 42 are smoothly opened.

  FIG. 13 shows a state in which the barrier blades 42 are fully opened in this way. In this state, the cam surface 44a of the barrier driving member 44 and the cam surface 37a of the rear barrel 37 shown in FIG. Away. Therefore, the barrier driving member 44 rotates in the arrow B direction to enter the “barrier opening phase”, and the charge amount of the barrier driving spring 43 is further reduced.

  In the state shown in FIG. 13, the contact point between the contact part 41d of the barrier cover 41 and the first contact part 42c of the barrier blade 42 is supported by the tension P of the barrier drive spring 43 (see FIG. 12). With the spring hooking portion 42a of the barrier blade 42 as a force point, and the fitting position between the rotation hole 42b of the barrier blade 42 and the rotation shaft 44b (see FIG. 8) of the barrier drive member 44 (see FIG. 9) as an action point The drive member 44 is urged in the arrow B direction (opening direction). Further, when the second contact portion 42d of the barrier blade 42 contacts a stopper 41e formed on the barrier cover 41, further rotation of the barrier blade 42 is restricted. Furthermore, at this time, since the relationship of the formula (1) (L1 × L4> L2 × L5) is satisfied, the barrier blade 42 is biased in the opening direction, and the fully opened state is maintained.

  Further, when the barrier blade 42 is forcibly opened from the state shown in FIG. 11, the state shown in FIG. 14 is obtained. In this state, the rotation of the barrier driving member 44 shown in FIG. 5 is restricted by the “barrier closing phase” by the cam surface 37 a of the rear barrel 37. Therefore, even if the barrier blade 42 is forcibly opened, the barrier drive member 44 does not rotate.

  Therefore, even if the barrier blade 42 is forcibly opened, the barrier drive spring 43 is charged. When the forced opening state of the barrier blade 42 is released, the charge of the barrier drive spring 43 is released and the barrier blade 42 is closed. Therefore, in this state, the barrier driving spring 43 functions in the same manner as a conventional barrier closing spring.

Incidentally, the barrier drive member 44 (see FIG. 7) is rotatably supported with respect to the barrier cover 41. In order to ensure smooth rotation of the barrier drive member 44, the barrier drive member 44 and It is necessary to provide a certain amount of radial gap between the barrier cover 41 and the barrier cover 41.
However, if such a gap is provided, the barrier driving member 44 may be eccentric with respect to the barrier cover 41.
Therefore, the opening operation of the barrier blade 42 when the barrier driving member 44 is eccentric will be described next.

FIG. 15 is an explanatory diagram showing an opening / closing operation of the barrier blade 42 in a state where the barrier driving member 44 (see FIG. 7) is eccentric in the barrier unit 40 of the lens barrel 20 shown in FIG.
When the barrier driving member 44 rotates to the “barrier opening phase” and is eccentric downward with respect to the barrier cover 41, the state shown in FIG. 15 is obtained. In this state, one of the pair of barrier blades 42 (the upper barrier blade 42A in FIG. 15) first comes into contact with the stopper 41e of the barrier cover 41.

  Here, in the conventional example, rotation of the barrier driving member 44 (see FIG. 7) in the arrow B direction is prevented by the one barrier blade 42A in contact with the stopper 41e. Therefore, the other barrier blade 42B that is not in contact with the stopper 41e remains inside the opening 41a.

  On the other hand, in the barrier unit 40 of the present embodiment, the barrier driving spring 43 hung on the barrier blade 42A and the barrier blade 42B independently releases the charge, and opens the barrier driving member 44 (see FIG. 7). Is energized. Therefore, the barrier drive spring 43 hooked on the barrier blade 42B not in contact with the stopper 41e continues to urge the barrier drive member 44 in the arrow B direction. As a result, the barrier driving member 44 rotates in the direction of arrow B, so that even if the barrier driving member 44 is eccentric, the barrier blade 42A and the barrier blade 42B are completely opened.

  As described above, the barrier unit 40 according to the present embodiment reliably opens the barrier blades 42 and opens the openings 41a even when the barrier driving member 44 (see FIGS. 7 and 9) is eccentric. Can do. The barrier drive spring 43 is attached between the spring hook 41 b of the barrier cover 41 and the spring hook 42 a of the barrier blade 42. The urging force of the barrier drive spring 43 is transmitted to the barrier drive member 44 via a rotation shaft 44b (see FIGS. 6 and 8) fitted in the rotation hole 42b of the barrier blade 42. Therefore, the degree of freedom in designing the lens barrel 20 (see FIG. 5) is improved, and both the size reduction of the lens barrel 20 and the operability of the barrier blades 42 can be achieved.

  Further, in the barrier unit 40 of the present embodiment, from the rotation center of the barrier driving member 44 (see FIG. 7) in the direction perpendicular to the direction of the tension P (see FIG. 12) acting on the barrier blade 42 by the barrier driving spring 43. The fitting position of the rotating shaft 44b (see FIG. 6) of the barrier driving member 44 on which the barrier blade 42 rotates and the rotating hole 42b of the barrier blade 42 (the tension of the barrier driving spring 43 is applied via the barrier blade 42). Thus, the distance L1 to the action point transmitted to the barrier driving member 44 can be set large. Therefore, it is advantageous in improving space efficiency and downsizing. In addition, since the moment Mo for rotating the barrier driving member 44 in the opening direction (arrow B direction) can be increased as much as possible, the operability and stability of the barrier blades 42 are improved. Further, since the moment Mo can be increased, the force of the barrier drive spring 43 can be reduced and a small spring can be obtained.

  Furthermore, in the barrier unit 40 of the present embodiment, the charge amount of the barrier drive spring 43 has a relationship of (forced open state in “barrier closing phase”)> (closed state)> (open state). Therefore, one barrier drive spring 43 can function as a conventional opening spring and closing spring. Thereby, the number of parts can be reduced, the cost and the number of assembling steps can be reduced, and the lens barrel 20 (see FIG. 5) can be reduced in size by saving space.

<2. Second Embodiment>
[External appearance of imaging device]

FIG. 16 is a perspective view showing a peripheral portion of the lens barrel 120 in the digital video camera 110 as one embodiment (second embodiment) of the imaging apparatus of the present invention, and shows a state at the time of photographing.
FIG. 17 is a perspective view showing a peripheral portion of the lens barrel 120 in the digital video camera 110 as one embodiment (second embodiment) of the imaging apparatus of the present invention, and shows a standby state. Show.
As shown in FIGS. 16 and 17, the digital video camera 110 includes a rectangular parallelepiped body 111 constituting an exterior. A front panel 112 is attached to the front portion of the body 111.

  Here, the lens barrel 120 is incorporated in the front panel 112, and the first lens group 121 attached to the inside of the lens barrel 120 is exposed in the photographing state shown in FIG. An imaging element (not shown) such as a CCD image sensor or a CMOS image sensor is disposed at the rear of the first lens group 121, and the light incident on the first lens group 121 is imaged on the imaging element to form a subject. Images can be taken.

  On the other hand, in the standby state shown in FIG. 17, the front portion of the first lens group 121 (see FIG. 16) is covered by the barrier unit 140. The barrier unit 140 is disposed so that the front portion of the first lens group 121 can be opened and closed, and is opened and closed by operating an open / close switch 113 provided on the side surface of the front panel 112. Specifically, as shown in FIG. 16, when the open / close switch 113 is moved upward with the optical axis 120a of the first lens group 121 oriented in the horizontal direction, the barrier unit 140 is moved as shown in FIG. close. Therefore, the first lens group 121 is protected by the barrier unit 140 when the digital video camera 110 is on standby.

When the open / close switch 113 is moved downward from the standby state shown in FIG. 17, the barrier unit 140 is opened, and the front portion of the first lens group 121 is opened as shown in FIG. For this reason, light enters the first lens group 121, so that the subject image formed by the first lens group 121 can be captured.
The configuration of the barrier unit 140 is the same as that of the barrier unit 40 shown in FIG.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, The following various deformation | transformation are possible. For example,
(1) In the embodiment, the digital still camera 10 and the digital video camera 110 are taken as examples of the imaging device. However, the present invention is not limited to this, and can be widely applied to imaging devices such as camera-equipped mobile phones.

  (2) Although the tension coil spring is used as the barrier drive spring 43 in the embodiment, the present invention is not limited to this, and various springs such as a wire spring and a leaf spring can be used. Further, in the embodiment, the barrier blade 42 opens and closes in conjunction with the retracting or feeding of the moving frame 33 due to the rotation of the rotating ring 35, and the rotating ring 35 rotates around the optical axis 20a and the light Move in the direction of the axis 20a. However, the axis of rotation center of the rotating ring may not coincide with the optical axis, and the rotating ring may not move in the optical axis direction. Further, the opening and closing of the barrier blades 42 may not be interlocked with the collapse or extension of the moving frame 33.

10 Digital still camera (imaging device)
20 Lens barrel 20a Optical axis 21 First lens group (imaging lens)
40 Barrier unit 41 Barrier cover (shooting aperture member)
41a Opening 42, 42A, 42B Barrier blade 42a Spring hook part 42c 1st contact part (contact part)
43 Barrier drive spring 44 Barrier drive member 44b Rotating shaft 110 Digital video camera (imaging device)
120 Lens barrel 120a Optical axis 121 First lens group (imaging lens)
140 barrier units

Claims (4)

An imaging aperture member disposed at the front of the imaging lens and having an imaging aperture for allowing light to enter the imaging lens;
A barrier blade disposed between the photographing aperture member and the imaging lens and covering the aperture so as to be freely opened and closed;
A barrier driving member that opens and closes the barrier blades according to switching between the photographing position and the standby position;
A barrier drive spring attached between the photographing aperture member and the barrier blade,
The barrier blade is rotatably supported on a rotation shaft provided on the barrier driving member,
The barrier driving member is rotatably supported by the photographing opening member, and when the barrier driving member is switched to the standby position, the barrier driving member moves to a closed position for closing the barrier blade with respect to the opening, and moves to the photographing position. When switched, move to the open position to open the barrier blades relative to the opening,
The barrier drive spring gradually decreases the amount of charge of the barrier drive spring and opens the barrier blade according to the opening operation of the barrier blade as the barrier drive member moves from the closed position to the open position. When the barrier driving member is moved to the closed position while being constrained in the direction, the amount of charge of the barrier driving spring gradually increases as the barrier driving member moves to the closed position, and the barrier driving When the barrier blade is opened while the member is constrained in the moving direction to the closed position, the charge amount of the barrier drive spring is gradually increased according to the opening operation of the barrier blade. The lens barrel. The lens barrel according to claim 1,
The distance from the rotation center of the barrier drive member to the rotation axis of the barrier drive member on which the barrier blade rotates is L1, and the barrier blade and the imaging opening from the rotation center of the barrier drive member. The distance from the contact portion to which the member abuts is L2, the distance from the contact portion to the spring hooking portion of the barrier blade to which the barrier drive spring is attached is L4, and from the rotating shaft, A lens barrel configured to satisfy the relationship of L1 × L4> L2 × L5 when the distance to the spring hook is L5. The lens barrel according to claim 1,
When the barrier driving member rotates so as to move between a closed position and an open position, the barrier driving member is attached to the rotating shaft of the barrier driving member on which the barrier blade rotates. A lens barrel configured to open and close the barrier blade, with the spring-loaded portion of the barrier blade as a force point and the contact portion between the barrier blade and the photographing aperture member as a fulcrum. An imaging aperture member disposed at the front of the imaging lens and having an imaging aperture for allowing light to enter the imaging lens;
A barrier blade disposed between the photographing aperture member and the imaging lens and covering the aperture so as to be freely opened and closed;
A barrier driving member that opens and closes the barrier blades according to switching between the photographing position and the standby position;
A barrier drive spring attached between the photographing aperture member and the barrier blade,
The barrier blade is rotatably supported on a rotation shaft provided on the barrier driving member,
The barrier driving member is rotatably supported by the photographing opening member, and when the barrier driving member is switched to the standby position, the barrier driving member moves to a closed position for closing the barrier blade with respect to the opening, and moves to the photographing position. When switched, move to the open position to open the barrier blades relative to the opening,
The barrier drive spring gradually decreases the amount of charge of the barrier drive spring and opens the barrier blade according to the opening operation of the barrier blade as the barrier drive member moves from the closed position to the open position. When the barrier driving member is moved to the closed position while being constrained in the direction, the amount of charge of the barrier driving spring gradually increases as the barrier driving member moves to the closed position, and the barrier driving When the barrier blade is opened while the member is constrained in the moving direction to the closed position, the charge amount of the barrier drive spring is gradually increased according to the opening operation of the barrier blade. An imaging device.

Images