JP3333004B2 - Zoom lens barrel - Google Patents

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 changing the distance between the optical axis directions when performing a zoom operation, and changing the distance between the optical axis directions when performing a focus operation. The present invention relates to a zoom lens barrel having a plurality of lens groups that move integrally in the optical axis direction while keeping a constant distance.

[0002]

2. Description of the Related Art Conventionally, various zoom lens barrels for moving a plurality of lens groups during a zoom operation and a focus operation have been proposed.
In the publication, the rotating barrel in the lens barrel is divided into two and arranged as an inner rotating barrel and an outer rotating barrel. During zooming, the inner rotating barrel and the outer rotating barrel are integrally rotated. There has been proposed a technical means for moving the one rotating cylinder in the front-rear direction during the focusing operation.

[0003]

However, in the above technical means, since the rotating barrel is disposed inside and outside, the size of the lens barrel in the radial direction increases, and in recent years, miniaturization has been demanded. Is not good for a camera that has it.

[0004] The present invention has been made in view of such a problem, and has as its object to provide a zoom lens barrel having a reduced radial dimension.

[0005]

In order to achieve the above object, a first zoom lens barrel according to the present invention is a zoom lens barrel having at least a first lens group and a second lens group. is driven during focusing operation, holds a full Oka <br/> scan end face cam you displaced along the circumferential direction at the end face of the optical axis, the first lens group, the light by the focusing end cam A first lens holding frame that is displaced in the axial direction, and the focusing end face cam with respect to the first lens holding frame are disposed on a side opposite to the optical axis direction;
A second lens holding frame that holds the second lens group and is displaced in the optical axis direction via the first lens holding frame by the focusing end face cam , and the first lens holding biasing means for biasing the frame and the second lens holding frame and the focusing end cam <br/> and direction abuts each other, said first
Is formed on the first lens holding frame, there may be relative displacement by rotation around the optical axis the second lens holding frame in the optical axis direction between the second lens holding frame, the optical axis
For zooming that displaces along the circumferential direction at the end face
An end cam, and the first lens holding frame during zoom operation.
Without rotating the zoom end face around the optical axis.
Arm and said rotating means for zooming which can rotate relative to the second lens holding frame and around the optical axis, the optical axis and the first lens holding frame and the focusing end cam during focusing operation A focus rotating means for relatively rotating around, and a focus rotation regulating means for regulating the rotation of the first lens holding frame and the second lens holding frame around the optical axis during a focusing operation. The zoom cam means and the second lens holding frame are relatively rotated around an optical axis during a zoom operation, so that the zoom end is rotated.
Activating the surface cam to move the first lens holding frame and the second lens holding frame
The distance in the optical axis direction of the lens holding frame can be changed, and the first lens holding frame and the focus end face cam are relatively rotated around the optical axis during the focusing operation, whereby The first lens holding frame and the second lens holding frame are integrally displaced in the optical axis direction. In order to achieve the above object, the second zoom lens barrel according to the present invention is characterized in that the first zoom lens barrel holds the second lens during the zoom operation.
The frame is rotated around the optical axis .

[0006]

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 are central sectional views showing the structure of a zoom lens barrel according to a first embodiment of the present invention.
5 to 8 are exploded perspective views showing a detailed configuration of the zoom lens barrel. FIG. 1 shows the state of the focus group initial position (infinity side) at the wide angle end, FIG. 2 shows the state of the focus group extension position (closest side) at the wide angle end, and FIG. The state of the focus group initial position (infinity side) at the telephoto end is shown.

As shown in FIGS. 1 to 3, the zoom lens barrel includes a first lens group 141, a second lens group 142 (corresponding to a second lens group of the present invention) , and a third lens group 143 from the front. (Corresponding to the first lens group of the present invention) , a fourth lens group 144 is provided. FIG. 4 is a view schematically showing the movement of each of the lens groups during the zoom operation. As shown in FIG. 4, among the lens groups, the first lens group 141 and the third lens group 143 are wide-angle. Intermediate focal length from end
While the telephoto end via the release, while the lens barrel in the optical axis direction
They move without changing the distance.

Hereinafter, each part will be described in detail with reference to FIGS. 1 to 3 and FIGS. 5 to 8. Note that FIGS. 5 to 8 are exploded views of each member in the optical axis direction.

As shown in FIGS. 1 and 5, a fixed frame 52 of the lens barrel is fixed to a camera body (not shown) at a rear end.
A rectilinear keyway 52a into which three rectilinear keys 53b disposed at the rear end of the first lens group frame 53 (see FIG. 6) are fitted.
, A straight keyway 52d into which the FPC guide 78 (see FIG. 8) fits is formed. A rotating frame 51 is rotatably fitted on the outer periphery of the fixed frame 52, and a groove 52c is formed on the outer periphery of the distal end portion of the fixed frame 52 along the circumferential direction.
And a C-ring 64 for locking the rotating frame 51 in the optical axis direction is mounted.

On the other hand, on the inner periphery of the fixed frame 52, a middle frame 59 is provided.
Cam groove 5 fitted with cam follower 59a (see FIG. 8)
2b is formed (FIG. 19 shows a developed view of the fixed frame 52). The inner periphery of the distal end of the fixed frame 52 is made of a flocked cloth or the like for preventing unnecessary light from entering the lens frame from a gap between the fixed frame 52 and the first lens group frame 53. The light blocking member 145 is fixed.

As described above, the rotating frame 51 is radially fitted to the outer periphery of the fixed frame 52 on the inner peripheral surface thereof, and is rotated in the optical axis direction by a C-ring 64 attached to the tip of the fixed frame 52. The movement is locked. This allows
The rotating frame 51 is movable in the rotation direction with respect to the fixed frame 52, but the movement in the optical axis direction is restricted.

A cam groove 51b having a bottom for moving the first lens group frame 53 in the optical axis direction and a bottom having a cam groove 51b for moving the FPC guide 78 in the optical axis direction are provided on the inner periphery of the rotary frame 51. A cam groove 51c is formed (an exploded view is shown in FIG. 20), and a gear 51a is formed on the outer periphery, and a zoom gear 227, which is an output gear of the zoom drive unit, meshes with the gear 51a to rotate. . further,
A pattern sheet 76 of a zoom encoder for a zoom photoreflector 139 for detecting the zooming position of the zoom lens is fixed to the outer periphery of the rotating frame 51.

As shown in FIG. 6, the first lens group 14
The first lens group frame 53, which is one lens frame (mirror frame), is formed with straight keys 53b fitted to the straight key grooves 52a of the fixed frame 52 at equal intervals on the outer periphery of the rear end thereof. 52 is movable in the optical axis direction. Further, a cam follower 53a that fits into the cam groove 51b of the rotary frame 51 is formed on the upper surface of the straight key 53b. Further, on the inner periphery of the first lens group frame 53, the positions of the shutter base plate 81 (see FIG. 7) in the radial and rotational directions are regulated, and the shutter base plate 81 (see FIG. 7) is sandwiched therebetween. Fastened by screws 65.

Further, a front frame 60 (see FIG. 7) and a middle frame 59 (see FIG. 8) are fitted around the inner periphery of the first lens group 53 so as to be freely rotatable in the circumferential direction. 57 (see FIG. 8)
The roller 77 attached to the first lens group enters and the straight key groove 53e (FIG. 1) for regulating the fourth lens group frame 57 in the rotation direction.
) Are formed at three locations on the inner circumference. Further, a through hole 53c for press-fitting a pin 75 for regulating the middle frame 59 in the optical axis direction is formed.

A barrier drive ring 69 for opening and closing the barrier is rotatably fitted in the optical axis of the first lens group frame 53 in the optical axis direction so as to be rotatable in the radial direction. It is connected to the drive gear 100b (see FIG. 7).

As shown in FIG. 8, the fourth lens group frame 57 is fastened by screws so that the fourth lens group holding frame 56 for holding the fourth lens group 144 is integrated therewith. Three pins 57a are implanted, and a roller 77 is rotatably fitted to the pins 57a. The roller 77 is
The first lens group frame 53 is fitted in a straight key groove 53e (see FIG. 1) provided on the inner periphery of the first lens group frame 53.
The lens group frame 57 is movable only in the optical axis direction with respect to the first lens group frame 53, and is not movable in the rotation direction.

A fourth lens group spring 62 is provided between the fourth lens group frame 57 and the shutter base plate 81 (see FIG. 7).
Is disposed with a spring receiver 63 therebetween, and the roller 7 is always
7 is urged to abut against the end face cam 59b of the middle frame 59.

The outer periphery of the middle frame 59 and the inner periphery of the first lens group frame 53 (see FIG. 6) are fitted in the radial direction, and the first lens group 59 is inserted into a groove 59c formed on the outer periphery. When the tip of the pin 75 press-fitted from the outer periphery of the frame 53 is fitted, the pin 75 integrally moves forward and backward in the optical axis direction with respect to the first lens group frame 53, and is freely rotatable. Also, the middle frame 59
A cam follower 59a that fits into the cam groove 52b of the fixed frame 52 is formed on the outer periphery of the fixed frame 52. Also, the middle frame 59
The interlocking plate 66 is fixed to the outer periphery of the. Further, an end cam 59b is formed at one end of the middle frame 59.

As shown in FIG. 7, the front frame 60 is rotatably fitted to the inner periphery of the first lens group frame 53 at the outer periphery thereof, and a plurality of second lens group frames 54 are fitted to the inner periphery. Straight key 5
A plurality of rectilinear keyways 60b into which 4a fits (see FIG. 10).
Is formed, and a second lens group spring 61 which is a compression spring is disposed between the second lens group frame 54 and the second lens group frame 54. A gap 66 at the tip of the interlocking plate 66 is provided around the front frame 60.
a is formed between the middle frame 59 and the projection 60a.
(See FIGS. 9 and 10).

As a result, the front frame 60 is fitted in the inner periphery of the first lens group frame 53 in the radial direction.
As compared with the case where the second lens group frame 54 is directly rotated, the eccentricity with respect to the rotation of the second lens group frame 54 can be minimized, and high optical performance can be maintained.

A barrier drive switching lever 101 for connecting the focus drive gear train 146 and the barrier drive gear train 147 is provided on the inner peripheral surface of the front frame 60, and in a state other than the collapsed state. The position of the barrier drive switching lever 101 is regulated so that the connection is not performed.
There is provided a barrier drive switching lever position regulating cam for regulating the position of the barrier drive switching lever 101 so as not to hinder the connection of the levers 1.

The second lens group frame 54 holds the second lens group 142, and is formed with a plurality of rectilinear keys 54a to be fitted into the plurality of rectilinear key grooves 60b of the front frame 60, and a rear key. A cam follower 54b is formed at an end of the third lens group frame 55 so as to contact an end cam 55c formed on the inner peripheral surface of the third lens group frame 55. Also, the second lens group frame 54
A second lens group spring 61 is interposed between the front end and the rear end of the front frame 60. Further, the straight key of the second lens group frame 54 is fitted in the key groove 60 b of the front frame 60. Thus, the second lens group frame 54 and the front frame 60 rotate integrally in the rotation direction, but can freely move back and forth in the optical axis direction. The urging force of the second lens group spring 61 is such that the cam follower 54b is moved to the third lens group frame 55.
In contact with the end face cam 55c formed at the end.

The third lens group frame 55 holds the third lens group 143. An end cam 55c having a displacement along the circumferential direction is formed on the end face in the optical axis direction on the inner periphery. A cam follower 55d is formed to abut on the cam portion 58a of the focus cam ring 58.

FIG. 11 shows the second lens group frame 54 and the third
FIG. 5 is a side view showing a lens group frame 55 and a focus cam ring 58, and the cam follower 54b and the end cam 55;
c, the positional relationship between the cam follower 55d and the cam portion 58a.

The cam follower 54b of the second lens group frame 54 comes into contact with the end face cam 55c of the third lens group frame 55 by the urging force of the second lens group spring 61, and the third
The cam follower 55d of the lens group frame 55 contacts the cam portion 58a of the focus cam ring 58.

As shown in FIG. 7, the third lens group frame 5
5 is formed on the outer peripheral surface with a hole 55a formed in the direction of the optical axis, and a linear key 55b is formed on the outer peripheral surface at a position substantially opposite to the protruding portion with respect to the optical axis. ing. A rod 89 held between the shutter base plate 81 and the shutter lid 82 of the shutter unit fits into the hole 55a, and the rectilinear key 55b fits into a groove (not shown) formed on the shutter base plate 81. Thus, the third lens group 55 cannot rotate with respect to the shutter base plate 81 and can move only in the light turning direction.

As shown in FIG. 9, the interlocking plate 66 is fixed to the outer peripheral portion of the middle frame 59, and has a gap 66 at the tip end thereof.
The middle frame 59 and the front frame 60 are connected so as to rotate integrally with each other by sandwiching the outer peripheral projection 60a of the front frame 60 between the two. When moving from the short focus end to the collapsed state, the barrier drive switching lever 101 that connects the focus drive gear train 146 and the barrier drive gear train 147 at the end face 66b is brought into a connected state.

As shown in FIG. 6, the barrier drive ring 69 has an inner diameter portion 6 at the front end 53f of the first lens group frame 53.
It is fitted rotatably at 9e. 16 and FIG.
As shown in (1), it is connected to the barrier drive gear 100b by an internal gear 69a, and the periphery of the connection portion is in a bag-like substantially closed state. On the surface (front side of the camera) opposite to the internal gear 69a, two plate-shaped barrier springs 70 in the figure are arranged at positions facing each other. The blade 71 and the barrier blade 73 are opened and closed (FIG. 16, FIG.
See FIG. 17).

The barrier spring 70 is a plate spring having a bent portion formed in the middle, and is disposed on the circumference of the barrier drive ring 69 as shown in FIGS.
Then, both ends of the protrusion 6 of the barrier drive ring 69 are formed.
9b and a guide groove 69 formed in the bent portion.
A projection 69d is fitted into c, and is disposed on the barrier drive ring 69 in a state where movement in the optical axis direction and the rotation direction is restricted.

As shown in FIG. 6, the barrier blade 71 is provided with a boss 53 projecting from the tip of the first lens group frame 53.
Two arms having the same shape are arranged on the first lens group frame 53 so as to be rotatable about g. As shown in FIG. 16, a projection 71c biased by the barrier spring 70, a projection 71a for driving the barrier blade 73 in the closed state, and a projection of the barrier blade 73 in the open state. Recess 71b for biasing 73b
Are formed.

The barrier blade 73 is connected to the barrier blade 7.
Similar to 1, the arm is rotatable about a boss 53g at the tip of the first lens group frame 53.
Are disposed in the first lens group frame 53. And
As shown in FIG. 16, when in the closed state, the barrier blade 71
In the open state, the projection 73b is urged by the barrier blade 71 to perform an opening / closing operation.

The cover ring 74 is attached to the front end of the first lens group frame 53 to regulate the positions of the barrier drive ring 69, the barrier blade 71, and the barrier blade 73 in the optical axis direction.

The FPC guide (flexible printed circuit board guide) 78 is, as shown in FIGS.
An engaging portion 78 that fits into the straight key 52d of the fixed frame 52.
b, a cam follower 78c that engages with the cam groove 51c of the rotating frame 51, and an arm portion 78a that presses the lens frame flexible substrate 302 disposed inside the lens frame. The lens frame flexible printed circuit board 302 is assembled so as to form a U-shape with the arm portion 78a, and is driven in the optical axis direction by a cam of the rotating frame 51 by a moving amount of about half of the extending amount of the first lens group frame 53. Further, the arm portion 78a regulates the operation guide of the lens frame flexible printed circuit board 302 and the spread in the optical axis direction. If the FPC guide 78 is not provided, the flexible printed circuit board 302 spreads as shown in FIG.

FIG. 24 is a block diagram showing a main configuration of a drive circuit in the zoom lens barrel according to the first embodiment. FIG. 23 is a conceptual diagram of a flexible printed circuit board for connecting the main parts of the drive circuit.

A shutter unit 3 is provided in the zoom lens barrel.
Inside the focus motor 108, shutter plunger 1
11, a shutter trigger photoreflector 110, a focus photointerrupter 109, and the like are provided. The actuator, sensor, etc., the zoom motor 201, the display device 307, the release switch 318, and the control circuit 12 mounted on the main board 301 in the camera body are connected by the lens frame flexible printed board 302. These actuators,
The sensors and the like will be described later in detail.

Returning to FIG. 1, behind the shutter base plate 81, two shutter blades 92A and 92B are provided. The shutter blades 92A and 92B are normally closed so as to block the light beam passing through each lens group, and are opened for a predetermined time by a release operation, and then closed. The shutter blades 92A, 9
2B is a blade holder 9 fixed to the shutter base plate 81.
The blade holders 93, 94 are movably sandwiched between the shutter blades 3, 94. The blade holders 93, 94 serve as a guide when opening and closing the shutter blades 92A, 92B.

The focus motor 108 is fixed to the shutter base plate 81, and a pinion gear 105 is fixed to an output shaft thereof. The rotation of the focus motor 108 is transmitted by a focus drive gear train 146 (see FIG. 7), and the focus cam ring 58 is rotated to perform a focusing operation.

The sealing member 68 provided at the end of the fixed frame 52 is a member for preventing water droplets from entering the inside of the camera, and is made of an elastic material. The fixed frame 52 is behind the camera.
The outer peripheral side is fixed to the front cover 21. On the inner diameter side, it is pressed against the first lens group frame 53,
The first lens group frame 5 can be moved straight forward to prevent the water droplets from entering the camera.
A lip 68a is provided which is in line contact with the ring 3 in a ring shape.

Next, the zoom operation of the zoom lens barrel according to the first embodiment will be described.

First, a zoom operation from the state of the short focus end of the lens frame shown in FIG. 1 to the long focus side shown in FIG. 3 will be described.

When drive power is supplied to the zoom motor 201 (see FIG. 24) disposed at a predetermined position in the camera body, the gear 227 (see FIG. 5) is driven and the rotary frame 51 is rotated. When the rotating frame 51 is rotated clockwise as viewed from the subject side, the cam follower 53a of the first lens group frame 53 fits into the cam groove 51b of the rotating frame 51, and is rotated by the linear keyway 52a of the fixed frame 52 in the rotating direction. Since the movement is restricted, the first lens group frame 53 goes straight to the left on the optical axis (toward the subject) in the figure.

At this time, the middle frame 59 is also connected to the first lens group frame 53.
Simultaneously moving to the left with respect to the optical axis,
Is rotated clockwise by the cam on the inner circumference of the. The rotation of the middle frame 59 changes the position of the cam 59b of the middle frame 59 that contacts the roller 77 of the fourth lens group frame 57, and thereby the relative position of the fourth lens group frame 57 with respect to the first lens group frame 53. Changes.

The interlocking plate 66 fixed on the outer periphery of the middle frame 59 rotates integrally with the middle frame 59, and accordingly, the front frame 60 is engaged with the front frame 60 by a straight key. The second lens group frame 54 also rotates by the same rotation angle as the middle frame 59. By this rotation, the second lens group frame 54
The contact position of the cam follower 54b with the end face cam 55c of the third lens group frame 55 changes, and as a result, the relative distance between the second lens group 142 and the third lens group 143 changes.

By the rotation of the rotary frame 51, the FPC guide 78 also moves to the left along the optical axis by about half the amount of the first lens group frame 53, so that the mirror frame flexible substrate 302 attached to the shutter base plate 81 is mirrored. Suppresses the attempt to spread toward the center of the optical axis inside the frame.

In the above description, the driving from the short focal length side to the long focal length side in the zoom lens barrel of the present embodiment has been described.
The reverse drive from the long focal point side to the short focal point side is performed by the rotation frame 5.
This can be realized by rotating 1 counterclockwise.

Next, a focus driving mechanism in the zoom lens barrel according to the present embodiment will be described.

FIGS. 12 and 13 are exploded perspective views showing the structure of the focus drive mechanism of this embodiment.

As shown in FIG.
Reference numeral 08 is fixed to the shutter base plate 81. A pinion gear 105 is fixed to an output shaft 108a of the focus motor 108. An idle gear 106 rotatably supported by the shutter base plate 81 is meshed with the pinion gear 105. Further, an idle gear 107 rotatably supported by the shutter base plate 81 is meshed with the pinion gear 105.

Further, the gear 83, the gear 84, the gear 8
5, a gear 86 is a two-stage reduction gear, which is rotatably supported by the shutter base plate 81. Further, the gear 87 is an idle gear, and the small-diameter gear portion 87b of the gear 87, the focus cam 58a, the gear portion 58
b.

When performing focusing, drive power is supplied to the focus motor 108 from the camera body side.
As a result, the focus cam ring 58 rotates, and the third
The rotation of the lens group frame 55 is regulated by the rod 89 and the rectilinear key 55b, and the lens group frame 55 is linearly moved leftward on the optical axis. At this time, since the second lens group frame 54 is also engaged with the straight key groove of the front frame 60, the second lens group frame 54 moves straight to the left of the optical axis by the same movement amount as the third lens group frame 55 without rotating. Moving.

As a result, the second lens group frame 54 and the third lens group frame 55 move integrally in the optical axis direction by the amount of focus adjustment without changing the mutual distance determined by the zoom operation. Then, the state shown in FIG. 1 changes to the state shown in FIG.

The gear 88 is rotatably supported by the shutter base plate 81 and has a slit blade 88b. The number of rotations of the motor is detected by counting the number of slit blades 88b by the focus photo interrupter 109. That is, by counting the pulses of the focus photo interrupter 109, the rotation angle of the focus cam ring 58, that is, the extension amount of the second lens group frame 54 and the third lens group frame 55 can be known.

The gear 98 and the two-stage gear 99 are both rotatably supported by the barrier drive switching lever 101, and the barrier drive gear 100 is rotatably supported by the shutter base plate 81. I have. The gear portion 100a at one end of the barrier drive gear 100 is meshed with the large-diameter gear portion 99b of the two-stage gear 99, and the barrier drive gear portion 100b at the other end is connected to the barrier drive ring 6.
9 with the internal gear 69a.

The barrier drive switching lever 101 is pivotally supported by the shutter base plate 81 so that one end 101a is pushed by the interlocking plate 66, and the gear 98 meshes with the gear 58b of the focus cam ring 58. And the pin 101b is pushed by the cam portion 60B of the front frame 60, and the gear 98 is moved to the gear portion 58 of the focus cam ring 58.
It moves between b and a position where it does not mesh.

Next, the operation of the above-described focus driving mechanism will be described.

FIG. 25 is a flowchart showing the operation of the focus driving mechanism in the zoom lens barrel according to this embodiment. Hereinafter, the operation of the mechanism will be described with reference to the flowchart and FIGS.

First, the release SW 318 (see FIG. 24)
Is turned on (step S0), distance measurement is performed by an unillustrated autofocus sensor (step S1). At this time, the extension amounts of the second lens group 142 and the third lens group 143 during the focus operation are obtained by calculation. Then, the target delivery pulse number NAF is obtained from the calculated delivery amount.

Next, the focus motor 108 is reversed to perform a lens reset operation (step S2). That is, when the focus motor 108 is rotated in the reverse direction, the focus cam ring 58 rotates in the direction of arrow A in FIG. Thus, the stopper 58c of the focus cam ring 58 comes into contact with the stopper 81d of the shutter base plate 81 and stops.

Simultaneously with the reverse rotation of the focus motor 108, a first timer is started (step S3), and every time a pulse input signal is received from the photo interrupter (PI) 109 (step S4), the first timer is reset. When the count of the first timer ends (step S5), it is determined that the reset operation has ended, and the focus motor 108 is stopped (step S6).

Next, the focus motor 108 is rotated forward (step S7), and at the same time, the second timer is started (step S8). This causes the focus cam ring 58 to rotate in the direction of arrow B in FIG. At this time, the pulse signal from the photo interrupter 109 is monitored. Then, the focus motor 108 is decelerated from the point in time when the number of pulses reaches the target number of pulses NAF-50 (steps S9 and S1).
0). When the number of pulses from the photo interrupter 109 reaches the target number of pulses NAF, the focus motor 108 is stopped (step S11,
Step S12).

As a result, the second lens group 142 and the third lens group 143 are extended according to the distance from the subject,
The focus operation ends. Thereafter, the shutter operates to perform exposure (step S13).

On the other hand, as described above, when the focus motor 108 is rotated forward, the second timer longer than the focus operation is started (step S8), and before the count of the target pulse number NAF is completed, When the counting by the second timer is completed (steps S14 and S16), it is determined that the camera has failed, and the failure is displayed on the display device 307 of the camera (steps S15 and S15).
Step S17).

Next, a lens barrier drive switching mechanism in the zoom lens barrel according to the present embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 14 is an explanatory view showing the state of transmission of the lens barrier drive switching mechanism to the barrier drive system. FIG. 15 is an explanatory diagram showing a non-transmission state of the lens barrier drive switching mechanism to the barrier drive system.

The barrier drive switching lever 101 is pivotally supported by a shutter base plate 81 so as to be swingable. Also, gear 98
And the two-stage gear 99 are connected to the barrier drive switching lever 1.
01 are fixedly rotatably supported by the fixedly implanted shafts. On the other hand, the barrier drive gear 100 is
1 and rotatably supported by the barrier drive gear 1
The gear 100a formed at one end of the gear 00 and the gear 99b of the two-stage gear 99 mesh with each other. Further, the gear 99a of the two-stage gear 99 is engaged with the gear 98.

The barrier drive switching lever 101 has a position where one end 101a is pushed by the end face of the interlocking plate 66 (see FIG. 1) when the lens is retracted, and meshes with the gear 98 and the gear 58b of the focus cam ring 58. 14 (see FIG. 14), the pin portion 101b is pushed by the cam portion 60c of the front frame 60, and the gear 108 and the gear 58b swing between positions where they do not mesh (see FIG. 15). .

In FIGS. 16, 17 and 18,
The barrier drive ring 69 is rotatably fitted to the distal end 53f of the first lens group frame 53. An internal gear 69a is provided on an inner diameter portion of the barrier drive ring 69, and meshes with a gear portion 100b formed at the other end of the barrier drive gear 100.

A barrier spring 70 is fixed to the barrier drive ring 69. Thus, the barrier blade 71 is urged. The barrier blade 71 is swingably attached to the first lens group frame 53 with a boss 53d provided at the end of the first lens group frame 53 as a swing center. Then, the projection 71c biased by the barrier spring 70, the projection 71a for driving the barrier blade 73 in the closed state, and the projection 73b of the barrier blade 73 in the open state are biased. Recess 71b is formed.

The barrier blade 73 is connected to the barrier blade 7
Similarly to 1, the boss 53d at the tip of the first lens group frame 53 is swingably attached to the first lens group frame 53 with the center of swing. When the barrier is closed, the projection is biased by the projection 71a of the barrier blade 71. When the barrier is open, the projection 73b is driven by the barrier blade 71 to open and close. A cover ring 74 is attached to the tip of the first lens group frame 53 to regulate the positions of the barrier drive ring 69, the barrier blade 71, and the barrier blade 73 in the optical axis direction.

Next, the operation of the lens barrier drive mechanism will be described.

First, when the power switch is turned off, power is supplied to a zoom drive unit (not shown), and the zoom motor 201 (see FIG. 24) rotates. As a result, the rotating frame 51 is rotated counterclockwise, and the first lens group frame 53 is further moved to the collapsed position. At this time, the middle frame 59
Also moves to the retracted position by the movement of the first lens group frame 53. Further, the interlocking plate 6 that rotates integrally with the middle frame 59
6, one end 1 of the barrier drive switching lever 101
01a is pressed, the barrier drive switching lever 101 is swung (in the direction of arrow c in FIG. 12), and the gear 98 and the gear 58b mesh (see FIG. 14). That is,
The power of the focus motor 108 is the barrier drive gear 10
0 is transmitted.

Next, power is supplied to the focus motor 108. When the focus motor 108 rotates counterclockwise, power is transmitted to the barrier drive gear 100 via the gear train, and the barrier drive gear 100 rotates counterclockwise. Thus, the gear 100b disposed at one end of the barrier drive gear 100 and the internal gear 69a mesh with each other, so that the barrier drive ring 69 rotates counterclockwise. At this time,
The barrier blade 71 is pressed by the barrier spring 70,
The barrier blade 71 swings in the barrier closing direction. on the other hand,
The barrier blade 73 is provided with the protrusion 7 of the barrier blade 71.
1a, and again swings in the barrier closing direction. At this time, the pulse signal from the photo interrupter 109 is counted, and a predetermined number of pulses necessary for closing the barrier are obtained.
When the rotation of the focus motor 108 is detected, the motor is stopped.

Next, the barrier opening operation will be described.

When the power switch is turned on, first, power is supplied to the focus motor 108 to rotate the focus motor 108 clockwise. Thus, the power of the focus motor 108 is transmitted, and the barrier drive ring 69 rotates clockwise. In addition, the barrier blade 71
The projection 71c of the barrier blade 71 is pushed by the barrier spring 70 and moves in the opening direction. On the other hand, the barrier blade 73
The projection 73b is pushed by the barrier blade 71 and also moves in the opening direction. At this time, the pulse signal from the photo interrupter 109 is counted in the same manner as in the above-described closing operation, and the focus motor 108 is counted by a predetermined number of pulses.
When it is detected that the motor has rotated, the motor is stopped.

Next, power is supplied to a zoom drive unit (not shown), and the zoom motor 201 rotates. As a result, the rotating frame 51 is rotated clockwise, and as a result, the first frame is rotated.
The lens group frame 53 moves to a position where photographing is possible. The middle frame 59 rotates with the movement of the first lens group frame 53. That is, the front frame 60 rotates via the interlocking plate 66.

At this time, the cam portion 60c of the front frame 60
Pushes the pin 101b of the barrier drive switching lever 101, so that the barrier drive switching lever 101 swings to a position where the gear 98 and the gear 58b do not mesh (FIG. 15).
reference). As a result, the transmission between the barrier drive gear 100 and the focus motor 108 is cut off, and normal photographing becomes possible.

According to the above-described embodiment, in a zoom lens optical system having a plurality of lens groups which are integrally extended during the focus operation, the distance between the lens groups is extended during the focus operation. Can be provided with high accuracy, and a zoom lens barrel having a structure for minimizing the radial dimension can be provided. That is, an end face cam is provided on one of a lens frame that rotates during a zoom operation and a lens frame that is held so as to be able to move straight in the optical axis direction, and a cam follower is provided on the other, in which a change in group spacing due to zooming of the focusing optical system is held during zoom operation. By suppressing the increase in the radial dimension and transmitting the driving force during zoom operation to the focusing group with a thin plate-like connecting member, it can be mounted in a very small space, resulting in other The members can be efficiently arranged in the empty space, and a compact zoom lens barrel can be realized as a whole.

Further, by using a very small number of simple members for the cam frame for transmitting the zooming driving force to the plurality of lens barrels, the lens barrels can be held easily and with high accuracy, and the small lens barrel can be reduced in height. Can be provided at cost.

Next, a zoom lens barrel according to a second embodiment of the present invention will be described.

The second embodiment differs from the first embodiment only in the drive mechanism of the FPC guide, and the other configurations and operations are the same. Therefore, only the differences will be described here.

FIGS. 27 and 28 are perspective views of the main part showing the drive mechanism of the FPC guide and the first lens group frame in the zoom lens barrel of the second embodiment.

As shown in FIG. 27, in the second embodiment, the first lens group frame 53 'and the FPC guide 78' are driven in opposite phases by using lead screws 351 and 352 of the same lead. Then, reduce the gear ratio of the gears 353 and 354 to about 2:
By setting it to 1, a feed mechanism is realized. FIG. 28
As shown in the figure, the reduction ratio of the gears 357 and 358 is 1: 1.
It can also be realized by making the leads of the lead screws 355, 356 of opposite phase approximately 2: 1.

In the second embodiment having such a configuration, the same effect as in the first embodiment can be expected.

Next, a zoom lens barrel according to a third embodiment of the present invention will be described.

The third embodiment is different from the first embodiment only in the lens barrier drive switching mechanism, and the other configurations and operations are the same. Therefore, only the differences will be described here.

FIG. 29 is a diagram showing a lens barrier drive switching mechanism in the zoom lens barrel according to the third embodiment.

In the first embodiment, the barrier drive switching lever 101 is pushed by the interlocking plate 66 in the direction in which the gear 98 and the gear 58b mesh. In the third embodiment,
As shown in FIG. 29, the pin 101c of the barrier drive switching lever 101 is pressed by a rib 60a protruding from the cam portion 60c of the front frame 60.

In the third embodiment having such a configuration, the same effect as in the first embodiment can be expected.

[0091]

As described above, according to the present invention, a zoom lens barrel having a reduced radial dimension can be provided.

[Brief description of the drawings]

FIG. 1 is a central cross-sectional view showing a state of a focus group initial position (infinity side) at a wide angle end in a zoom lens barrel according to a first embodiment of the present invention.

FIG. 2 illustrates a zoom lens barrel according to the first embodiment.
FIG. 5 is a central sectional view showing a state of a focus group extending position (closest side) at a wide angle end.

FIG. 3 shows the zoom lens barrel according to the first embodiment.
FIG. 6 is a central sectional view showing a state of a focus group initial position (infinity side) at a telephoto end.

FIG. 4 illustrates a zoom lens barrel according to the first embodiment.
Conceptual diagram showing the movement of each lens group during zooming

FIG. 5 is an exploded perspective view of the zoom lens barrel according to the first embodiment.

FIG. 6 is an exploded perspective view of the zoom lens barrel according to the first embodiment.

FIG. 7 is an exploded perspective view of the zoom lens barrel according to the first embodiment.

FIG. 8 is an exploded perspective view of the zoom lens barrel according to the first embodiment.

FIG. 9 illustrates a zoom lens barrel according to the first embodiment.
It is explanatory drawing which showed the connection state of the middle frame, the interlocking plate, and the front frame.

FIG. 10 is a cross-sectional view of a main part showing a state of coupling of a front frame, a second lens group frame, and an interlocking plate in the zoom lens barrel according to the first embodiment.

FIG. 11 is a side view showing a second lens group frame, a third lens group frame, and a focus cam ring in the zoom lens barrel of the first embodiment.

FIG. 12 is an exploded perspective view of a main part showing a connecting portion of a focus drive unit and a barrier drive gear in the zoom lens barrel according to the first embodiment.

FIG. 13 is an exploded perspective view of a main part of the connecting portion of the focus driving unit and the barrier driving gear in the zoom lens barrel according to the first embodiment, as seen from another angle.

FIG. 14 is an explanatory diagram showing a transmission state of a lens barrier drive switching mechanism to a barrier drive system in the zoom lens barrel according to the first embodiment.

FIG. 15 is an explanatory diagram showing a non-transmission state of a lens barrier drive switching mechanism to a barrier drive system in the zoom lens barrel according to the first embodiment.

FIG. 16 is a diagram showing an opened state of a barrier in the zoom lens barrel according to the first embodiment.

FIG. 17 is a view showing a closed state of a barrier in the zoom lens barrel according to the first embodiment.

FIG. 18 is a longitudinal sectional view and a transverse sectional view showing a barrier drive ring and a barrier drive gear in the zoom lens barrel according to the first embodiment.

FIG. 19 is a developed view showing an inner surface of a fixed frame in the zoom lens barrel according to the first embodiment.

FIG. 20 is a developed view showing an inner peripheral portion of a rotating frame in the zoom lens barrel according to the first embodiment.

FIG. 21 is a sectional view of a lens barrel flexible printed circuit board, an FPC guide, and peripheral portions thereof in the wide, standard, and tele states of the zoom lens barrel according to the first embodiment.

FIG. 22 is an essential part perspective view showing a lens frame flexible printed circuit board and an FPC guide in the zoom lens barrel according to the first embodiment.

FIG. 23 is a conceptual diagram of a flexible printed circuit board for connecting main parts of a drive circuit in the zoom lens barrel according to the first embodiment.

FIG. 24 is a block diagram showing a main configuration of a drive circuit in the zoom lens barrel according to the first embodiment.

FIG. 25 is a flowchart showing an operation of a focus drive mechanism in the zoom lens barrel according to the first embodiment.

FIG. 26 is a cross-sectional view of the lens frame flexible printed circuit board and its peripheral portion in the wide, standard, and tele states when the FPC guide is not provided in the zoom lens barrel of the first embodiment.

FIG. 27 is an essential part perspective view showing a first lens group frame and an FPC guide driving mechanism in a zoom lens barrel according to a second embodiment of the present invention.

FIG. 28 is a perspective view of a main part showing a first lens group frame and an FPC guide driving mechanism in a zoom lens barrel according to a modified example of the second embodiment.

FIG. 29 is an explanatory diagram showing a lens barrier drive switching mechanism in a zoom lens barrel according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 51 rotating frame 52 fixed frame 53 first lens group frame 54 second lens group frame 55 third lens group frame 57 fourth lens group frame 59 middle frame 60 front frame 61 second lens group Spring 62 Fourth lens group spring 66 Interlocking plate 69 Barrier drive ring 71, 73 Barrier blade 78 FPC guide 81 Shutter base plate 100 Barrier drive gear 101 Barrier drive switching lever 108 Focus motor 141 First Lens group 142: second lens group 143: third lens group 144: fourth lens group 302: mirror frame flexible printed circuit board

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinya Takahashi 2-43-2, Hatagaya, Shibuya-ku, Tokyo Referee, Olympus Optical Industry Co., Ltd. References JP-A-4-106511 (JP, A) JP-A-55-106409 (JP, A) JP-A-61-259210 (JP, A)

Claims (2)

(57) [Claims] 1. A least a zoom lens barrel having first lens group and the second lens group is driven during focusing operation, the optical axis direction for full Okasu you displaced along the circumferential direction at the end face of holding an end face cam, the first lens group, Tanmenka for the focusing
A first lens holding frame that is displaced in the optical axis direction by the camera, and the focusing end face cover with respect to the first lens holding frame.
A second lens holding unit that is disposed on the opposite side of the optical axis direction and holds the second lens group, and is displaced in the optical axis direction via the first lens holding frame by the focusing end surface cam. A frame, biasing means for biasing the first lens holding frame and the second lens holding frame, and the focusing end face cam in a direction in which they come into contact with each other; and a biasing means formed on the first lens holding frame; by relative rotation around the optical axis between the second lens holding frame met can displace the second lens holding frame in the optical axis direction
A zoom end face cam displaced along the circumferential direction at the end face in the optical axis direction; and the first lens holding frame around the optical axis during the zoom operation.
A zoom rotating means capable of rotating the end cam for zoom and the second lens holding frame relatively around the optical axis without rotating the first cam and the first lens holding frame during a focusing operation; A focusing rotating means for relatively rotating the focus end face cam around the optical axis; and a rotation of the first lens holding frame and the second lens holding frame around the optical axis during a focusing operation. A focus rotation restricting means for restricting the movement, wherein the zoom end face cam and the second lens holding frame are relatively rotated around the optical axis during the zoom operation, so that An end cam can be operated to change the distance between the first lens holding frame and the second lens holding frame in the optical axis direction. Around the optical axis with the end cam A zoom lens barrel characterized in that the first lens holding frame and the second lens holding frame are integrally displaced in the optical axis direction by relatively rotating the first lens holding frame and the second lens holding frame. 2. The zoom lens according to claim 1 , wherein said second lens holding mechanism is provided during said zoom operation.
2. The holding frame is rotated about an optical axis.
The zoom lens barrel described in 1. above.