JPH0452628A - Zoom lens barrel - Google Patents

Abstract

PURPOSE:To offer the zoom lens barrel which is made shorter in overall length, simple in structure, and advantageous in cost by structuring a cam ring in two separated bodies, rotating and moving them forward and backward at the time of zooming, and moving one body straight at the time of focusing. CONSTITUTION:The zoom ring 4 is provided rotatably to a fixed frame 1 and rotated at the time of zooming and the zoom ring 5 can freely be rotated and moved forward and backward inside or outside the zoom ring 4. The zoom rings 4 and 5 are coupled by a coupling member 4f and cam grooves 4a and 4b and cam grooves 5c and 5d are provided. Then the zoom rings 4 and 5 are rotated on the optical axis to move all lens groups forward and backward in the direction of the optical axis and thus vary the focal length, and the zoom ring 5 is moved forward and backward to move only a focusing lens group forward and backward and thus perform focusing operation. Therefore, the zoom rings 4 and 5 are arranged one over the other, so the overall length of the lens barrel can be made shorter and the zoom lens barrel which has short overall length can be realized.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a zoom lens barrel, and more specifically, it has a fixed frame and a movable lens holding frame, and the movable frame is rotated or moved forward and backward for zooming. Or related to a zoom lens barrel that performs focusing.

[Prior Art] In recent years, many proposals have been made regarding lens frame drive mechanisms for zoom lens barrels in order to respond to the need for smaller, lighter, more accurate, and lower priced cameras. For example, JP-A-5
The zoom lens barrel disclosed in Publication No. 7-116309 is
It has a structure in which the cam rings for zooming are made into two parts, so that they can be rotated together when zooming, and one of them can be moved back and forth when focusing. Also, JP-A-60-4
The zoom lens barrel disclosed in Japanese Patent No. 3619 has a structure that allows zooming and focus adjustment using a single cam ring.

[Problems to be Solved by the Invention] However, in the zoom lens barrel disclosed in the above-mentioned Japanese Patent Laid-Open No. 57-116309, when the number of lens groups is increased, the cam ring must be extended in the optical axis direction. Because there is no lens, there was a problem that the total length of the lens barrel became longer. Furthermore, the zoom lens barrel disclosed in Japanese Patent Application Laid-Open No. 60-43619 is
Straight grooves are required in the cams of the cam ring related to lens groups other than the lens group for focus adjustment, and as the number of lens groups increases, the number of straight grooves increases accordingly. As a result, there were problems such as the possibility that the cam could not be placed on the cam ring.

It is an object of the present invention to have a structure in which the cam ring of the zoom lens barrel is separated into two parts, and one of the lens barrels rotates and moves forward and backward during zooming, and one moves straight during focusing, thereby enabling high-magnification zooming. It is an object of the present invention to provide a zoom lens barrel that can shorten the overall length of the lens barrel, has a simple structure, and is advantageous in terms of cost.

[Means and effects for solving the problems] The zoom lens barrel of the present invention includes a first frame that is rotatably provided with respect to a fixed frame and is rotationally driven during zooming, and an inner side of the first frame. or a second frame provided on the outside so as to be rotatable and freely advance and retreat with respect to the fixed frame, and a connecting member that integrally connects the first frame and the second frame around the optical axis; A first cam means for connecting a lens group frame other than the focusing lens group and the first frame, and a second cam means for connecting the focusing lens group frame and the second frame, By rotating the first frame and the second frame around the optical axis, all the lens groups move forward and backward in the optical axis direction to change the focal length, and by moving the second frame back and forth, only the focusing lens group moves forward and backward. It is characterized by performing a focusing operation.

[Example] The present invention will be described below based on illustrated embodiments.

1 and 2 are an exploded perspective view and a vertical sectional view of a zoom lens barrel in a collapsed state, respectively, showing an embodiment of the present invention. This zoom lens barrel allows zooming, focusing, and collapsing operations. The main components of this zoom lens barrel are a fixed frame 1, a fixed frame 2 fixed to the fixed frame, and a focus ring 3.
, an inner zoom ring 4 that is a first frame, an outer zoom ring 5 that is a second frame, a first group frame 6 that is a focusing lens group frame, and a first group frame that is also a focusing lens group frame. 2nd group lens holding frame 7
, the third and fourth group lens holding frames 8 and 9, which are lens group frames other than the focusing lens, and the fifth group lens holding frame 10, and the first and second lens groups held directly or indirectly by each of the above lenses. ，
3, 4.5 group lens 20. 21. 22. 23.
24 (see FIG. 2), and the focus drive unit 11
, a zoom drive unit 12, an aperture unit 13, and a zoom encoder section. The above lens groups 20 to 24 are shown in FIGS. 1(A) and 1(B).
Although not shown in FIG. 2, they are shown in the cross-sectional view of FIG.

The fixed frame 1 is fixed to the mirror box 16 of the camera body via spacers 14 and 15.

The spacers 14 and 15 adjust the distance between the fixed frame 1 and the mirror frame 17 that holds the movable reflective mirror 19 mounted on the mirror box 16, as shown in FIG. Further, the fixed frame 1 has a hole 1a in the center thereof for supporting the fifth group lens frame 10, and a fitting part 1d into which the fixed lens frame 2 is fitted, integrally formed in the mounting flange part. Furthermore, it has a cylindrical portion 1e that supports the inner zoom ring 4 rotatably around the optical axis 0, and is provided with a sliding pin 1g or a screw 1f for regulating the movement of the inner zoom ring 4 in the optical axis direction. It is fixed on the cylindrical portion 1e.

Further, the fixed frame 1 is provided with a fitting hole portion 1b and a fitting elongated hole IC that slidably support the second group main rod 7e and the second group sub-rod 7f in the optical axis direction. Furthermore,
The focus drive unit 11 is attached to a mounting surface 1h provided by cutting out a part of the cylindrical portion 1e. Further, the zooming drive unit 12 is similarly attached to the fixed frame 1. Further, a charge lever 25 for operating the aperture unit 13 is also pivotally mounted to the fixed frame 1 through its shaft hole 25a.

The fixed lens frame 2 has a cylindrical shape and is fixed with its inner circumferential portion 2a fitted into the fitting portion 1d of the fixed frame 1. The cylindrical part has straight grooves 2b and 2c for guiding the first group frame 6 and second group lens holding frame 7 along the optical axis O, and along the circumferential direction of the inner periphery on the fixed frame 1 side. A bottomed inner circumferential groove 2g for regulating the axial position of the focus ring 3 is formed along the circumferential direction of the cylindrical portion opposite to the fixed frame side, and an elongated hole 2d for regulating the axial position of the contact base 13. are provided for each. As shown in the developed view of FIG. 14, the straight groove 2C has a zoom area groove 2h having a width equal to the outer diameter of the roller 7j to be fitted, and a groove 2h having a width larger than the outer diameter. It shall be formed from the groove portion 21 of the collapsible barrel region. This groove portion 2L is a portion used when collapsing the lens frame.

The focus ring 3 has a ring shape, and its outer circumference fits into the inner circumference 2a of the fixed lens frame 2, and the inner circumference has an internal gear that meshes with the output gear 118 of the focus drive unit 11. 3e is provided. Further, a sliding bottle 3b is fixed to the bottle fixing portion on the outer periphery with a screw 3a. The sliding pin 3b is slidably fitted into the inner circumferential groove 2g of the fixed lens frame 2, and prohibits movement of the focus ring 3 in the optical axis 0 direction. In addition, the outer zoom ring 5
A sliding pin 3d for moving the zoom ring 5 in the optical axis direction is attached to the screw 3 on the bottle fixing portion 3g on the protrusion that loosely fits into the inner periphery of the lens.
It is fixed by c. The sliding pin 3d is slidably fitted into the focus cam groove 5b of the zoom ring 5.

The inner zoom ring 4 is a cylindrical member, and its inner circumferential portion is rotatably fitted into the cylindrical portion 1e of the fixed frame 1, and the fixed frame is fitted into an inner circumferential groove 4d provided in the inner circumferential portion. The sliding pin 1g of No. 1 is inserted, and movement of the main zoom ring 4 in the optical axis direction is prohibited. An internal gear 40 is provided on the inner peripheral portion, and is engaged with the output gear 12a of the zoom drive unit 12, which is driven based on a zoom control signal.

Further, this zoom ring 4 is attached to the third and fourth group lens holding frames 8 and 9.
Cam grooves 4a and 4b are provided as first cam means for zooming and driving. Sliding pins 8j are fixed to the third and fourth group lens holding frames 8 and 9 in these cam grooves 4a and 4b.

9f is fitted, but the cam shape is as shown in the developed view of FIG. 13, and the cam grooves 4g and 4h in the collapsible region correspond to the collapsible state of the lens frame with no displacement in the optical axis direction, respectively.
and cam grooves 4i and 4j in the zoom area having zoom displacement in the optical axis direction. Further, a roller 4f, which is a connecting member that is fitted into the rectilinear groove 5a of the outer zoom ring 5, is rotatably supported on the outer circumference by a pin 4e.

The outer zoom ring 5 is a cylindrical member, and its outer circumference and inner circumference are connected to the fixed lens frame 2 and the first group frame 6.
Each is fitted so as to be rotatable or slidable. and,
A rectilinear groove 5a is provided along the optical axis O, and the inner zoom ring 4 is rotated in accordance with the zoom amount via a roller 4f fitted in the groove. Furthermore, the main zoom ring 5 is provided with a focus cam groove 5b corresponding to the focusing amount, into which the sliding pin 3d of the focus ring 3 is fitted, so that the main zoom ring 5 moves straight in the optical axis direction by the focusing amount. be forced to move.

Further, the zoom ring 5 is provided with cam grooves 5C and 5d, which are second cam means. The first and second group rollers 6b and 7j supported by the first group frame 6 and the second group lens holding frame 7 are fitted into these cam grooves 5c and 5d. Therefore, the first group frame 6 and the second group lens holding frame 7 are displaced in the direction of the optical axis 0 in accordance with the rotation of the main zoom ring 5 during zooming or in accordance with the movement in the axial direction during focusing. Note that the cam grooves 5c, 5
d is for moving the zoom area cam portions 5i and 5h that provide driving positions during focusing and zooming, respectively, and the first group frame 6 or the second group lens holding frame 7 to the retracted position when the camera is not in use. , and cam portions 5j and 5g of collapsible areas for retracting into the camera body. Note that the groove width of the cam portion 5g is formed to be larger than the outer diameter of the roller 7j to be inserted, so that interference between the lens groups does not occur during the retraction (see Fig. 14). .

Further, the main zoom ring 5 is provided with a stepped square hole 5f for guiding a contact piece base 13 for a zoom encoder, which will be described later, at a position corresponding to the elongated hole 2d of the fixed lens frame 2. .

The first group frame 6 has a cylindrical shape to which the first group lens holding frame 6C is screwed. Its outer peripheral portion is slidably fitted into the outer zoom ring 5. and,
A first group roller 6b is rotatably attached to a corresponding portion 6f of the cam groove 5c on the outer circumference by a pin 6a. The first group roller 6b is also fitted into the cam groove 5C and the straight groove 2b of the fixed lens frame 2. Therefore, the first group frame 6 is guided in a straight line in the direction of the optical axis O by the straight groove 2, and is moved in accordance with the rotational or straight movement of the zoom ring 5. Note that four parts 6e forming thin-walled parts are provided on the inner periphery of the first group frame 6 along the axial direction. This recessed portion 6e becomes a relief portion of a second group drive plate 7h, which will be described later.

The first group lens 20 is held by a first group lens holding frame 6c, and the distance between the lenses is adjusted by a spacer 6d.
It is supported by the first group frame 6.

The second group lens holding frame 7 holds the second group lens frame 7a to which the second group lens 21 is attached.

As shown in FIG. 3, two U-shaped notches 7b are provided in the outer shape of the lens frame, facing each other with respect to the optical axis, in order to securely support the rod, which is a rod-shaped guide member. ing. The surfaces formed by the two sides 7C of the notch are formed by molding, machining, etc. so as to be parallel to the optical axis of the lens frame. The above notch 7
Insert one end of the second group main rod 7e or the second group sub-rod 7f, which is a rod-shaped guide member, into b, and use the dogleg-shaped fixing piece 7 to tighten the screw 7g with the slope of the fixing piece 7. The rods 7e and 7f are pressed and fixed.

Since each rod is pressed by the slope of the fixing piece 7, the rods 7e and 7f are pressed against the two sides of the notch 7b, respectively.
They come into contact with the sides 7C, and as a result, they are mounted parallel to the optical axis of the lens frame.

The other ends of the attached rods 7e and 7f are slidably inserted into the fitting holes 1b and the fitting elongated holes IC of the fixed frame 1. Therefore, the second group lens holding frame 7 to which the second group lens 21 is mounted can be moved along the optical axis O without rotating.
It is possible to slide forward and backward along. In addition, the rod 7e,
A third group lens holding frame 8, which is another lens holding frame that is slidably supported and guided by these rods, is inserted into the intermediate portion of 7f.

Further, a second group drive plate 7h for driving in the axial direction of the main holding frame 7 and extending in the optical axis direction is fixed to the main holding frame 7 via screws. A roller 7j is rotatably attached to the tip of the drive plate 7h via a pin 7i. Further, the roller 7j is fitted into the cam groove 5C of the outer zoom ring 5 and the straight groove 20 of the fixed lens frame 2, as described above.

Therefore, as the outer zoom ring 5 rotates and moves in the axial direction, the second group lens holding frame 7 moves in the optical axis O direction via the drive plate 7h, and the second group lens 21 is also moved in the same manner. It will be done. Note that, due to its arrangement, the drive plate 7h is
It is located in the space of a recess 6e provided in the group frame 6.

The third group lens holding frame 8 holds the third group lens 22, and includes a second group main rod 7e and a sub rod fixed in pairs with respect to the optical axis on the second group lens frame 7. 7f to be slidably supported in the optical axis direction. That is, the rod 7e is fitted into the notch 8C of the third group lens holding frame 8, while the rod 7f is inserted through the sleeve 8a into which it fits, as shown in the installation state diagram of FIG. Supports the holding frame 8. This sleeve 8a is fixed to the holding frame 8 with adhesive H, and the outer diameter of the sleeve itself is dimensioned to fit loosely into the mounting hole 8b of the holding frame 8.

In order to perform the above bonding, first, the convex fitting portion 7 of the second group lens holding frame 7, which is formed concentrically with the optical axis, and the third
The concave fitting portion 8d of the group lens holding frame 8 is fitted, and at this time, the rod 7e is inserted into the notch 8C, and the rod 8 is fitted into the notch 8C.
f is inserted into the mounting hole 8b with the sleeve 8a fitted thereto. Then, the adhesive H is flowed into the gap between the sleeve 8a and the hole 8b to perform bonding. In this way, the third group lens holding frame 8 and furthermore, the third group lens 22 are correctly installed concentrically with the optical axis centered, and can slide forward and backward parallel to the optical axis direction without rotation and without play. state. It is assumed that a compression spring 18 is inserted into the rod 7f between the third group lens holding frame 8 and the second group lens holding frame 7 to remove looseness between both frames.

Furthermore, two third group rods 8h and a sub-rod 8k are attached to the third group lens holding frame 8 to slidably support a fourth group lens holding frame 9, which will be described later, in the direction of the optical axis O. ing. The sub-rod 8 is implanted and fixed to the third group lens holding frame 8 in parallel to the optical axis O. The hole 8r to be planted is formed with high precision in terms of hole diameter and parallelism by machining or molding. Then, the rod 8k is press-fitted into the extraction hole 8'' and implanted.The sub-rod 8 and the rod 8h are arranged substantially opposite to the optical axis 0 (see Fig. 5). ).On the other hand, the rod 8h is
As shown in the figure, it is supported by the third group lens holding frame 8 and the arms 8e provided on the frame, and its mounting holes 8g and 8f.
is loosely fitted to the rod 8h, and is fixed by adhesive. Note that, prior to the adhesion, the sleeve 9C that loosely fits into the fourth group lens holding frame 9 is fixed with adhesive.

That is, the through hole 9 provided in the sliding arm portion 9a of the holding frame 9
A loosely fitting sleeve 9C is inserted into b, and held using a mechanical jig so that the inner diameter of the sleeve 9 is parallel to the optical axis of the punching frame 9. In this state, the sleeve 9C is fixed to the hole 9b using adhesive H. Then, the rod 8h is inserted into the sleeve 9C and passed through it, and further inserted into the holes 8f and 8g, which are the loose fitting holes of the arm 8e. In addition, the rod 8h is equipped with an E-type retaining ring 8m to prevent positional displacement before bonding.
is attached to its end.

Next, the convex fitting portion 9g of the fourth group lens holding frame 9, which is provided concentrically with the optical axis, is connected to the concave fitting portion 8p of the second group lens holding frame 8, which is similarly provided concentrically with the optical axis. At the same time, fit the sub-rod 8k into the notch 9d of the holding frame 9.
be inserted into the In this way, the optical axes of the holding frames 8 and 9 are aligned, and the direction of the rod 8h is also aligned, and the rod 8h and the holes 8g and 8f of the holding frame 8 are bonded and fixed with adhesive H. . Third and fourth group lenses 22 held by the holding frames 8 and 9. - 23 is attached concentrically to the optical axis O and can be moved in parallel.

A sliding pin 8j that is fitted into a cam groove 4a provided in the inner zoom ring 4 is fixed to the pin attachment portion 8s of the third group lens holding frame 8 with a screw 81, so that the rotation of the zoom ring 4 is fixed. As a result of the movement, the holding frame 8 is moved forward and backward in the direction of the optical axis O.

Further, an aperture unit 13 is attached to the subject-side surface of the third group lens holding frame 8. Then, the charging lever 25 pivotally mounted on the fixed frame 1 performs the aperture operation of the aperture unit 13 via the charged lever 13a. Note that since the charged lever 13a is a long member in the optical axis direction, it does not disengage from the charging lever 25 even if the holding frame 8 moves in the optical axis direction. Furthermore, since the aperture unit 13 contains a photointerrupter and an electromagnetic device for adjusting the aperture, it must be electrically connected to the camera side. Therefore, this unit 13 is equipped with a flexible board 13b for connecting the aperture.

The fourth group lens holding frame 9 holds the fourth group lens 23, and is slidable in the optical axis direction by the two rods 8h and 8k of the third group lens holding frame 8, as described above. is supported by In addition, the rod 8h has a sleeve 9c.
Support through.

A sliding pin 9f that is fitted into a cam groove 4b provided in the inner zoom ring 4 is fixed to the sliding arm 9a of the fourth group lens holding frame 9 with a screw 9e.
By rotating the zoom ring 4, the holding frame 9 is moved forward and backward in the direction of the optical axis O.

The fifth group lens holding frame 10 holds the fifth group lens 24, and its attachment is first carried out by first
Oa is fitted into the fitting hole 1a of the fixed frame, and the optical axis of the lens is made to coincide with the optical axis O. Then, for positioning in the optical axis direction, the fixing part 10b of the holding frame 1o is fixed to the fixing frame 1 with a screw or the like.
shall be installed on the

The zoom encoder section detects the rotation angle of the outer zoom ring 5 or the inner zoom ring 4 around the optical axis,
As shown in FIG. 6, the contact piece 13, the contact piece 13d fixed to the contact piece stand 13 and sliding on the conductive pattern of the encoder board 14, the encoder board 14, and the board 14 It is composed of a metal plate 14a for protection. The contact piece base 13 has protrusions 13c on both sides, and edge protrusions 13a having a slight height in the direction of the contact piece 13d on both sides.
It has Then, it is inserted into a stepped square hole 5f having a stepped portion 5k of the outer zoom ring 5, and the contact piece base 13 is mounted with the back surface of the edge 13b in contact with the stepped portion 5k of the square hole 5f. The square hole 5f has dimensions such that the fitting surface 5e of the zoom ring 5 in the rotational direction fits with the edge 13b of the contact piece base 13 without a gap, and the length in the axial direction The width is greater than the width of the edge protrusion 13a of the base 13 plus the maximum axial movement amount of the zoom ring 5.

The elongated hole 2d of the fixed lens frame 2 is positioned above the square hole 5f, and the width of the elongated hole 2d in the rotational direction is larger than that of the outer zoom ring with respect to the movement of the contact piece base 13 in the circumferential direction. On the other hand, the width in the axial direction, which is the fitting width portion 2e, is a fitting dimension that allows the edge protrusion 13a or both side surfaces of the contact piece base 13 to slide. Therefore, the armature base 13 can move over the elongated hole 2d in accordance with the rotation angle of the outer zoom ring 5 over the entire range of axial movement. Since the contact piece 13d slides on the encoder substrate 14 disposed along the elongated hole 2d and moves in the rotational direction, the rotational angle of the zoom ring 5 during zooming can be detected.

In addition, in the encoder section, the protrusion 13c of the contact piece base 13 is held down by the edge of the width part 2e of the elongated hole 2d, so that the contact piece base 13 has a structure that does not easily come off from the square hole 5f. There is.

The focus drive unit 11 will be explained with reference to FIGS. 7 to 11. FIG. 7 is a perspective view of the external appearance of the unit 1, and FIG. 8 is a perspective view of the unit as seen from the back side. Moreover, FIG. 9 is a diagram showing the YY cross section of FIG. 7 above. The unit 11 is arranged in a unit case 2.
o, focus drive motor 21, and motor output shaft 2
Motor output gear 21b, which is an output gear fixed to 1a.
and constitutes a reduction gear train, in which the gear 2
1b, the sun gear, the planetary gear, the unit output gear 11a, and the unit case stopper plate 31.
, a drive unit rotation detection section, and the motor 20
．． Flexible printed circuit board 1 for electrical connection to PI23
1s. And this unit 1
1 is attached to the mounting surface 1h of the cutout part of the cylindrical portion 1e of the fixed frame 1 as described above, and the motor 21, the reduction gear train, the case 20 or the case stopper plate 31 are attached to the mounting surface 1h of the fixed frame 1. etc. are arranged along the curvature of the cylindrical portion 1e (see FIG. 10).

The rotation detection section is composed of a slit plate 22 and a photointerrupter PI23. The PI 23 is fixed to the unit case 2o with screws via a lubricating slide plate 23a. The slit plate 22, which provides an input signal to the PI 23 through its rotation, is formed integrally with a gear 22a that meshes with the motor output gear 21b, and is rotatably fitted into the shaft portion 20a of the case 20. The slide plate 23 acts as a stopper for the gear 22a to be pulled out in the axial direction.

From motor output gear 21b to unit output gear 1la
In the power transmission path by the reduction gear train between the two, first, the motor output rotation is transmitted to the gear 24 having the sun gear portion 24b via the gear 22a meshing with the gear 21b. The rotation of the sun gear part 24b is transmitted to the three planetary gears 25 that mesh with it. The planetary gear 25 is pivotally supported by a shaft portion provided integrally with the support body of the sun gear 28, with an axial removal stop being provided. It meshes with an internal gear 206 provided on the inner wall of the case 2o. Therefore, the planetary gear 25 rotates and revolves around its axis due to the rotation of the sun gear part 24b, and the sun gear 28 also rotates due to the rotation. Hereinafter, the rotation is caused by the planetary gear 26 meshing with the sun gear 28 and the sun gear 29 rotated by the gear, and then by the planetary gear 27 meshing with the sun gear 29 and the gear 3 rotated by the gear.
Further, the gear 30 is in mesh with the final stage unit output gear 11a, and the output gear 11
A rotational output that is decelerated from a is obtained.

Note that the gear 24. Gear 30 and output gear-1
1a is pivotally supported by shaft portions 20b, 20c, and 20d, which are formed integrally with the unit case 20, respectively. The sun gears 28 and 29 are held at their axial center positions by meshing with the three planetary gears 26 and 27, without using any support shafts. Further, the axial direction is held and rotated by abutting each end face.

A unit case retaining plate 31 is attached to position and hold the gear 30 and Ha within the case 20. The case retaining plate 31 is attached to the case by engaging the two retaining claws 31b with the seats of the attachment holes 20e of the case 20 using elasticity.

To attach the unit 11 to the lens barrel, as shown in FIGS. 1 and 9, the case stopper plate 31 side is brought into contact with the mounting surface 1h of the fixed frame 1, and the positioning dowel 31a is inserted into the corresponding fixed frame 1. This unit 11 is fixed to the lens barrel by inserting it into the hole and screwing the screw into the mounting screw part 20e. Then, the internal gear 38 of the focus ring 3, which is a driven member rotatably supported by the fixed frame 1, and the unit output gear 11a are meshed to enable focus driving. Then, an output shaft 2 to which a motor output gear 21b of the motor 21 is fixed.
1a extends in the M direction parallel to the optical axis direction, and the transmission path of the series of reduction gear trains meshing with the gear 21b is for transmission in the N direction opposite to the M direction. Then, rotational output is taken out from the unit output gear 11a located on the mounting surface side.

As shown in FIG. 7.8, the electrical connection printed circuit board IIs has a board portion 11s connected to the PI2B and guide pieces 20g, 20h, 20i that are integrated with the case 20.
It is hung and arranged.

Note that the L-shaped portion 11t at the tip of the substrate IIs is used to prevent it from coming off the guide piece 20i (see FIG. 7).

FIG. 11 is a cross-sectional view taken along the line XX in FIG. 10, showing a vertical cross-section of the unit 11 in the installed state. There is a small pitch on the inner diameter side of the curvature of the unit case 20 facing the optical path side. It has a light shielding surface 2Of with a triangular groove cross section, and blocks unnecessary light outside the light beam.

Further, it is assumed that the printed circuit board IIs is bent into an S-shape and guided to the rear side of the fixed frame 1.

The zooming, focusing, and collapsing operations of the zoom lens barrel of this embodiment configured as described above will be explained. Note that in the following description, the direction of rotation is indicated by the direction of rotation seen from the subject side. FIG. 2 shows the lens barrel retracted state, in which the first group frame 6 and the second group lens holding frame 7 are retracted, and the second group main rod 7e protrudes behind the fixed frame. It is in a state. First, the zooming operation from this state to the long focal point side will be explained.

FIG. 12 shows the extended position of each lens group from the wide end to the telephoto end, and the zoom driving unit 12 moves the first to the telephoto end positions to the above extended position based on the zoom instruction from the system controller (not shown). Move the 4th group lens. That is, the inner zoom ring 4 is rotated clockwise via the output gear 12a of the drive unit 12. As the sliding pins 8j and 9f rotate, the sliding pins 8j and 9f move from the collapsing region grooves 4g and 4h of the cam grooves 4a and 4b to the zooming region grooves 4i and 4.
It comes to be located at part j (see Fig. 13). and,
3rd and 4th group lens frames 8 and 9 to which the above pins are fixed
moves, and the third and fourth lens groups 22 and 23 are extended to each zoom position. On the other hand, the outer zoom ring 5 and the inner zoom ring 4
It rotates in the same direction via a roller 4f supported by. Due to the rotation, the rollers 6b, 7j or the cam grooves 5c, 5d are moved from the grooves 5j, 5g in the collapsing area to the groove 5i in the zoom area.
, 5h (see FIG. 14(A)). At the same time, the rollers 6b and 7j move in the straight groove 2b of the fixed lens frame 2.
, 2c, so it can be moved straight in the direction of the subject. In addition, in the said straight groove 2C, it shifts from the groove|channel 21 of a collapsible area|region to the straight groove 2h of a zoom area.

Furthermore, since the sliding pin 3d, which does not move in position during zoom driving, is fitted into the focus cam groove 5b of the outer zoom ring 5, the outer zoom ring 5 itself moves the amount of focus correction toward the subject due to the action of this cam. move only. Therefore, the amount of movement due to zooming of the first group frame 6 or the second group lens holding frame 7 to which the rollers 6b and 7j are directly or indirectly fixed is limited to the cam groove 5c of the outer zoom ring 5.
, 5d and the focus correction amount driven by the focus cam groove 5b. Note that the above description of the zoom movement amount shows the case of zoom drive toward the long focus side, but zoom drive toward the short focus side can be performed by driving the inner zoom ring counterclockwise; The operation is in the opposite direction to the zoom drive described above.

The zoom state accompanying the zoom drive is detected by a zoom encoder section that detects the rotation of the outer zoom ring 5.The operation of this encoder section will be explained with reference to FIGS. 1 and 6.
A contact piece 13d supported on a contact piece base 13 is brought into sliding contact with a conductive pattern on an encoder board 14 attached to a fixed lens frame 2 to extract a coded signal related to the zoom position. As described above, the contact piece base 13 is inserted into the square hole 5f of the outer zoom ring 5 in a fitted state only in the circumferential direction, and furthermore, in the axial direction, it is inserted into the width part 2e of the elongated hole 2d of the fixed lens frame 2. Since they are fitted, as the zoom ring 5 rotates, the contact piece 13d
slides on the conductive pattern.

Furthermore, the zoom ring 5 also moves in the axial direction;
In that case, since the square hole 5f is larger in the axial direction than the contact piece base 13, the edge protrusion 13a of the contact piece base 13 is guided to the width part 2e of the elongated hole 2d of the fixed lens frame 2. , contact piece 13
d can slide on the encoder board 14 and output a zoom position detection signal.

Next, regarding the focusing operation, the flash distance of the subject (
The operation when focusing from a state corresponding to an infinite distance to a predetermined subject distance will be described. The focus drive unit 11 is driven based on a focus instruction from the system controller, and the unit output gear 11a is
Rotate the focus ring 3 counterclockwise through the . As the lens rotates, the sliding pin 3d of the focus ring 3 slides on the focus cam groove 5b of the outer zoom ring 5, so that the zoom ring 5 moves toward the subject.

In this case, since the inner zoom ring 4 is stationary, the outer zoom ring 5 moves straight. And rollers 6b, 7j
The first group frame 6 or the second group lens holding frame 7 is moved via the first group lens 20 . The second group lens 21 is extended toward the subject. Note that the focusing operation from a close distance to a far distance of a subject is performed by driving the focus ring 3 in the opposite direction to that described above.

Next, regarding the lens barrel collapsing operation at the end of photography in the zoom lens barrel of this embodiment, Fig. 1, Fig. 4 (A),
This will be explained using (B). First, the focus drive unit 11 is driven, the focus ring 3 is rotated clockwise, and the first and second lens groups are retreated toward the camera body to the infinity focusing position.

Next, the zoom drive unit 12 is driven to rotate the inner zoom ring 4 counterclockwise, but the rotation angle is rotated to the lens frame collapsing phase, which is further rotated counterclockwise from the zooming short focus state phase. make it move.

As a result, the sliding pins gj, gf fitted into the cam grooves 4a, 4b of the inner zoom ring 4 are in the cam groove 4g, which is the collapsible region.
, 4h.

At the same time, the outer zoom ring 5 also rotates by the same rotation angle as the zoom ring 4. Then, as shown in FIG. 14(B), the rollers 6b and 7j move into the cam grooves 5c and 5d of the zoom ring 5.
5g cam groove in the collapsible area.

It is located at 5j. Therefore, the first group frame 6.degree. and the second group lens holding frame 7 are retracted to the retracted position where they are pulled further toward the camera body than the position corresponding to the camera distance. Note that when the first group frame 6 retreats to the retracted position as described above, the second group lens holding frame 7 does not move to a position outside the normal zoom range, unless the first group lens holding frame 6C and the first group lens holding frame 7 move out of the normal zoom range.
Interference with the group lens 20 or the like or a clogging condition may occur.

Therefore, the rectilinear groove 21 in the collapsible region. The cam groove 5g is loosely fitted into the roller 7j that is fitted into the cam groove 5g, thereby avoiding the above-mentioned interference and reliably collapsing the barrel.

Next, a modification of the structure for fixing the frame supporting main rod 7e and sub rod 7f to the second group lens holding frame 7 will be described with reference to FIGS. 15 and 16. This modified example differs from that of the previous embodiment in the shape of the U-shaped notch for fixing each of the woods 7e and 7f.

In FIG. 15, the rod 57e has good straightness.

The notch 57b holding the lens 57f is disposed on the outer circumferential portion of the second group lens holding frame 57 so as to be substantially opposed to the optical axis of the holding frame. The notch 57b is connected to the rod 57.
e, a side contact surface 57 parallel to the optical axis that 57f comes into contact with;
c and the bottom contact surface 57k.

It has a length of 57m. The cylindrical portion 57m provided on the holding frame 7 is used as the cylindrical outer diameter surface 57 which becomes the bottom abutting surface. A length of 57 m on the cylindrical outer diameter surface 57 is concentric with the optical axis, and the outer diameter dimensions are the same. Further, the portion between 57m and 57m of the bottom abutment surface 57 is a surface 57n that is recessed from the abutment surface.

Each rod is fixed by the rod 57e.

57f is inserted into the notch, and the inclined surfaces of the tips of the two fixing pieces 57d are connected to the rods 57e.

57f, and press and fix with the screw 57g. Bottom abutment surface 57k as described above.

Since the portion between 57m and 57m is recessed, the rods 57e and 57f are connected to the side contact surface 57C1 and the bottom contact surface 5.
7k 57m, it can be brought into contact more reliably. Therefore, according to this modification, the rod supporting the lens holding frame can be fixed parallel to the optical axis of the frame with high precision.

Further, as another modification of the fixing structure of the rods 7e and 7f, it is also possible to propose a structure in which a V-shaped notch groove is used in place of the U-shaped notch fixing groove of the above-described embodiment. In this modification, the V-shaped notch groove is provided on the outer periphery of the lens holding frame so as to be substantially opposed to the optical axis, and the notch groove is also parallel to the optical axis. Then, the rods 7e and 7f are fitted in contact with the notched grooves, and fixed to the holding frame using a flat fixing plate. The rod fixed in this way is still supported parallel to the optical axis with high accuracy, but the V-shaped notch allows for higher precision because it is easier to obtain parallelism accuracy during machining or molding. Fixation is possible.

As described above, the zoom lens barrel of this embodiment has the zoom ring in the first position. The zooming operation, that is, the focal length, is changed by dividing the second frame into two frames, inner and outer, and by rotating or linearly driving the inner and outer zoom rings 4 and 5.

Further, the outer zoom ring 5 is driven in a straight line to move only the focusing lens group back and forth to perform a focusing operation. According to this embodiment, since the inner and outer zoom rings 4 and 5 are disposed overlapping each other, the total length of the lens barrel can be further shortened.

Furthermore, the main rod 7e and the sub-rod 7f, which are rod-shaped guide members for sliding the second group lens holding frame 7 in the zoom lens barrel of this embodiment, are fixed by attaching the rods to the holding frame 7 on the optical axis. It is pressed against the U-shaped notch 7b having two abutment surfaces parallel to each other and fixed. If the notch, especially the abutting surface, is formed with high precision by machining or molding, the rod can be fixedly supported on the holding frame more accurately than by conventional methods such as press-fitting. Furthermore, since the above structure fixes the rod to the outer periphery of the frame, it can be applied to small-sized lens frames.

Furthermore, in this embodiment, the sleeve 8a into which the rod 7f for sliding support of the third group lens holding frame 8 is fitted is fixed.
It is done by gluing. That is, in order to align the optical axes of both the second group lens holding frame 7 and the above-mentioned holding frame 8, the second group lens holding frame 7 and the holding frame 8 are held in a state in which fitting portions concentric with the respective optical axes are fitted,
The sleeve 8a loosely fitted into the holding frame 8 is slidably fitted into the rod 7f fixedly supported by the holding frame 7, and in this state the sleeve 8a loosely fitted is fixed to the holding frame 8 by adhesive. do. Therefore, the positional accuracy of each member can be maintained during bonding, and in particular, it is possible to assemble the holding frames with higher positional accuracy without increasing the accuracy of each member itself. .

Furthermore, the fourth lens barrel in the zoom lens barrel of this embodiment
The rod 8h, which is a guide member for the group lens holding frame 9, is fixed to the third group lens holding frame 8 by adhesion. That is, in order to align the optical axes of both frames, the fitting parts concentric with the optical axes of both frames are fitted into each other, and the rod 8h fitted into the holding frame 9 is loosely fitted into the holding frame 8. Insert the rod 8h, and in this state adhere the rod 8h to the holding frame 8.

Since the sleeve 8a is fixed in this way, the positional accuracy of each member can be maintained during bonding.
In particular, it becomes possible to assemble the holding frames with higher positional accuracy without increasing the fitting accuracy of each member.

In addition, in order to store the focus drive unit 11 of the zoom lens barrel of this embodiment efficiently, it is disposed in a part of the donut-shaped space inside the lens barrel, and its outer shape is adjusted to a predetermined shape corresponding to the cylindrical portion of the lens barrel. The motor and reduction gear train are arranged according to the curvature. Further, the output shaft center of the motor and the shaft center of the reduction gear train are arranged so as to be parallel to the optical axis O. In order to conveniently drive the focus ring 3, a motor output gear 21b and a unit output gear 11a for extracting the rotational output of the drive unit are provided.
is located on the motor mounting side, which is the side where the internal gear 3e of the focus ring 3, which is the driven part, is located. Therefore,
The extending direction of the motor output shaft to which the motor output gear 21b is fixed is the opposite direction to the driven part side, and the extending direction of the shaft part of the reduction gear train to which the unit output gear 11a is mounted in front thereof is the opposite direction to the driven part side. By setting the direction opposite to the above-mentioned direction of extension, a more efficient drive train path can be achieved.

The drive unit 11 configured in this manner makes it possible to efficiently utilize the storage space of the lens barrel, and there is no need to unnecessarily increase the diameter of the lens barrel.

[Effects of the Invention] As described above, the zoom lens barrel of the present invention changes the focal length by rotating or moving the first frame and the second frame having respective cam means, and , the focusing operation is performed by advancing and retracting the second frame, and according to the present invention, since the first and second frames are arranged overlapping each other, the total length of the lens barrel can be made shorter. can,
A high-magnification zoom lens barrel with a short overall length can be realized. Further, since the structure is simple, it is possible to provide a zoom lens barrel that has many remarkable effects such as being advantageous in terms of cost.

[Brief explanation of drawings]

1A and 1B are exploded perspective views of a zoom lens barrel showing an embodiment of the present invention, and FIG. 2 is a view of the zoom lens barrel shown in FIG. 1 in a retracted state. 3 is a view taken in the direction of arrow A in FIG. 1, FIG. 4 is a diagram showing the state in which the rods of each lens holding frame of the zoom lens barrel in FIG. 1 are fixed, and FIG. , FIG. 6 is a developed view of the zoom encoder section of the zoom lens barrel in FIG. 1, and FIGS. 7 and 8 are a cross-sectional view taken along line B-B in FIG. FIG. 9 is a perspective view of the focus drive unit attached to the zoom lens barrel shown in FIG. 11 is a cross-sectional view taken along the line XX in FIG. 10, FIG. 12 is a diagram showing the extended position of each lens group during zoom driving of the zoom lens barrel in FIG. 1, FIG. 13 is a developed view of the cam groove of the inner zoom ring of the zoom lens barrel shown in FIG. Developed view during operation, Figure 14 (B
) is a developed view of the inner and outer zoom ring of the zoom lens barrel shown in Fig. 1 above when the lens frame is collapsed, and Fig. 15 is a rod of the second group lens holding frame of the zoom lens barrel shown in Fig. 1 above. FIG. 16 is a vertical sectional view showing a rod fixed state of the second group lens holding frame in a modification of the fixing structure; FIG. 16 is a perspective view showing a rod fixed state of the second group lens holding frame in the modification of FIG. be. 1...Fixed frame 4...Inner zoom ring (first frame) 5...
......Outer zoom ring (second frame) 4f...
...Rollers (connecting members) 4a, 4b...Cam grooves (first cam means) 5c
, 5d... cam groove (second cam means) 6...
・・・・・・・・・・・・1st group frame (focusing lens group frame)
7.57... Second group lens holding frame (focusing lens group frame) 10th garden 11th circle 14 (A) 12th 13th circle 13th diagram 15

Claims (1)

[Claims] (1) A first frame that is rotatably provided with respect to the fixed frame and is rotationally driven during zooming, and a first frame that is rotatably provided with respect to the fixed frame and can be freely advanced and retreated inside or outside the first frame. a connecting member that integrally connects the first frame and the second frame together around the optical axis; and a connecting member that connects the lens group frame other than the focusing lens group and the first frame. a first cam means for connecting the focusing lens group frame and the second frame; and a second cam means for connecting the focusing lens group frame and the second frame. A zoom lens barrel characterized in that all the lens groups are moved back and forth in the optical axis direction to change the focal length, and only the focusing lens group is moved back and forth by moving the second frame back and forth to perform a focusing operation.