JP4581209B2 - Lens barrel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel used in a camera.
[0002]
[Prior art]
In recent years, in compact cameras, a method in which a lens barrel is degenerated (hereinafter referred to as “collapse”) while being carried and the lens is extended and used at the time of photographing has become common.
For example, as described in Japanese Patent Application Laid-Open No. 7-43583, when the nut for driving the lens frame is configured to be restricted in the optical axis direction, the focusing lens is previously retracted when the lens is retracted. It is necessary to retract the entire lens barrel after moving to the retracted position.
[0003]
[Problems to be solved by the invention]
However, in the conventional lens barrel as described in the above publication, since the lens barrel is retracted after a part of the lenses is moved to the retracted position during the retracting operation, the retracting operation takes time. Recently, there is a need for a more compact camera by shortening the overall length in the retracted state as much as possible, but in the lens barrel , the lens frame and nut are engaged without any gaps in the optical axis direction. When the lens barrel is retracted, a certain amount of clearance is required before and after the lens frame, which is an obstacle in terms of making it more compact.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to provide a lens barrel that can shorten the collapsing time, can be configured more compactly, and can contribute to downsizing of the camera.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a lens barrel according to the present invention includes at least three lens groups, a photographing state in which the lens group is photographed, and a degenerated state (collapsed state) in which the lens group is degenerated from the photographing state. In a lens barrel that moves between the photographing state and the degenerated state, and a lens group that is fixed to the frame member and guided substantially parallel to the optical axis in the frame member A lens frame that holds one of the groups and can move relative to the frame member, and the lens frame that can move relative to the frame member in a direction away from the lens group fixed to the frame member in the optical axis direction. comprising an elastic member for biasing the lead screw which is substantially parallel to the optical axis, a drive member for rotating the lead screw, and a nut member screwed to the lead screw, the front Movable relative with made lens frame has a rotation regulating portion for regulating the rotation of said nut member, said nut member engaging with the rotation restricting portion by the elastic biasing force of the elastic member in front Symbol photographing state The lead screw rotates by driving the drive member, and the nut member moves in a direction substantially parallel to the optical axis, so that the lens frame that is relatively movable is moved while being guided substantially parallel to the optical axis. When the frame member is moved from the photographing state to the contracted state, the lens frame that has become relatively movable is brought into contact with a lens frame that holds another lens group. moving the frame member, characterized by Rukoto a fixed lens group in the frame member and the relatively movable and made a lens frame against the elastic biasing force to close than the shooting state [0 06]
According to this lens barrel, since the lens frame is engaged with the nut member by the elastic biasing force in the optical axis direction by the elastic member, 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 photographing state, the time for the retracting operation can be shortened.
[0007]
Moreover, even without implementing the evacuation operation of lenses frames shrinkage elastic member, it is possible to carry out the collapsing not applied large load on the lens frame. Further, since the lens frame is in contact with another lens frame, the clearance between the lens frame and the other lens frame can be made zero, so that the lens barrel can be made compact.
[0008]
Further, when the transition from the photographing state to the contracted state is performed, the lens frame and the nut member that are relatively movable are disengaged, and when the transition from the contracted state to the photographing state is performed, the relative movable and made the lens frame can be configured so that the adjust engagement with the nut member by the rotation restricting portion. Thus, even when the lens frame and the nut member are disengaged when the lens frame is retracted, the lens frame can be re-engaged with the shift to the photographing state.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
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 photographing state according to an embodiment of the present invention cut in the optical axis direction, and FIG. 2 is a cross-sectional view showing a retracted state of the lens barrel of FIG. FIG. 3 is a perspective view of the third group lens frame of FIG.
[0010]
As shown in FIG. 1, a lens barrel of this embodiment, four are configured zoom lens consisting of lens groups, a first group lens frame 1 which holds the first lens 1a, the second group The second group lens frame 2 holding the lens 2a, the shutter unit 5, the third group lens frame 3 holding the third group lens 3a, and the third group lens frame 3 in the optical axis p direction. A coil spring 7 that is an elastic member that is compressed and disposed between a guide pole 6 that guides the vehicle in a straight line and a frame portion 2b of the second group lens frame 2 to urge the third group lens frame 3; A rectilinear groove (not shown) that guides the first group lens frame 1 and the second group lens frame 2 to travel straight in the optical axis p direction and restricts the movement of the second group lens frame 2 and the third group lens frame 3 in the rotational direction. A fourth lens group connected to a fixed barrel 4b having a fourth lens group 4a. And a cam cylinder 8 having a cam groove with which a cam pin (not shown) embedded in the first group lens frame 1 and the second group lens frame 2 is engaged through a straight groove of the fixed barrel 4b. Yes.
[0011]
When the cam cylinder 8 is rotated, the cam pins of the first group lens frame 1 and the second group lens frame 2 engaged with the cam groove of the cam cylinder 8 are straight movement grooves of the fixed barrel 4 b connected to the fourth group lens frame 4. By moving straight, the positions of the first group lens frame 1 and the second group lens frame 2 can be changed in the optical axis p direction to change the focal length. The third lens group frame 3 is mainly adjusted in focus and is moved in the optical axis p direction by the motor 9 (FIG. 3).
[0012]
As shown in FIG. 3, the third lens group frame 3 is linearly guided in the direction of the optical axis p by the guide pole 6, is urged to the direction n in FIG. 3 by the coil spring 7, and rotates the motor 9. Is provided with a rotation restricting groove portion 3b for restricting rotation in order to change the rotation to straight drive in the direction of the optical axis p. The rotation restricting groove 3b is formed in a concave shape in the direction of the optical axis p in the plane 3e of the third group lens frame 3, and wall surfaces 3c and 3c are formed so as to sandwich the groove 3b above and below in FIG. A side 3d of the groove 3b is formed on the opposite direction n ′ side.
[0013]
The motor 9 for adjusting the focus 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 can move in the optical axis p direction while rotating. The nut member 10 has a plurality of protrusions 10a protruding from the outer periphery thereof.
[0014]
As shown in the partial plan view of FIG. 5, the motor 9 and the nut member 10 are disposed so that the protrusion 10 a engages with the rotation regulating groove 3 b of the third group lens frame 3, and the third group lens frame 3. Is biased in the biasing direction n by the coil spring 7, and the side surface 10b on the opposite side of the projection 10a in FIG. 3 is in contact with the side 3d of the groove 3b. Thus, since the third group lens frame 3 is urged in the urging direction n by the coil spring 7, the third group lens frame 3 moves in the optical axis p direction by rotating the motor 9, and focusing is performed. It can be implemented.
[0015]
Next, an operation when the above-described 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 retracting operation from the photographing state of FIG. 1, the second group lens frame 2 moves in the direction of the fourth group lens 4a together with the third group lens frame 3, and this movement causes the third group lens frame 3 to move. abuts the end of the fixed body part 4c of the fourth group lens frame 4, stop Suruga further second group lens frame 2 is allowed movement in the same direction. At this time, the third group lens frame 3 because the contact with the fixed barrel 4c, the second group lens frame 2 moves while Mase contraction against the biasing force of the coil spring 7. Along with this movement, the third group lens frame 3 moves relative to the second group lens frame 2 in the direction n ′ side (see FIG. 3), so that the protrusion 10a of the nut member 10 extends from the rotation restricting groove 3b. Come off. In this way, the retracting of the lens barrel is completed, and the retracted state of FIG. 2 is obtained.
[0016]
Further, when the lens barrel shifts from the retracted state of FIG. 2 to the photographing state of FIG. 1, the movement is reversed, and when the second group lens frame 2 moves in the direction of the first group lens frame 1 , the third group. With the lens frame 3 in contact with the end of the fixed body 4c, the third group lens frame 3 is relative to the second group lens frame 2 in the direction n side (see FIG. 3) by the biasing force of the coil spring 7. The nut member 10 and the third group lens frame 3 approach each other, and the protrusion 10a of the nut member 10 engages with the rotation restricting groove 3b of the third group lens frame 3. Further, the second group lens frame 2 is moved in the same direction so that the third group lens frame 3 is separated from the end of the fixed body 4c, and enters the photographing state of FIG.
[0017]
When the position of the protrusion 10a of the nut member 10 and the position of the rotation restricting groove 3b of the third group lens frame 3 are not relatively aligned during the movement described above, the protrusion 10a of the nut member 10 is in contact with the third group lens frame 3. It will be in the state which got on the wall surface 3c, 3c of the both sides of this rotation control groove part 3b. 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 and 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. 5, the protrusion 10 a of the nut member 10 can be engaged again in the rotation restricting groove 3 b of the third group lens frame 3.
[0018]
When the lens barrel performs focusing in the shooting state of FIG. 1, the projection 10a of the nut member 10 engages with the rotation restricting groove 3b of the third group lens frame 3 and the side surface 10b of the projection 10a is aligned as shown in FIG. When the motor 9 rotates in a state of being in contact with the side portion 3d of the rotation restriction groove portion 3b, the nut member 10 screwed into the screw portion 9b of the rotation shaft 9a tries to rotate, but the projection portion 10a is restricted from rotation. Since the rotation of the nut member 10 is restricted by engaging with the groove 3b, the nut member 10 moves in the direction parallel to the optical axis p along the rotation shaft 9a of the motor 9. By this movement, the third lens group frame 3 moves in the optical axis p direction, and focusing is performed.
[0019]
As described above, according to the present embodiment, when the lens barrel is retracted, the third lens unit 3a can be moved to the retracted position in accordance with the operation of the retracting lens so that the third lens unit 3a can be retracted in advance. Since it is not necessary to move to the retracted position, the retracting operation time can be shortened, and at the time of retracting, one side of the third lens group frame 3 can be abutted against the end of the fixed barrel part 4c of the fourth group lens frame 4, so that clearance is provided. The lens barrel in the retracted state can be made compact in size. In addition, since the third lens group frame 3 is engaged with the nut member 10 by the elastic biasing force of the coil spring 7 in the optical axis p direction, the fourth lens group frame 3 is not retracted when the lens barrel is retracted. The coil spring 7 contracts due to interference with the group lens frame 4 side, and a large load is not applied to the third lens group frame 3, so that the collapsing can be performed. For this reason, since it is possible to start the retracting operation immediately from the photographing state, the time for the retracting operation can be shortened.
[0020]
Next, a modification of FIGS. 1 to 3 will be described with reference to FIG. FIG. 4 is a perspective view of a third lens group frame 3 according to a modification. In this example, the protrusion 10 a of the nut member in FIG. 3 is omitted, and a disc-shaped nut member 11 is provided, and a groove 11 a is provided in the outer peripheral portion of the nut member 11.
Further, a protrusion 3g is provided on the side surface 3f of the third lens group frame 3, and a rotation restricting protrusion 3h that engages with the groove 11a of the nut member 11 is provided on the protrusion 3g.
[0021]
In the example of FIG. 4, the third group lens frame 3 is urged in the urging direction n of FIG. 3 by the coil spring 7, and the groove 11 a of the nut member 11 and the rotation restricting projection 3 h of the third group lens frame 3 are formed. Since it engages, it operate | moves similarly to FIGS. 1-3, and can acquire the same effect. In the case of this example, it is particularly suitable when the nut member is formed of a plastic resin.
[0022]
As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the technical idea of the present invention. For example, in the present embodiment, the configuration of four lens groups is used, but it is needless to say that the configuration of other lens groups may be used.
[0023]
【The invention's effect】
According to the present invention, it is possible to provide a lens barrel capable of shortening the retracting time, and it is possible 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 photographing state according to an embodiment of the present invention cut along an optical axis direction.
2 is a cross-sectional view showing a retracted state of the lens barrel of FIG. 1. FIG.
3 is a perspective view showing a third group lens frame of FIG. 1 and its vicinity. FIG.
FIG. 4 is a perspective view showing a third group lens frame and its vicinity showing a modification of the present embodiment.
5 is a partial plan view showing an engagement state between a rotation restricting groove of the third group lens frame of FIG. 3 and a protrusion 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 (rotation regulation part)
4 4th lens group frame 4a 4th lens group 6 Guide pole 7 Coil spring (elastic member)
8 Cam cylinder 9 Motor 9a Rotating shaft 9b Screw part 10 Nut member 10a Protrusion 11 Nut member 11a Groove 3h of nut member Rotation restricting protrusion (rotation restricting part) of the third lens group frame engaged with the groove 11a of the nut member

Claims (2)

In a lens barrel that includes at least three lens groups, and transitions between a photographing state in which photographing is performed with the lens group and a degenerate state in which the lens group is degenerated from the photographing state.
A moving frame in the member between the degenerate state and the photographing state, and the frame fixed lens group member, said frame member being substantially parallel to the guide to the optical axis to hold one of said lens unit A lens frame that is relatively movable , an elastic member that urges the lens frame that is relatively movable in a direction away from a lens group fixed to the frame member in an optical axis direction , and an optical axis substantially A lead screw disposed in parallel; a drive member for rotating the lead screw; and a nut member screwed into the lead screw;
The relative movable and made lens frame has a rotation regulating portion for regulating a rotation of the nut member, the nut member engageable by the elastic biasing force of the elastic member in front Symbol photographing state by the rotation restricting portion When the drive member is driven, the lead screw rotates and the nut member moves in a direction substantially parallel to the optical axis, so that the lens frame that is relatively movable is guided substantially parallel to the optical axis. Move and
When the frame member moves from the photographing state to the retracted state, the frame member is moved and brought into contact with a lens frame that holds another lens group, and then the frame is further moved. moving the member, the lens barrel, wherein Rukoto said against the elastic biasing force is relatively movable with made lens frame and the said frame member which is fixed to the lens group is closer than the shooting state. When shifting from the shooting state to the contracted state, the lens frame and the nut member that are allowed to move relative to each other are disengaged, and when moving from the retracted state to the shooting state, the relative movement is possible. the lens barrel according to claim 1, and made a lens frame, characterized the nut member and the engagement match Rukoto by the rotation regulating portion.

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