JPH10123389A - Lens barrel and optical device with this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the assembling of a lens barrel and to reduce the cost of the barrel by regulating the guiding of a lens holding member in an optical direction and turning with a guide part with an engaging part in a center. SOLUTION: As a holding frame part 2a rotates in the peripheral direction of the optical direction and the combining part of the part 2a and the rack part 4 moves in the same direction, the posture of the rack part 4 with respect to a screw shaft 3 varies. However, mutually meshing state of the part 4 and the shaft 3 is maintained by energizing force given from the arm part 5a of a twisting coil spring 5. In addition, the pressing state of a guiding projection 2b and a turning regulating projection 2c to the inner surface of a guiding groove 6a and a turning regulating surface 6b is also maintained by energizing force given from the arm part 5b of a twisting coil spring 5. The lens barrel without the backlash of the lens holding member 2 and the bending of the optical axis with this is obtained like this and at the time of fitting this lens barrel to a camera, proper zoom photographing, etc., without the shake of an image is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a moving lens group and an optical apparatus having the same.

[0002]

2. Description of the Related Art A lens barrel having a movable lens such as a zoom lens has been widely used as an interchangeable lens of a camera. Such a lens barrel includes a lens holding member for holding a moving lens, a screw shaft extending in the optical axis direction and engaging with a rack provided on the lens holding member, and a screw. A guide bar that engages with a lens holding member that is driven by rotation of a shaft and guides the lens holding member in the optical axis direction; and a lens barrel that engages with the lens holding member so that the lens holding member centers on the guide bar. And a rotation restricting bar for preventing rotation in the inside.

[0003]

However, when assembling the lens barrel constructed as described above, there is a problem that the assembling of the guide bar and the rotation restricting bar is required, so that it is difficult to assemble the lens barrel.

Further, a space (gap) for absorbing thermal expansion and thermal contraction of each member is required at an engagement portion between the guide bar and the rotation regulating bar and the lens holding member. For this reason, there is a problem that the lens holding member moves out of control by the amount of the gap (that is, rattle occurs). And
If such movement of the lens holding member is out of the control, image deterioration due to displacement of the optical axis or group rotation, image shake during movement of the lens holding member or at the time of reversal of the movement, and an actuator for rotating the screw shaft are rotated. Control errors and the like may occur.

If the gap between the lens holding member and each bar can be set to the minimum necessary, such a problem will be reduced. However, to minimize the gap, the arrangement of each bar in the lens barrel member is reduced. In addition, it is necessary to manufacture the components and each member with extremely high precision, which causes an increase in the cost of the lens barrel.

Accordingly, the present invention provides a lens barrel and an optical apparatus equipped with the lens barrel, in which uncontrolled movement of a lens holding member can be minimized as much as possible without assembling and increasing the cost. It is intended to provide.

[0007]

In order to achieve the above object, according to the present invention, there is provided a lens barrel, a drive shaft extending in the optical axis direction within the lens barrel, and a drive shaft. A lens holding member having an engaging portion to be engaged and a holding frame portion holding the lens, and a lens holding member driven in the optical axis direction within the lens barrel member by rotation of the drive shaft; A guide portion that contacts the holding frame portion to guide the lens holding member in the optical axis direction on the inner surface portion, and a rotation restricting portion that restricts rotation around the contact portion of the holding frame portion with the guide portion. Is formed.

That is, a guide portion and a rotation restricting portion provided with a groove portion and a ridge portion are provided on the inner surface portion of the lens barrel member. The provision of the guide bar eliminates the need for a guide bar and a rotation restricting bar that are conventionally mounted in the lens barrel member, facilitates assembly of the lens barrel, and reduces the cost of the lens barrel.

In the above-mentioned invention, the guide portion and the rotation restricting portion are spirally extended around the optical axis, so that the lens holding member with respect to the lens barrel member can cope with the taper at the time of lens barrel molding. It is desirable that movement outside the control (for example, movement that tilts with respect to the optical axis) does not easily occur.

[0010] Further, a pressing means for pressing the holding frame portion against the guide portion and the rotation restricting portion is provided, so that the holding frame portion and the guide portion and the rotation restricting portion which cause the movement outside the above-mentioned control are provided. It is desirable that no gap is formed in the engaging portion.

As a pressing means, a spring which urges the engaging portion of the lens holding member in the direction engaging with the drive shaft and urges the holding frame portion in the direction of pressing the guide frame and the rotation restricting portion. Alternatively, when the holding frame portion and the engaging portion are connected to each other by an elastic portion and are integrally formed, the elastic portion may be used as a pressing unit.

According to the present invention, by providing such a lens barrel, it is possible to realize an optical apparatus such as a camera capable of performing appropriate zoom photographing or the like without causing image shaking.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a lens barrel according to a first embodiment of the present invention. In this figure, reference numeral 6 denotes a lens barrel member. Inside the upper part of the lens barrel member 6, a screw shaft 3 that is driven to rotate by a motor (not shown) extends in the optical axis direction. 1 is a moving lens group, 2 is a lens holding member, and this lens holding member 2
Is a rack portion (engagement portion in the claims) 4 which meshes with the holding frame portion 2a holding the movable lens group 1 and the screw shaft 3.
And is configured. The rack 4 is rotatably mounted on the holding frame 2a in a plane perpendicular to the optical axis, and the arm 4 is provided between the rack 4 and the holding frame 2a by the arm 5a. The arm portion 5b is urged in a direction (clockwise direction in FIG. 1) for meshing with the screw shaft 3.
A torsion coil spring 5 for urging the holding frame 2a counterclockwise in FIG. 1 is attached.

A guide groove 6a having a V-shaped cross-section and extending helically with respect to the optical axis is provided in an upper portion of an inner surface portion of the lens barrel member 6 for accommodating the holding frame 2a of the lens holding member 2. Are formed. A rotation restricting surface 6b is formed below the inner surface portion so as to extend spirally in the same direction as the guide groove 6a with respect to the optical axis.

A guide projection 2b is formed on the upper portion of the holding frame 2a to engage with the inner surface of the guide groove 6a.
In the lower part, a regulating protrusion 2c engaging with the rotation regulating surface 6b is provided.
Are formed.

Here, as shown in FIGS. 2 and 3, the guide projection 2b and the regulating projection 2c are respectively provided on the holding frame 2
a, the optical axis of the lens held by the holding frame 2b is aligned with the optical axis of the lens barrel member 6 even if the guide groove 6a and the rotation restricting surface 6b are spiral. The projection height of the projection 2b, 2c on one side in the optical axis direction (right side in FIGS. 2 and 3) from the line parallel to the optical axis is adjusted so as to coincide with the projection height of the other projection 2b, 2c in the optical axis direction. It is bigger than it is.

The guide projection 2b is pressed against the inner surface of the guide groove 6a by the urging force applied from the arm 5b of the torsion coil spring 5 to the holding frame 2b. Accordingly, it is possible to reliably prevent a gap from being formed between the guide protrusion 2b and the inner surface of the guide groove 6a, and to prevent uncontrolled movement of the lens holding member 2.

In the thus constructed lens barrel, when the screw shaft 3 rotates, the rack portion 4 receives a driving force in the optical axis direction from the screw shaft 3. Thus, the driving force in the optical axis direction also acts on the holding frame 2a connected to the rack 4, but since the guide 6a and the rotation restricting surface 6a are formed in a spiral shape, the holding frame is formed. The portion 2a moves in the optical axis direction while rotating around the optical axis along the guide portion 6a and the rotation restricting surface 6a.

When the holding frame 2a rotates in the direction around the optical axis, the joint between the holding frame 2a and the rack 4 moves in the same direction as shown in FIG. Of the torsion coil spring 5, the meshing state between the rack 4 and the screw shaft 3 is maintained by the urging force applied from the arm 5 a of the torsion coil spring 5, and is applied from the arm 5 b of the torsion coil spring 5. Guide protrusion 2b and rotation restricting protrusion 2c
Is pressed against the inner surface of the guide groove 6a and the rotation restricting surface 6b.

As described above, according to the present embodiment, it is possible to realize a lens barrel in which the lens holding member 2 has no backlash (movement outside of control) and the optical axis is not broken. If attached to a camera, appropriate zoom shooting without image shaking can be performed.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. In the first embodiment, the holding frame portion 2a and the rack portion 4 formed separately are provided.
Are rotatably connected to each other, and the urging force of the torsion coil spring 5 guides the guide protrusion 2 b of the holding frame 2 a and the rotation restricting protrusion 2.
c is pressed against the inner surface of the guide groove 6a of the lens barrel member 6 and the rotation restricting surface 6b, but in the present embodiment, the lens is formed by connecting the holding frame 2a and the rack 2f by the elastic portion 2e. The entire holding member 2 is integrally formed, and the guide protrusion 2b and the rotation restricting protrusion 2c are pressed against the inner surface of the guide groove 6a and the rotation restricting surface 6b by the elastic force of the elastic portion 2e.

The rack portion 2f is also pressed by the screw shaft 3 by the elastic force of the elastic portion 2e.

According to the present embodiment, as in the first embodiment, it is possible to realize a lens barrel in which the lens holding member 2 has no backlash (movement outside of control) and the optical axis is not broken. If this lens barrel is attached to a camera, it is possible to perform proper zoom photography without image shaking.

The present invention can be applied to lens barrels of various types of cameras such as a single-lens reflex camera, a lens shutter camera, a video camera, etc., and further to optical equipment other than a camera. be able to.

[0025]

As described above, according to the present invention, the lens holding member is brought into contact with the guide portion and the rotation restricting portion formed on the inner surface of the lens barrel member. The guide bar in the optical axis direction and the rotation around the engagement portion with the guide portion are regulated, so that the guide bar and the rotation regulation bar conventionally mounted in the lens barrel member are not required. And make it easier to assemble the lens barrel,
The cost of the lens barrel can be reduced.

In addition, if the guide portion and the rotation restricting portion are extended spirally around the optical axis, the lens holding member is not controlled with respect to the lens barrel member while coping with the draft taper at the time of lens barrel molding. Movement (for example, movement tilting with respect to the optical axis) can be made less likely to occur, and shift (breaking) of the optical axis can be prevented.

Further, if means for pressing the lens holding member against the guide portion and the rotation restricting portion is provided, a gap is formed in the engaging portion between the holding frame portion and the guide portion which may cause uncontrolled movement. Can be reliably prevented.

By providing such a lens barrel, it is possible to realize an optical device such as a camera capable of performing appropriate zoom photographing or the like without causing image shaking.

[Brief description of the drawings]

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

FIG. 2 is a partial cross-sectional view (a cross-sectional view in the direction of arrow II in FIG. 1) showing a configuration around a guide groove in the lens barrel of the first embodiment.

FIG. 3 is a partial cross-sectional view (a cross-sectional view as viewed in a direction indicated by an arrow III in FIG. 1) illustrating a configuration around a rotation restricting unit in the lens barrel according to the first embodiment.

FIG. 4 is an operation explanatory view of the first embodiment.

FIG. 5 is a front sectional view of a lens barrel according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 moving lens group 2 lens holding member 2 a holding frame 2 b guide projection 2 c rotation restricting projection 2 e elastic part 3 screw shaft 4, 2 f rack 5 torsion coil spring 6 lens barrel member 6 a guide groove 6 b rotation restriction surface

Claims (6)

[Claims] An optical system includes a lens barrel member, a drive shaft extending in the optical axis direction within the lens barrel member, an engagement portion that engages with the drive shaft, and a holding frame that holds a lens. And a lens holding member driven in the optical axis direction within the lens barrel member by rotation of the drive shaft, wherein the lens holding member is engaged with an inner surface portion of the lens barrel member. A guide portion for guiding the lens holding member in the optical axis direction, and a rotation restricting portion for restricting rotation of the holding frame portion around an engagement portion with the guide portion are formed. Lens barrel. 2. The device according to claim 1, wherein the guide portion and the rotation restricting portion extend spirally around an optical axis.
The lens barrel according to item 1. 3. The lens barrel according to claim 1, further comprising a pressing unit configured to press the holding frame portion against the guide portion and the rotation restricting portion. 4. The pressing means urges the engaging portion in a direction in which the engaging portion is engaged with the drive shaft, and urges the holding frame portion in a direction in which the holding frame portion is pressed by the guide portion and the rotation restricting portion. The lens barrel according to claim 3, wherein the lens barrel is a spring. 5. The lens barrel according to claim 3, wherein the holding frame portion and the engaging portion are connected to each other by an elastic portion and are integrally formed, and the elastic portion is used as the pressing unit. . 6. An optical apparatus comprising the lens barrel according to claim 1.