JP2003287670A - Lens barrel of camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel of a camera, which can be made small-sized and makes a driving device such as a motor stored in the lens barrel and a lens frame not interfere with each other in a collapse state. <P>SOLUTION: One of a plurality of lens groups is moved along an optical axis 30 by a driving motor 62 arranged in the lens barrel and a lens frame 80 of another lens group has a cut 80a formed to avoid interference with the driving motor. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel of a camera, and more particularly to a lens barrel of a camera which is suitable for a small-sized and high-pixel camera.

[0002]

2. Description of the Related Art In recent years, digital cameras are increasingly constructed so that the lens barrel can be housed in the camera body when not in use due to the demand for compactness. That is, each lens group that constitutes the taking lens is movably supported along the optical axis, and only when taking a picture, the lens is extended to a predetermined position for taking a picture, and when not in use, it can be retracted and stored in the camera body. The number of configured items is increasing.

By the way, in recent years, the lens barrel of a digital camera is required to have high zoom performance and high performance of the optical system itself, and the number of lenses and the number of groups of lenses are increasing. There is. On the other hand, in order to make the lens barrel more compact, a drive device such as a motor is increasingly housed in the lens barrel. For example, Japanese Unexamined Patent Publication No. 10-228394,
Japanese Patent Laid-Open No. 2001-100078 discloses such a configuration example.

[0004]

However, in the above-mentioned conventional lens barrel, when a compact lens barrel is used, a driving device such as a motor and a lens frame housed in the lens barrel, particularly the frontmost lens on the subject side. The frame and the frame tend to interfere with each other when retracted. On the other hand, if the design is designed to avoid interference, the shape of the lens barrel will be unnecessarily increased, and it will not be possible to meet the demand for compactness.

The present invention has been made in view of the above circumstances. The lens barrel can be downsized, and a driving device such as a motor housed in the lens barrel and the lens frame interfere with each other when the lens barrel is collapsed. It is an object of the present invention to provide a lens barrel of a camera that does not have a structure.

[0006]

In order to achieve the above object, the present invention provides a lens barrel in which a plurality of lens groups are movably held along an optical axis in a cylindrical body. At least one lens group among the plurality of lens groups is moved along the optical axis by a drive motor disposed in the cylinder, and the drive motor is attached to a lens frame of any one of the plurality of lens groups. Provided is a lens barrel of a camera, which is formed with a notch for avoiding interference with the lens barrel.

According to the present invention, since the notch for avoiding the interference with the drive motor is formed in the lens frame of one of the lens groups, the lens barrel can be downsized and A drive device such as a motor housed in the lens barrel does not interfere with the lens frame when the lens barrel is collapsed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a lens barrel of a camera according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an external configuration of a digital camera to which a lens barrel of a camera according to the present invention is applied.

As shown in FIG. 1, the digital camera 1 has a camera body formed in a rectangular box shape, and a lens barrel 2, a finder window 3 and a strobe light control sensor 4 are provided on the front surface thereof. , A self-timer lamp 5 and the like are provided. A pop-up strobe 6, a release switch 7 and the like are provided on the upper surface thereof, and a finder eyepiece, a liquid crystal display panel, operation keys and the like (not shown) are provided on the rear surface thereof. The digital camera 1 is a collapsible type, and the lens barrel 2 is extended from the camera body only when it is used, and projects from the front part of the camera body.

2 to 4 are side sectional views of the lens barrel 2 applied to the digital camera 1 described above. 2 shows the lens barrel 2 in the wide position, and FIGS. 3 and 4 show the lens barrel 2 in the tele position and the retracted position, respectively. Shows.

As shown in FIGS. 2 to 4, the lens barrel 2 includes a first zoom lens group 12, a second zoom lens group 14, a focus lens 16, and a first zoom lens barrel 1.
8, the second zoom lens barrel (corresponding to the second lens frame) 20,
The cam cylinder 22, the fixed cylinder 24, the drive cylinder 26, the aperture shutter unit 28, and the like are included.

A gear portion 26a is formed on the outer periphery of the drive cylinder 26, and the driving force of a zoom motor (not shown) is transmitted to the gear portion 26a. The driving force of the motor causes the drive barrel 26 to rotate around the optical axis 30 as the center of rotation while contacting the outer periphery of the fixed barrel 24.

Further, the lens barrel 2 is moved from the retracted position to the tele position by the drive barrel 26 rotating in the "storage rotation range" from the "initial position" to the "intermediate position".
Further, the drive barrel 26 is moved from the tele position to the wide position by rotating in the "variable rotation range" from the "intermediate position" to the "end position".

A straight-moving groove 26b for moving the cam barrel 22 along the optical axis 30 is formed on the inner peripheral surface of the drive barrel 26. The rectilinear groove 26b transmits the rotational force of the drive cylinder 26 to the cam cylinder 22 via the cam follower 32.

The fixed barrel 24 includes a second zoom lens barrel 20.
A straight groove 24a for moving the cam barrel 22 along the optical axis 30 and a cam groove 24b for moving the cam barrel 22 along the optical axis 30 are formed.

A cam follower 32 is provided on the outer peripheral surface of the cam barrel 22.
Is provided. This cam follower 32 has a cam groove 24.
It is fitted in the groove b, penetrates the cam groove 24b, and is fitted in the rectilinear groove 26b. Therefore, the cam cylinder 22
Moves in the optical axis 30 direction with respect to the fixed barrel 24 while rotating in association with the rotation of the drive barrel 26. A first cam groove 22a is formed on the inner peripheral surface of the cam barrel 22. The cam groove 24b, the rectilinear groove 26b, and the cam follower 32 are provided at three divided positions around the optical axis 30, respectively.

Inside the first zoom lens barrel 18, there is a first
The zoom lens group 12 is held. Further, a straight groove 34 is formed on the inner peripheral surface of the first zoom lens barrel 18,
Further, a cam follower 36 that fits in the first cam groove 22a is provided on the outer peripheral surface of the first zoom lens barrel 18.
Therefore, the first zoom lens barrel 18 is moved to the cam barrel 22 by the linear movement guide action (described later) by the second zoom lens barrel 20 as the cam barrel 22 rotates and the feeding action of the first cam groove 22a of the cam barrel 22. On the other hand, it moves back and forth in the direction of the optical axis 30. The cam follower 36 and the first cam groove 22a are provided at three divided positions around the optical axis 30, respectively.

Inside the second zoom lens barrel 20, there is a second
The zoom lens group 14 is held. The second cam groove 22 b of the cam barrel 22 is formed on the outer peripheral surface of the second zoom lens barrel 20.
There is provided a cam follower 38 that fits in the. A tip arm portion 50 is formed at the front end of the second zoom lens barrel 20, and a straight advance guide protrusion 52 is formed on the outer peripheral surface side of the tip of each tip arm portion 50. The straight-line guide projections 52 are fitted into the straight-line grooves 34 of the first zoom lens barrel 18, so that the straight-line guide function described above is produced. The cam follower 38, the second cam groove 22b,
The straight-movement guide protrusion 52 and the straight-movement groove 34 are respectively provided at three divided positions around the optical axis 30.

A rear end arm portion 51 is formed at the rear end of the second zoom lens barrel 20, and each rear end arm portion 51 is formed.
A straight guide projection 53 is formed on the outer peripheral surface side of the rear end. Since these straight-movement guide protrusions 53 are fitted in the straight-movement grooves 24a of the fixed cylinder 24, a straight-movement guide action is generated.

That is, the second zoom lens barrel 20 is driven by the rotation of the driving barrel 26 so that the driving force is changed to the cam barrel 22 and the first barrel.
It is transmitted via the zoom lens barrel 18 and moves back and forth with respect to the fixed barrel 24 in the optical axis 30 direction. The straight-movement guide protrusion 53 and the straight-movement groove 24a are provided at three divided positions around the optical axis 30, respectively.

According to the above construction, the first zoom lens barrel 18, the second zoom lens barrel 20, the cam barrel 22, and the fixed barrel 2 are provided.
Of the drive barrel 26 and the drive barrel 26, the fixed barrel 24 has its rear end fixed to the base B and is immovable, and the first zoom lens barrel 18 and the second zoom lens barrel 20 are constrained from moving in the rotational direction. It moves back and forth only in the direction of the axis 30. The drive barrel 26 is constrained from moving in the direction of the optical axis 30 with respect to the fixed barrel 24, and only rotates. The cam barrel 22 is rotated by the drive barrel 26 and moves back and forth in the direction of the optical axis 30.

In each figure, reference numeral 10a indicates an image plane of the lens barrel 2, and an image plane of a CCD (not shown) is arranged at this position.

The focus lens 16 is arranged at the rear stage position of the second zoom lens group 14, and is held by the focus lens frame 40. The focus lens frame 40 is
It is supported by the focus lens drive unit 60. Here, the focus lens frame 40 is movably supported in the fixed barrel 24 along the optical axis.

The lens barrel 2 has a focus lens frame 40.
The focus lens frame 40 is driven by a focus lens drive unit 60 described below. The focus lens frame 40 is driven by moving the focus lens frame 40 along the optical axis 30.

The focus lens drive unit 60 is composed of a ball screw unit 64, which is a combination of a drive motor 62, a screw shaft 64a and a nut 64b, and a bracket 66 having a substantially U shape.

One end of the bracket 66 is fixed to the base B, and the drive motor 62 is fixed to the other end of the bracket 66. Ball screw unit 64 screw shaft 64
Both ends of a are rotatably supported by brackets 66. Also, at the other end of the bracket 66,
The screw shaft 64 a is connected to the shaft of the drive motor 62.
The nut 64b of the ball screw unit 64 is slidably supported so as to prevent the nut 64b from rotating with respect to the screw shaft 64a. Therefore, drive the drive motor 62,
When the screw shaft 64a is rotated, the nut 64b moves back and forth according to the rotation amount of the screw shaft 64a.

The focus lens frame 40 is supported by a connecting member 68 fixed to the nut 64b. Therefore, when the drive motor 62 is operated and the screw shaft 64a is rotated, the focus lens 16 supported by the focus lens frame 40 moves back and forth according to the rotation amount of the screw shaft 64a.

Further, the focus lens frame 40 is provided with a cover member 70 which can cover a part of the side surface of the drive motor 62. The cover member 70 is not limited in its shape and material as long as it has a function of preventing incident light or the like from being reflected by the drive motor 62 and preventing the reflected light from being incident on the CCD, which is a light receiving element. Absent.

However, as shown in FIG. 5, the circle is arranged on the optical axis 30 side with respect to the drive motor 62 and in the vicinity of the drive motor 62, and the side surface shape follows the outer peripheral shape of the drive motor 62. The arc shape is preferable because the lens barrel can be downsized and the damage due to reflection of incident light can be effectively prevented.

As the material of the cover member 70, various resin materials are preferable in terms of molding accuracy, manufacturing cost, weight, corrosion resistance and the like. Further, if the cover member 70 is black and has a matte surface, there is little concern that light will be reflected by the cover member 70 to generate harmful light, which is preferable.

The cover member 70 of the focus lens frame 40
A light-blocking blade 74 is fixed on the opposite side of
A light blocking cover 76 is provided on the subject side (left side in FIGS. 2 to 4) of the light blocking blade 74. A photointerrupter 72 having a substantially π shape is fixed to the base B so as to sandwich the light shielding cover 76. A of the above configuration in FIG.
-A line arrow view is shown in FIG.

The photo interrupter 72 is used for detecting the origin position of the focus lens 16 and the like, and is used in combination with the light shielding blade 74. That is, the light is emitted from the side wall on one side of the groove portion 72a of the photo interrupter 72 shown in FIG. 6 and is received by the side wall on the opposite side of the groove portion 72a. The origin position of the focus lens 16 can be detected by blocking this light by the light blocking blade 74.

However, if incident light or the like entering the lens barrel enters the groove portion 72a of the photo interrupter 72, it may cause a malfunction. Therefore, the light shielding cover 7 is provided at the position described above.
6 is provided to prevent such malfunction.

In the example of the present embodiment, the focus lens 16 has a single-element configuration, unlike the other lens groups.
Of course, it may be a lens group including two or more lenses.

2 to 4, the support structure of the first zoom lens group 12 is constructed as follows. The periphery of the first zoom lens group 12 is supported by the first lens frame 80. As shown in FIG. 7, the first lens frame 80 has a notch 80a formed in the upper portion thereof to avoid interference with the drive motor 62 (see FIG. 4).

Further, the first lens frame 80 is provided with rotation restricting projections 80c at three divided positions around the optical axis 30,
A rotation regulating groove 84 of an adjustment ring support flange 84 described later.
The rotation around the optical axis 30 is restricted by engaging with c.

A male screw portion 8 is provided on the outer peripheral portion of the first lens frame 80.
0b is formed, and the male screw portion 80b is supported by the adjusting ring 82 by being screwed with the female screw portion 82b formed on the inner peripheral portion of the adjusting ring 82 arranged on the outer peripheral side of the first lens frame 80. To be done.

The adjustment ring 82 has a front end face plate 88 having a flange 82a formed on the outer peripheral portion thereof fixed to the front end of the first zoom lens barrel 18, and an inner periphery of the first zoom lens barrel 18 on the back surface of the adjustment ring 82. It is rotatably supported by being sandwiched between the adjustment ring support flange 84 supported by the section. The tip face plate 88 and the flange 82
A ring-shaped plate spring 86 is disposed between the plate spring 86a and a, and the plate spring 86 urges both the front end face plate 88 and the flange 82a to prevent backlash.

An L-shaped arm-shaped portion 84a is provided on the rear side of the adjustment ring support flange 84, and the rotation restricting groove 84c is formed at the tip of the arm-shaped portion 84a. Further, on the front surface side of the adjustment ring 82, a pin hole 82d into which a tip pin of a rotary jig used to rotate the adjustment ring 82 can be fitted is formed.

The operation of the support structure for the first zoom lens group 12 configured as described above will be described below. At the time of assembling and adjusting the lens barrel 2, the front and rear positions of the first zoom lens group 12 are finely adjusted (tracking adjustment) in the wide position and the tele position, respectively.

At this time, the first structure adopted in the conventional structure
In the screw fixing of the frame of the zoom lens group and the first zoom lens barrel, even if the frame of the first zoom lens group is provided with a notch as in the configuration of the embodiment of the present invention, the frame of the first zoom lens group is not removed. Due to the rotation, the notch does not always match the position of the drive motor, and interference with the drive motor was unavoidable.

On the other hand, according to the configuration of the embodiment of the present invention, the fine adjustment of the front-back position of the first zoom lens group 12 is performed by rotating the adjustment ring 82. And
The rotation of the first lens frame 80 is prevented by the engagement of the rotation restriction protrusion 80c and the rotation restriction groove 84c. This allows
The effect of the notch 80a of the first lens frame 80 can be exhibited, and interference between the first lens frame 80 and the drive motor 62 can be avoided.

Although the example of the embodiment of the lens barrel of the camera according to the present invention has been described above, the present invention is not limited to the example of the above embodiment, and various modes can be adopted. For example, in the present embodiment, the lens group that is moved along the optical axis 30 by the drive motor 62 is the focus lens 16, but it is also applicable to a configuration in which this lens group is the second zoom lens group 14, for example. You can

Further, the present invention can be applied to a construction in which the lens group in which the lens frame has a notch in order to avoid interference with the drive motor 62 is the second zoom lens group 14. The configuration for restricting the rotation of the lens frame of the lens group around the optical axis is not limited to the example of the above embodiment, and other configurations can be applied.

In the above embodiment, the zoom lens has a three-group structure, but the present invention is not limited to this, and the zoom lens is not limited to this.
It may have a configuration of more than one group.

For example, in a 4-group zoom lens, the first and second lens groups are supported by three suspensions, and the third and fourth lens groups are supported by guide rods. You may comprise. In this case, depending on the diameter of the lens group, it is preferable to select whether to support by hanging three or by supporting with a guide rod. That is, two lens groups each having a large diameter are supported by three suspensions, and the remaining lens groups are supported by a guide rod. Thereby, each lens group can be stably operated.

The present invention can be applied not only to the zoom lens camera, but also to a bifocal camera that switches to a tele position, a wide position, and a retracted position, for example.

Further, in the above embodiment, the tele position is set between the retracted position and the wide position, but it is also possible to set the wide position between the retracted position and the tele position. In this case, the boundary between the variable power guide portion and the storage guide portion is the wide position.

Further, in the above embodiment, the straight groove 34
And the straight-movement guide protrusions 52 and the like are provided at three divided positions around the optical axis.
They may be provided at two positions around the optical axis, respectively.

[0050]

As described above, according to the lens barrel of the present invention, the lens frame of one lens group is formed with the notch for avoiding interference with the drive motor. The lens barrel can be downsized, and the driving device such as a motor housed in the lens barrel and the lens frame do not interfere with each other when the lens barrel is collapsed.

[Brief description of drawings]

FIG. 1 is a perspective view of a digital camera to which a lens barrel according to the present invention is applied.

FIG. 2 is a side sectional view showing a configuration of a lens barrel (extended state (wide end)).

FIG. 3 is a side sectional view showing a configuration of a lens barrel (extended state (tele end)).

FIG. 4 is a side sectional view showing a configuration of a lens barrel (in a collapsed state).

FIG. 5 is a sectional view showing the first zoom lens barrel cut in a direction intersecting the optical axis.

FIG. 6 is a view of A- of FIG.
A line arrow view

FIG. 7 is a partially cutaway conceptual diagram showing an outline of a first zoom lens barrel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Digital camera, 2 ... Lens barrel, 12 ... 1st zoom lens group, 14 ... 2nd zoom lens group, 16 ... Focus lens, 18 ... 1st zoom lens barrel, 20 ... 2nd zoom lens barrel, 22 ... Cam barrel, 24 ... Fixed barrel, 26 ... Driving barrel, 30 ... Optical axis, 40 ... Focus lens frame, 62 ...
Drive motor, 70 ... cover member, 80 ... first lens frame,
80a ... Notch, 80c ... Rotation regulation projection, 82 ... Adjustment ring, 84 ... Adjustment ring support flange, 84c ... Rotation regulation groove, 86 ... Leaf spring, 88 ... Tip face plate

Claims (3)

[Claims] 1. A lens barrel in which a plurality of lens groups are movably held along an optical axis in a cylinder, wherein at least one lens group among the plurality of lens groups is arranged in the cylinder. While being moved along the optical axis by the drive motor, the lens frame of any one of the plurality of lens groups is provided with a notch for avoiding interference with the drive motor. The characteristic lens barrel of the camera. 2. The lens barrel of a camera according to claim 1, wherein any one of the lens groups is a frontmost lens group on the subject side. 3. The lens barrel of a camera according to claim 1, wherein the lens frame of any one of the lens groups is configured to be restricted from rotating about an optical axis.