JPH01217408A - Zoom lens device - Google Patents

Abstract

PURPOSE:To efficiently execute zooming operation by means of a simple constitution by fixing a shutter driving mechanism for opening/closing a shutter blade and a focusing mechanism for moving a focusing lens group in an optical axis direction to execute focusing to a moving frame and arranging them on both the sides of a shutter blade. CONSTITUTION:The focusing mechanism 58 and the shutter driving mechanism 60 are fixed to the moving frame 36 and respectively arranged on a 3rd group lens 33 side and a 1st group lens 31 side of the shutter blade 48, and the mechanism 58 is arranged between the moving frame 36 and a rear holding frame 42b and the mechanism 60 is arranged between the moving frame 36 and a front holding frame 42a. Thereby it is unnecessary to insert the interlocking axis of both the mechanism 58, 60 into a lens barrel, and since both the mechanisms 58, 60 are supported by the moving frame and moved unitedly with a focusing lens group at the time of zooming operation, the formation of a gear, etc., is unnecessary. Consequently, the zooming operation can be efficiently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a zoom lens device for a camera, and particularly to an inner focus type zoom lens device.

(Prior Art) Generally, as a camera lens equipped with an autofocus function, there is a so-called front lens focusing type in which focusing is performed by moving the first group lens located at the tip of the lens barrel in the photographing optical system. A so-called inner focus type is known in which focusing is performed by moving the second group lens or the third group lens. For example, in an inner focus camera, a drive motor is provided inside the camera body, and an interlocking shaft rotated by this motor passes through the lens barrel and passes from the camera body to the second or third group. It extends to the vicinity of the lens.

Focusing is performed by moving the lens group by driving the interlocking shaft with a gear attached to the interlocking shaft meshing with a gear portion formed on the holding frame of the lens group.

Furthermore, in recent years, many zoom lenses equipped with an autofocus function have been provided.

(Problems to be Solved by the Invention) However, when the above-described autofocus mechanism is applied to a zoom lens, the following problems occur.

First, an interlocking shaft for transmitting the driving force of the motor installed on the camera body side must be installed inside the lens barrel, which increases the size of the lens barrel and requires additional parts installed inside the lens barrel. In order to avoid interference between the shaft and the interlocking shaft, various measures are required, resulting in a complicated configuration. Also,
In a zoom lens, each lens group including a focusing lens group moves in the optical axis direction in response to zooming.

Therefore, in order to keep the driving gear of the interlocking shaft in mesh with the gear part formed on the holding frame of the focusing lens group even during zooming operation, it is necessary to lengthen the interlocking shaft and to make the driving gear or the gear part It is necessary to increase the length in the optical axis direction. However, in this case,
A larger installation space must be provided within the lens barrel for the focusing mechanism, and the drive gear or gear portion interferes with other lens groups during zooming, making it difficult to perform a zooming operation well.

The present invention has been made in view of the above points, and an object of the present invention is to provide a compact zoom lens device that has a simple configuration and can perform zooming of a photographic optical system satisfactorily.

(Means and Effects for Solving the Problems) In order to achieve the above object, the zoom lens device of the present invention includes a movable frame that is moved in the optical axis direction of the photographing optical system by the zooming operation, and a A holding frame is provided that is movably supported along the optical axis direction and holds a group of focusing lenses. The focusing lens group includes first and second lens groups, and a shutter blade is provided between these lens groups. A shutter drive mechanism that opens and closes the shutter blade and a focusing mechanism that moves the focusing lens group in the optical axis direction to perform focusing are attached to the moving frame and arranged on both sides of the shutter blade. .

It is located near Shinglens County. Therefore, there is no need to insert the interlocking shaft into the lens barrel like in the past.
It is possible to downsize the device and simplify the configuration. Also,
These mechanisms are supported by a moving frame and move integrally with the focusing lens group during zooming operation.
There is no need to provide a long drive gear or gear section as in the conventional case. Therefore, the zooming operation can be performed satisfactorily without interfering with other lens groups, and the focusing mechanism can be easily miniaturized. Furthermore, by effectively utilizing the space on both sides of the shutter blade, it is possible to further downsize the entire device.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a lens shutter camera equipped with an inner focus type zoom lens device according to an embodiment of the present invention. This camera includes a camera body 10,
The zoom lens device 11 protrudes forward from approximately the center of the front surface of the main body. The main body 10 also has a grip portion 14 that protrudes forward along the lens device 11 from a side portion of the front surface. A finder mechanism 16, a strobe mechanism 18, and a drive mechanism 20 for zooming the photographing optical system of the lens device 11, which will be described later, are provided within the grip portion 14 and are located close to the side of the lens device. Furthermore, a battery chamber (not shown) containing a battery is formed within the grip portion 14.

As shown in FIG. 1, the zoom lens device 11 includes a lens barrel 12. As shown in FIG. The lens barrel 12 includes a cylindrical fixed frame 22, and a cylindrical cam ring 24 is provided on the outer periphery of the fixed frame.
are rotatably fitted. A threaded portion 23 is formed on the inner circumferential surface of the tip of the cam ring 24, and a focus adjustment ring 26 is screwed into this threaded portion. And adjustment ring 26
By rotating the cam ring 24, the cam ring 24 can be slightly moved in the axial direction. Further, a presser ring 27 is attached to the outer periphery of the distal end of the fixed frame 22 and is in contact with the adjustment ring 26 . A cylindrical zoom frame 28 is inserted into the fixed frame 22 so as to be movable along the axial direction. Three roller pins 29 (only one is shown) are attached to the outer periphery of the zoom frame 28, and each roller pin is attached to the fixed frame 28.
It passes through a straight groove 22a formed in the cam ring 24, and is inserted into a first cam groove 24a formed in the cam ring 24.

The straight groove 22a extends along the axial direction of the fixed frame 22 and has 1. The cam groove 24a is formed in a spiral shape.

Therefore, by rotating the cam ring 24, the zoom frame 28 moves linearly along its axial direction. Further, in order to prevent light from entering the gap between the fixed frame 22 and the cam ring 24 from the outside, a light-shielding cloth 30 is attached to the outer circumferential surface of the tip of the fixed frame and is in sliding contact with the inner circumferential surface of the cam ring.

Inside the zoom frame 28, first to third lens groups 31, 32, and 33 constituting a photographing optical system are arranged. Specifically, the first group lens 31 is supported within the zoom frame by a first group frame 34 screwed into the tip of the zoom frame 28. A substantially cylindrical moving frame 36 is fitted into an intermediate portion of the zoom frame 28 so as to be movable along the axial direction.

Three roller pins 37 (only one is shown) are protruded from the moving frame 36, and each roller pin 37 has a straight groove 38 formed in the zoom frame 28 and a straight groove 22a formed in the fixed frame 22. The second cam groove 24b is inserted into the second spiral cam groove 24b formed in the cam ring 24. Therefore, by rotating the cam ring 24, the moving frame 36
moves within the zoom frame 28 along the axial direction. Moving frame 3
A focusing guide shaft 40 is fixed to 6 and extends parallel to the axis of the zoom frame 28 . Note that the right end of the guide shaft 40 is immovably fixed to the moving frame 36, and the left end is supported by a spring washer 41 so as to be able to move slightly. Therefore, by adjusting the position of the left end of the guide shaft 40, the parallelism of the guide shaft to the optical axis of the photographing optical system can be adjusted. A holding frame 42 holding the second group lens 32 is supported movably along the axial direction of the zoom frame 28 by the guide shaft 40 . The second group lens is
It constitutes the focusing lens group in this invention, and includes a front lens group 32a and a rear lens group 32b. Further, the holding frame 42 includes a front holding frame 42a that holds the front lens group 32a and a rear holding frame 42b that holds the rear lens group 32b. A focusing spring 45 is wound around the guide shaft 40, and this spring biases the front holding frame 42a and the rear holding frame 42b toward the rear. As a result, the bin 44 protruding from the rear holding frame 42b is pressed against the cam surface of a focusing cam 47 of a focusing mechanism 58, which will be described later. Then, by rotating the focusing cam 47, the front holding frame 42a and the rear holding frame 42b are moved forward by the cam 47 against the urging force of the spring 45, and as a result, focusing of the photographing optical system is performed. Moreover, a shutter blade 48 that also serves as an aperture is provided between the front holding frame 42a and the rear holding frame 42b, and this shutter blade is opened and closed by a shutter drive mechanism 60, which will be described later.

A third group frame 5o is fitted into the base end of the zoom frame 28 so as to be movable along the axial direction of the zoom frame. There are three roller bins 51 in the third group frame 50 (only one is shown).
are provided protrudingly, and each roller bin has a straight groove 52 formed in the zoom frame 28 and a straight groove 2 formed in the fixed frame.
2a, and is inserted into a spiral third cam groove 24c formed in the cam ring 24. Therefore, cam ring 2
4 is rotated, the third group frame 50 becomes the zoom frame 2.
8 along the axial direction. Further, a holding frame 54 holding the third group lens 33 is fitted and fixed to the inner periphery of the third group frame 50. By adjusting the relative position between the third group frame 50 and the holding frame 54 using a known mechanism (not shown), it is possible to correct focus movement during zooming.

The lens barrel 12 configured as described above has a fixed frame 22
It is fixed to the main body 10 by screwing a flange 22b formed at the base end thereof to the main body 10.

As shown in FIGS. 1 and 3, an arc-shaped interlocking plate 56 is fixed to the outer peripheral surface of the cam ring 24 with screws. A gear portion 57 extending along an arc parallel to the cam ring 24 is formed on the outer surface of the interlocking plate 56 . The cam ring 24 is rotated by a driving force transmitted from the driving mechanism 20 provided on the side of the lens barrel 12 via the gear portion 57. When the cam ring 24 is rotated, the photographing optical system is moved to the wide mode position (Fig. 4A).
, the tele mode position (Figure 4B), and the macro mode position (Figure 4C). When switching from wide mode to tele mode, the first to third group lenses 31, 32
．． 33 is moved forward, and when switching from tele mode to macro mode, the first and second group lenses are held in a stopped state and only the third group lens is moved rearward. In addition, in FIG. 4, reference numeral 43 indicates the film surface.

Further, as shown in FIG. 3, the finder mechanism 16 and the flash mechanism 18 are provided on the side of the lens barrel 12, and are zoomed by an interlocking plate 56 in conjunction with the rotation of the cam ring 24.

On the other hand, as described above, in the zoom lens device 11, focusing of the imaging optical system is performed by moving the second lens group 32 as a group of focusing lenses in the optical axis direction, which is a so-called inner focus type. The focusing mechanism 58 and shutter drive mechanism 60 of the zoom lens device 11 will be described in detail below.

As shown in FIG. 1, the focusing mechanism 58 and the shutter drive mechanism 60 are attached to the moving frame 36, and are arranged on the second group lens 33 side and the first group lens 31 side of the shutter blade 48, respectively. Further, the focusing mechanism 58 is located between the moving frame 36 and the rear holding frame 42b.
The shutter drive mechanism 60 is disposed between the moving frame and the front holding frame 42a.

As shown in FIG. 5, the moving frame 36 includes a substantially cylindrical main body 62 supported by the zoom frame 28 by a roller bin 37;
An annular focusing frame 64 attached to the third group lens 33 side of the main body, a shutter frame 66 attached to the first group lens 31 side of the main body, and an annular cover 67 provided opposite to the shutter frame. It consists of The focusing frame 64 mainly includes a focusing mechanism 5.
8 is attached to the shutter frame 66, and a shutter drive mechanism 60 is attached to the shutter frame 66.

The focusing guide shaft 40 is provided between the main body 62 and the shutter frame 66, and this guide shaft allows the holding frame 42 to
is movably supported. Further, the holding frame 42 is also guided by a pair of guide posts 62a protruding from the main body 66.

The focusing mechanism 58 has a focusing cam 47 rotatably attached to a focusing frame 64 around the optical axis of the photographing optical system, and a cam surface 47a of the cam 47.
A bin 44 formed on the rear holding frame 42b is in contact with the rear holding frame 42b. The focusing mechanism 58 also includes a focusing drive gear train 68 that is attached to the focusing frame 64 and meshes with the cam 47, and a timing switch 70 that is fixed to the focusing frame and contacts the outer peripheral surface of the cam 47. We are prepared. The switch 70 detects the initial position of the cam 47 at the start of focusing, and also controls the amount of rotation of the cam 47 in accordance with a signal from a photointerturbator, which will be described later. Also,
The focusing frame 64 includes a shutter drive gear train 71.
and a planetary clutch 72 located between these gear trains 68 and 71.

The main body 62 includes a motor 7 that operates as a common drive source for the focusing mechanism 58 and the shutter drive mechanism 60.
4 is fixed. A rotating shaft 74a of the motor 74 extends toward the focusing frame 64, and a driving gear 75 and the above-mentioned planetary clutch 72 are attached to this rotating shaft. As shown in FIG. 6, the planetary clutch 72 is
A planetary lever 76 is rotatably attached to the rotating shaft 74a of the motor 74 with a predetermined friction, and a drive gear 7 is rotatably supported by the planetary lever.
A pair of planetary gears 77a mesh with 5.

77b. When the rotating shaft 74a of the motor 74 is rotated forward in the direction of arrow A, the planetary lever 76 also rotates in the direction of arrow A, and the planetary gear 77a meshes with the focusing drive gear train 68. As a result, focusing cam 47
is rotated to perform focusing. In addition, the rotating shaft 7
When 4a is reversely rotated, the planetary gear 77b meshes with the shutter drive gear train 71 and drives the gear train 71. In addition,
A comb gear 78 is fixed to the tip of the rotating shaft 74a, and a photointerlab turf 9 is disposed opposite to the comb gear. The photointerlab turf 9 pulse-counts the rotation of the comb gear 78, that is, the rotation of the motor 74, and controls the rotation of the motor by a control circuit (not shown).

On the other hand, as shown in FIGS. 5 and 7, the shutter drive mechanism 60 attached to the shutter frame 66 has an idler gear 80, and this idler gear is connected to the shutter drive gear train 71 via a connection gear 81. ing. Further, the idler gear 80 meshes with an exposure adjustment cam gear 82 attached to the shutter frame 66. cam gear 8
On the upper surface of 2, there is a pin 8 eccentrically located from the rotation center of the cam gear.
2a is provided protrudingly, and a cam surface 82b is provided on the lower surface.
is formed. A terminal of an exposure adjustment switch 83 fixed to the shutter frame 66 is engaged with this cam surface 82b. Further, the shutter drive mechanism 60 has a drive arm 84, and the intermediate portion of this arm is rotatably supported by the shutter frame 66 by a shaft 84a. An iron piece 85 is fixed to the left end of the arm 84 and is positioned opposite to an electromagnet 86 fixed to the shutter frame 66.

At the right end of the arm 84, the middle part of the opening/closing arm 88 is attached to the shaft 8.
It is rotatably supported by 8a. Drive supply 84
is biased clockwise around the shaft 84a by a torsion spring 87, and the opening/closing arm 88 is biased clockwise around the shaft 84a by a torsion spring 89.
It is biased clockwise around point a. Opening/closing arm 88
A cam surface 88b that can come into contact with the pin 82a of the exposure adjustment gear 82 is formed at the right end. In addition, the opening/closing arm 8
An opening/closing pin 90 is protruded from the left end of the shutter frame 8 , and this opening/closing pin passes through an elongated hole 66 a formed in the shutter frame 66 and extends toward the main body 62 of the moving frame 36 . Furthermore,
A regulating lever 91 that adjusts the amount of movement of the opening/closing pin 90 is rotatably attached to the shutter frame 66. The regulating lever 91 is urged counterclockwise by a spring 92, and the arm 91a of the regulating lever is attached to the cam ring 24 of the lens barrel 12.
is being pressed against. Further, the other arm 91b of the regulation lever 91 can enter into the movement path of the opening/closing bin 90 as the lever rotates.

The shutter blade 48, which is opened and closed by the shutter drive mechanism 60, is composed of a pair of blade members 48a and 48b, as shown in FIGS. 5, 7, and 8. These blade members 48a.

48b is arranged between the flange 43a of the front holding frame 42a and the flange 43b of the rear holding frame 42b, and the pin 94 formed on the flange 43b allows the eighth
It is supported so as to be rotatable between the closed position shown in the figure and the open position shown in FIG.

Further, the blade members 48a and 48b each have a long hole 96a,
96b, and these elongated holes are formed so that a portion always overlaps with each other. The opening/closing bin 90 of the shutter drive mechanism 60 is attached to the flange 43 of the front holding frame 42a.
The blade members 48a, 48 through the through holes 97 formed in the a.
b are inserted into long holes 96a and 96b. Therefore, the blade members 48a and 48b are opened and closed according to the movement of the opening and closing pin 90.

Next, the focusing mechanism 58 configured as above
And the operation of the shutter drive mechanism 60 will be explained.

When the shutter button provided on the camera body 10 is pressed after zooming of the photographic optical system is completed, the motor 74 rotates forward, and the planetary gear 77a of the planetary clutch 72 meshes with the focusing drive gear train 71. As a result, the focusing cam 47 is rotated via the focusing drive gear train 71, and the bin 44 of the rear holding frame 42b pressed against the cam surface 47a of the cam 47 moves following the displacement of the cam surface. As a result, the second group lens 32 of the photographing optical system is moved along the optical axis direction together with the holding frame 42, and focusing is performed. At this time, focusing cam 47
The switch 45 for detecting the initial position of the cam 47 is turned off at the same time as the cam 47 starts rotating, and in synchronization with this, the photointerlab turf 9 starts counting drive pulses. Then, when the count reaches a predetermined value, that is, when the rotation amount of the focusing cam 47 reaches a predetermined value, the motor 74 is stopped and focusing ends.

Subsequently, the motor 74 starts rotating in reverse, and the driving of the shutter drive mechanism 60 starts. That is, by reversing the motor 74, the planetary gear 77b of the planetary clutch 72 meshes with the shutter drive gear train 71 and drives it. This driving force is transmitted to the idler gear 80 via the connection gear 81,
As a result, the exposure adjustment gear 82 is rotated in the direction of arrow B in FIG. At the beginning of rotation of the gear 82, the opening/closing arm 88 is pressed by the pin 82a in contact with the cam surface 88b, and the drive arm 84 is rotated counterclockwise against the biasing force of the torsion spring 87. Thereby, as shown in FIG. 7, the iron piece 85 of the drive arm 84 is attracted to the electromagnet 86, and charging of the shutter drive mechanism 60 is completed. In this state, the opening/closing pin 90 of the opening/closing arm 88 is located at the lower end of the elongated hole 66a, and the shutter 48 is closed.

When the exposure adjustment gear 82 is further rotated, the bin 82 a moves away from the opening/closing arm 88 , and the opening/closing arm is rotated clockwise by the biasing force of the torsion spring 89 .
Move following 2a.

Thereby, the opening/closing pin 90 of the opening/closing arm 88 is inserted into the elongated hole 66.
a and gradually open the shutter blades 48. Here, the terminal of the exposure adjustment switch 83 is simultaneously connected to the cam surface 82b of the exposure adjustment gear 82, and the terminal is connected to the cam surface 42b again.
switch 83 to turn off. and,
When the switch 83 is turned off, a shutter control rotation (not shown) is activated to determine an appropriate shutter opening time. When the proper opening time is reached, that is, when the proper exposure is reached, the drive of the motor 74 is stopped, the electromagnet 86 is switched off, and the attractive force of the iron piece 85 is removed. Thereby, the drive arm 84 is rotated clockwise together with the opening/closing arm 88 by the torsion spring 87. Therefore, the opening/closing pin 90 of the opening/closing arm 88
falls to the lower end of the elongated hole 66a, and in conjunction with this, the shutter blade 48 is closed.

Note that when the photographing optical system is set to the wide mode (FIG. 4A), the regulation lever 91 is pressed by the cam ring 24 and rotated clockwise. As a result, the regulation lever 91
The arm 91b projects into the movement path of the opening/closing pin 90.

Therefore, the amount of movement of the opening/closing pin 90 is regulated by the regulating lever 91, and the opening diameter of the shutter blade 48 is regulated.

According to the zoom lens device configured as described above, the following advantages can be obtained.

That is, the focusing mechanism 58 and the shutter mechanism 60 are attached to the moving frame 36 and are located near the second lens group 32 as a group of focusing lenses. Therefore, there is no need to insert the interlocking shaft into the lens barrel 12 as in the conventional case, and it is possible to downsize the device and simplify the configuration. Further, these mechanisms are supported by a moving frame 36 and move integrally with the focusing lens group during a zooming operation. Therefore, the focusing mechanism and the focusing lens group can be maintained in an engaged state at all times without providing a long driving gear or gear section as in the conventional art. Therefore, the zooming operation can be performed satisfactorily without interfering with other lens groups, and the focusing mechanism can be easily miniaturized. Furthermore, by arranging the focusing mechanism 58 and the shutter drive mechanism 60 on both sides of the shutter blade, the space on both sides of the shutter blade can be used effectively.
Since the single motor 74 attached to the moving frame 36 is shared as a drive source for the focusing mechanism 58 and the shutter drive mechanism 60, the entire device can be further miniaturized.

Furthermore, since the second group lens 32 is supported by one focusing guide shaft 40 whose tilt is adjustable, the tilt of the second group lens with respect to other lens groups can be easily adjusted. Furthermore, the aperture diameter of the shutter blade 48, that is, the aperture, can be adjusted according to the zooming mode of the photographing optical system by the regulation lever 91 that operates in conjunction with the cam ring 24, and as a result, each zooming mode of the photographic optical system can be adjusted. It is possible to reduce the difference in F value during mode.

In the case of an inner focus type zoom lens device, compared to a front lens focus type, the amount of movement of the focusing lens group during focusing is smaller, and the focusing speed can be increased and the focusing mechanism can be made smaller. can.

(Effects of the Invention) As detailed above, the zoom lens device of the present invention has the following features:
a movable frame that is moved along the optical axis direction of the photographic optical system by a zooming operation;
a holding frame holding a focusing lens group having a lens group and a second lens group; a shutter blade supported by the holding frame and positioned between the first and second lens groups; a shutter drive mechanism provided on one side of the shutter blade and supported by the moving frame to open and close the shutter blade; and a shutter drive mechanism provided on the other side of the shutter blade along the optical axis direction and supported by the moving frame. a focusing mechanism that is supported by and moves the holding frame along the optical axis direction;
It is equipped with

Therefore, it is possible to provide a compact zoom lens device with a simple configuration that allows the photographing optical system to perform zooming well.

[Brief explanation of the drawing]

1 to 9 show a zoom lens device according to an embodiment of the present invention, FIG. 1 is a vertical sectional view of the zoom lens device, and FIG. 2 shows the entire camera equipped with the zoom lens device. 3 is a plan view of the zoom lens device, FIGS. 4A to 4C are diagrams showing different operating modes of the photographing optical system, and FIG. 5 is an exploded view showing the configuration around the focusing mechanism and shutter drive mechanism. 6 is a perspective view showing the configuration around the motor, FIG. 7 is a front view of the shutter drive mechanism, and FIGS. 8 and 9 are front views showing the shutter blade in a closed state and an open state, respectively. be. 12... Lens barrel, 22... Fixed frame, 28...
Zoom frame, 31... First group lens, 32... Second group lens, 32a... Front lens group, 32b... Rear lens group, 33... Third group lens, 36... moving frame, 4
0... Focusing guide shaft, 42... Holding frame,
48... Shutter blade, 58... Focusing mechanism, 60... Shutter drive mechanism. Figure 2 Figure 3

Claims (3)

[Claims] (1) a movable frame that is moved along the optical axis direction of the photographic optical system by a zooming operation; a first lens that is supported by the movable frame so as to be movable along the optical axis direction of the photographic optical system; County and 2nd
a holding frame holding a focusing lens group having lens groups; a shutter blade supported by the holding frame and positioned between the first and second lens groups; and one side of the shutter blade along the optical axis direction. a shutter drive mechanism, which is provided on the other side of the shutter blade along the optical axis direction and supported by the moving frame, and which opens and closes the shutter blade; A zoom lens device comprising: a focusing mechanism that moves the holding frame along the optical axis direction; (2) The zoom lens device according to claim 1, wherein the shutter drive mechanism and the focusing mechanism include a common drive source attached to the moving frame. (3) The holding frame is guided by a guide shaft that is attached to the movable frame and extends along the optical axis direction, and the guide shaft has one end fixed to the movable frame and a guide shaft with respect to the optical axis. 3. The zoom lens device according to claim 1, further comprising a second end attached to the moving frame so that the position thereof can be adjusted.