JP2002107600A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel whose collapsing time is shortened and which is constituted to be more compact and contributes to the compaction of a camera. SOLUTION: This lens barrel is equipped with a photographing state which takes a photograph by at least two lens groups, a lens frame 3 which shifts the lens groups between a photographing state and a degradation state which is degradated than the photographing state and holding one lens group 3a of the lens groups, an elastic member 7 energizing the lens frame in an optical axis direction, lead screws 9a and 9b arranged nearly in parallel with an optical axis, a driving member 9 rotating the lead screws, and a nut member 10 screwed with the lead screw. The lens frame has a rotation regulating part 3b regulating the rotation of the nut member. In the photographing state, the lens frame is engaged with the nut member at the rotation regulating part by the elastic energizing force of the elastic member, and the lead screw is rotated by the driving of the driving member so as to move the nut member nearly in a parallel direction with the optical axis, whereby the lens frame is moved nearly in the parallel direction with the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel used for a camera.

[0002]

2. Description of the Related Art In recent years, in a compact camera, a method of retracting a lens barrel (hereinafter referred to as "collapse") when carrying the camera and extending the lens at the time of photographing has been generally used. For example, as described in JP-A-7-43583, when the nut for driving the lens frame is configured to be restricted in the optical axis direction, when the collapsing is performed, the focusing lens is previously set in the collapsing state. After moving to the retracted position, the entire lens barrel needs to be retracted.

[0003]

However, in the conventional lens barrel as disclosed in the above-mentioned publication, since a part of the lens is moved to a retracted position in advance at the time of collapsing, the collapsing is performed. It was hanging. Recently, there has been a demand for a more compact camera by shortening the overall length in the collapsed state as much as possible.However, in the lens barrel, since the lens frame and the nut are engaged without any gap in the optical axis direction, When the lens barrel is collapsed, a certain amount of clearance is required before and after the lens frame, which has been an obstacle in terms of making the lens frame more compact.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a lens barrel which can shorten the retracting time, can be made more compact, and can contribute to downsizing of a camera.

[0005]

In order to achieve the above object, a lens barrel according to the present invention includes at least two lens groups, and a photographing state in which photographing is performed by the lens groups;
In a lens barrel that transitions between a retracted state (retracted state) in which the lens group is retracted from the photographing state, one of the lens groups is held in the lens barrel while being guided substantially parallel to the optical axis. A lens frame, an elastic member for urging the lens frame in the optical axis direction, a lead screw arranged substantially parallel to the optical axis, a driving member for rotating the lead screw, and a nut screwed to the lead screw The lens frame has a rotation restricting portion that restricts rotation of the nut member, and the lens frame is rotated by the elastic biasing force of the elastic member in the photographing state. And the drive of the drive member rotates the lead screw to move the nut member in a direction substantially parallel to the optical axis, so that the lens frame is substantially parallel to the optical axis. Characterized by moving while being id.

According to this lens barrel, since the lens frame is engaged with the nut member by the elastic biasing force of the elastic member in the optical axis direction, the elastic member can be contracted when the lens frame is retracted. For this reason, since the retracting operation can be performed immediately from the shooting state, the time for the retracting operation can be reduced.

In the transition from the photographing state to the contracted state, the lens frame contracts until it comes into contact with a lens frame holding another lens group, and then the elastic member is contracted while being compressed. Can be configured to do so. As a result, the lens frame comes into contact with another lens frame, the lens group holding the lens frame moves to the retracted position, and the elastic member contracts without performing the retracting operation of the lens frame, and a large load is applied to the lens frame. Collapse can be performed without any delay. Further, since the lens frame is in contact with another lens frame, the clearance between the lens frame and another lens frame can be made zero, so that the lens barrel can be made compact.

Further, when the lens frame is shifted from the retracted state to the photographing state, the lens frame can be re-engaged with the nut member by the rotation restricting portion by the elastic urging force of the elastic member. Thus, even if the lens frame and the nut member are disengaged when the lens frame is retracted, the lens frame can be re-engaged with the transition to the photographing state.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a lens barrel in a shooting state according to an embodiment of the present invention cut along the optical axis direction, and FIG. 2 is a cross-sectional view showing a collapsed state of the lens barrel of FIG. FIG. 3 is a perspective view of the third lens group frame of FIG.

As shown in FIG. 1, the lens barrel of the present embodiment is configured as a zoom lens composed of four lens groups, and a first lens group frame 1 holding a first lens group 1a.
And the second lens group frame 2 holding the second lens group 2a
A shutter unit 5, a third group lens frame 3 holding a third group lens 3a, a guide pole 6 for guiding the third group lens frame 3 to move straight in the optical axis p direction, and a third
The frame portion 2 of the second group lens frame 2 to bias the group lens frame 3
b, a coil spring 7 which is an elastic member compressed and disposed between the first lens group 1 and the second lens group 2 so as to move straight in the direction of the optical axis p. A fourth group lens frame 4 that is connected to a fixed barrel 4b having a rectilinear groove (not shown) that regulates the movement of the third group lens frame 3 in the rotation direction, and that holds the fourth group lens 4a; A cam cylinder (not shown) embedded in the lens frame 1 and the second group lens frame 2 includes a cam cylinder 8 having a cam groove that engages with a straight-moving groove of the fixed barrel 4b.

When the cam barrel 8 is rotated, the cam pins of the first group lens frame 1 and the second group lens frame 2 engaged with the cam grooves of the cam barrel 8 are connected to the fixed barrel 4 b connected to the fourth group lens frame 4. By traveling straight in the rectilinear groove, the positions of the first lens group frame 1 and the second lens group frame 2 can be changed in the direction of the optical axis p to change the focal length. The third lens group 3 mainly adjusts the focus, and the motor 9 (FIG. 3)
Moves in the direction of the optical axis p.

As shown in FIG. 3, the third lens group frame 3 is
3 is urged in one direction by a coil spring 7 in the direction n of FIG. 3. The rotation of the motor 9 is regulated to change the rotation of the motor 9 to the linear drive in the direction of the optical axis p. The rotation regulating groove 3b is provided. The rotation restricting groove 3b is formed in the plane 3e of the third lens group frame 3 so as to be concave in the direction of the optical axis p, and the wall surfaces 3c, 3c are formed so as to sandwich the groove 3b at the top and bottom in FIG. Opposite direction n '
The side 3d of the groove 3b is formed on the side.

The motor 9 for focus adjustment is arranged so that its rotating shaft 9a extends substantially parallel to the guide pole 6, and is fixed in the lens barrel. A screw (not shown) is formed on the rotating shaft 9a, and a nut member 10 is screwed onto the screw of the rotating shaft 9a, and is movable in the optical axis p direction while rotating.
The nut member 10 has a plurality of protrusions 10 protruding from the outer periphery thereof.
a.

The motor 9 and the nut member 10 are arranged such that the projection 10a engages with the rotation regulating groove 3b of the third lens group frame 3, as shown in the partial plan view of FIG.
Since the third lens group frame 3 is urged in the urging direction n by the coil spring 7, the side surface 10b of the protrusion 10a on the opposite side of FIG. 3 is in contact with the side 3d of the groove 3b. in this way,
Since the third group lens frame 3 is urged in the urging direction n by the coil spring 7, the third lens group frame 3 is moved in the direction of the optical axis p by rotating the motor 9, so that focusing can be performed. Has become.

Next, the operation when the above-mentioned lens barrel shifts from the photographing state of FIG. 1 to the retracted state of FIG. 2 will be described. When the lens barrel enters the collapsing operation from the photographing state of FIG. 1, the second lens group frame 2 and the third lens group frame 3
It moves in the direction of the group lens 4a, and the third group lens frame 3 abuts on the end of the fixed body 4c of the fourth group lens frame 4 by this movement, stops there, and moves to the retracted position of the third group lens 3a. Is completed. Further, the second group lens frame 2 moves in the same direction, and the frame portion 2b of the second lens frame 2 approaches the third group lens frame 3 while contracting against the urging force of the coil spring 7, and collapses. With this movement, the third lens group frame 3 and the nut member 10 move and move away from each other, so that the protrusion 10a of the nut member 10 is
Get off. Thus, the collapsing of the lens barrel is completed, and the collapsing state shown in FIG. 2 is obtained.

When the lens barrel shifts from the collapsed state in FIG. 2 to the photographing state in FIG. 1, when the second lens group frame 2 moves in the direction of the first lens group frame 1, the frame portion 2b Move away from the third group lens frame 3, and the relative position with respect to the third group lens frame 3 becomes as shown in FIG. 1. With this movement, the nut member 10 approaches the third group lens frame 3, and the nut member 10
Of the third group lens frame 3 engages with the rotation restricting groove 3b. Further, when the second group lens frame 2 moves in the same direction, the third group lens frame 3 also moves, the third group lens 3a moves from the retracted position, and enters the photographing state of FIG.

During the above-described movement, the protrusion 1 of the nut member 10
In the case where the position of the rotation restricting groove 3b of the third lens group 3 is not aligned with the position of the rotation restricting groove 3b of the third lens group 3, the protrusion 10a of the nut member 10 is fixed to the wall 3c on both sides of the rotation restricting groove 3b of the third lens frame 3. 3c. When the motor 9 is rotated in this state, the protrusion 10a of the nut member 10 moves while rotating on the wall surfaces 3c, 3c, while the third lens group frame 3 is urged by the coil spring 7 in the urging direction n of FIG. Therefore, as shown in FIG.
0a can re-engage with the rotation restricting groove 3b of the third lens group frame 3.

When focusing is performed with the lens barrel in the photographing state shown in FIG. 1, the projection 10a of the nut member 10 engages with the rotation restricting groove 3b of the third lens frame 3 as shown in FIG. When the motor 9 rotates in a state where the side surface 10b is in contact with the side portion 3d of the rotation regulating groove 3b, the nut member 10 screwed to the screw portion 9b of the rotating shaft 9a tries to rotate. Engages with the rotation restricting groove 3b to restrict the rotation of the nut member 10, so that the optical axis p along the rotation shaft 9a of the motor 9
The nut member 10 moves in a direction parallel to the above. By this movement, the third lens group frame 3 moves in the direction of the optical axis p, and focusing is performed.

As described above, according to the present embodiment, when the lens barrel is retracted, the third lens group 3a can be moved to the retracted position with the retracting operation, and the third lens group 3a is retracted. Therefore, it is not necessary to move the lens barrel to the retracted position in advance, so that the retracting operation time can be reduced, and one side of the third lens unit frame 3 is fixed to the fixed barrel unit 4 of the fourth lens unit frame 4 during the retracting operation.
Since it can be abutted against the end of c, there is no need to take clearance, and the dimensions of the lens barrel in the collapsed state can be made compact. The third lens group frame 3 is a nut member 1
0 is engaged by the elastic biasing force of the coil spring 7 in the optical axis p direction, so that the coil spring 7 interferes with the fourth lens group frame 4 without retracting the third lens group frame 3 when retracted. The third lens unit frame 3 can be retracted without applying a large load. Therefore, since it is possible to immediately start the retracting operation from the photographing state, the time of the retracting operation can be reduced.

Next, a modification of FIGS. 1 to 3 will be described with reference to FIG. FIG. 4 is a perspective view of the third group lens frame 3 of the modified example. In this example, the projection 10a of the nut member in FIG. 3 is omitted, and the disk-shaped nut member 11 is formed. A groove 11a is provided on the outer peripheral portion of the nut member 11. The third lens group frame 3
A protrusion 3g is provided on the side surface 3f of the second member, and a rotation restricting protrusion 3h with which the groove 11a of the nut member 11 is engaged is provided on the protrusion 3g.

In the example of FIG. 4, the third lens frame 3 is urged by the coil spring 7 in the urging direction n of FIG. 3, and the groove 11a of the nut member 11 and the rotation regulating projection of the third lens frame 3 are rotated. 3h is engaged, so that it operates similarly to FIGS.
Similar effects can be obtained. In addition, the case of this example is particularly suitable when the nut member is formed of a plastic resin.

As described above, the present invention has been described based on the embodiments, but the present invention is not limited to these embodiments.
Various modifications are possible within the scope of the technical idea of the present invention. For example, although the present embodiment has a configuration of four lens groups, it is needless to say that a configuration of another plurality of lens groups may be used.

[0023]

According to the present invention, it is possible to provide a lens barrel capable of shortening the retracting time, and to make the lens barrel more compact, thereby contributing to the downsizing of the camera.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a lens barrel in a shooting state according to an embodiment of the present invention, cut along an optical axis direction.

FIG. 2 is a sectional view showing a collapsed state of the lens barrel in FIG. 1;

FIG. 3 is a perspective view showing a third lens group frame of FIG. 1 and its vicinity.

FIG. 4 is a perspective view showing a third group lens frame showing a modification of the present embodiment and the vicinity thereof.

FIG. 5 is a partial plan view showing an engagement state between a rotation regulating groove of the third lens group frame in FIG. 3 and a projection of a nut member;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st group lens frame 1a 1st group lens 2 2nd group lens frame 2a 2nd group lens 3 3rd group lens frame 3a 3rd group lens 3b Rotation regulation groove part (rotation regulation part) 4 4th group lens frame 4a Fourth group lens 6 Guide pole 7 Coil spring (elastic member) 8 Cam cylinder 9 Motor 9a Rotating shaft 9b Screw part 10 Nut member 10a Projection 11 Nut member 11a Nut groove 3h Nut groove 11a engages with groove 11a Frame rotation control projection (rotation control section)

Claims (3)

[Claims] 1. A lens barrel comprising at least two lens groups, wherein the lens barrel shifts between a shooting state in which shooting is performed by the lens groups and a contracted state in which the lens groups are reduced from the shooting state. A lens frame guided substantially parallel to the optical axis within the lens group and holding one of the lens groups, an elastic member for urging the lens frame in the optical axis direction, and a lead screw disposed substantially parallel to the optical axis. A driving member for rotating the lead screw, and a nut member screwed to the lead screw, the lens frame has a rotation restricting portion for restricting rotation of the nut member, and the lens frame is In a photographing state, the nut is engaged with the nut member by the rotation restricting portion by the elastic urging force of the elastic member, and the lead screw is rotated by the driving of the driving member, whereby the nut member is rotated. The lens barrel moves in a direction substantially parallel to the optical axis, whereby the lens frame moves while being guided substantially parallel to the optical axis. 2. When shifting from the photographing state to the contracted state, the lens frame contracts until it comes into contact with a lens frame holding another lens group, and then the elastic member is contracted while being compressed. 2. The method according to claim 1, wherein the step is performed.
The lens barrel according to item 1. 3. The lens frame can be re-engaged with the nut member at the rotation restricting portion by the elastic biasing force of the elastic member when the state shifts from the retracted state to the photographing state. Or the lens barrel according to 2.