JP2003066311A - Zoom lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens barrel equipped with a shutter which can make the size of the barrel in an optical axis direction smaller at the non- photographing time. SOLUTION: In this zoom lens barrel 10, the shutter 17 is opened at the non-photographing time, and at least a part of a lens 13 adjacent to the shutter 17 is housed in the aperture part 17a thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel, and more particularly to a zoom lens barrel having a shutter.

[0002]

2. Description of the Related Art Conventionally, various techniques have been proposed for reducing the dimension in the optical axis direction of a zoom lens barrel that is extended from the camera body during photographing and retracted into the camera body during non-photographing. ing.

For example, in Japanese Unexamined Patent Publication No. 11-119080, a diaphragm device is urged by a spring to separate the diaphragm from an adjacent lens at the time of photographing, and to bring the diaphragm closer to the lens at the time of non-photographing, and the optical axis at the time of non-photographing A technique for reducing the dimension in the direction is disclosed.

Further, Japanese Patent Laid-Open No. 10-288731 discloses that
A technique is disclosed in which a space for accommodating a zoom or focus drive mechanism during non-shooting is provided in the zoom lens barrel to reduce the dimension in the optical axis direction during non-shooting.

[0005]

By the way, in the zoom lens barrel having the shutter, there is a limit in reducing the dimension in the optical axis direction during non-shooting due to the influence of the thickness of the shutter.

Therefore, a technical problem to be solved by the present invention is to provide a zoom lens barrel having a shutter, which can further reduce the dimension in the optical axis direction during non-shooting.

[0007]

In order to solve the above technical problems, the present invention provides a zoom lens barrel having the following configuration.

The zoom lens barrel expands and contracts in the optical axis direction,
It is a type that extends when shooting and retracts when not shooting, and is equipped with a shutter. The shutter is opened at the time of non-shooting, and at least a part of the lens adjacent to the shutter is housed in the opening of the shutter.

According to the above arrangement, the zoom lens barrel is
Since at least a part of the lens is housed in the opening of the shutter during non-shooting, it is possible to further reduce the dimension in the optical axis direction during non-shooting.

Preferably, a diaphragm for opening at the time of non-photographing and accommodating at least a part of the lens is provided in the opening.

According to the above arrangement, when the zoom lens barrel is provided with the diaphragm, at least a part of the lens is housed in the opening of the diaphragm when the photographing is not performed, so that the dimension in the optical axis direction can be further reduced. Is.

Preferably, the opening portion of the shutter is larger than the opening diameter optically required at the time of photographing (that is, the opening diameter for not blocking the light flux imaged by the zoom lens barrel). It has an opening diameter.

According to the above construction, the opening diameter of the opening of the shutter can be increased so that, for example, the entire lens or the lens frame outside the lens can be housed in the opening of the shutter when the photographing is not performed. Therefore, it is possible to bring the lenses on both sides of the shutter close to each other and to reduce the dimension of the zoom lens barrel in the non-photographing direction without being restricted by a portion outside the opening of the shutter.

Preferably, the aperture of the diaphragm is larger than an aperture diameter (that is, an aperture diameter so as not to block a light beam imaged by the zoom lens barrel) which is optically required at the time of photographing. Has a caliber.

According to the above arrangement, when the zoom lens barrel is provided with an aperture, the aperture diameter of the aperture of the aperture is increased so that, for example, the entire lens or a lens frame outside the lens is placed inside the aperture of the aperture when not photographing. Can be stored in. Therefore, it is possible to bring the lenses on both sides of the diaphragm close to each other without being restricted by the portion outside the aperture of the diaphragm, and to reduce the dimension of the zoom lens barrel in the non-photographing direction along the optical axis.

[0016] In each of the above-mentioned configurations, it is preferable that the non-shooting light beam interferes with the light beam passing through the zoom lens barrel to block the light beam, and the shooting light beam retracts from the light beam passing through the zoom lens barrel to form an image. It has a member.

According to the above arrangement, it is possible to prevent the color filter for the image pickup element from being exposed to external light even during non-shooting to accelerate deterioration (fading) and to prevent the photographic film from being exposed during non-shooting. .

Preferably, the light shielding member is a lens barrier that covers the subject end surface of the zoom lens barrel so as to be openable and closable.

According to the above construction, by using the light shielding member also as the lens barrier, it is possible to reduce the dimension of the zoom lens barrel in the optical axis direction with the construction.

Preferably, the lens barrier is composed of two blade members.

According to the above arrangement, the number of blade members can be reduced to make the lens barrier as thin as possible, and the size of the zoom lens barrel in the optical axis direction can be further reduced.

Preferably, the shutter and the lens adjacent to the shutter are held by the same holding member so as to be relatively movable.

According to the above construction, it is easy to construct such that at least a part of the adjoining lenses enters the opening of the shutter at the time of non-photographing and retracts from the opening of the shutter at the time of photographing.

The present invention also provides a camera provided with the zoom lens barrel having each of the above configurations.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

First, an embodiment will be described with reference to FIGS. 1 to 5 as an embodiment of the present invention.

1 to 3 show a zoom lens barrel 10 used in a digital camera. 1 and 2 are cross-sectional views of the zoom lens barrel 10 during shooting (extended state). FIG. 1 shows the maximum focal length (telephoto end), and FIG. 2 shows the minimum focal length (wide-angle end). Show. FIG. 3 is a cross-sectional view of the zoom lens barrel 10 when it is not imaged (collapsed state).

In the zoom lens barrel 10, a cam ring 24, a rectilinear barrel 25, and a forward barrel 26 are arranged inside the fixed barrel 22. On the outer side of the fixed barrel 22, the long gear 20 is attached to the fixed barrel 2.
2 is arranged in parallel with the optical axis and is rotationally driven by a zoom drive actuator (not shown). The cam ring 24 and the advancing barrel 26 are projected from and retracted from the fixed barrel 22 by the rotation of the long gear 20, whereby the light of the first lens group 11, the second lens group 12, the third lens group 13 and the fourth lens group 14 is emitted. The relative position in the axial direction changes. A CCD image pickup device 15 can be fixed to the rear end of the zoom lens barrel 10.

The fourth lens group 14 is provided at the rear end of the fixed barrel 22.
The fourth group lens frame 14a for holding is fixed. As shown in the cross-sectional view of FIG. 5A and the developed view of FIG. 5B, on the inner peripheral surface of the fixed cylinder 22, the spiral first portion 22 a extending in the circumferential direction and the axial direction and the circumference are formed. The cam grooves 22a and 22b formed of the second portion 22b extending in the direction and the straight guide groove 22s extending in the axial direction and penetrating in the radial direction are formed.

The cam ring 24 is arranged inside the fixed barrel 22, and a pin 24a protruding outward on the outer peripheral surface of the cam ring 24 engages with the cam grooves 22a and 22b of the fixed barrel 22. . A gear portion 24b is formed at the rear end of the outer peripheral surface of the cam ring 24, and is meshed with the long gear 20 that is inserted from one of the straight guide grooves 22s of the fixed cylinder 22. As shown in the sectional view of FIG. 5C and the development view of FIG.
On the inner peripheral surface of the cam ring 24, first cam grooves 24q and 24r formed of a first portion 24q having a spiral shape and a second portion 24r curved in a substantially V shape, and a first portion extending in the axial direction. 24s
And second cam grooves 24s and 24t formed of a second portion 24t that is curved in a substantially V shape.

The straight-moving barrel 25 is arranged inside the cam ring 24, and is engaged with the cam ring 24 so as to be rotatable but immovable in the axial direction. An engaging piece 25a is provided at the rear end of the straight-moving barrel 25 so as to engage with the straight-moving guide groove 22s provided in the fixed barrel 22. As a result, the straight-moving barrel 25 is
It is guided in the axial direction while its rotation is restricted.

The advancing cylinder 26 is arranged inside the cam ring 24. A pin 26a is provided on the outer peripheral surface of the forward movement barrel 26 so as to project outward, and is engaged with the first cam grooves 24q and 24r of the cam ring 24. On the inner peripheral surface of the forward cylinder 26,
A rectilinear groove 26b extending in the optical axis direction is formed, and the rectilinear cylinder 2
5 is movably engaged in the axial direction, and the forward cylinder 26 is the straight cylinder 25.
Due to this, rotation is restricted. Forward cylinder 26
A lens barrier 16 and a first group lens frame 11a holding the first lens group 11 are fixed to the front end of the.

The lens barrier 16 is, as shown in FIG.
Two blade members 16a and 16b, which are respectively supported by the support shafts 16s and 16t, have a closed position (shown by a solid line) that closes the opening 16d of the base plate 16c and an open position (shown by a dotted line) that is retracted from the opening 16d. It is designed to rotate between. The blade members 16a and 16b are biased to an open position by a spring (not shown), and the lens barrier 16 is opened in a photographing state. On the other hand, when the zoom lens barrel 10 is retracted, the tip of the rectilinear barrel 25 is moved to the blade members 16a and 16b.
The blade members 16a, 16b against the spring biasing force.
Is driven to the closed position, and the lens barrier 16 is closed. The lens barrier 16 includes two blade members 16
Since it is composed of a and 16b, it is possible to reduce the axial dimension by the thickness of one blade member, as compared with the case of using four blade members.

A moving frame 18 is arranged inside the straight-moving barrel 25. A second group lens frame 12a holding the second lens group 12, a shutter unit 17, and a focus unit (not shown) are fixed to the moving frame 18.

The shutter unit 17 is provided with a shutter curtain, a diaphragm, and actuators for driving them. The shutter curtain and the diaphragm are normally located outside the opening 17a of the shutter unit 17 and enter the inside of the opening 17a during photographing. The opening and closing of the diaphragm may be used as a shutter instead of providing the mechanical shutter mechanism independently of the diaphragm. In any case, the opening diameter of the opening 17a of the shutter unit 17 is larger than the optically necessary opening diameter, and as will be described later in detail, the third lens group 13 and the third group lens frame 13a have Part of it can enter.

On the rear end side of the moving frame 18, the third lens group 1
The third group lens frame 13a holding 3 is fixed so as to be movable in the optical axis direction, and is driven in the optical axis direction by a focus unit (not shown).

A pin 18a is provided on the moving frame 18 so as to project outward in the radial direction, and the second portion 24 of the second cam groove of the cam ring 24 is provided.
It is adapted to engage with t. The moving frame 18 is engaged with the rectilinear barrel 25 so as to be movable in the axial direction, is restricted in rotation, and is guided in the axial direction.

Next, the operation of the zoom lens barrel 10 will be described.

The zoom lens barrel 10 is used when not photographing.
As shown in FIG. 3, the retracted state is the shortest length.

At this time, the shutter unit 17 is in a state where the opening 17a is open (that is, the shutter and the diaphragm are both retracted outside the opening 17a), and the third lens group 13 and the third lens group 13 are provided in the opening 17a. A part of the third group lens frame 13a is designed to enter. Thereby, while avoiding the interference of the shutter unit 17, the distance between the second and third lens groups 12 and 13 is shortened as much as possible, and the total length of the zoom lens barrel 10 when retracted is smaller than that of the conventional one. be able to.

When the long gear 20 is rotated by a zoom drive actuator (not shown), the cam ring 24 is rotated,
As shown by an arrow 80 in (b), the pin 24 a moves along the first portion 22 a of the cam groove of the fixed barrel 22, and the cam ring 24 is extended from the fixed barrel 22. At this time, the gear portion 24b of the cam ring 24 moves in the axial direction along the long gear 20 while maintaining the mesh with the long gear 20.

At the same time, as shown by the arrow 82 in FIG. 5D, the pin 26a moves along the first portion 24q of the first cam groove of the cam ring 24, and the advance cylinder 26 extends from the cam ring 24. . Further, as indicated by an arrow 86, the cam ring 24
The pin 18a moves along the second portion 24t of the second cam groove, and the moving frame 18 moves rearward with respect to the cam ring 24.

Then, as shown in FIG. 2, the zoom lens barrel 10 is most extended and is in a photographing state. At this time, the focal length of the zoom lens barrel 10 is the minimum, that is, the wide-angle end.

Further, when driven, the pin 24a moves along the second portion 22b of the cam groove of the fixed barrel 22 as shown by the arrow 81 in FIG. The state of being extended from 22 is retained. On the other hand, the pin 26a of the advancing cylinder 26 moves along the second portion 24r of the first cam groove of the cam ring 24, as indicated by the arrow 83 in FIG. Come out. Also,
The pin 18a of the moving frame 18 moves forward with respect to the cam ring 24 along the second portion 24t of the second cam groove of the cam ring 24, as shown by the arrow 85.

When driven most, the zoom lens barrel 10 has the maximum focal length, that is, the telephoto end, as shown in FIG.

Next, the operation sequence of the digital camera using the zoom lens barrel 10 will be described.

When the main switch is OFF, the shutter is generally closed in the conventional camera, but in the digital camera using the zoom lens barrel 10, the shutter is open as described above. Further, the diaphragm is in a wide open state. At this time, the lens barrier 16
Is closed, so even if the shutter is open, CCD
A color filter or the like for the image sensor 15 can be protected from outside light.

When the main switch is turned on, the zoom lens barrel 10 extends from the retracted state to the wide-angle end with the shutter open. Lens barrier 1 on the way out
6 is opened, and a preview is possible in the shooting state. The lens barrier 16 may be opened at the wide-angle end.

When the zoom button of the digital camera is operated,
The focal length of the zoom lens barrel 10 can be changed.

When the shutter button of the digital camera is pressed,
Take a picture. Specifically, the charge of the CCD image pickup device 15 is once discharged, and then the exposure is started. At this time, the aperture becomes smaller up to the set aperture value. The shutter is closed at the time of proper exposure, and data (charge accumulated in the CCD image pickup device 15) is read out. After reading the data, the shutter opens again and the aperture opens greatly.

When the main switch is turned off, the zoom lens barrel 10 retracts with the shutter open and the aperture wide open, and returns to the retracted position. In the middle of this, the lens barrier 16 closes.

As described above, the zoom lens barrel 1
0 allows the third lens group 13 and a part of the third group lens frame 13a to be inserted into the opening 17a of the shutter unit 17, so that the opening diameters of the shutter and the aperture are larger than those determined by a normal optical system. Also needs to be larger. Therefore, the outer diameter tends to increase due to the reduction in thickness in the axial direction.

However, as the outer diameter increases, the space for retracting the blade members 16a and 16b of the lens barrier 16 can be increased. Therefore, the blade members 16a and 16b can be increased in number to reduce the number of lenses and the lens barrier 16 can be made thinner. The axial dimension of the lens barrel 10 can be further reduced.

Further, due to the larger diameter, a stepping motor having a larger outer diameter (having a large torque margin and a low cost) or the like can be used as the actuator of the shutter unit 17 and the focus unit.

When the zoom lens barrel 10 is used in a silver salt camera (lens shutter camera), light is leaked to the film because the shutter is open when the lens barrel is retracted.
In order to prevent this, it is necessary to provide a light blocking member in addition to the shutter. For example, it is necessary to configure the lens barrier 16 to have a sufficient light blocking effect.

The lens barrier 16 may not be provided on the end surface of the zoom lens barrel 10 on the object side, but a light blocking member may be provided inside the zoom lens barrel. In that case, if the amount of movement of the optical system is large, With a two-stage extension type zoom lens barrel, the cam cannot be inserted, and there is no choice but to let out three stages.
As a result, the outer diameter of the zoom lens barrel may increase. Further, a light shielding member may be provided on the camera body, but in that case, since the optical path diameter is large, the space for retracting the light shielding member also becomes radially outward and the camera body becomes large.

6 to 8 show a modified zoom lens barrel 10s.
Indicates. 6 and 7 are cross-sectional views of the zoom lens barrel 10s at the time of shooting (extended state). FIG.
FIG. 7 shows the wide-angle end. FIG. 8 is a cross-sectional view at the time of non-imaging (collapsed state). Since the zoom lens barrel 10s of the modified example is configured substantially the same as the zoom lens barrel 10 of the embodiment, the same reference numerals are used for the same components. Below, it demonstrates centering around difference.

In the zoom lens barrel 10s of the modified example, a shutter unit 19 having the same structure as that of the embodiment and a focus unit (not shown) are fixed to a moving frame 18 arranged inside the rectilinear barrel 25. . Unlike the embodiment, the second lens group frame 12s holding the second lens group 12 is arranged behind the shutter unit 19 and is supported by the movable frame 18 so as to be movable in the optical axis direction. Shutter unit 1
A spring 19s is arranged between 9 and the second lens group frame 12s so that the second lens group frame 12s is biased in a direction away from the shutter unit 19 (rearward).

In the photographing state, as shown in FIGS. 6 and 7, the second lens group frame 12s is moved rearward by the bias of the spring 19s, and the second lens group 12 is moved to the shutter unit 1.
Located away from 9.

On the other hand, in the non-photographing state, as shown in FIG. 8, the spring 19s is compressed and the second lens group 12 and the second group lens frame 12s are moved to the shutter unit 19 side. Then, a part of the second lens group 12 and the second group lens frame 12s enters into the opening 19a of the shutter unit 19 in the opened state.

9 to 11 show a zoom lens barrel 50 of a comparative example. 9 and 10 are cross-sectional views of the zoom lens barrel 50 at the time of shooting (extended state). FIG. 9 shows the telephoto end and FIG. 10 shows the wide-angle end. FIG. 11 is a cross-sectional view at the time of non-imaging (collapsed state).

The zoom lens barrel 50 of the comparative example has substantially the same structure as the zoom lens barrel 10 of the embodiment.

That is, inside the fixed barrel 62 of the zoom lens barrel 50, the cam ring 64, the rectilinear barrel 65, and the forward barrel 66.
And the cam ring 64 and the advancing cylinder 66 are projected from and retracted from the fixed cylinder 62 by the rotation of the long gear 60.
The relative positions of the lens group 51, the second lens group 52, the third lens group 53, and the fourth lens group 54 in the optical axis direction are changed. CC at the rear end of the zoom lens barrel 50
The D image sensor 55 can be fixed. A moving frame 58 to which the shutter unit 57 and the like are fixed is arranged inside the straight-moving barrel 65. Pins 58a, 64a, 66a
The gear portion 64b, the engagement piece 65a, and the like are also configured in the same manner as in the embodiment.

On the other hand, unlike the embodiment, the opening 57a of the shutter unit 57 is designed to be closed during non-photographing (in the collapsed state). Therefore, as shown in FIG. 11, the second and third lens groups 52 and 53 are separated from each other by the thickness of the shutter unit 57. Therefore, the total length of the zoom lens barrel 50 in the collapsed state is
The length is inevitably longer than that of the zoom lens barrel 10 of the embodiment.

The present invention is not limited to the above embodiments and modifications, but can be implemented in various other modes.

For example, the opening diameter of the opening of the shutter is smaller than the outer diameter of the lens, and a part of the lens (for example, a curved portion of the convex lens) is placed inside the opening of the shutter when the photographing is not performed.
You may let only enter.

The zoom lens barrel of the present invention can be applied not only to photographing but also to projection, for example.

[Brief description of drawings]

FIG. 1 is a sectional view of a zoom lens barrel according to an embodiment of the present invention.

FIG. 2 is a sectional view of a zoom lens barrel according to an embodiment of the present invention.

FIG. 3 is a sectional view of a zoom lens barrel according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of the lens barrier in FIGS. 1 to 3.

5 is a sectional view and a developed view of the fixed barrel and the cam ring of FIGS. 1 to 3. FIG.

FIG. 6 is a sectional view of a modified zoom lens barrel.

FIG. 7 is a sectional view of a modified zoom lens barrel.

FIG. 8 is a sectional view of a modified zoom lens barrel.

FIG. 9 is a sectional view of a zoom lens barrel of a comparative example.

FIG. 10 is a sectional view of a zoom lens barrel of a comparative example.

FIG. 11 is a sectional view of a zoom lens barrel of a comparative example.

[Explanation of symbols]

10, 10s zoom lens barrel 12 Second lens group (lens) 16 Lens barrier (light blocking member) 16a, 16b blade members 17,19 Shutter unit (shutter, diaphragm) 17a, 19a openings

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 9/02 G03B 9/08 Z 9/08 17/04 17/04 G02B 7/04 Z F term (reference) 2H044 AJ04 BF03 DA02 DB02 EC01 EF07 2H080 DD07 2H081 CC47 DD00 2H101 DD62

Claims (5)

[Claims] 1. A zoom lens barrel that expands and contracts in the direction of the optical axis, is extended during shooting, and is extended during non-shooting. The shutter is opened during the non-shooting, and at least a part of an adjacent lens is housed in the opening. A zoom lens barrel characterized by being equipped with. 2. The opening at the time of non-shooting, inside the opening,
The zoom lens barrel according to claim 1, further comprising an aperture for accommodating at least a part of the lens. 3. The zoom lens barrel according to claim 1, wherein the opening portion of the shutter has an opening diameter larger than an opening diameter optically required for the photographing. 4. A light-shielding member that interferes with a light beam that passes through the zoom lens barrel during the non-shooting period to block the light beam, and that retracts from a light beam that passes through the zoom lens barrel and forms an image during the shooting period. The zoom lens barrel according to claim 1, 2 or 3, which is characterized in that. 5. The zoom lens barrel according to claim 1, wherein the shutter and the lens adjacent to the shutter are held by the same holding member so as to be relatively movable.