JPH0534563A - Lens barrel for zoom lens - Google Patents

Abstract

PURPOSE:To efficiently place plural members in a lens barrel by placing a motor-driven zoom decelerating system, a motor-driven focus decelerating system, a control member and a driving shaft of a motor in a roughly circular shape on almost the same face. CONSTITUTION:On a zoom bear base plate 23, a zoom motor 31 is fixed. Driving force of the zoom motor 31 is transmitted to a motor-driven zoom declerating system 32 consisting of plural gears 32a-32e placed on the zoom gear base plate 23 through a worm gear 41 attached to its driving shaft 31a. A motor- driven zoom transmission block 37 consists of a flexible substrate 38, and electronic parts 37a-37i being plural control members placed on both its faces. A motor-driven focus decelerating block 40 consists of a focus gear base plate 22, and decelerating gears 33, 34 attached thereon. The zoom gear base plate 25, the flexible substrate 38, and the focus gear base plate 22 are placed so as to surround an optical axis on about the periphery on almost the same face being vertical to 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 zoom lens barrel, and more particularly to arrangement of members in the zoom lens barrel.

[0002]

2. Description of the Related Art Recently, as a single-lens reflex camera, AF
The (autofocus) type has become the majority, and a memory for sending information such as focal length and open aperture value necessary for focus adjustment from the interchangeable lens to the body is built in the lens. Need to be installed in.

As an interchangeable lens attached to such a single-lens reflex camera, a monofocal lens has hitherto been the mainstream, but as a recent tendency, the mainstream is a zoom lens, which also has a high magnification. , The information such as the focal length that changes with the focal length and the maximum aperture value increases,
For this purpose, control members such as memories and arithmetic elements have become larger or more numerous.

On the other hand, there are cameras that perform not only focusing but also zooming electrically. For these types of cameras, focusing is performed by a motor inside the body, a type that has a zooming motor inside the lens barrel separately, a type that has a focusing motor and a zooming motor inside the lens barrel, and a lens There is a type in which both focusing and zooming are switched by the motor in the lens barrel. In the former case, a zooming motor must be provided inside the lens barrel, and in the latter case, a focusing and zooming switching member must be provided inside the lens barrel.

As described above, various members are housed in the lens barrel of the recent interchangeable lens, and it is necessary to house these members in the lens barrel.

Japanese Utility Model Laid-Open No. 3-8307 discloses a lens barrel in which a gear reduction system, a flexible substrate and a driving motor are arranged in a substantially arcuate shape in the lens barrel.

Japanese Utility Model Publication No. 61-145909 discloses a lens barrel in which a driving motor is located in a plane perpendicular to the lens optical axis.

[0008]

However, in the conventional example as described above, it cannot be said that the plurality of members including the motor for the electric zoom are efficiently arranged in the lens barrel, and the size of the lens is small. Could not proceed.

According to the present invention, a plurality of members including an electric zoom motor can be efficiently arranged in the lens barrel, and the arrangement of the members that can minimize the influence of the respective members on each other can be obtained. The purpose is to

[0010]

According to the present invention, in order to solve the above problems, the driving force of a zoom motor is transmitted in a zoom lens barrel which performs a zooming operation and a focusing operation by a driving force of a motor. An electric zoom deceleration system for transmitting the driving force of the focusing motor, an electric focus deceleration system for transmitting the driving force of the focusing motor, a motor for transmitting the driving force to at least one of the electric zoom deceleration system or the electric focus deceleration system, And a control member for controlling the zoom and electric focus operations, wherein the electric zoom speed reduction system, the electric focus speed reduction system, the control member and the drive axis of the motor surround the optical axis on substantially the same plane perpendicular to the optical axis. The present invention provides a zoom lens barrel characterized by being arranged in a substantially circular shape.

Here, a zoom operation may be performed by a motor provided in the lens barrel, and a focusing operation may be performed by a motor provided in the body.

The rear end of the motor may be adjacent to the control member, or a worm gear may be attached to the tip of the drive shaft so as to be connected to the electric zoom reduction system.

[0013]

According to the above construction, a plurality of members including the electric zoom motor are arranged in the lens barrel in a substantially circular shape on the same plane perpendicular to the optical axis.

[0014]

1 is a sectional view of a zoom lens barrel showing an embodiment of the present invention, and FIGS. 2 and 3 are partial sectional views of the same barrel. FIG. 4 is a perspective view of main components. In the drawings, the same members are designated by the same reference numerals. The state of this zoom lens barrel shown in FIGS. 1, 2, 3 and 4 is a wide-angle state at infinity. The optical system consists of 5 groups, L ₁
˜L ₅ is a zoom lens group, and L ₃ ˜L ₅ are focus lens groups, which are varifocal type zoom lens barrels.

This lens is a so-called in-body motor AF lens which has a motor in the body and transmits a driving force to the lens side through a coupler to perform a focusing operation.
In addition, it has a zoom motor in the lens, so that power zoom operation can be performed by the operation ring.

The fixed cylinder 5 is fixed to the mount 51 by mount fixing screws 52, and the outer cylinder 2 is fixed to the outer side of the fixed cylinder 5 by unillustrated outer cylinder fixing screws. Inside the mount 51, a light-shielding member 51b extending toward the front end in the optical axis direction is formed. The light-shielding member 51b also serves as an oil splash prevention plate for preventing lubricating oil from entering the moving frame from the gear train 32. ing. A fixing member 53 is screwed into the tip of the outer cylinder 2 to prevent the operation ring 1 fitted to the outside from falling out, a helicoid 2a is provided inside, and a clutch member 55 is fitted to the rear. Clutch mounting member 5 having a groove
4 is fixed. In the lens of this embodiment, power is normally received from the body by operating the operation ring 1, and power zoom can be performed by the motor in the lens barrel, but the mount is common, but the contact for power supply is provided. Power zoom is not possible when used on a body that does not have it. that time,
In order to perform a manual zoom operation, it is necessary to disconnect the power zoom motor from the manual zoom operation member (the zoom cam ring 4 in this embodiment). The clutch member 55 is provided for that purpose and is connected to a clutch mechanism to be described later, and the connection can be broken by operating the clutch member 55 in the optical axis direction.

Zoom speed reduction system 32 for power focus
Is connected to a zoom motor via a clutch mechanism to be described later, and a gear portion 4 provided inside the rear end of the zoom cam ring 4
It meshes with c. The zoom ring 4 is provided with a rectilinear groove 4a, a claw 4b at the tip, and a partial rib 4d on the inside, and is fitted to the outside of the fixed barrel 5. Fixed cylinder 5
Has a cam groove 5a and a circumferential groove 5b at its tip, and has a third zoom gear base plate 36 constituting a zoom reduction system 32 fixed at the rear end thereof, and one end of the focus drive ring 12 inside thereof. A straight-ahead groove 5c is provided while making contact. The zoom cam ring 4 is rotatable only by the partial rib 4d fitted in the circumferential groove 5b, and is prevented from moving out.

The first group moving frame 3 is a linear rib 3 provided inside.
It is fitted to the outside of the zoom cam ring 4 via b and the first inside
The lens group L ₁ is held and a helicoid 3 a that engages with the helicoid 2 a of the outer cylinder 2 is provided outside.

The zoom drive ring 6 is held inside the fixed barrel 5, has a cam groove 6a, a fitting portion 6b at the rear end, and a partial rib 6c inside, and a third group guide pin 24 is planted. Was set up,
The pin 24 is provided in the cam groove 5a of the fixed barrel 5, the zoom cam ring 4
Through the straight groove 4a.

The straight-moving barrel 7 is fitted inside the zoom driving ring 6, and has a straight-moving escape hole 7b, a notch 7c at the front end, a partial rib 7d at the rear end, and a protrusion 7a and a helicoid 7e on the inner side.
Is provided. Since the partial rib 7d fits with the partial rib 6c of the zoom drive ring 6, the rectilinear barrel 7 is only rotatable with respect to the zoom drive ring 6 and moves integrally in the optical axis direction.

The focus rotary cylinder 8 is an outer helicoid 8
a is meshed with the helicoid 7e of the straight-moving barrel 7, has a partial rib 8b on the inner side, and a longitudinal portion 8c having a straight-moving groove 8d is provided toward the mount surface direction.

The third group moving frame 9 is fitted inside the straight-moving barrel 7 and has straight-moving grooves 9a and 9b, a groove 9c and a circumferential groove 9e on the outer side, and a fourth-group drive ring retainer 14 screwed to the rear end. A threaded portion 9g is provided for this purpose, and a straight advance key 10 is screwed onto the tip of the cut portion 7c so as to fit into the straight advance groove 5c. The fitting portion 10a of the rectilinear key 10 with the rectilinear groove 5c is attached to the rectilinear groove 5c even if the attached third group moving frame 9 is extended by zooming or focusing operation.
It's long enough not to slip out. Third
The third lens unit L ₃ is held inside the group moving frame 9, a well-known diaphragm mechanism 56 that operates according to a shutter release operation (not shown) is provided in the center, and the C-shaped plate spring 19 is circular. It is held in the circumferential groove 9d. Straight barrel 7
Since the groove 9c and the protrusion 7a are fitted to each other, can move along the groove 9c in the optical axis direction but move integrally in the rotating direction. The focus rotation barrel 8 has a circumferential groove 9e with respect to the third group moving frame 9.
With the partial ribs 8b fitted together, only rotation is possible and they move integrally in the optical axis direction.

The second lens group moving frame 11 is fitted inside the third lens group moving frame 9, holds the second lens group L ₂ inside, and the second lens group guiding pin 26 is planted outside. Pin 2
Reference numeral 6 passes through the rectilinear groove 9a of the third lens group moving frame 9, the rectilinear escape hole 7b of the rectilinear cylinder 7, and the cam groove 6a of the zoom drive ring 6.

The fourth group drive ring 13 is located outside the rear end of the third group moving frame 9 and has a cam groove 13b and an adjusting member insertion groove 13c inside. A support portion 13a is provided at the tip end and extends toward the outside, and the tip end is a lid. The fitting portion 6b of the zoom drive ring 6 is fitted to the support portion 13a.

The fourth group moving frame 17 is fitted inside the third group moving frame 9 and has a plurality of jig engaging grooves on the rear end surface at equal intervals along the circumference, and the fourth lens group is provided inside. While holding L ₄ , two fourth group moving guides 18 having an arcuate surface along the outer circumferential groove 17a are fitted at symmetrical positions on the circumference. A fourth group guide pin 28 is planted on the outer side of the guide, and the pin penetrates through the rectilinear groove 9b of the third moving frame 9 and the cam groove 13b of the fourth group drive ring 13.

The fifth lens group frame 20 is fitted so as to come into contact with the C-shaped plate spring 19 on the inner side of the third lens group moving frame 9, holds the fifth lens group L ₅ on the inner side, and penetrates the jig. A plurality of cutouts at equal intervals along the circumference, and the rear end inclines inward toward the outside of the circumference,
A C-shaped line spring 21 is fitted and fixed in the gap between the group moving frame 9.

At the rear end of the fitting portion between the third group moving frame 9 and the fourth group driving ring 13, the third-fourth group spacing adjusting ring 16 and the third-fourth group spacing adjusting washer 15 are provided in the adjusting member insertion groove 13c. Is inserted, and the fourth group moving ring retainer 14 is screwed into the threaded portion 9g at the rear end of the third group moving frame 9 to fix them.

Further, in FIG. 2, the coupler 30 for AF is used.
By fitting with the AF coupler on the camera side in the fitting hole 51a on the mount member 51 having the light shielding member 51b inside, the driving force can be transmitted from the motor inside the body (not shown). The driving force transmitted to the coupler 30 is transmitted to the focus drive ring 12 via the electric focus reduction gears 33, 34, 35 attached to the focus gear base plate 22. Focus drive ring 1
Reference numeral 2 is attached to the rear end of the fixed barrel 5, has an outer gear portion 12b and meshes with the electric focus reduction gear 35, and wraps around the zoom drive ring 6 and the rear end of the straight-moving barrel 7.
An engagement arm 12a is provided so as to be fitted in the straight advance groove 8d of the focus rotation barrel 8. The straight groove 8d and the engaging arm 1
Each of the engagements 2a has a sufficient length so that the focus rotation barrel 8 does not come off even if the focus rotation barrel 8 moves in the optical axis direction by the zooming operation and the focusing operation.

Next, the arrangement of the control members such as the motor, the speed reduction mechanism and the IC in the lens barrel of this embodiment will be described with reference to FIGS. 5 and 7.

FIG. 5 is an arrangement view showing the arrangement of members such as reduction gears at the rear of the lens, and FIG. 7 is an enlarged view of the vicinity of the zoom gear base plate 23 as seen from the optical axis direction. In addition, A-A in FIG.
FIG. 8 shows a power zoom state in which the gear 32d and gear 32e mesh with each other in the cross-sectional view, and FIG. 9 shows a manual zoom state in which the mesh is disengaged by the clutch mechanism.

The zoom gear base plate 23 is fixed to the rear end of the fixed barrel 5, and its shape is a part of a substantially circular shape surrounding the optical axis of the lens. This zoom gear base plate 2
A zoom motor 31 having an oval cross-section is fixed on the disk 3 so that its drive shaft 31a is at right angles to the optical axis and extends along the substantially circular shape, and its end face 31g is parallel to the optical axis. Has been done. As shown in FIG. 3, the end face 3
A light shielding member 51b is arranged closer to the optical axis than 1g, and a third group moving frame 9 is arranged further closer to the optical axis. By making the end surface 31g parallel to the optical axis, the space in the radial direction of the lens barrel is efficiently used, and the electric zoom deceleration arranged in a substantially circular shape without increasing the outer diameter of the outer cylinder 2. Since a large space can be taken inside the system, the lens moving frame and the light shielding plate 51b can be easily installed. Unlike the present embodiment, it is easy to separately provide the oil splattering prevention plate and the light shielding plate 51b.

An example in which the oil splash prevention plate is provided separately from the light shielding plate 51b is shown in FIGS. The members having the same reference numerals are the same members as those in the above-mentioned embodiment, and the description thereof is omitted. FIG. 11 is a partial cross-sectional view, and FIG. 12 is a member arrangement view of the rear portion of the lens barrel. As shown in the figure, the oil splash prevention plate 70 is arranged outside the light blocking member 51b and has a width in the optical axis direction along the optical axis side end surface of the zoom gear base plate 23 that sufficiently covers the electric zoom reduction system.
It has mounting portions 70a at both ends. Then, together with the zoom gear base plate 23, the mounting portion 70a is fixed to the fixed barrel 5 with a screw.

A worm gear 41 is attached to the drive shaft 31a, and a spherical surface portion 31b is formed at the tip. Further, the thrust bearing 23a projects from the zoom gear base plate 23 in the optical axis direction, and the spherical surface portion 31b is supported at one point on the thrust bearing 23a. The driving force of the zoom motor 31 is transmitted via the worm gear 41 to the helical gear 32a of the electric zoom reduction system 32 including a plurality of gears arranged on the zoom gear base plate 23 in a substantially arc shape so as to surround the optical axis. At the same time as being transmitted and decelerated, the driving direction is changed from the direction orthogonal to the optical axis to the direction parallel to the optical axis.

In such a thrust bearing, when the motor rotates in the normal direction (clockwise when viewed from the arrow P), the spherical portion 31c provided at the other end of the drive shaft 31a is provided in the motor. Although 31d supports at one point and does not occur, the thrust load generated at the contact surface between the radial bearing 31e and the collar 31f at the time of reverse rotation (when rotating in the counterclockwise direction as viewed from the arrow P) is not affected by the radial bearing 31e and the collar. Three
It is provided to prevent the clearance C by providing a clearance C between the two. This also has the role of enabling the adjustment of the thrust backlash of the motor and reducing the backlash of the lens barrel.

The driving force from the zoom motor is further transmitted to the gear portion 4c provided inside the rear end of the zoom cam ring 4 via the gears 32b to 32f. These gears 3
2b to f are incorporated between the zoom gear base plate 23 and the second zoom gear base plate 61 that are connected by a plurality of columns, and only one end of the gear 32f that transmits the driving force to the gear portion 4C is the second zoom gear base plate 61. It is fixed to the third zoom gear base plate 36 fixed to. The second zoom gear base plate 61
Has a shape that forms a part of a substantially circular shape that surrounds the optical axis of the lens, and the third zoom gear base plate 36 is fixed 5 or the like.
It is fixed in the notch.

More specifically, a bidirectional spring clutch 32g is interposed between the helical gear 32a and the gear 32b. This spring clutch 32g is a helical gear 32a.
When the load of the motor exceeds a predetermined value, for example, when the end of the wide-angle side or the telephoto side is reached during zooming, the spring clutch 32g moves against the gear 32b. Prevents the motor from spinning and excessive current flowing. The gear 32b is transmitted to the gear 32e via the gears 32c and 32d. A spring clutch 32h is interposed as a one-way clutch between the gear 32e and the gear 32f. This is a member for preventing the gear from being damaged by an external force.
Both the gear 32f and the gear 32f are strongly tightened, and they are normally rotated integrally with each other, so that both of them rotate idly only when an excessive external force acts on the first group moving frame 3. This can occur, for example, when the camera is dropped or forcibly pushed by hand in the telephoto state in which the first group moving frame 3 is extended.

In addition, a clutch for switching between power zoom and manual zoom is provided in the deceleration mechanism. This clutch mechanism will be described in detail. In FIG. 8, a clutch member 55 is provided on the outer cylinder 2, and a clutch interlocking lever 57 integrally fixed to the outer cylinder 2 extends in the optical axis direction and is provided at an end of the clutch lever 58. The engagement portion 58a is engaged. The gear 32d is provided with a groove 32i at the end thereof, and the U-shaped end 58b provided at the other end of the clutch lever 58 is engaged with the groove 32i. Clutch lever 58 and gear 32
“D” is integrally movable in the optical axis direction with the support column 59 as a guide axis.

When the clutch member 55 is operated in the direction of M in FIG. 1, the clutch interlocking lever 57 displaces the clutch lever 58 integrally in the optical axis direction, disengaging the gear 32d and the gear 32e, and the manual zoom. It is ready (Fig. 9). In this state, by manually operating the first group moving frame 3 in the optical axis direction, manual zooming operation becomes possible. Further, when the clutch member 55 is returned in the direction of P in FIG.
Move in the direction that meshes with e. At this time, the gear 32d is 3
Even if you get on the 2e, the motor 31
When is rotated, both gears mesh with each other, and the power zoom state is set.

Further, in FIG. 5, the electric zoom electric component block 37 includes a flexible substrate 39 and ICs 37a to e used for various controls arranged on both sides thereof, a ROM 37f in which lens information is stored, a transistor 37g,
It is composed of a plurality of electronic components such as h and a resistor 37i. One end thereof is fixed to the fixed cylinder 5 by the flexible print holding plate 38, and the other end is also fixed inside the lens barrel at a portion not shown, and the flexible substrate 39 itself is arranged at right angles to the optical axis along the substantially circular shape. Has been done.

The electric focus deceleration block 40 is composed of the focus gear base plate 22 and the electric focus deceleration gears 33, 34 and 35 mounted on the focus gear base plate 22, and transmits the driving force to the focus drive ring 12. It is fixed to the fixed cylinder 5 at the portion shown. The driving force is transmitted from the camera body into the lens barrel through the autofocus coupler, and is transmitted to the focus rotation barrel 8 through the electric focus deceleration block 40 and the focus drive ring 12.

As described above, the zoom gear base plate 23,
The zoom motor 31, the flexible substrate 38, and the focus gear base plate 22 are arranged so as to surround the optical axis on a substantially circle on substantially the same plane perpendicular to the optical axis.

Next, the operation of the entire zoom lens barrel having the above structure will be described. This lens is an AF lens having a zoom motor in the body, and power focusing is also possible by switching the power zoom operation ring 1.

The method of power zoom and power focus operation using the operation ring 1 will now be described.
An I-shaped groove as shown in FIG. 10 is provided on the outer circumference of the outer cylinder 2, and when the operation ring 1 is operated, the switch 80 implanted inside the groove moves inside the groove, depending on its position. The operation signal is output to the lens control IC. The switch 80 is always urged to the initial position a, and the switch 80 returns to the initial position a even if an operation such as zooming is performed. The power zoom operation is performed by rotating the operation ring 1 in the circumferential direction from the initial position a. When the power ring is rotated right, the telescopic state is set, and when it is rotated left, the wide state is set. At this time, the switch 80 is provided with a known encoder structure of brushes and pattern contacts in the grooves, so that the output signal changes depending on the rotation angle from the initial position a, and the zoom speed becomes variable accordingly. ing. When the operating ring 1 is pulled toward you, the switch reaches the position d. At this position, a signal is output and the AF operation through the coupler is not performed. Power focusing is performed by rotating the operation ring 1 from this position in the circumferential direction. When the operating ring 1 is turned to the right, the focus is moved to the near direction, and when turned to the left, the focus is moved to infinity. Also at this time,
With the encoder configuration described above, the focus lock position d
The focus speed can be varied depending on the rotation angle from.

First, the zooming operation will be described. When the zooming operation of rotating the operation ring 1 from the initial position a in the circumferential direction is performed, the zoom motor 3 arranged in the lens barrel is
1 is driven, and the driving force is transmitted to the zoom cam ring 4 via the zoom reduction system 32. The zoom cam ring 4 has a claw 4d
Since the movement of the fixed barrel 5 in the optical axis direction is restricted by the ribs 5b of the fixed barrel 5 and only the rotation is possible, the first group moving frame 3 is rotated by the engagement of the pawls 4b and the linear ribs 3b when the zoom cam ring 4 rotates. At the same time, the helicoids 3a and 2a are engaged with each other. Therefore, the first lens group L ₁ supported by the first group moving frame 3 is extended in the optical axis direction.

On the other hand, the rotation of the zoom cam ring 4 causes the zoom drive ring 6 to move to the third groove which penetrates the straight groove 4a and the cam groove 5a.
By the action of the group guide pin 24, it is extended in the optical axis direction while rotating.

The rotation of the zoom drive ring 6 is performed by the second group moving frame 1
For 1, the cam groove 6a, the straight escape hole 7b, the straight groove 9
By the action of the second group guide pin 26 penetrating a, it is transmitted as a straight advance to the optical axis. At this time, the amount of extension of the second group moving frame 11 in the optical axis direction is determined by the cam grooves 5a and 6a.
Will be the synthetic lead. Therefore, the second lens group L ₂ supported by the second group moving frame 11 is extended in the optical axis direction.

On the other hand, the rectilinear barrel 7 is rotatable only by the action of the partial ribs 6c and 7d with respect to the zoom driving ring 6 and is integrally movable in the optical axis direction. Further, the rectilinear barrel 7 can move in the optical axis direction by fitting the projection 7a and the groove 9c of the third group moving frame 9 to which the rectilinear key 10 is attached, but the movement in the rotational direction is restricted. Has been done.
The focus rotation cylinder 8 is composed of a straight advance cylinder 7 and helicoids 7e and 8e.
It is helicoidally coupled at a, and can be rotated only by a partial rib 8b and a circumferential groove 9e with the third group moving group 9 and move integrally in the optical axis direction.

As described above, when the zoom drive ring 6 is extended while rotating, the amount of movement of the zoom drive ring 6, the rectilinear barrel 7, the focus rotary barrel 8 and the third group moving frame 9 in the optical axis direction is the same. As a result, the third group moving frame 9 is eventually extended in the optical axis direction according to the lead of the cam groove 5a. As a result, the third lens unit L ₃ and the fifth lens unit L ₅ attached to the fifth lens unit frame 20 are extended in the optical axis direction. At this time, the linear movement of the zoom drive ring 6 by the rectilinear barrel 7 causes the helicoids 7e and 8a to move to the focus rotary barrel 8.
It is not transmitted as a rotation by the lead.

Further, the fourth group drive ring 13 is rotated by the engagement of the fitting portion 6b at the rear end and the support portion 13a with respect to the rotation of the zoom drive ring 6, and is rotated with respect to the third group moving frame 9. It is possible only and it moves integrally in the optical axis direction. Further, the action of the cam groove 13b and the rectilinear groove 9b causes the fourth group guide guide 18 to be extended in the optical axis direction via the fourth group guide pin 28. Along with this extension, the fourth lens unit L ₄ is integrally extended together with the fourth unit moving frame 17. At this time, the amount of extension of the fourth group moving frame 17 in the optical axis direction corresponds to the combined lead of the cam groove 5a and the cam groove 13b.

Next, the focusing operation will be described.
When the AF operation by the switch operation of the camera body (not shown) or the manual focusing operation of rotating the operation ring 1 from the focus lock position d in the circumferential direction is performed, the driving force of the motor in the body is passed through the coupler 30 to the inside of the lens barrel. Is transmitted to. This drive force rotates the focus drive ring 12 via the electric focus reduction gears 33, 34, 35. This rotation is transmitted to the focus rotation barrel 8 by the engagement arm 12a via the straight advance groove 8d. Straight groove 8 of both
d and the engaging arm 12a each have a sufficient length,
Even if the focus rotation barrel 8 is extended in the optical axis direction integrally with the third group moving frame 9 by the zooming operation, the engagement is not disengaged.

When the focus rotary cylinder 8 rotates, it is driven in the optical axis direction by the action of the helicoids 7e and 8a.
The third group moving frame 9 can only rotate with respect to the focus rotation barrel 8, and is guided by the fitting portion 10a and the rectilinear groove 5c in the optical axis direction to move integrally. The third lens unit L ₃ and the fifth lens unit L ₅ are extended by the extension of the third unit movement frame 9. At this time, the fourth lens group L ₄ supported by the fourth group moving frame 17 is moved out integrally with the third group moving frame 9 because the fourth group driving ring 13 does not rotate. At this time, the second
The lens unit L ₂ does not move due to the action of the rectilinear groove 9a.

Next, the means for adjusting the eccentricity or the like of the lens group after the lens assembly is completed in the lens barrel having the above-mentioned structure will be described.

In the zoom lens of this embodiment, the optical design has a great influence on the performance of the entire lens due to the deviation from the optical axis of each lens and decentering. In particular, the error of the air gap between the third group and the fourth group, and the decentering of the optical axis of the fourth group including the aspherical lens have a great influence on the image plane, so these are adjusted after the lens assembly is completed. It has an adjustment mechanism for

First, the air gap between the third group and the fourth group is adjusted by changing the relative positions of the third group moving frame 9 and the fourth group moving frame 13 in the optical axis direction.

That is, when the lens of the above-mentioned embodiment is assembled, the performance of each assembled lens is measured to obtain the required lens performance.
A correction amount for the interval between the group and the fourth group is determined. Next, the fourth group drive ring retainer 14 is removed from the third group moving ring 9, and the fourth group drive ring 13 is pulled out to the film surface side. In this state, the third-fourth group interval adjustment washer 15 is replaced. By exchanging the washers, the fourth group moving ring 13 can adjust the relative position in the optical axis direction with respect to the third group moving frame 9. This third
-4 group spacing adjustment washers 15 are provided with several thicknesses, and the third group and the fourth group are provided according to the determined correction amount.
Choose one that optimizes the spacing between the group lenses. After the washer is replaced, the fourth group moving ring 13 is returned to the position where it is brought into contact with the replaced third to fourth group spacing adjustment washer 15, and the fourth group moving ring retainer 14 is tightened again. At this time, the optical design is performed so that the distance between the fourth group and the fifth group, which changes in association with the adjustment, does not significantly affect the lens performance.

Next, the eccentricity adjustment with respect to the optical axis of the fourth group is
This is performed by rotating the fourth lens group using a jig and searching for a position where the optical performance is well balanced.

That is, after adjusting the air gap between the third group and the fourth group, a jig having two claws is passed through the notch provided in the fifth group lens frame 20 from the rear portion of the lens barrel. Then, the jig is rotated by engaging with the groove provided at the rear end of the fourth group moving frame 17. By the rotation of the jig, the fifth lens group frame 20 held by the fifth lens group frame holding spring 21 also rotates at the same time, but the optical design is performed so that the rotation of the fifth lens group does not affect the lens performance. Has been done. After determining the optimum position by rotating the jig, remove the jig from the rear end of the lens.

Further, in the case of the configuration of this embodiment,
By increasing the number of parts, the fourth group moving frame 17
Play occurs between the group moving frame guides 18. This backlash inevitably occurs due to the processing accuracy of the parts, but depending on the amount of backlash, it may become so large that the adjustment of the lens frame is wasted. Therefore, this embodiment has a mechanism for removing this play. (See FIGS. 1 and 6) First, the fourth group moving frame 17 and the fourth group
The play between the group moving frame guides 18 in the optical axis direction is a ring-shaped bias spring 6 in the optical axis direction, which is wavy in the optical axis direction.
It is offset by 2. The optical-axis-direction biased spring 62 is fitted to the tip end side of the optical axis between the fourth group moving frame 17 and the fourth group moving frame guide 18 during lens assembly.

The radial play between the fourth group moving frame 17 and the fourth group moving frame guide 18 is offset in the radial direction by a U-shaped radial biasing spring 63. this,
The radial bias spring 63 has an inclination of 90 degrees with respect to the optical axis between the fourth group moving frame guide 18 and the third group moving frame 9 at the time of assembly so that the bulge portion faces the outside in the radial direction. Two are inserted.

[0060]

[Effect] In the above embodiment, the electric zoom reduction system, the electric focus reduction system, the motor drive shaft, and the control member are arranged in a substantially circular shape on the same plane perpendicular to the optical axis. The arrangement of the members inside can be concentrated in a certain area, and the lens barrel member can be easily processed.

Further, since the drive shaft of the motor is arranged on a plane perpendicular to the optical axis and a worm gear is attached to the tip of the drive shaft and is connected to the helical gear of the reduction system, the reduction ratio of rotation of the motor is increased. The gear structure as a reduction mechanism can be simplified, and the rear end of the motor and the control member are located very close to each other, so the lead wires for connecting the two can be shortened, which reduces vibration of the gear train. This has the effect of preventing the resulting noise.

[Brief description of drawings]

FIG. 1 is a sectional view of a zoom lens barrel showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the same zoom lens barrel.

FIG. 3 is a partial cross-sectional view of the same zoom lens barrel.

FIG. 4 is a perspective view of main components of the zoom lens barrel.

FIG. 5 is a member layout diagram of a rear portion of the zoom lens barrel.

FIG. 6 is a sectional view of the zoom lens barrel.

7 is a partially enlarged view of FIG.

FIG. 8 is a diagram showing a power zoom state in the AA cross section of FIG. 5;

FIG. 9 is a diagram showing a manual zoom state in the AA cross section of FIG. 5;

FIG. 10 is a diagram showing a groove provided on the outer circumference of the zoom lens barrel.

FIG. 11 is a partial cross-sectional view of a zoom lens barrel showing another embodiment of the present invention.

12 is a member layout diagram of a rear portion of the zoom lens barrel of the embodiment shown in FIG.

[Explanation of symbols]

 32: Electric zoom deceleration system 40: Electric focus deceleration system 31: Motor 37a-i: Control member 31a: Motor drive shaft 41: Worm gear

Claims (4)

[Claims] 1. In a zoom lens barrel which performs zooming and focusing operations by the driving force of a motor, an electric zoom reduction system for transmitting the driving force of a zooming motor and a driving force of a focusing motor And an electric focus deceleration system, a motor for transmitting a driving force to at least one of the electric zoom deceleration system and the electric focus deceleration system, and a control member for controlling the electric zoom and the electric focus operation. A zoom lens, in which the drive shafts of the reduction gear system, the electric focus reduction gear system, the control member and the motor are arranged so as to surround the optical axis on a substantially same plane perpendicular to the optical axis and have a substantially circular shape. Lens barrel. 2. The zoom lens barrel according to claim 1, wherein a zoom operation is performed by the motor provided in the lens barrel, and a focus operation is performed by the motor provided in the body. 3. The zoom lens barrel according to claim 1, further comprising a motor for performing a zooming operation and a focusing operation in the lens barrel. 4. The rear end of the motor is adjacent to the control member,
The zoom lens barrel according to claim 1, wherein a worm gear is attached to the tip of the drive shaft and is connected to the electric zoom reduction system.