JPH0723766Y2 - Zoom lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a zoom lens barrel used in optical equipment such as a camera for photographing, a small-sized photographing machine, a video camera, a copying machine, and an enlarger.

"Prior Art" In a zoom lens barrel, a cam barrel having a long and narrow cam hole along the periphery and a cam follower protruding into the cam hole are fixed, and the zoom lens barrel is internally mounted in the cam barrel to correct a zoom lens and correction. In many cases, there is provided a movable barrel that supports a lens for use, and the movable barrel is optically driven by rotating the cam barrel to move the movable barrel in the optical axis direction.

Specifically, a cam barrel fixed in the direction of the optical axis is rotatably provided, and a plurality of moving frames are installed inside the cam barrel. Each of the moving frames is guided by the fixed barrel while the cam barrel is being guided. It is configured to move in the optical axis direction in conjunction with the rotation of.

A zoom lens barrel of this type is provided with a moving frame that supports an optical system for focus adjustment, and the moving frame is moved by a driving means other than the cam barrel to control focusing. Many of them include a program lens shutter in which the shutter blade is also used as a diaphragm.

[Problems to be Solved by the Invention] In most of the conventional zoom lens barrels described above, the program lens shutter is attached to the zooming movement frame.

Therefore, since the F value of the diaphragm changes due to the focusing of the focus matching mechanism, it is necessary to add correction information to the shutter control circuit.

For example, in the configuration in which the shutter control is performed by the microcomputer, the code of the F value change for focusing must be incorporated in the program.

Since such correction of the F value is determined in consideration of zooming, it is difficult to sufficiently correct the F value, and the work of setting the correction amount becomes considerably troublesome.

The present invention was developed in view of the above-mentioned circumstances, and an object thereof is to develop a zoom lens barrel with a program lens shutter whose F-number does not change by focusing.

[Means for Solving the Problem] In order to achieve the above-mentioned object, in the present invention, a plurality of movable frames supporting the optical system are moved in the optical axis direction in conjunction with the rotation of the cam frame. In a zoom lens barrel that performs zooming and focusing control, an optical axis is rotatable about an optical axis with respect to a zooming moving frame that moves in the optical axis direction in conjunction with a first cam frame. In the direction, a second cam frame connected so as to move together, and a focus alignment moving frame that moves in the optical axis direction in conjunction with the second cam frame are provided, and the focus alignment moving frame includes an optical system. In addition to the above, there is proposed a zoom lens barrel characterized in that a program lens shutter is provided and the shutter is displaced in the optical axis direction during zooming operation and focus matching operation.

[Operation] In the zoom lens barrel described above, when the first cam frame is driven to perform zooming, the second cam frame moves in the optical axis direction together with the zooming moving frame.

When the second cam frame is driven at the zoomed position, the focus matching moving frame moves in the optical axis direction and focusing control is performed.

In this case, since the program lens shutter is displaced together with the focus matching optical system, the F value of the diaphragm during shutter operation does not change.

However, the focal length changes due to zooming and the movement of the image point occurs, but this movement of the image point is easy to correct.

[Example] Next, an example of the present invention will be described with reference to the drawings.

1 is a sectional view of the zoom lens barrel taken along the line BB in FIG. 2, and FIG. 2 is a sectional view of the same lens barrel taken along the line AA in FIG. 3 and 4 are sectional views of the same lens barrel showing the upper half of the same taken along the line C-C in FIG. 2, and FIG. 4 is an exploded perspective view of the same lens barrel.

In these figures, 11 is a cylindrical fixed frame that is fixed to the camera body, 12 is a movable cylinder that serves as a main moving frame that slides on the outer surface of the fixed frame 11, and 13 is a first cam on the outer peripheral surface of the movable cylinder 12. A cam barrel for zooming, which is rotatably provided as a frame, 14 is a cam barrel for focus adjustment, which is rotatably provided as a second cam frame around the outer periphery of the moving barrel 12, like the above-mentioned cam barrel 13, and 15 is A first moving frame that moves in the fixed frame 11 and a second moving frame 16 that moves in the fixed frame 11 like the first moving frame 15.

L ₁ is a moving lens supported at the tip of the moving barrel 12, L ₂
Is a fixed lens supported by the fixed frame 11, L ₃ is the first moving frame 15
Moving lens is supported, L ₄ is a moving lens that is supported by the second moving frame 16, L ₂ with respect to the focal length of L _1, L _3, L ₄
Multiply by the focal length of to change the magnification, and the L ₄ also works as a focusing lens.

First, each component of the zoom lens barrel will be described with reference to FIG.

The fixed frame 11 is a flange portion 11a integrally formed at the rear end.
Is fixed to a lens base plate (not shown), and wide cutouts 11b, 11c, 11d are formed in the circumferential direction at equal intervals, leaving a tip end portion.

These notch holes 11b, 11c, 11d are provided in the first and second moving frames 15, 16
Is connected to the moving cylinder 12, its rear side is open, and arcuate cut grooves 11e, 11f, 11g are formed in the flange portion 11a according to the width of each cutout hole. There is. The concave portion 11h provided on the groove edge of the cut groove 11e is a portion into which a stopper 30c that defines the rotation range of the cam cylinder for focus matching is inserted. Further, a cell frame 17 fitted with a fixed lens L ₂ is screwed to a middle partition portion 11i provided near the tip of the fixed frame 11, and further, three cam followers 18a are provided around the outer periphery of the tip slightly near the tip. , 18b, 18c are fixed at equal intervals in the circumferential direction.

In addition, the fixed frame 11 is provided with three spring receiving portions 11m for receiving springs that give a pushing force to the first moving frame 15, and slides the key projections of the moving barrel 12 at the tip end portion. Three key grooves 11n are provided on the outer peripheral surface so as to extend along the cylinder axis direction.

The above-mentioned moving cylinder 12 is provided with arcuate ridges 12a and 12b for connecting the two cam cylinders 13 and 14 to the front and rear and connecting them to the bayonet. These ridges 12a and 12b are integrally provided at a position on the outer surface of the movable barrel 12 rearward of the center of the movable barrel 12 at a narrow interval so as to be parallel to the circumferential direction.

The ridges 12a are 12a ₁ and 12a as shown in FIG. 5 (a).
₂ , 12a ₃ and the ridge 12b is formed of 12b ₁ , 12b ₂ , 12b ₃ as shown in FIG. 6 (a).

In addition, a female helicoid screw is attached to the inner diameter of the tip of the moving barrel 12.
12c is formed, and for this helicoid screw 12c,
The moving lens L ₁ (objective lens) is attached by screwing a male helicoid screw 19a formed on the cell frame 19. It should be noted that there are three long holes 12d inclined at the tip of the moving barrel 12 in accordance with the helicoid screw 12c. This is for shift adjustment, and after adjustment, the small screw 20 is inserted from this long hole 12d. The cell frame 19 is screwed and fixed to the corresponding taps 19b.

Further, the movable barrel 12 is provided with various escape holes.
Of the rectilinear holes 12e, 12f formed in front of the ridge 12a,
The longer straight hole 12e is the cam follower 1 of the fixed frame 11 described above.
8a, 18b, 18c are clearance holes provided at three locations around the circumference, and the shorter straight-advance hole 12f has a circumference 3 so as to penetrate the cam followers 23a, 23b, 23c of the first moving frame 15 described later.
It is an escape hole provided at a point. The rectilinear hole 12g formed on the rear side of the ridge 12b is used for the cam follower 2 of the second moving frame 16 described later.
It is an escape hole that penetrates 6a, 26b, and 26c, and is also provided at three places around it. In addition, the movable cylinder 12, the positioning groove 12h of the filter frame 21, which will be described later, a tap 12i for fixing the filter frame 21 with a machine screw 22,
Three small holes 12j for fixing a spring receiving frame 30, which will be described later, are provided, and sliding grooves 12o, 12p for sliding the first and second moving frames 15, 16 are provided on the inner surface of the moving barrel 12. It is formed in parallel along the cylinder axis direction.

The filter frame 21 is fitted on the outer surface of the front part of the movable barrel 12, and the convex portion 21a provided therein is fitted into the positioning groove 12h, and then the machine screw 22 is passed through the screw hole 21b and the tap 12i of the movable barrel 12 is inserted.
Secure it by screwing in. In addition, 21c is a cam cylinder 1 described below.
It is a stopper that determines the rotation range of 3.

Three first cam holes 13a into which the cam followers 18a, 18b and 18c of the fixed frame 11 are projected and the cam followers 23a, 23b and 23c of the first moving frame 15 are projected into the zoom cam barrel 13 described above. Each of the two second cam holes 13b is formed at equal intervals along the circumferential direction, and the cam cylinder 13 is provided with an inverted V-shaped drive gear 13c bent from the rear end to the middle.

In addition, around the rear end of the cam barrel 13, the moving barrel
In order to fit the twelve ridges 12a to form a bayonet structure, three arc-shaped recesses are formed on the inner circumference, and three arc-shaped pores 13d that are displaced in the circumferential direction are formed in the recesses. The arc-shaped notch 13 provided on the inner periphery of the front end of the cam cylinder 13
e defines the rotation range. (See FIG. 5 (b)) The above-described focus matching cam cylinder 14 has three cam holes 14a formed at equal intervals in the circumferential direction. A drive gear 14b is provided at the rear end portion of the cam cylinder 14 and the front end thereof is provided. The moving cylinder 12
In order to form the bayonet structure by fitting the convex streak portion 12b, an arc-shaped fine hole 14c and an arc-shaped concave portion provided on the inner circumference of the front end at a position displaced from the fine hole 14c are formed. The cam cylinder 14 is an arcuate notch formed along the inner circumference of the rear end.
The rotation range is determined by 14d. (6th
The first moving frame 15 described above is a circular plate having a moving lens L ₃ fixed to the center thereof, and its circular diameter is slightly smaller than the cylindrical diameter of the fixed frame 11, Further, three sliding arms 15a are integrally formed on the peripheral edge of the circular plate at equal intervals. These sliding arms 1
5a is parallel to the optical axis direction of the moving lens L ₃ and has a fixed frame
It is fitted into a sliding groove 12o provided on the inner surface of the moving cylinder 12 through the notch holes 11b, 11c, 11d of 11. (See FIG. 2) The cam followers 23a, 23b, 23c are fixed to the respective sliding arms 15a, and as described above, these cam followers 23a, 23b
3b and 23c pass through the respective rectilinear holes 12f of the moving cylinder 12 and project into the respective second cam holes 13b provided in the cam cylinder 13.

The first moving frame 15 is constantly subjected to a rearward pushing force by three small-diameter guide rods 24 fixed to the front surface side and three springs 25 into which these guide rods 24 are inserted. Has become. One end of each guide rod 24 penetrates the spring receiving portion 11m of the fixed frame 11, and the spring 25 is received by this spring receiving portion 11m. (See FIG. 3) The above-mentioned second moving frame 16 has substantially the same form as the above-mentioned first moving frame 15, but has a moving lens at the center thereof.
A lens holding barrel 16b for holding L ₄ (focus matching lens) is provided.

The three sliding arms 16a provided at equal intervals around the circular plate of the second moving frame 16 are fitted into the sliding groove 12p on the inner surface of the moving barrel 12 through the notches 11b, 11c, 11d of the fixed frame 11. Let (See FIG. 2) Further, cam followers 26a, 26b, and 26c are fixed to the respective sliding arms 16a, and these cam followers 26a, 26b, and 26c penetrate through the rectilinear holes 12g of the moving cylinder 12 and the respective cam cylinders 14a. It is designed to rush into the cam hole 14a.

On the front side of the second moving frame 16, a program lens shutter 28 that also functions as a diaphragm blade is screwed, and a spring 29 gives a forward pushing force to the second moving frame 16. .

The spring 29 is provided between the second moving frame 16 and the spring receiving frame 30, and the spring receiving frame 30 projects three positioning arms 30a from the peripheral portion of the circular plate at equal intervals and forms a circular recess in the central portion. It has a hole 30b that allows light to pass through, and this has a stopper that determines the rotation range of the cam barrel 14.
30c is integrally formed.

The spring receiving frame 30 is fixed to the rear end of the moving barrel 12 such that each positioning arm 30a is fitted into the sliding groove 12o on the inner surface of the moving barrel 12. That is, the small-diameter elastic ring 31 and the small screw 32
Is inserted through the small hole 14e of the cam cylinder 14, the elastic ring 31 is positioned in the small hole 12j of the moving cylinder 12, and the machine screw 32 is screwed and fixed to the positioning arm 30a. (See FIG. 7) In this case, the stopper 30c passes through the recess 11h of the flange 11a and projects into the notch 14d of the cam barrel 14.

Next, the assembly of the above-mentioned components will be described.

First, the cam cylinder 13 is fitted to the outer peripheral surface of the moving cylinder 12 from the front side. At this time, the projection 12a of the moving barrel 12 is fitted into the arcuate pore 13d of the cam barrel 13 to form a known bayonet structure, and the cam barrel 13 is rotatably connected around the barrel axis.

Next, the cam cylinder 14 is fitted to the outer peripheral surface of the moving cylinder 12 from the rear side. In this case, the ridge 12b of the moving barrel 12 should be attached to the cam barrel 14
As with the cam barrel 13, it has a bayonet structure and is rotatably connected so as to fit into the arc-shaped pore 14c.

The movable cylinder 12 in which the cam cylinders 13 and 14 are connected is fitted on the outer peripheral surface of the fixed frame 11 from the front side. In this case, the key protrusions provided on the inner surface of the moving cylinder 12 (provided on the inner surface of the moving cylinder so as to correspond to the key groove 11n) are fitted so as to slide in the key groove 11n of the fixed frame 11. Then, the position of the movable barrel 12 in the circumferential direction is determined.

After that, with the spring 25 inserted in each of the guide rods 24 fixed to the first moving frame 15, the first moving frame is fixed.
Insert from the back of 11. For this insertion, slide arm 15
Each of the a is positioned between the cutout holes 11b, 11c, 11d of the fixed frame 11, and these sliding arms 15a are fitted into the respective sliding grooves 12o provided on the inner surface of the moving barrel 12. . Also,
As shown in FIG. 3, the tip of the guide rod 24 is made to project forward from the spring receiving portion 11m of the fixed frame 11.

With respect to the first moving frame 15 inserted in this way, the cam barrel 13
The cam followers 23a, 23b, and 23c passing through the respective second cam holes 13b and the rectilinear holes 12f of the moving barrel 12 are fixed to the sliding arms 15a.

The cam followers 18a, 18b, 18c are fixed to the fixed frame 11 through the first cam holes 13a of the cam barrel 13 and the rectilinear holes 12e of the moving barrel 12.

Subsequently, the second moving frame 16 is similarly inserted from the rear of the fixed frame 11, and the program lens shutter 28 is attached to this in advance.

Also in this second moving frame 16, each sliding arm 16a is positioned in the notches 11b, 11c, 11d of the fixed frame 11.

That is, the sliding arms 16a are inserted into the sliding grooves 12p on the inner surface of the moving barrel 12 so as to be parallel to the sliding arms 15a of the first moving frame 15. With respect to the second moving frame 16 inserted in this way, each cam hole 14a of the cam barrel 14 and the moving barrel 1
The cam followers 26a, 26b, and 26c passing through the rectilinear holes 12g of 2 are fixed to the sliding arms 16a. The sliding groove 12o on the inner surface of the moving cylinder 12 is formed so as to pass through the rectilinear hole 12f, and the sliding groove 12p is formed so as to pass through the rectilinear hole 12g. (See FIG. 2) Next, the spring 29 is inserted, and then the spring receiving frame 30 is moved.
Stick to the rear end of 12.

In this case, each positioning arm 30a is fitted in the sliding groove 12o on the inner surface of the moving barrel 12 into which the sliding arm 15a of the first moving frame 15 is inserted, and as described above, the cam barrel The elastic ring 31 and the small screw 32 inserted through the 14 small holes 14e are fixed as shown in FIG.

When the spring receiving frame 30 is fixed, as shown in FIG. 6 (b),
The stopper 30c projects into the notch 14d of the cam barrel 14
14 rotation range is set. Then, the cell frame 17 is screwed to the partition part 11i of the fixed frame 11, and the cell frame 19 is attached to the tip of the moving barrel 12 by screwing helicoid screws (12c, 19a). At the time of this attachment, the cell frame 19 is appropriately rotated to perform shift adjustment, and then the machine screw 20 is screwed in and fixed.

Finally, the filter frame 21 is fitted and fixed to the front outer peripheral surface of the moving cylinder 12. In this filter frame 21, the convex portion 21a is fitted into the positioning groove 12h of the movable cylinder 12, and the screw hole 21b
Insert 22 and screw in.

When the filter frame 21 is fixed in this way, the stopper 21c thereof projects into the notch 13e of the cam barrel 13 to define the range of rotation of the cam barrel 13 as shown in FIG. 5 (b).

The zoom lens barrel assembled as described above has the sectional structure shown in FIGS.

The operation of the zoom lens barrel described above will be described.

1 to 3 show the state in the wide-angle position, and in this state, when the cam barrel 13 is rotated counterclockwise as viewed from the front, each cam surface of the first cam hole 13a causes the fixed frame 11 to move. Since the cam followers 18a, 18b, and 18c fixed to the above are moved in contact with each other, the cam cylinder 13 moves forward. The cam barrel 13 is a drive gear.
It is driven to rotate by a motor-operated pinion meshed with 13c.

Since the movable barrel 12 is connected to the cam barrel 13 by the bayonet, it moves forward together with the cam barrel 13 without rotating. In this case, the rectilinear hole 12e functions as an escape hole.

Further, since the cam barrel 14 is bayonet-connected to the moving barrel 12, the cam barrel 13 moves in the forward direction together with the moving barrel 12 without rotating by the movement of the cam barrel 13 as described above.

The first moving frame 15 pushes the cam followers 23a, 23b, 23c projecting into the respective second cam holes 13b by the rotation of the cam barrel 13, so that the shape of the second cam hole 13b and the cam As the tube 13 moves, it moves forward.

The second moving frame 16 moves in the forward direction together with the cam barrel 14 because the cam barrel 14 moves without rotating.

FIG. 8 shows a state of shifting to the telephoto position according to the above zooming operation.

In addition, during the above-mentioned zooming operation process, the spring 25
The pushing force of the first moving frame 15, the cam followers 23a, 23b,
23c, it is added to the cam barrel 13 via the cam surface of the second cam hole 13b, and acts to push the cam barrel 13 rearward. Therefore, when zooming from the wide-angle position to the telephoto position as described above, the cam follower 23
The a, 23b and 23c are pushed and moved by the right side wall of the second cam hole 13b to advance the first moving frame 15 and compress the spring 25.

When zooming from the telephoto position to the wide-angle position shown in FIG. 8, the cam barrel 13 is driven to rotate in the opposite direction to the above.

As a result, the cam barrel 13 moves rearward, so that the moving barrel 12 and the cam barrel 14 move backward together with the cam barrel 13 without rotating.

Therefore, the second moving frame 16 retracts integrally with the cam barrel 14, and the first moving frame 15 retracts in accordance with the reverse rotation of the cam barrel 13, and finally the wide angle shown in FIGS. Return to position.

Focus alignment drives the cam barrel 14 to rotate. The cam barrel
14 is rotationally driven by a motor-driven pinion meshed with a drive gear 14b.

When the cam barrel 14 is rotated at the wide-angle position shown in FIGS. 1 to 3, only the second moving frame 16 moves forward and backward without rotating. For example, when the cam barrel 14 is rotated to the left when viewed from the front, each cam hole 14
The cam followers 26a, 26b, and 26c are pushed by the cam surface of a, and the second moving frame 16 moves backward as shown in FIG. 9 to control focusing. Since the cam barrel 14 moves together with the movable barrel 12 by the zooming operation as described above, by rotating the cam barrel 14 at each operation stage of zooming, the second moving frame 16 is advanced and retracted in the same manner as described above. Focus can be controlled.
Since the second moving frame 16 receives a pushing force in the forward direction by the spring 29, the cam followers 26a, 26b, 26c push the left side wall of each cam hole 14a as a cam surface during the focusing operation process. Will be done.

As described above, the program lens shutter 28 moves in the optical axis direction together with the lenses L ₁ , L ₃ and L ₄ by zooming, and is displaced integrally with the lens L _{4 in} the case of focusing. As a result, the F value of the aperture does not change due to focus control.

However, when the rear focus type is used as in the above-described embodiment, the focal length changes due to zooming and the image point moves, so this correction needs to be performed.

In addition, as in the above-described embodiment, the first moving frame 15 is spring
By applying a pushing force to the second moving frame 16 by the spring 29 by means of 25, each cam follower abuts one side wall of each cam hole as a cam surface, so that the cam hole width of the cam barrel is highly accurate. This is not required, and the cam cylinder can be easily processed and formed with a synthetic resin material.

[Advantages of the Invention] As described above, in the zoom lens barrel according to the present invention, the program lens shutter moves integrally with the optical system for focus matching, so that the F value of the diaphragm does not change due to the focus matching operation. Therefore, unlike a conventional zoom lens barrel, the shutter control circuit can be operated as a highly accurate F-number program lens shutter without adding means such as adding positive F-number information of the diaphragm.

In addition, the zoom lens barrel of the present invention is configured such that each optical system (L ₁ , L ₃ , L ₄ ) moves forward and backward along the optical axis during zooming and focusing operation. Therefore, the image becomes stable without any change in eccentricity that occurs during operation.

[Brief description of drawings]

The drawing shows one embodiment of the present invention, and FIG.
-B is a sectional view of the zoom lens barrel taken along line B, FIG. 2 is a sectional view of the zoom lens barrel taken along line AA in FIG. 1, and FIG. Sectional drawing of the upper half part of the same zoom lens barrel cut along the CC line in the figure, FIG. 4 is an exploded perspective view of the same zoom lens barrel, FIG. 5 (a)
Is a simplified view showing the front surface of the zooming cam barrel, FIG. 5 (b) is a simplified view showing the rear face of the same cam barrel, and FIG. 6 (a) is a simplified view showing the front face of the focusing cam barrel. FIG. 8B is a simplified view showing the rear surface of the cam cylinder, FIG. 7 is a partial view showing a screw fixing structure for fixing the spring receiving frame to the movable cylinder, and FIG. 8 is a partial sectional view showing a zooming operation, and FIG. The figure is a partial cross-sectional view showing a focus matching operation. 11 …… Fixed frame 12 …… Moveable barrels 12a, 12b …… Slits 13 …… Cam barrel for zooming 13a …… First cam hole 13b …… Second cam hole 13d …… Arcuate pore 13e… … Cut groove 14 …… Cam tube for focus adjustment 14a …… Cam hole 14c …… Arc-shaped hole 14d …… Cut groove 15 …… First moving frame 16 …… Second moving frame 18a, 18b, 18c… … Cam followers 21c …… Stoppers 23a, 23b, 23c …… Cam followers 26a, 26b, 26c …… Cam followers 28 …… Program lens shutter 30c …… Stoppers

Front page continuation (72) Nobuhiro Sakai Inventor Nozhiro Sakai 2800 Nagachi, Okaya City, Nagano President, Nookaya Plant, Kyocera Stock Association (72) Inventor Kanji Nakao 2800, Nagachi Prefecture Okaya City, Nagano President, Nookaya Plant ( 72) Creator Toshikazu Atsuta 6-27-8, Jingumae, Shibuya-ku, Tokyo Kyocera Corporation, Tokyo Harajuku Works (56) References JP 63-85512 (JP, A) JP 63-149616 ( JP, A) Actual development Sho 63-68618 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A zoom lens barrel for performing optical zooming and focusing control by moving a plurality of movable frames supporting an optical system in the optical axis direction in association with the rotation of a cam frame. A second cam frame that is connected to a moving frame for zooming that moves in the optical axis direction in conjunction with one cam frame so as to be rotatable in the optical axis direction and move together in the optical axis direction, A focus matching moving frame that moves in the optical axis direction in conjunction with the second cam frame is provided. The focus matching moving frame is provided with a program lens shutter in addition to the optical system for zooming and focus matching operations. A zoom lens barrel, wherein the shutter is configured to be displaced in the optical axis direction.